4 * Copyright (C) 2005 David Brownell
5 * Copyright (C) 2008 Secret Lab Technologies Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #include <linux/kernel.h>
19 #include <linux/device.h>
20 #include <linux/init.h>
21 #include <linux/cache.h>
22 #include <linux/dma-mapping.h>
23 #include <linux/dmaengine.h>
24 #include <linux/mutex.h>
25 #include <linux/of_device.h>
26 #include <linux/of_irq.h>
27 #include <linux/clk/clk-conf.h>
28 #include <linux/slab.h>
29 #include <linux/mod_devicetable.h>
30 #include <linux/spi/spi.h>
31 #include <linux/of_gpio.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/pm_domain.h>
34 #include <linux/export.h>
35 #include <linux/sched/rt.h>
36 #include <linux/delay.h>
37 #include <linux/kthread.h>
38 #include <linux/ioport.h>
39 #include <linux/acpi.h>
41 #define CREATE_TRACE_POINTS
42 #include <trace/events/spi.h>
44 static void spidev_release(struct device *dev)
46 struct spi_device *spi = to_spi_device(dev);
48 /* spi masters may cleanup for released devices */
49 if (spi->master->cleanup)
50 spi->master->cleanup(spi);
52 spi_master_put(spi->master);
57 modalias_show(struct device *dev, struct device_attribute *a, char *buf)
59 const struct spi_device *spi = to_spi_device(dev);
62 len = acpi_device_modalias(dev, buf, PAGE_SIZE - 1);
66 return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
68 static DEVICE_ATTR_RO(modalias);
70 #define SPI_STATISTICS_ATTRS(field, file) \
71 static ssize_t spi_master_##field##_show(struct device *dev, \
72 struct device_attribute *attr, \
75 struct spi_master *master = container_of(dev, \
76 struct spi_master, dev); \
77 return spi_statistics_##field##_show(&master->statistics, buf); \
79 static struct device_attribute dev_attr_spi_master_##field = { \
80 .attr = { .name = file, .mode = S_IRUGO }, \
81 .show = spi_master_##field##_show, \
83 static ssize_t spi_device_##field##_show(struct device *dev, \
84 struct device_attribute *attr, \
87 struct spi_device *spi = container_of(dev, \
88 struct spi_device, dev); \
89 return spi_statistics_##field##_show(&spi->statistics, buf); \
91 static struct device_attribute dev_attr_spi_device_##field = { \
92 .attr = { .name = file, .mode = S_IRUGO }, \
93 .show = spi_device_##field##_show, \
96 #define SPI_STATISTICS_SHOW_NAME(name, file, field, format_string) \
97 static ssize_t spi_statistics_##name##_show(struct spi_statistics *stat, \
100 unsigned long flags; \
102 spin_lock_irqsave(&stat->lock, flags); \
103 len = sprintf(buf, format_string, stat->field); \
104 spin_unlock_irqrestore(&stat->lock, flags); \
107 SPI_STATISTICS_ATTRS(name, file)
109 #define SPI_STATISTICS_SHOW(field, format_string) \
110 SPI_STATISTICS_SHOW_NAME(field, __stringify(field), \
111 field, format_string)
113 SPI_STATISTICS_SHOW(messages, "%lu");
114 SPI_STATISTICS_SHOW(transfers, "%lu");
115 SPI_STATISTICS_SHOW(errors, "%lu");
116 SPI_STATISTICS_SHOW(timedout, "%lu");
118 SPI_STATISTICS_SHOW(spi_sync, "%lu");
119 SPI_STATISTICS_SHOW(spi_sync_immediate, "%lu");
120 SPI_STATISTICS_SHOW(spi_async, "%lu");
122 SPI_STATISTICS_SHOW(bytes, "%llu");
123 SPI_STATISTICS_SHOW(bytes_rx, "%llu");
124 SPI_STATISTICS_SHOW(bytes_tx, "%llu");
126 #define SPI_STATISTICS_TRANSFER_BYTES_HISTO(index, number) \
127 SPI_STATISTICS_SHOW_NAME(transfer_bytes_histo##index, \
128 "transfer_bytes_histo_" number, \
129 transfer_bytes_histo[index], "%lu")
130 SPI_STATISTICS_TRANSFER_BYTES_HISTO(0, "0-1");
131 SPI_STATISTICS_TRANSFER_BYTES_HISTO(1, "2-3");
132 SPI_STATISTICS_TRANSFER_BYTES_HISTO(2, "4-7");
133 SPI_STATISTICS_TRANSFER_BYTES_HISTO(3, "8-15");
134 SPI_STATISTICS_TRANSFER_BYTES_HISTO(4, "16-31");
135 SPI_STATISTICS_TRANSFER_BYTES_HISTO(5, "32-63");
136 SPI_STATISTICS_TRANSFER_BYTES_HISTO(6, "64-127");
137 SPI_STATISTICS_TRANSFER_BYTES_HISTO(7, "128-255");
138 SPI_STATISTICS_TRANSFER_BYTES_HISTO(8, "256-511");
139 SPI_STATISTICS_TRANSFER_BYTES_HISTO(9, "512-1023");
140 SPI_STATISTICS_TRANSFER_BYTES_HISTO(10, "1024-2047");
141 SPI_STATISTICS_TRANSFER_BYTES_HISTO(11, "2048-4095");
142 SPI_STATISTICS_TRANSFER_BYTES_HISTO(12, "4096-8191");
143 SPI_STATISTICS_TRANSFER_BYTES_HISTO(13, "8192-16383");
144 SPI_STATISTICS_TRANSFER_BYTES_HISTO(14, "16384-32767");
145 SPI_STATISTICS_TRANSFER_BYTES_HISTO(15, "32768-65535");
146 SPI_STATISTICS_TRANSFER_BYTES_HISTO(16, "65536+");
148 static struct attribute *spi_dev_attrs[] = {
149 &dev_attr_modalias.attr,
153 static const struct attribute_group spi_dev_group = {
154 .attrs = spi_dev_attrs,
157 static struct attribute *spi_device_statistics_attrs[] = {
158 &dev_attr_spi_device_messages.attr,
159 &dev_attr_spi_device_transfers.attr,
160 &dev_attr_spi_device_errors.attr,
161 &dev_attr_spi_device_timedout.attr,
162 &dev_attr_spi_device_spi_sync.attr,
163 &dev_attr_spi_device_spi_sync_immediate.attr,
164 &dev_attr_spi_device_spi_async.attr,
165 &dev_attr_spi_device_bytes.attr,
166 &dev_attr_spi_device_bytes_rx.attr,
167 &dev_attr_spi_device_bytes_tx.attr,
168 &dev_attr_spi_device_transfer_bytes_histo0.attr,
169 &dev_attr_spi_device_transfer_bytes_histo1.attr,
170 &dev_attr_spi_device_transfer_bytes_histo2.attr,
171 &dev_attr_spi_device_transfer_bytes_histo3.attr,
172 &dev_attr_spi_device_transfer_bytes_histo4.attr,
173 &dev_attr_spi_device_transfer_bytes_histo5.attr,
174 &dev_attr_spi_device_transfer_bytes_histo6.attr,
175 &dev_attr_spi_device_transfer_bytes_histo7.attr,
176 &dev_attr_spi_device_transfer_bytes_histo8.attr,
177 &dev_attr_spi_device_transfer_bytes_histo9.attr,
178 &dev_attr_spi_device_transfer_bytes_histo10.attr,
179 &dev_attr_spi_device_transfer_bytes_histo11.attr,
180 &dev_attr_spi_device_transfer_bytes_histo12.attr,
181 &dev_attr_spi_device_transfer_bytes_histo13.attr,
182 &dev_attr_spi_device_transfer_bytes_histo14.attr,
183 &dev_attr_spi_device_transfer_bytes_histo15.attr,
184 &dev_attr_spi_device_transfer_bytes_histo16.attr,
188 static const struct attribute_group spi_device_statistics_group = {
189 .name = "statistics",
190 .attrs = spi_device_statistics_attrs,
193 static const struct attribute_group *spi_dev_groups[] = {
195 &spi_device_statistics_group,
199 static struct attribute *spi_master_statistics_attrs[] = {
200 &dev_attr_spi_master_messages.attr,
201 &dev_attr_spi_master_transfers.attr,
202 &dev_attr_spi_master_errors.attr,
203 &dev_attr_spi_master_timedout.attr,
204 &dev_attr_spi_master_spi_sync.attr,
205 &dev_attr_spi_master_spi_sync_immediate.attr,
206 &dev_attr_spi_master_spi_async.attr,
207 &dev_attr_spi_master_bytes.attr,
208 &dev_attr_spi_master_bytes_rx.attr,
209 &dev_attr_spi_master_bytes_tx.attr,
210 &dev_attr_spi_master_transfer_bytes_histo0.attr,
211 &dev_attr_spi_master_transfer_bytes_histo1.attr,
212 &dev_attr_spi_master_transfer_bytes_histo2.attr,
213 &dev_attr_spi_master_transfer_bytes_histo3.attr,
214 &dev_attr_spi_master_transfer_bytes_histo4.attr,
215 &dev_attr_spi_master_transfer_bytes_histo5.attr,
216 &dev_attr_spi_master_transfer_bytes_histo6.attr,
217 &dev_attr_spi_master_transfer_bytes_histo7.attr,
218 &dev_attr_spi_master_transfer_bytes_histo8.attr,
219 &dev_attr_spi_master_transfer_bytes_histo9.attr,
220 &dev_attr_spi_master_transfer_bytes_histo10.attr,
221 &dev_attr_spi_master_transfer_bytes_histo11.attr,
222 &dev_attr_spi_master_transfer_bytes_histo12.attr,
223 &dev_attr_spi_master_transfer_bytes_histo13.attr,
224 &dev_attr_spi_master_transfer_bytes_histo14.attr,
225 &dev_attr_spi_master_transfer_bytes_histo15.attr,
226 &dev_attr_spi_master_transfer_bytes_histo16.attr,
230 static const struct attribute_group spi_master_statistics_group = {
231 .name = "statistics",
232 .attrs = spi_master_statistics_attrs,
235 static const struct attribute_group *spi_master_groups[] = {
236 &spi_master_statistics_group,
240 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
241 struct spi_transfer *xfer,
242 struct spi_master *master)
245 int l2len = min(fls(xfer->len), SPI_STATISTICS_HISTO_SIZE) - 1;
250 spin_lock_irqsave(&stats->lock, flags);
253 stats->transfer_bytes_histo[l2len]++;
255 stats->bytes += xfer->len;
256 if ((xfer->tx_buf) &&
257 (xfer->tx_buf != master->dummy_tx))
258 stats->bytes_tx += xfer->len;
259 if ((xfer->rx_buf) &&
260 (xfer->rx_buf != master->dummy_rx))
261 stats->bytes_rx += xfer->len;
263 spin_unlock_irqrestore(&stats->lock, flags);
265 EXPORT_SYMBOL_GPL(spi_statistics_add_transfer_stats);
267 /* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
268 * and the sysfs version makes coldplug work too.
