2 * Freescale MXS SPI master driver
4 * Copyright 2012 DENX Software Engineering, GmbH.
5 * Copyright 2012 Freescale Semiconductor, Inc.
6 * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
8 * Rework and transition to new API by:
9 * Marek Vasut <marex@denx.de>
11 * Based on previous attempt by:
12 * Fabio Estevam <fabio.estevam@freescale.com>
14 * Based on code from U-Boot bootloader by:
15 * Marek Vasut <marex@denx.de>
17 * Based on spi-stmp.c, which is:
18 * Author: Dmitry Pervushin <dimka@embeddedalley.com>
20 * This program is free software; you can redistribute it and/or modify
21 * it under the terms of the GNU General Public License as published by
22 * the Free Software Foundation; either version 2 of the License, or
23 * (at your option) any later version.
25 * This program is distributed in the hope that it will be useful,
26 * but WITHOUT ANY WARRANTY; without even the implied warranty of
27 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
28 * GNU General Public License for more details.
31 #include <linux/kernel.h>
32 #include <linux/init.h>
33 #include <linux/ioport.h>
35 #include <linux/of_device.h>
36 #include <linux/of_gpio.h>
37 #include <linux/platform_device.h>
38 #include <linux/delay.h>
39 #include <linux/interrupt.h>
40 #include <linux/dma-mapping.h>
41 #include <linux/dmaengine.h>
42 #include <linux/highmem.h>
43 #include <linux/clk.h>
44 #include <linux/err.h>
45 #include <linux/completion.h>
46 #include <linux/gpio.h>
47 #include <linux/regulator/consumer.h>
48 #include <linux/module.h>
49 #include <linux/stmp_device.h>
50 #include <linux/spi/spi.h>
51 #include <linux/spi/mxs-spi.h>
53 #define DRIVER_NAME "mxs-spi"
55 /* Use 10S timeout for very long transfers, it should suffice. */
56 #define SSP_TIMEOUT 10000
58 #define SG_MAXLEN 0xff00
61 * Flags for txrx functions. More efficient that using an argument register for
64 #define TXRX_WRITE (1<<0) /* This is a write */
65 #define TXRX_DEASSERT_CS (1<<1) /* De-assert CS at end of txrx */
72 static int mxs_spi_setup_transfer(struct spi_device *dev,
73 struct spi_transfer *t)
75 struct mxs_spi *spi = spi_master_get_devdata(dev->master);
76 struct mxs_ssp *ssp = &spi->ssp;
79 hz = dev->max_speed_hz;
81 hz = min(hz, t->speed_hz);
83 dev_err(&dev->dev, "Cannot continue with zero clock\n");
87 mxs_ssp_set_clk_rate(ssp, hz);
89 writel(BM_SSP_CTRL0_LOCK_CS,
90 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
91 writel(BF_SSP_CTRL1_SSP_MODE(BV_SSP_CTRL1_SSP_MODE__SPI) |
92 BF_SSP_CTRL1_WORD_LENGTH
93 (BV_SSP_CTRL1_WORD_LENGTH__EIGHT_BITS) |
94 ((dev->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) |
95 ((dev->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0),
96 ssp->base + HW_SSP_CTRL1(ssp));
98 writel(0x0, ssp->base + HW_SSP_CMD0);
99 writel(0x0, ssp->base + HW_SSP_CMD1);
104 static int mxs_spi_setup(struct spi_device *dev)
106 if (!dev->bits_per_word)
107 dev->bits_per_word = 8;
112 static uint32_t mxs_spi_cs_to_reg(unsigned cs)
117 * i.MX28 Datasheet: 17.10.1: HW_SSP_CTRL0
119 * The bits BM_SSP_CTRL0_WAIT_FOR_CMD and BM_SSP_CTRL0_WAIT_FOR_IRQ
120 * in HW_SSP_CTRL0 register do have multiple usage, please refer to
121 * the datasheet for further details. In SPI mode, they are used to
122 * toggle the chip-select lines (nCS pins).