271 static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
272 const struct spi_device *sdev)
274 while (id->name[0]) {
275 if (!strcmp(sdev->modalias, id->name))
282 const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
284 const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
286 return spi_match_id(sdrv->id_table, sdev);
288 EXPORT_SYMBOL_GPL(spi_get_device_id);
290 static int spi_match_device(struct device *dev, struct device_driver *drv)
292 const struct spi_device *spi = to_spi_device(dev);
293 const struct spi_driver *sdrv = to_spi_driver(drv);
295 /* Attempt an OF style match */
296 if (of_driver_match_device(dev, drv))
300 if (acpi_driver_match_device(dev, drv))
304 return !!spi_match_id(sdrv->id_table, spi);
306 return strcmp(spi->modalias, drv->name) == 0;
309 static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
311 const struct spi_device *spi = to_spi_device(dev);
314 rc = acpi_device_uevent_modalias(dev, env);
318 add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
322 struct bus_type spi_bus_type = {
324 .dev_groups = spi_dev_groups,
325 .match = spi_match_device,
326 .uevent = spi_uevent,
328 EXPORT_SYMBOL_GPL(spi_bus_type);
331 static int spi_drv_probe(struct device *dev)
333 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
334 struct spi_device *spi = to_spi_device(dev);
337 ret = of_clk_set_defaults(dev->of_node, false);
342 spi->irq = of_irq_get(dev->of_node, 0);
343 if (spi->irq == -EPROBE_DEFER)
344 return -EPROBE_DEFER;
349 ret = dev_pm_domain_attach(dev, true);
350 if (ret != -EPROBE_DEFER) {
351 ret = sdrv->probe(spi);
353 dev_pm_domain_detach(dev, true);
359 static int spi_drv_remove(struct device *dev)
361 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
364 ret = sdrv->remove(to_spi_device(dev));
365 dev_pm_domain_detach(dev, true);
370 static void spi_drv_shutdown(struct device *dev)
372 const struct spi_driver *sdrv = to_spi_driver(dev->driver);
374 sdrv->shutdown(to_spi_device(dev));
378 * spi_register_driver - register a SPI driver
379 * @sdrv: the driver to register
382 * Return: zero on success, else a negative error code.
384 int spi_register_driver(struct spi_driver *sdrv)
386 sdrv->driver.bus = &spi_bus_type;
388 sdrv->driver.probe = spi_drv_probe;
390 sdrv->driver.remove = spi_drv_remove;
392 sdrv->driver.shutdown = spi_drv_shutdown;
393 return driver_register(&sdrv->driver);
395 EXPORT_SYMBOL_GPL(spi_register_driver);
397 /*-------------------------------------------------------------------------*/
399 /* SPI devices should normally not be created by SPI device drivers; that
400 * would make them board-specific. Similarly with SPI master drivers.
401 * Device registration normally goes into like arch/.../mach.../board-YYY.c
402 * with other readonly (flashable) information about mainboard devices.
406 struct list_head list;
407 struct spi_board_info board_info;
410 static LIST_HEAD(board_list);
411 static LIST_HEAD(spi_master_list);
414 * Used to protect add/del opertion for board_info list and
415 * spi_master list, and their matching process
417 static DEFINE_MUTEX(board_lock);
420 * spi_alloc_device - Allocate a new SPI device
421 * @master: Controller to which device is connected
424 * Allows a driver to allocate and initialize a spi_device without
425 * registering it immediately. This allows a driver to directly
426 * fill the spi_device with device parameters before calling
427 * spi_add_device() on it.
429 * Caller is responsible to call spi_add_device() on the returned
430 * spi_device structure to add it to the SPI master. If the caller
431 * needs to discard the spi_device without adding it, then it should
432 * call spi_dev_put() on it.
434 * Return: a pointer to the new device, or NULL.
436 struct spi_device *spi_alloc_device(struct spi_master *master)
438 struct spi_device *spi;
440 if (!spi_master_get(master))
443 spi = kzalloc(sizeof(*spi), GFP_KERNEL);
445 spi_master_put(master);
449 spi->master = master;
450 spi->dev.parent = &master->dev;
451 spi->dev.bus = &spi_bus_type;
452 spi->dev.release = spidev_release;
453 spi->cs_gpio = -ENOENT;
455 spin_lock_init(&spi->statistics.lock);
457 device_initialize(&spi->dev);
460 EXPORT_SYMBOL_GPL(spi_alloc_device);
462 static void spi_dev_set_name(struct spi_device *spi)
464 struct acpi_device *adev = ACPI_COMPANION(&spi->dev);
467 dev_set_name(&spi->dev, "spi-%s", acpi_dev_name(adev));
471 dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
475 static int spi_dev_check(struct device *dev, void *data)
477 struct spi_device *spi = to_spi_device(dev);
478 struct spi_device *new_spi = data;
480 if (spi->master == new_spi->master &&
481 spi->chip_select == new_spi->chip_select)
487 * spi_add_device - Add spi_device allocated with spi_alloc_device
488 * @spi: spi_device to register
490 * Companion function to spi_alloc_device. Devices allocated with
491 * spi_alloc_device can be added onto the spi bus with this function.
493 * Return: 0 on success; negative errno on failure
495 int spi_add_device(struct spi_device *spi)
497 static DEFINE_MUTEX(spi_add_lock);
498 struct spi_master *master = spi->master;
499 struct device *dev = master->dev.parent;
502 /* Chipselects are numbered 0..max; validate. */
503 if (spi->chip_select >= master->num_chipselect) {
504 dev_err(dev, "cs%d >= max %d\n",
506 master->num_chipselect);
510 /* Set the bus ID string */
511 spi_dev_set_name(spi);
513 /* We need to make sure there's no other device with this
514 * chipselect **BEFORE** we call setup(), else we'll trash
515 * its configuration. Lock against concurrent add() calls.
517 mutex_lock(&spi_add_lock);
519 status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check);
521 dev_err(dev, "chipselect %d already in use\n",
526 if (master->cs_gpios)
527 spi->cs_gpio = master->cs_gpios[spi->chip_select];
529 /* Drivers may modify this initial i/o setup, but will
530 * normally rely on the device being setup. Devices
531 * using SPI_CS_HIGH can't coexist well otherwise...
533 status = spi_setup(spi);
535 dev_err(dev, "can't setup %s, status %d\n",
536 dev_name(&spi->dev), status);
540 /* Device may be bound to an active driver when this returns */
541 status = device_add(&spi->dev);
543 dev_err(dev, "can't add %s, status %d\n",
544 dev_name(&spi->dev), status);
546 dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
549 mutex_unlock(&spi_add_lock);
552 EXPORT_SYMBOL_GPL(spi_add_device);
555 * spi_new_device - instantiate one new SPI device
556 * @master: Controller to which device is connected
557 * @chip: Describes the SPI device
560 * On typical mainboards, this is purely internal; and it's not needed
561 * after board init creates the hard-wired devices. Some development
562 * platforms may not be able to use spi_register_board_info though, and
563 * this is exported so that for example a USB or parport based adapter
564 * driver could add devices (which it would learn about out-of-band).
566 * Return: the new device, or NULL.
568 struct spi_device *spi_new_device(struct spi_master *master,
569 struct spi_board_info *chip)
571 struct spi_device *proxy;
574 /* NOTE: caller did any chip->bus_num checks necessary.
576 * Also, unless we change the return value convention to use
577 * error-or-pointer (not NULL-or-pointer), troubleshootability
578 * suggests syslogged diagnostics are best here (ugh).
581 proxy = spi_alloc_device(master);
585 WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
587 proxy->chip_select = chip->chip_select;
588 proxy->max_speed_hz = chip->max_speed_hz;
589 proxy->mode = chip->mode;
590 proxy->irq = chip->irq;
591 strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
592 proxy->dev.platform_data = (void *) chip->platform_data;
593 proxy->controller_data = chip->controller_data;
594 proxy->controller_state = NULL;
596 status = spi_add_device(proxy);
604 EXPORT_SYMBOL_GPL(spi_new_device);
606 static void spi_match_master_to_boardinfo(struct spi_master *master,
607 struct spi_board_info *bi)
609 struct spi_device *dev;
611 if (master->bus_num != bi->bus_num)
614 dev = spi_new_device(master, bi);
616 dev_err(master->dev.parent, "can't create new device for %s\n",
621 * spi_register_board_info - register SPI devices for a given board
622 * @info: array of chip descriptors
623 * @n: how many descriptors are provided
626 * Board-specific early init code calls this (probably during arch_initcall)
627 * with segments of the SPI device table. Any device nodes are created later,
628 * after the relevant parent SPI controller (bus_num) is defined. We keep
629 * this table of devices forever, so that reloading a controller driver will
630 * not make Linux forget about these hard-wired devices.
632 * Other code can also call this, e.g. a particular add-on board might provide
633 * SPI devices through its expansion connector, so code initializing that board
634 * would naturally declare its SPI devices.
636 * The board info passed can safely be __initdata ... but be careful of
637 * any embedded pointers (platform_data, etc), they're copied as-is.
639 * Return: zero on success, else a negative error code.
641 int spi_register_board_info(struct spi_board_info const *info, unsigned n)
643 struct boardinfo *bi;
649 bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
653 for (i = 0; i < n; i++, bi++, info++) {
654 struct spi_master *master;
656 memcpy(&bi->board_info, info, sizeof(*info));
657 mutex_lock(&board_lock);
658 list_add_tail(&bi->list, &board_list);
659 list_for_each_entry(master, &spi_master_list, list)
660 spi_match_master_to_boardinfo(master, &bi->board_info);
661 mutex_unlock(&board_lock);
667 /*-------------------------------------------------------------------------*/
669 static void spi_set_cs(struct spi_device *spi, bool enable)
671 if (spi->mode & SPI_CS_HIGH)
674 if (gpio_is_valid(spi->cs_gpio))
675 gpio_set_value(spi->cs_gpio, !enable);
676 else if (spi->master->set_cs)
677 spi->master->set_cs(spi, !enable);
680 #ifdef CONFIG_HAS_DMA
681 static int spi_map_buf(struct spi_master *master, struct device *dev,
682 struct sg_table *sgt, void *buf, size_t len,
683 enum dma_data_direction dir)
685 const bool vmalloced_buf = is_vmalloc_addr(buf);
688 struct page *vm_page;
694 desc_len = PAGE_SIZE;
695 sgs = DIV_ROUND_UP(len + offset_in_page(buf), desc_len);
697 desc_len = master->max_dma_len;
698 sgs = DIV_ROUND_UP(len, desc_len);
701 ret = sg_alloc_table(sgt, sgs, GFP_KERNEL);
705 for (i = 0; i < sgs; i++) {
709 len, desc_len - offset_in_page(buf));
710 vm_page = vmalloc_to_page(buf);
715 sg_set_page(&sgt->sgl[i], vm_page,
716 min, offset_in_page(buf));
718 min = min_t(size_t, len, desc_len);
720 sg_set_buf(&sgt->sgl[i], sg_buf, min);
728 ret = dma_map_sg(dev, sgt->sgl, sgt->nents, dir);
741 static void spi_unmap_buf(struct spi_master *master, struct device *dev,
742 struct sg_table *sgt, enum dma_data_direction dir)
744 if (sgt->orig_nents) {
745 dma_unmap_sg(dev, sgt->sgl, sgt->orig_nents, dir);
750 static int __spi_map_msg(struct spi_master *master, struct spi_message *msg)
752 struct device *tx_dev, *rx_dev;
753 struct spi_transfer *xfer;
756 if (!master->can_dma)
760 tx_dev = master->dma_tx->device->dev;
762 tx_dev = &master->dev;
765 rx_dev = master->dma_rx->device->dev;
767 rx_dev = &master->dev;
769 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
770 if (!master->can_dma(master, msg->spi, xfer))
773 if (xfer->tx_buf != NULL) {
774 ret = spi_map_buf(master, tx_dev, &xfer->tx_sg,
775 (void *)xfer->tx_buf, xfer->len,
781 if (xfer->rx_buf != NULL) {
782 ret = spi_map_buf(master, rx_dev, &xfer->rx_sg,
783 xfer->rx_buf, xfer->len,
786 spi_unmap_buf(master, tx_dev, &xfer->tx_sg,
793 master->cur_msg_mapped = true;
798 static int __spi_unmap_msg(struct spi_master *master, struct spi_message *msg)
800 struct spi_transfer *xfer;
801 struct device *tx_dev, *rx_dev;
803 if (!master->cur_msg_mapped || !master->can_dma)
807 tx_dev = master->dma_tx->device->dev;
809 tx_dev = &master->dev;
812 rx_dev = master->dma_rx->device->dev;
814 rx_dev = &master->dev;
816 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
817 if (!master->can_dma(master, msg->spi, xfer))
820 spi_unmap_buf(master, rx_dev, &xfer->rx_sg, DMA_FROM_DEVICE);
821 spi_unmap_buf(master, tx_dev, &xfer->tx_sg, DMA_TO_DEVICE);
826 #else /* !CONFIG_HAS_DMA */
827 static inline int __spi_map_msg(struct spi_master *master,
828 struct spi_message *msg)
833 static inline int __spi_unmap_msg(struct spi_master *master,
834 struct spi_message *msg)
838 #endif /* !CONFIG_HAS_DMA */
840 static inline int spi_unmap_msg(struct spi_master *master,
841 struct spi_message *msg)
843 struct spi_transfer *xfer;
845 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
847 * Restore the original value of tx_buf or rx_buf if they are
850 if (xfer->tx_buf == master->dummy_tx)
852 if (xfer->rx_buf == master->dummy_rx)
856 return __spi_unmap_msg(master, msg);
859 static int spi_map_msg(struct spi_master *master, struct spi_message *msg)
861 struct spi_transfer *xfer;
863 unsigned int max_tx, max_rx;
865 if (master->flags & (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX)) {
869 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
870 if ((master->flags & SPI_MASTER_MUST_TX) &&
872 max_tx = max(xfer->len, max_tx);
873 if ((master->flags & SPI_MASTER_MUST_RX) &&
875 max_rx = max(xfer->len, max_rx);
879 tmp = krealloc(master->dummy_tx, max_tx,
880 GFP_KERNEL | GFP_DMA);
883 master->dummy_tx = tmp;
884 memset(tmp, 0, max_tx);
888 tmp = krealloc(master->dummy_rx, max_rx,
889 GFP_KERNEL | GFP_DMA);
892 master->dummy_rx = tmp;
895 if (max_tx || max_rx) {
896 list_for_each_entry(xfer, &msg->transfers,
899 xfer->tx_buf = master->dummy_tx;
901 xfer->rx_buf = master->dummy_rx;
906 return __spi_map_msg(master, msg);
910 * spi_transfer_one_message - Default implementation of transfer_one_message()
912 * This is a standard implementation of transfer_one_message() for
913 * drivers which impelment a transfer_one() operation. It provides
914 * standard handling of delays and chip select management.
916 static int spi_transfer_one_message(struct spi_master *master,
917 struct spi_message *msg)
919 struct spi_transfer *xfer;
920 bool keep_cs = false;
922 unsigned long ms = 1;
923 struct spi_statistics *statm = &master->statistics;
924 struct spi_statistics *stats = &msg->spi->statistics;
926 spi_set_cs(msg->spi, true);
928 SPI_STATISTICS_INCREMENT_FIELD(statm, messages);
929 SPI_STATISTICS_INCREMENT_FIELD(stats, messages);
931 list_for_each_entry(xfer, &msg->transfers, transfer_list) {
932 trace_spi_transfer_start(msg, xfer);
934 spi_statistics_add_transfer_stats(statm, xfer, master);
935 spi_statistics_add_transfer_stats(stats, xfer, master);
937 if (xfer->tx_buf || xfer->rx_buf) {
938 reinit_completion(&master->xfer_completion);
940 ret = master->transfer_one(master, msg->spi, xfer);
942 SPI_STATISTICS_INCREMENT_FIELD(statm,
944 SPI_STATISTICS_INCREMENT_FIELD(stats,
946 dev_err(&msg->spi->dev,
947 "SPI transfer failed: %d\n", ret);
953 ms = xfer->len * 8 * 1000 / xfer->speed_hz;
954 ms += ms + 100; /* some tolerance */
956 ms = wait_for_completion_timeout(&master->xfer_completion,
957 msecs_to_jiffies(ms));
961 SPI_STATISTICS_INCREMENT_FIELD(statm,
963 SPI_STATISTICS_INCREMENT_FIELD(stats,
965 dev_err(&msg->spi->dev,
966 "SPI transfer timed out\n");
967 msg->status = -ETIMEDOUT;
971 dev_err(&msg->spi->dev,
972 "Bufferless transfer has length %u\n",
976 trace_spi_transfer_stop(msg, xfer);
978 if (msg->status != -EINPROGRESS)
981 if (xfer->delay_usecs)
982 udelay(xfer->delay_usecs);
984 if (xfer->cs_change) {
985 if (list_is_last(&xfer->transfer_list,
989 spi_set_cs(msg->spi, false);
991 spi_set_cs(msg->spi, true);
995 msg->actual_length += xfer->len;
999 if (ret != 0 || !keep_cs)
1000 spi_set_cs(msg->spi, false);
1002 if (msg->status == -EINPROGRESS)
1005 if (msg->status && master->handle_err)
1006 master->handle_err(master, msg);
1008 spi_finalize_current_message(master);
1014 * spi_finalize_current_transfer - report completion of a transfer
1015 * @master: the master reporting completion
1017 * Called by SPI drivers using the core transfer_one_message()
1018 * implementation to notify it that the current interrupt driven
1019 * transfer has finished and the next one may be scheduled.