125 select |= BM_SSP_CTRL0_WAIT_FOR_CMD;
127 select |= BM_SSP_CTRL0_WAIT_FOR_IRQ;
132 static int mxs_ssp_wait(struct mxs_spi *spi, int offset, int mask, bool set)
134 const unsigned long timeout = jiffies + msecs_to_jiffies(SSP_TIMEOUT);
135 struct mxs_ssp *ssp = &spi->ssp;
139 reg = readl_relaxed(ssp->base + offset);
148 } while (time_before(jiffies, timeout));
153 static void mxs_ssp_dma_irq_callback(void *param)
155 struct mxs_spi *spi = param;
159 static irqreturn_t mxs_ssp_irq_handler(int irq, void *dev_id)
161 struct mxs_ssp *ssp = dev_id;
162 dev_err(ssp->dev, "%s[%i] CTRL1=%08x STATUS=%08x\n",
164 readl(ssp->base + HW_SSP_CTRL1(ssp)),
165 readl(ssp->base + HW_SSP_STATUS(ssp)));
169 static int mxs_spi_txrx_dma(struct mxs_spi *spi,
170 unsigned char *buf, int len,
173 struct mxs_ssp *ssp = &spi->ssp;
174 struct dma_async_tx_descriptor *desc = NULL;
175 const bool vmalloced_buf = is_vmalloc_addr(buf);
176 const int desc_len = vmalloced_buf ? PAGE_SIZE : SG_MAXLEN;
177 const int sgs = DIV_ROUND_UP(len, desc_len);
181 struct page *vm_page;
185 struct scatterlist sg;
191 dma_xfer = kzalloc(sizeof(*dma_xfer) * sgs, GFP_KERNEL);
195 INIT_COMPLETION(spi->c);
197 /* Chip select was already programmed into CTRL0 */
198 ctrl0 = readl(ssp->base + HW_SSP_CTRL0);
199 ctrl0 &= ~(BM_SSP_CTRL0_XFER_COUNT | BM_SSP_CTRL0_IGNORE_CRC |
201 ctrl0 |= BM_SSP_CTRL0_DATA_XFER;
203 if (!(flags & TXRX_WRITE))
204 ctrl0 |= BM_SSP_CTRL0_READ;
206 /* Queue the DMA data transfer. */
207 for (sg_count = 0; sg_count < sgs; sg_count++) {
208 /* Prepare the transfer descriptor. */
209 min = min(len, desc_len);
212 * De-assert CS on last segment if flag is set (i.e., no more
213 * transfers will follow)
215 if ((sg_count + 1 == sgs) && (flags & TXRX_DEASSERT_CS))
216 ctrl0 |= BM_SSP_CTRL0_IGNORE_CRC;
218 if (ssp->devid == IMX23_SSP) {
219 ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT;
223 dma_xfer[sg_count].pio[0] = ctrl0;
224 dma_xfer[sg_count].pio[3] = min;
227 vm_page = vmalloc_to_page(buf);
232 sg_buf = page_address(vm_page) +
233 ((size_t)buf & ~PAGE_MASK);
238 sg_init_one(&dma_xfer[sg_count].sg, sg_buf, min);
239 ret = dma_map_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
240 (flags & TXRX_WRITE) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
245 /* Queue the PIO register write transfer. */
246 desc = dmaengine_prep_slave_sg(ssp->dmach,
247 (struct scatterlist *)dma_xfer[sg_count].pio,
248 (ssp->devid == IMX23_SSP) ? 1 : 4,
250 sg_count ? DMA_PREP_INTERRUPT : 0);
253 "Failed to get PIO reg. write descriptor.\n");
258 desc = dmaengine_prep_slave_sg(ssp->dmach,
259 &dma_xfer[sg_count].sg, 1,
260 (flags & TXRX_WRITE) ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM,
261 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
265 "Failed to get DMA data write descriptor.\n");
272 * The last descriptor must have this callback,
273 * to finish the DMA transaction.
275 desc->callback = mxs_ssp_dma_irq_callback;
276 desc->callback_param = spi;
278 /* Start the transfer. */
279 dmaengine_submit(desc);
280 dma_async_issue_pending(ssp->dmach);
282 ret = wait_for_completion_timeout(&spi->c,
283 msecs_to_jiffies(SSP_TIMEOUT));
285 dev_err(ssp->dev, "DMA transfer timeout\n");
287 dmaengine_terminate_all(ssp->dmach);
294 while (--sg_count >= 0) {
296 dma_unmap_sg(ssp->dev, &dma_xfer[sg_count].sg, 1,
297 (flags & TXRX_WRITE) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
305 static int mxs_spi_txrx_pio(struct mxs_spi *spi,
306 unsigned char *buf, int len,
309 struct mxs_ssp *ssp = &spi->ssp;
311 writel(BM_SSP_CTRL0_IGNORE_CRC,
312 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
315 if (len == 0 && (flags & TXRX_DEASSERT_CS))
316 writel(BM_SSP_CTRL0_IGNORE_CRC,
317 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
319 if (ssp->devid == IMX23_SSP) {
320 writel(BM_SSP_CTRL0_XFER_COUNT,
321 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
323 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