1021 void spi_finalize_current_transfer(struct spi_master *master)
1023 complete(&master->xfer_completion);
1025 EXPORT_SYMBOL_GPL(spi_finalize_current_transfer);
1028 * __spi_pump_messages - function which processes spi message queue
1029 * @master: master to process queue for
1030 * @in_kthread: true if we are in the context of the message pump thread
1032 * This function checks if there is any spi message in the queue that
1033 * needs processing and if so call out to the driver to initialize hardware
1034 * and transfer each message.
1036 * Note that it is called both from the kthread itself and also from
1037 * inside spi_sync(); the queue extraction handling at the top of the
1038 * function should deal with this safely.
1040 static void __spi_pump_messages(struct spi_master *master, bool in_kthread)
1042 unsigned long flags;
1043 bool was_busy = false;
1047 spin_lock_irqsave(&master->queue_lock, flags);
1049 /* Make sure we are not already running a message */
1050 if (master->cur_msg) {
1051 spin_unlock_irqrestore(&master->queue_lock, flags);
1055 /* If another context is idling the device then defer */
1056 if (master->idling) {
1057 queue_kthread_work(&master->kworker, &master->pump_messages);
1058 spin_unlock_irqrestore(&master->queue_lock, flags);
1062 /* Check if the queue is idle */
1063 if (list_empty(&master->queue) || !master->running) {
1064 if (!master->busy) {
1065 spin_unlock_irqrestore(&master->queue_lock, flags);
1069 /* Only do teardown in the thread */
1071 queue_kthread_work(&master->kworker,
1072 &master->pump_messages);
1073 spin_unlock_irqrestore(&master->queue_lock, flags);
1077 master->busy = false;
1078 master->idling = true;
1079 spin_unlock_irqrestore(&master->queue_lock, flags);
1081 kfree(master->dummy_rx);
1082 master->dummy_rx = NULL;
1083 kfree(master->dummy_tx);
1084 master->dummy_tx = NULL;
1085 if (master->unprepare_transfer_hardware &&
1086 master->unprepare_transfer_hardware(master))
1087 dev_err(&master->dev,
1088 "failed to unprepare transfer hardware\n");
1089 if (master->auto_runtime_pm) {
1090 pm_runtime_mark_last_busy(master->dev.parent);
1091 pm_runtime_put_autosuspend(master->dev.parent);
1093 trace_spi_master_idle(master);
1095 spin_lock_irqsave(&master->queue_lock, flags);
1096 master->idling = false;
1097 spin_unlock_irqrestore(&master->queue_lock, flags);
1101 /* Extract head of queue */
1103 list_first_entry(&master->queue, struct spi_message, queue);
1105 list_del_init(&master->cur_msg->queue);
1109 master->busy = true;
1110 spin_unlock_irqrestore(&master->queue_lock, flags);
1112 if (!was_busy && master->auto_runtime_pm) {
1113 ret = pm_runtime_get_sync(master->dev.parent);
1115 dev_err(&master->dev, "Failed to power device: %d\n",
1122 trace_spi_master_busy(master);
1124 if (!was_busy && master->prepare_transfer_hardware) {
1125 ret = master->prepare_transfer_hardware(master);
1127 dev_err(&master->dev,
1128 "failed to prepare transfer hardware\n");
1130 if (master->auto_runtime_pm)
1131 pm_runtime_put(master->dev.parent);
1136 trace_spi_message_start(master->cur_msg);
1138 if (master->prepare_message) {
1139 ret = master->prepare_message(master, master->cur_msg);
1141 dev_err(&master->dev,
1142 "failed to prepare message: %d\n", ret);
1143 master->cur_msg->status = ret;
1144 spi_finalize_current_message(master);
1147 master->cur_msg_prepared = true;
1150 ret = spi_map_msg(master, master->cur_msg);
1152 master->cur_msg->status = ret;
1153 spi_finalize_current_message(master);
1157 ret = master->transfer_one_message(master, master->cur_msg);
1159 dev_err(&master->dev,
1160 "failed to transfer one message from queue\n");
1166 * spi_pump_messages - kthread work function which processes spi message queue
1167 * @work: pointer to kthread work struct contained in the master struct
1169 static void spi_pump_messages(struct kthread_work *work)
1171 struct spi_master *master =
1172 container_of(work, struct spi_master, pump_messages);
1174 __spi_pump_messages(master, true);
1177 static int spi_init_queue(struct spi_master *master)
1179 struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
1181 master->running = false;
1182 master->busy = false;
1184 init_kthread_worker(&master->kworker);
1185 master->kworker_task = kthread_run(kthread_worker_fn,
1186 &master->kworker, "%s",
1187 dev_name(&master->dev));
1188 if (IS_ERR(master->kworker_task)) {
1189 dev_err(&master->dev, "failed to create message pump task\n");
1190 return PTR_ERR(master->kworker_task);
1192 init_kthread_work(&master->pump_messages, spi_pump_messages);
1195 * Master config will indicate if this controller should run the
1196 * message pump with high (realtime) priority to reduce the transfer
1197 * latency on the bus by minimising the delay between a transfer
1198 * request and the scheduling of the message pump thread. Without this
1199 * setting the message pump thread will remain at default priority.
1202 dev_info(&master->dev,
1203 "will run message pump with realtime priority\n");
1204 sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
1211 * spi_get_next_queued_message() - called by driver to check for queued
1213 * @master: the master to check for queued messages
1215 * If there are more messages in the queue, the next message is returned from
1218 * Return: the next message in the queue, else NULL if the queue is empty.
1220 struct spi_message *spi_get_next_queued_message(struct spi_master *master)
1222 struct spi_message *next;
1223 unsigned long flags;
1225 /* get a pointer to the next message, if any */
1226 spin_lock_irqsave(&master->queue_lock, flags);
1227 next = list_first_entry_or_null(&master->queue, struct spi_message,
1229 spin_unlock_irqrestore(&master->queue_lock, flags);
1233 EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
1236 * spi_finalize_current_message() - the current message is complete
1237 * @master: the master to return the message to
1239 * Called by the driver to notify the core that the message in the front of the
1240 * queue is complete and can be removed from the queue.
1242 void spi_finalize_current_message(struct spi_master *master)
1244 struct spi_message *mesg;
1245 unsigned long flags;
1248 spin_lock_irqsave(&master->queue_lock, flags);
1249 mesg = master->cur_msg;
1250 spin_unlock_irqrestore(&master->queue_lock, flags);
1252 spi_unmap_msg(master, mesg);
1254 if (master->cur_msg_prepared && master->unprepare_message) {
1255 ret = master->unprepare_message(master, mesg);
1257 dev_err(&master->dev,
1258 "failed to unprepare message: %d\n", ret);
1262 spin_lock_irqsave(&master->queue_lock, flags);
1263 master->cur_msg = NULL;
1264 master->cur_msg_prepared = false;
1265 queue_kthread_work(&master->kworker, &master->pump_messages);
1266 spin_unlock_irqrestore(&master->queue_lock, flags);
1268 trace_spi_message_done(mesg);
1272 mesg->complete(mesg->context);
1274 EXPORT_SYMBOL_GPL(spi_finalize_current_message);
1276 static int spi_start_queue(struct spi_master *master)
1278 unsigned long flags;
1280 spin_lock_irqsave(&master->queue_lock, flags);
1282 if (master->running || master->busy) {
1283 spin_unlock_irqrestore(&master->queue_lock, flags);
1287 master->running = true;
1288 master->cur_msg = NULL;
1289 spin_unlock_irqrestore(&master->queue_lock, flags);
1291 queue_kthread_work(&master->kworker, &master->pump_messages);
1296 static int spi_stop_queue(struct spi_master *master)
1298 unsigned long flags;
1299 unsigned limit = 500;
1302 spin_lock_irqsave(&master->queue_lock, flags);
1305 * This is a bit lame, but is optimized for the common execution path.
1306 * A wait_queue on the master->busy could be used, but then the common
1307 * execution path (pump_messages) would be required to call wake_up or
1308 * friends on every SPI message. Do this instead.
1310 while ((!list_empty(&master->queue) || master->busy) && limit--) {
1311 spin_unlock_irqrestore(&master->queue_lock, flags);
1312 usleep_range(10000, 11000);
1313 spin_lock_irqsave(&master->queue_lock, flags);
1316 if (!list_empty(&master->queue) || master->busy)
1319 master->running = false;
1321 spin_unlock_irqrestore(&master->queue_lock, flags);
1324 dev_warn(&master->dev,
1325 "could not stop message queue\n");
1331 static int spi_destroy_queue(struct spi_master *master)
1335 ret = spi_stop_queue(master);
1338 * flush_kthread_worker will block until all work is done.
1339 * If the reason that stop_queue timed out is that the work will never
1340 * finish, then it does no good to call flush/stop thread, so
1344 dev_err(&master->dev, "problem destroying queue\n");
1348 flush_kthread_worker(&master->kworker);
1349 kthread_stop(master->kworker_task);
1354 static int __spi_queued_transfer(struct spi_device *spi,
1355 struct spi_message *msg,
1358 struct spi_master *master = spi->master;
1359 unsigned long flags;
1361 spin_lock_irqsave(&master->queue_lock, flags);
1363 if (!master->running) {
1364 spin_unlock_irqrestore(&master->queue_lock, flags);
1367 msg->actual_length = 0;
1368 msg->status = -EINPROGRESS;
1370 list_add_tail(&msg->queue, &master->queue);
1371 if (!master->busy && need_pump)
1372 queue_kthread_work(&master->kworker, &master->pump_messages);
1374 spin_unlock_irqrestore(&master->queue_lock, flags);
1379 * spi_queued_transfer - transfer function for queued transfers
1380 * @spi: spi device which is requesting transfer
1381 * @msg: spi message which is to handled is queued to driver queue
1383 * Return: zero on success, else a negative error code.
1385 static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
1387 return __spi_queued_transfer(spi, msg, true);
1390 static int spi_master_initialize_queue(struct spi_master *master)
1394 master->transfer = spi_queued_transfer;
1395 if (!master->transfer_one_message)
1396 master->transfer_one_message = spi_transfer_one_message;
1398 /* Initialize and start queue */
1399 ret = spi_init_queue(master);
1401 dev_err(&master->dev, "problem initializing queue\n");
1402 goto err_init_queue;
1404 master->queued = true;
1405 ret = spi_start_queue(master);
1407 dev_err(&master->dev, "problem starting queue\n");
1408 goto err_start_queue;
1414 spi_destroy_queue(master);
1419 /*-------------------------------------------------------------------------*/
1421 #if defined(CONFIG_OF)
1422 static struct spi_device *
1423 of_register_spi_device(struct spi_master *master, struct device_node *nc)
1425 struct spi_device *spi;
1429 /* Alloc an spi_device */
1430 spi = spi_alloc_device(master);
1432 dev_err(&master->dev, "spi_device alloc error for %s\n",
1438 /* Select device driver */
1439 rc = of_modalias_node(nc, spi->modalias,
1440 sizeof(spi->modalias));
1442 dev_err(&master->dev, "cannot find modalias for %s\n",
1447 /* Device address */
1448 rc = of_property_read_u32(nc, "reg", &value);
1450 dev_err(&master->dev, "%s has no valid 'reg' property (%d)\n",
1454 spi->chip_select = value;
1456 /* Mode (clock phase/polarity/etc.) */
1457 if (of_find_property(nc, "spi-cpha", NULL))
1458 spi->mode |= SPI_CPHA;
1459 if (of_find_property(nc, "spi-cpol", NULL))
1460 spi->mode |= SPI_CPOL;
1461 if (of_find_property(nc, "spi-cs-high", NULL))
1462 spi->mode |= SPI_CS_HIGH;
1463 if (of_find_property(nc, "spi-3wire", NULL))
1464 spi->mode |= SPI_3WIRE;
1465 if (of_find_property(nc, "spi-lsb-first", NULL))
1466 spi->mode |= SPI_LSB_FIRST;
1468 /* Device DUAL/QUAD mode */
1469 if (!of_property_read_u32(nc, "spi-tx-bus-width", &value)) {
1474 spi->mode |= SPI_TX_DUAL;
1477 spi->mode |= SPI_TX_QUAD;
1480 dev_warn(&master->dev,
1481 "spi-tx-bus-width %d not supported\n",
1487 if (!of_property_read_u32(nc, "spi-rx-bus-width", &value)) {
1492 spi->mode |= SPI_RX_DUAL;
1495 spi->mode |= SPI_RX_QUAD;
1498 dev_warn(&master->dev,
1499 "spi-rx-bus-width %d not supported\n",
1506 rc = of_property_read_u32(nc, "spi-max-frequency", &value);
1508 dev_err(&master->dev, "%s has no valid 'spi-max-frequency' property (%d)\n",
1512 spi->max_speed_hz = value;
1514 /* Store a pointer to the node in the device structure */
1516 spi->dev.of_node = nc;
1518 /* Register the new device */
1519 rc = spi_add_device(spi);
1521 dev_err(&master->dev, "spi_device register error %s\n",
1534 * of_register_spi_devices() - Register child devices onto the SPI bus
1535 * @master: Pointer to spi_master device
1537 * Registers an spi_device for each child node of master node which has a 'reg'
1540 static void of_register_spi_devices(struct spi_master *master)
1542 struct spi_device *spi;
1543 struct device_node *nc;
1545 if (!master->dev.of_node)
1548 for_each_available_child_of_node(master->dev.of_node, nc) {
1549 spi = of_register_spi_device(master, nc);
1551 dev_warn(&master->dev, "Failed to create SPI device for %s\n",
1556 static void of_register_spi_devices(struct spi_master *master) { }
1560 static int acpi_spi_add_resource(struct acpi_resource *ares, void *data)
1562 struct spi_device *spi = data;
1564 if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
1565 struct acpi_resource_spi_serialbus *sb;
1567 sb = &ares->data.spi_serial_bus;
1568 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_SPI) {
1569 spi->chip_select = sb->device_selection;
1570 spi->max_speed_hz = sb->connection_speed;
1572 if (sb->clock_phase == ACPI_SPI_SECOND_PHASE)
1573 spi->mode |= SPI_CPHA;
1574 if (sb->clock_polarity == ACPI_SPI_START_HIGH)
1575 spi->mode |= SPI_CPOL;
1576 if (sb->device_polarity == ACPI_SPI_ACTIVE_HIGH)
1577 spi->mode |= SPI_CS_HIGH;
1579 } else if (spi->irq < 0) {
1582 if (acpi_dev_resource_interrupt(ares, 0, &r))
1586 /* Always tell the ACPI core to skip this resource */
1590 static acpi_status acpi_spi_add_device(acpi_handle handle, u32 level,
1591 void *data, void **return_value)
1593 struct spi_master *master = data;
1594 struct list_head resource_list;
1595 struct acpi_device *adev;
1596 struct spi_device *spi;
1599 if (acpi_bus_get_device(handle, &adev))
1601 if (acpi_bus_get_status(adev) || !adev->status.present)
1604 spi = spi_alloc_device(master);
1606 dev_err(&master->dev, "failed to allocate SPI device for %s\n",
1607 dev_name(&adev->dev));
1608 return AE_NO_MEMORY;
1611 ACPI_COMPANION_SET(&spi->dev, adev);
1614 INIT_LIST_HEAD(&resource_list);
1615 ret = acpi_dev_get_resources(adev, &resource_list,
1616 acpi_spi_add_resource, spi);
1617 acpi_dev_free_resource_list(&resource_list);
1619 if (ret < 0 || !spi->max_speed_hz) {
1624 adev->power.flags.ignore_parent = true;
1625 strlcpy(spi->modalias, acpi_device_hid(adev), sizeof(spi->modalias));
1626 if (spi_add_device(spi)) {
1627 adev->power.flags.ignore_parent = false;
1628 dev_err(&master->dev, "failed to add SPI device %s from ACPI\n",
1629 dev_name(&adev->dev));
1636 static void acpi_register_spi_devices(struct spi_master *master)
1641 handle = ACPI_HANDLE(master->dev.parent);
1645 status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
1646 acpi_spi_add_device, NULL,
1648 if (ACPI_FAILURE(status))
1649 dev_warn(&master->dev, "failed to enumerate SPI slaves\n");
1652 static inline void acpi_register_spi_devices(struct spi_master *master) {}
1653 #endif /* CONFIG_ACPI */
1655 static void spi_master_release(struct device *dev)
1657 struct spi_master *master;
1659 master = container_of(dev, struct spi_master, dev);
1663 static struct class spi_master_class = {
1664 .name = "spi_master",
1665 .owner = THIS_MODULE,
1666 .dev_release = spi_master_release,
1667 .dev_groups = spi_master_groups,
1672 * spi_alloc_master - allocate SPI master controller
1673 * @dev: the controller, possibly using the platform_bus
1674 * @size: how much zeroed driver-private data to allocate; the pointer to this
1675 * memory is in the driver_data field of the returned device,
1676 * accessible with spi_master_get_devdata().
1677 * Context: can sleep
1679 * This call is used only by SPI master controller drivers, which are the
1680 * only ones directly touching chip registers. It's how they allocate
1681 * an spi_master structure, prior to calling spi_register_master().
1683 * This must be called from context that can sleep.
1685 * The caller is responsible for assigning the bus number and initializing
1686 * the master's methods before calling spi_register_master(); and (after errors
1687 * adding the device) calling spi_master_put() to prevent a memory leak.
1689 * Return: the SPI master structure on success, else NULL.
1691 struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
1693 struct spi_master *master;
1698 master = kzalloc(size + sizeof(*master), GFP_KERNEL);
1702 device_initialize(&master->dev);
1703 master->bus_num = -1;
1704 master->num_chipselect = 1;
1705 master->dev.class = &spi_master_class;
1706 master->dev.parent = get_device(dev);
1707 spi_master_set_devdata(master, &master[1]);
1711 EXPORT_SYMBOL_GPL(spi_alloc_master);
1714 static int of_spi_register_master(struct spi_master *master)
1717 struct device_node *np = master->dev.of_node;
1722 nb = of_gpio_named_count(np, "cs-gpios");
1723 master->num_chipselect = max_t(int, nb, master->num_chipselect);
1725 /* Return error only for an incorrectly formed cs-gpios property */
1726 if (nb == 0 || nb == -ENOENT)
1731 cs = devm_kzalloc(&master->dev,
1732 sizeof(int) * master->num_chipselect,
1734 master->cs_gpios = cs;
1736 if (!master->cs_gpios)
1739 for (i = 0; i < master->num_chipselect; i++)
1742 for (i = 0; i < nb; i++)
1743 cs[i] = of_get_named_gpio(np, "cs-gpios", i);
1748 static int of_spi_register_master(struct spi_master *master)
1755 * spi_register_master - register SPI master controller
1756 * @master: initialized master, originally from spi_alloc_master()
1757 * Context: can sleep
1759 * SPI master controllers connect to their drivers using some non-SPI bus,
1760 * such as the platform bus. The final stage of probe() in that code
1761 * includes calling spi_register_master() to hook up to this SPI bus glue.
1763 * SPI controllers use board specific (often SOC specific) bus numbers,
1764 * and board-specific addressing for SPI devices combines those numbers
1765 * with chip select numbers. Since SPI does not directly support dynamic
1766 * device identification, boards need configuration tables telling which
1767 * chip is at which address.
1769 * This must be called from context that can sleep. It returns zero on
1770 * success, else a negative error code (dropping the master's refcount).
1771 * After a successful return, the caller is responsible for calling
1772 * spi_unregister_master().
1774 * Return: zero on success, else a negative error code.
1776 int spi_register_master(struct spi_master *master)
1778 static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
1779 struct device *dev = master->dev.parent;
1780 struct boardinfo *bi;
1781 int status = -ENODEV;
1787 status = of_spi_register_master(master);
1791 /* even if it's just one always-selected device, there must
1792 * be at least one chipselect
1794 if (master->num_chipselect == 0)
1797 if ((master->bus_num < 0) && master->dev.of_node)
1798 master->bus_num = of_alias_get_id(master->dev.of_node, "spi");
1800 /* convention: dynamically assigned bus IDs count down from the max */
1801 if (master->bus_num < 0) {
1802 /* FIXME switch to an IDR based scheme, something like
1803 * I2C now uses, so we can't run out of "dynamic" IDs
1805 master->bus_num = atomic_dec_return(&dyn_bus_id);
1809 INIT_LIST_HEAD(&master->queue);
1810 spin_lock_init(&master->queue_lock);
1811 spin_lock_init(&master->bus_lock_spinlock);
1812 mutex_init(&master->bus_lock_mutex);
1813 master->bus_lock_flag = 0;
1814 init_completion(&master->xfer_completion);
1815 if (!master->max_dma_len)
1816 master->max_dma_len = INT_MAX;
1818 /* register the device, then userspace will see it.
1819 * registration fails if the bus ID is in use.
1821 dev_set_name(&master->dev, "spi%u", master->bus_num);
1822 status = device_add(&master->dev);
1825 dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
1826 dynamic ? " (dynamic)" : "");
1828 /* If we're using a queued driver, start the queue */
1829 if (master->transfer)
1830 dev_info(dev, "master is unqueued, this is deprecated\n");
1832 status = spi_master_initialize_queue(master);
1834 device_del(&master->dev);
1838 /* add statistics */
1839 spin_lock_init(&master->statistics.lock);
1841 mutex_lock(&board_lock);
1842 list_add_tail(&master->list, &spi_master_list);
1843 list_for_each_entry(bi, &board_list, list)
1844 spi_match_master_to_boardinfo(master, &bi->board_info);
1845 mutex_unlock(&board_lock);
1847 /* Register devices from the device tree and ACPI */
1848 of_register_spi_devices(master);
1849 acpi_register_spi_devices(master);
1853 EXPORT_SYMBOL_GPL(spi_register_master);
1855 static void devm_spi_unregister(struct device *dev, void *res)
1857 spi_unregister_master(*(struct spi_master **)res);
1861 * dev_spi_register_master - register managed SPI master controller
1862 * @dev: device managing SPI master
1863 * @master: initialized master, originally from spi_alloc_master()
1864 * Context: can sleep
1866 * Register a SPI device as with spi_register_master() which will
1867 * automatically be unregister
1869 * Return: zero on success, else a negative error code.
1871 int devm_spi_register_master(struct device *dev, struct spi_master *master)
1873 struct spi_master **ptr;
1876 ptr = devres_alloc(devm_spi_unregister, sizeof(*ptr), GFP_KERNEL);
1880 ret = spi_register_master(master);
1883 devres_add(dev, ptr);
1890 EXPORT_SYMBOL_GPL(devm_spi_register_master);
1892 static int __unregister(struct device *dev, void *null)
1894 spi_unregister_device(to_spi_device(dev));
1899 * spi_unregister_master - unregister SPI master controller
1900 * @master: the master being unregistered
1901 * Context: can sleep
1903 * This call is used only by SPI master controller drivers, which are the
1904 * only ones directly touching chip registers.
1906 * This must be called from context that can sleep.
1908 void spi_unregister_master(struct spi_master *master)
1912 if (master->queued) {
1913 if (spi_destroy_queue(master))
1914 dev_err(&master->dev, "queue remove failed\n");
1917 mutex_lock(&board_lock);
1918 list_del(&master->list);
1919 mutex_unlock(&board_lock);
1921 dummy = device_for_each_child(&master->dev, NULL, __unregister);
1922 device_unregister(&master->dev);
1924 EXPORT_SYMBOL_GPL(spi_unregister_master);
1926 int spi_master_suspend(struct spi_master *master)
1930 /* Basically no-ops for non-queued masters */
1931 if (!master->queued)
1934 ret = spi_stop_queue(master);
1936 dev_err(&master->dev, "queue stop failed\n");
1940 EXPORT_SYMBOL_GPL(spi_master_suspend);
1942 int spi_master_resume(struct spi_master *master)
1946 if (!master->queued)
1949 ret = spi_start_queue(master);
1951 dev_err(&master->dev, "queue restart failed\n");
1955 EXPORT_SYMBOL_GPL(spi_master_resume);
1957 static int __spi_master_match(struct device *dev, const void *data)
1959 struct spi_master *m;
1960 const u16 *bus_num = data;
1962 m = container_of(dev, struct spi_master, dev);
1963 return m->bus_num == *bus_num;
1967 * spi_busnum_to_master - look up master associated with bus_num
1968 * @bus_num: the master's bus number
1969 * Context: can sleep
1971 * This call may be used with devices that are registered after
1972 * arch init time. It returns a refcounted pointer to the relevant
1973 * spi_master (which the caller must release), or NULL if there is
1974 * no such master registered.
1976 * Return: the SPI master structure on success, else NULL.
1978 struct spi_master *spi_busnum_to_master(u16 bus_num)
1981 struct spi_master *master = NULL;
1983 dev = class_find_device(&spi_master_class, NULL, &bus_num,
1984 __spi_master_match);
1986 master = container_of(dev, struct spi_master, dev);
1987 /* reference got in class_find_device */
1990 EXPORT_SYMBOL_GPL(spi_busnum_to_master);
1993 /*-------------------------------------------------------------------------*/
1995 /* Core methods for SPI master protocol drivers. Some of the
1996 * other core methods are currently defined as inline functions.
1999 static int __spi_validate_bits_per_word(struct spi_master *master, u8 bits_per_word)
2001 if (master->bits_per_word_mask) {
2002 /* Only 32 bits fit in the mask */
2003 if (bits_per_word > 32)
2005 if (!(master->bits_per_word_mask &
2006 SPI_BPW_MASK(bits_per_word)))
2014 * spi_setup - setup SPI mode and clock rate
2015 * @spi: the device whose settings are being modified
2016 * Context: can sleep, and no requests are queued to the device
2018 * SPI protocol drivers may need to update the transfer mode if the
2019 * device doesn't work with its default. They may likewise need
2020 * to update clock rates or word sizes from initial values. This function
2021 * changes those settings, and must be called from a context that can sleep.
2022 * Except for SPI_CS_HIGH, which takes effect immediately, the changes take
2023 * effect the next time the device is selected and data is transferred to
2024 * or from it. When this function returns, the spi device is deselected.
2026 * Note that this call will fail if the protocol driver specifies an option
2027 * that the underlying controller or its driver does not support. For
2028 * example, not all hardware supports wire transfers using nine bit words,
2029 * LSB-first wire encoding, or active-high chipselects.
2031 * Return: zero on success, else a negative error code.
2033 int spi_setup(struct spi_device *spi)
2035 unsigned bad_bits, ugly_bits;
2038 /* check mode to prevent that DUAL and QUAD set at the same time
2040 if (((spi->mode & SPI_TX_DUAL) && (spi->mode & SPI_TX_QUAD)) ||
2041 ((spi->mode & SPI_RX_DUAL) && (spi->mode & SPI_RX_QUAD))) {
2043 "setup: can not select dual and quad at the same time\n");
2046 /* if it is SPI_3WIRE mode, DUAL and QUAD should be forbidden
2048 if ((spi->mode & SPI_3WIRE) && (spi->mode &
2049 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD)))
2051 /* help drivers fail *cleanly* when they need options
2052 * that aren't supported with their current master
2054 bad_bits = spi->mode & ~spi->master->mode_bits;
2055 ugly_bits = bad_bits &
2056 (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD);
2059 "setup: ignoring unsupported mode bits %x\n",
2061 spi->mode &= ~ugly_bits;
2062 bad_bits &= ~ugly_bits;
2065 dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
2070 if (!spi->bits_per_word)
2071 spi->bits_per_word = 8;
2073 status = __spi_validate_bits_per_word(spi->master, spi->bits_per_word);
2077 if (!spi->max_speed_hz)
2078 spi->max_speed_hz = spi->master->max_speed_hz;
2080 if (spi->master->setup)
2081 status = spi->master->setup(spi);
2083 spi_set_cs(spi, false);
2085 dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s%u bits/w, %u Hz max --> %d\n",
2086 (int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
2087 (spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
2088 (spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
2089 (spi->mode & SPI_3WIRE) ? "3wire, " : "",
2090 (spi->mode & SPI_LOOP) ? "loopback, " : "",
2091 spi->bits_per_word, spi->max_speed_hz,
2096 EXPORT_SYMBOL_GPL(spi_setup);
2098 static int __spi_validate(struct spi_device *spi, struct spi_message *message)
2100 struct spi_master *master = spi->master;
2101 struct spi_transfer *xfer;
2104 if (list_empty(&message->transfers))
2107 /* Half-duplex links include original MicroWire, and ones with
2108 * only one data pin like SPI_3WIRE (switches direction) or where
2109 * either MOSI or MISO is missing. They can also be caused by
2110 * software limitations.
2112 if ((master->flags & SPI_MASTER_HALF_DUPLEX)
2113 || (spi->mode & SPI_3WIRE)) {
2114 unsigned flags = master->flags;
2116 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2117 if (xfer->rx_buf && xfer->tx_buf)
2119 if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
2121 if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
2127 * Set transfer bits_per_word and max speed as spi device default if
2128 * it is not set for this transfer.
2129 * Set transfer tx_nbits and rx_nbits as single transfer default
2130 * (SPI_NBITS_SINGLE) if it is not set for this transfer.
2132 list_for_each_entry(xfer, &message->transfers, transfer_list) {
2133 message->frame_length += xfer->len;
2134 if (!xfer->bits_per_word)
2135 xfer->bits_per_word = spi->bits_per_word;
2137 if (!xfer->speed_hz)
2138 xfer->speed_hz = spi->max_speed_hz;
2139 if (!xfer->speed_hz)
2140 xfer->speed_hz = master->max_speed_hz;
2142 if (master->max_speed_hz &&
2143 xfer->speed_hz > master->max_speed_hz)
2144 xfer->speed_hz = master->max_speed_hz;
2146 if (__spi_validate_bits_per_word(master, xfer->bits_per_word))
2150 * SPI transfer length should be multiple of SPI word size
2151 * where SPI word size should be power-of-two multiple
2153 if (xfer->bits_per_word <= 8)
2155 else if (xfer->bits_per_word <= 16)
2160 /* No partial transfers accepted */
2161 if (xfer->len % w_size)
2164 if (xfer->speed_hz && master->min_speed_hz &&
2165 xfer->speed_hz < master->min_speed_hz)
2168 if (xfer->tx_buf && !xfer->tx_nbits)
2169 xfer->tx_nbits = SPI_NBITS_SINGLE;
2170 if (xfer->rx_buf && !xfer->rx_nbits)
2171 xfer->rx_nbits = SPI_NBITS_SINGLE;
2172 /* check transfer tx/rx_nbits:
2173 * 1. check the value matches one of single, dual and quad
2174 * 2. check tx/rx_nbits match the mode in spi_device
2177 if (xfer->tx_nbits != SPI_NBITS_SINGLE &&
2178 xfer->tx_nbits != SPI_NBITS_DUAL &&
2179 xfer->tx_nbits != SPI_NBITS_QUAD)
2181 if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
2182 !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
2184 if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
2185 !(spi->mode & SPI_TX_QUAD))
2188 /* check transfer rx_nbits */
2190 if (xfer->rx_nbits != SPI_NBITS_SINGLE &&
2191 xfer->rx_nbits != SPI_NBITS_DUAL &&
2192 xfer->rx_nbits != SPI_NBITS_QUAD)
2194 if ((xfer->rx_nbits == SPI_NBITS_DUAL) &&
2195 !(spi->mode & (SPI_RX_DUAL | SPI_RX_QUAD)))
2197 if ((xfer->rx_nbits == SPI_NBITS_QUAD) &&
2198 !(spi->mode & SPI_RX_QUAD))
2203 message->status = -EINPROGRESS;
2208 static int __spi_async(struct spi_device *spi, struct spi_message *message)
2210 struct spi_master *master = spi->master;
2214 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_async);
2215 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_async);
2217 trace_spi_message_submit(message);
2219 return master->transfer(spi, message);
2223 * spi_async - asynchronous SPI transfer
2224 * @spi: device with which data will be exchanged
2225 * @message: describes the data transfers, including completion callback
2226 * Context: any (irqs may be blocked, etc)
2228 * This call may be used in_irq and other contexts which can't sleep,
2229 * as well as from task contexts which can sleep.
2231 * The completion callback is invoked in a context which can't sleep.
2232 * Before that invocation, the value of message->status is undefined.
2233 * When the callback is issued, message->status holds either zero (to
2234 * indicate complete success) or a negative error code. After that
2235 * callback returns, the driver which issued the transfer request may
2236 * deallocate the associated memory; it's no longer in use by any SPI
2237 * core or controller driver code.
2239 * Note that although all messages to a spi_device are handled in
2240 * FIFO order, messages may go to different devices in other orders.
2241 * Some device might be higher priority, or have various "hard" access
2242 * time requirements, for example.
2244 * On detection of any fault during the transfer, processing of
2245 * the entire message is aborted, and the device is deselected.
2246 * Until returning from the associated message completion callback,
2247 * no other spi_message queued to that device will be processed.
2248 * (This rule applies equally to all the synchronous transfer calls,
2249 * which are wrappers around this core asynchronous primitive.)
2251 * Return: zero on success, else a negative error code.
2253 int spi_async(struct spi_device *spi, struct spi_message *message)
2255 struct spi_master *master = spi->master;
2257 unsigned long flags;
2259 ret = __spi_validate(spi, message);
2263 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2265 if (master->bus_lock_flag)
2268 ret = __spi_async(spi, message);
2270 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2274 EXPORT_SYMBOL_GPL(spi_async);
2277 * spi_async_locked - version of spi_async with exclusive bus usage
2278 * @spi: device with which data will be exchanged
2279 * @message: describes the data transfers, including completion callback
2280 * Context: any (irqs may be blocked, etc)
2282 * This call may be used in_irq and other contexts which can't sleep,
2283 * as well as from task contexts which can sleep.
2285 * The completion callback is invoked in a context which can't sleep.
2286 * Before that invocation, the value of message->status is undefined.
2287 * When the callback is issued, message->status holds either zero (to
2288 * indicate complete success) or a negative error code. After that
2289 * callback returns, the driver which issued the transfer request may
2290 * deallocate the associated memory; it's no longer in use by any SPI
2291 * core or controller driver code.
2293 * Note that although all messages to a spi_device are handled in
2294 * FIFO order, messages may go to different devices in other orders.
2295 * Some device might be higher priority, or have various "hard" access
2296 * time requirements, for example.
2298 * On detection of any fault during the transfer, processing of
2299 * the entire message is aborted, and the device is deselected.
2300 * Until returning from the associated message completion callback,
2301 * no other spi_message queued to that device will be processed.
2302 * (This rule applies equally to all the synchronous transfer calls,
2303 * which are wrappers around this core asynchronous primitive.)
2305 * Return: zero on success, else a negative error code.
2307 int spi_async_locked(struct spi_device *spi, struct spi_message *message)
2309 struct spi_master *master = spi->master;
2311 unsigned long flags;
2313 ret = __spi_validate(spi, message);
2317 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2319 ret = __spi_async(spi, message);
2321 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2326 EXPORT_SYMBOL_GPL(spi_async_locked);
2329 /*-------------------------------------------------------------------------*/
2331 /* Utility methods for SPI master protocol drivers, layered on
2332 * top of the core. Some other utility methods are defined as
2336 static void spi_complete(void *arg)
2341 static int __spi_sync(struct spi_device *spi, struct spi_message *message,
2344 DECLARE_COMPLETION_ONSTACK(done);
2346 struct spi_master *master = spi->master;
2347 unsigned long flags;
2349 status = __spi_validate(spi, message);
2353 message->complete = spi_complete;
2354 message->context = &done;
2357 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics, spi_sync);
2358 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics, spi_sync);
2361 mutex_lock(&master->bus_lock_mutex);
2363 /* If we're not using the legacy transfer method then we will
2364 * try to transfer in the calling context so special case.
2365 * This code would be less tricky if we could remove the
2366 * support for driver implemented message queues.
2368 if (master->transfer == spi_queued_transfer) {
2369 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2371 trace_spi_message_submit(message);
2373 status = __spi_queued_transfer(spi, message, false);
2375 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2377 status = spi_async_locked(spi, message);
2381 mutex_unlock(&master->bus_lock_mutex);
2384 /* Push out the messages in the calling context if we
2387 if (master->transfer == spi_queued_transfer) {
2388 SPI_STATISTICS_INCREMENT_FIELD(&master->statistics,
2389 spi_sync_immediate);
2390 SPI_STATISTICS_INCREMENT_FIELD(&spi->statistics,
2391 spi_sync_immediate);
2392 __spi_pump_messages(master, false);
2395 wait_for_completion(&done);
2396 status = message->status;
2398 message->context = NULL;
2403 * spi_sync - blocking/synchronous SPI data transfers
2404 * @spi: device with which data will be exchanged
2405 * @message: describes the data transfers
2406 * Context: can sleep
2408 * This call may only be used from a context that may sleep. The sleep
2409 * is non-interruptible, and has no timeout. Low-overhead controller
2410 * drivers may DMA directly into and out of the message buffers.
2412 * Note that the SPI device's chip select is active during the message,
2413 * and then is normally disabled between messages. Drivers for some
2414 * frequently-used devices may want to minimize costs of selecting a chip,
2415 * by leaving it selected in anticipation that the next message will go
2416 * to the same chip. (That may increase power usage.)
2418 * Also, the caller is guaranteeing that the memory associated with the
2419 * message will not be freed before this call returns.
2421 * Return: zero on success, else a negative error code.
2423 int spi_sync(struct spi_device *spi, struct spi_message *message)
2425 return __spi_sync(spi, message, 0);
2427 EXPORT_SYMBOL_GPL(spi_sync);
2430 * spi_sync_locked - version of spi_sync with exclusive bus usage
2431 * @spi: device with which data will be exchanged
2432 * @message: describes the data transfers
2433 * Context: can sleep
2435 * This call may only be used from a context that may sleep. The sleep
2436 * is non-interruptible, and has no timeout. Low-overhead controller
2437 * drivers may DMA directly into and out of the message buffers.
2439 * This call should be used by drivers that require exclusive access to the
2440 * SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
2441 * be released by a spi_bus_unlock call when the exclusive access is over.
2443 * Return: zero on success, else a negative error code.
2445 int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
2447 return __spi_sync(spi, message, 1);
2449 EXPORT_SYMBOL_GPL(spi_sync_locked);
2452 * spi_bus_lock - obtain a lock for exclusive SPI bus usage
2453 * @master: SPI bus master that should be locked for exclusive bus access
2454 * Context: can sleep
2456 * This call may only be used from a context that may sleep. The sleep
2457 * is non-interruptible, and has no timeout.
2459 * This call should be used by drivers that require exclusive access to the
2460 * SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
2461 * exclusive access is over. Data transfer must be done by spi_sync_locked
2462 * and spi_async_locked calls when the SPI bus lock is held.
2464 * Return: always zero.
2466 int spi_bus_lock(struct spi_master *master)
2468 unsigned long flags;
2470 mutex_lock(&master->bus_lock_mutex);
2472 spin_lock_irqsave(&master->bus_lock_spinlock, flags);
2473 master->bus_lock_flag = 1;
2474 spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
2476 /* mutex remains locked until spi_bus_unlock is called */
2480 EXPORT_SYMBOL_GPL(spi_bus_lock);
2483 * spi_bus_unlock - release the lock for exclusive SPI bus usage
2484 * @master: SPI bus master that was locked for exclusive bus access
2485 * Context: can sleep
2487 * This call may only be used from a context that may sleep. The sleep
2488 * is non-interruptible, and has no timeout.
2490 * This call releases an SPI bus lock previously obtained by an spi_bus_lock
2493 * Return: always zero.
2495 int spi_bus_unlock(struct spi_master *master)
2497 master->bus_lock_flag = 0;
2499 mutex_unlock(&master->bus_lock_mutex);
2503 EXPORT_SYMBOL_GPL(spi_bus_unlock);
2505 /* portable code must never pass more than 32 bytes */
2506 #define SPI_BUFSIZ max(32, SMP_CACHE_BYTES)
2511 * spi_write_then_read - SPI synchronous write followed by read
2512 * @spi: device with which data will be exchanged
2513 * @txbuf: data to be written (need not be dma-safe)
2514 * @n_tx: size of txbuf, in bytes
2515 * @rxbuf: buffer into which data will be read (need not be dma-safe)
2516 * @n_rx: size of rxbuf, in bytes
2517 * Context: can sleep
2519 * This performs a half duplex MicroWire style transaction with the
2520 * device, sending txbuf and then reading rxbuf. The return value
2521 * is zero for success, else a negative errno status code.
2522 * This call may only be used from a context that may sleep.
2524 * Parameters to this routine are always copied using a small buffer;
2525 * portable code should never use this for more than 32 bytes.
2526 * Performance-sensitive or bulk transfer code should instead use
2527 * spi_{async,sync}() calls with dma-safe buffers.
2529 * Return: zero on success, else a negative error code.
2531 int spi_write_then_read(struct spi_device *spi,
2532 const void *txbuf, unsigned n_tx,
2533 void *rxbuf, unsigned n_rx)
2535 static DEFINE_MUTEX(lock);
2538 struct spi_message message;
2539 struct spi_transfer x[2];
2542 /* Use preallocated DMA-safe buffer if we can. We can't avoid
2543 * copying here, (as a pure convenience thing), but we can
2544 * keep heap costs out of the hot path unless someone else is
2545 * using the pre-allocated buffer or the transfer is too large.
2547 if ((n_tx + n_rx) > SPI_BUFSIZ || !mutex_trylock(&lock)) {
2548 local_buf = kmalloc(max((unsigned)SPI_BUFSIZ, n_tx + n_rx),
2549 GFP_KERNEL | GFP_DMA);
2556 spi_message_init(&message);
2557 memset(x, 0, sizeof(x));
2560 spi_message_add_tail(&x[0], &message);
2564 spi_message_add_tail(&x[1], &message);
2567 memcpy(local_buf, txbuf, n_tx);
2568 x[0].tx_buf = local_buf;
2569 x[1].rx_buf = local_buf + n_tx;
2572 status = spi_sync(spi, &message);
2574 memcpy(rxbuf, x[1].rx_buf, n_rx);
2576 if (x[0].tx_buf == buf)
2577 mutex_unlock(&lock);
2583 EXPORT_SYMBOL_GPL(spi_write_then_read);
2585 /*-------------------------------------------------------------------------*/
2587 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
2588 static int __spi_of_device_match(struct device *dev, void *data)
2590 return dev->of_node == data;
2593 /* must call put_device() when done with returned spi_device device */
2594 static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
2596 struct device *dev = bus_find_device(&spi_bus_type, NULL, node,
2597 __spi_of_device_match);
2598 return dev ? to_spi_device(dev) : NULL;
2601 static int __spi_of_master_match(struct device *dev, const void *data)
2603 return dev->of_node == data;
2606 /* the spi masters are not using spi_bus, so we find it with another way */
2607 static struct spi_master *of_find_spi_master_by_node(struct device_node *node)
2611 dev = class_find_device(&spi_master_class, NULL, node,
2612 __spi_of_master_match);
2616 /* reference got in class_find_device */
2617 return container_of(dev, struct spi_master, dev);
2620 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
2623 struct of_reconfig_data *rd = arg;
2624 struct spi_master *master;
2625 struct spi_device *spi;
2627 switch (of_reconfig_get_state_change(action, arg)) {
2628 case OF_RECONFIG_CHANGE_ADD:
2629 master = of_find_spi_master_by_node(rd->dn->parent);
2631 return NOTIFY_OK; /* not for us */
2633 spi = of_register_spi_device(master, rd->dn);
2634 put_device(&master->dev);
2637 pr_err("%s: failed to create for '%s'\n",
2638 __func__, rd->dn->full_name);
2639 return notifier_from_errno(PTR_ERR(spi));
2643 case OF_RECONFIG_CHANGE_REMOVE:
2644 /* find our device by node */
2645 spi = of_find_spi_device_by_node(rd->dn);
2647 return NOTIFY_OK; /* no? not meant for us */
2649 /* unregister takes one ref away */
2650 spi_unregister_device(spi);
2652 /* and put the reference of the find */
2653 put_device(&spi->dev);
2660 static struct notifier_block spi_of_notifier = {
2661 .notifier_call = of_spi_notify,
2663 #else /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2664 extern struct notifier_block spi_of_notifier;
2665 #endif /* IS_ENABLED(CONFIG_OF_DYNAMIC) */
2667 static int __init spi_init(void)
2671 buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
2677 status = bus_register(&spi_bus_type);
2681 status = class_register(&spi_master_class);
2685 if (IS_ENABLED(CONFIG_OF_DYNAMIC))
2686 WARN_ON(of_reconfig_notifier_register(&spi_of_notifier));
2691 bus_unregister(&spi_bus_type);
2699 /* board_info is normally registered in arch_initcall(),
2700 * but even essential drivers wait till later
2702 * REVISIT only boardinfo really needs static linking. the rest (device and
2703 * driver registration) _could_ be dynamically linked (modular) ... costs
2704 * include needing to have boardinfo data structures be much more public.
2706 postcore_initcall(spi_init);