325 writel(1, ssp->base + HW_SSP_XFER_SIZE);
328 if (flags & TXRX_WRITE)
329 writel(BM_SSP_CTRL0_READ,
330 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
332 writel(BM_SSP_CTRL0_READ,
333 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
335 writel(BM_SSP_CTRL0_RUN,
336 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
338 if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 1))
341 if (flags & TXRX_WRITE)
342 writel(*buf, ssp->base + HW_SSP_DATA(ssp));
344 writel(BM_SSP_CTRL0_DATA_XFER,
345 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
347 if (!(flags & TXRX_WRITE)) {
348 if (mxs_ssp_wait(spi, HW_SSP_STATUS(ssp),
349 BM_SSP_STATUS_FIFO_EMPTY, 0))
352 *buf = (readl(ssp->base + HW_SSP_DATA(ssp)) & 0xff);
355 if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 0))
367 static int mxs_spi_transfer_one(struct spi_master *master,
368 struct spi_message *m)
370 struct mxs_spi *spi = spi_master_get_devdata(master);
371 struct mxs_ssp *ssp = &spi->ssp;
372 struct spi_transfer *t, *tmp_t;
376 /* Program CS register bits here, it will be used for all transfers. */
377 writel(BM_SSP_CTRL0_WAIT_FOR_CMD | BM_SSP_CTRL0_WAIT_FOR_IRQ,
378 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR);
379 writel(mxs_spi_cs_to_reg(m->spi->chip_select),
380 ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET);
382 list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) {
384 status = mxs_spi_setup_transfer(m->spi, t);
388 /* De-assert on last transfer, inverted by cs_change flag */
389 flag = (&t->transfer_list == m->transfers.prev) ^ t->cs_change ?
390 TXRX_DEASSERT_CS : 0;
393 * Small blocks can be transfered via PIO.
394 * Measured by empiric means:
396 * dd if=/dev/mtdblock0 of=/dev/null bs=1024k count=1
398 * DMA only: 2.164808 seconds, 473.0KB/s
399 * Combined: 1.676276 seconds, 610.9KB/s
402 writel(BM_SSP_CTRL1_DMA_ENABLE,
403 ssp->base + HW_SSP_CTRL1(ssp) +
404 STMP_OFFSET_REG_CLR);
407 status = mxs_spi_txrx_pio(spi,
409 t->len, flag | TXRX_WRITE);
411 status = mxs_spi_txrx_pio(spi,
415 writel(BM_SSP_CTRL1_DMA_ENABLE,
416 ssp->base + HW_SSP_CTRL1(ssp) +
417 STMP_OFFSET_REG_SET);
420 status = mxs_spi_txrx_dma(spi,
421 (void *)t->tx_buf, t->len,
424 status = mxs_spi_txrx_dma(spi,
430 stmp_reset_block(ssp->base);
434 m->actual_length += t->len;
438 spi_finalize_current_message(master);
443 static const struct of_device_id mxs_spi_dt_ids[] = {
444 { .compatible = "fsl,imx23-spi", .data = (void *) IMX23_SSP, },
445 { .compatible = "fsl,imx28-spi", .data = (void *) IMX28_SSP, },
448 MODULE_DEVICE_TABLE(of, mxs_spi_dt_ids);
450 static int mxs_spi_probe(struct platform_device *pdev)
452 const struct of_device_id *of_id =
453 of_match_device(mxs_spi_dt_ids, &pdev->dev);
454 struct device_node *np = pdev->dev.of_node;
455 struct spi_master *master;
458 struct resource *iores;
462 int ret = 0, irq_err;
465 * Default clock speed for the SPI core. 160MHz seems to
466 * work reasonably well with most SPI flashes, so use this
467 * as a default. Override with "clock-frequency" DT prop.
469 const int clk_freq_default = 160000000;
471 iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
472 irq_err = platform_get_irq(pdev, 0);
476 base = devm_ioremap_resource(&pdev->dev, iores);
478 return PTR_ERR(base);
480 clk = devm_clk_get(&pdev->dev, NULL);
484 devid = (enum mxs_ssp_id) of_id->data;
485 ret = of_property_read_u32(np, "clock-frequency",
488 clk_freq = clk_freq_default;
490 master = spi_alloc_master(&pdev->dev, sizeof(*spi));
494 master->transfer_one_message = mxs_spi_transfer_one;
495 master->setup = mxs_spi_setup;
496 master->bits_per_word_mask = SPI_BPW_MASK(8);
497 master->mode_bits = SPI_CPOL | SPI_CPHA;
498 master->num_chipselect = 3;
499 master->dev.of_node = np;
500 master->flags = SPI_MASTER_HALF_DUPLEX;
502 spi = spi_master_get_devdata(master);
504 ssp->dev = &pdev->dev;
509 init_completion(&spi->c);
511 ret = devm_request_irq(&pdev->dev, irq_err, mxs_ssp_irq_handler, 0,
514 goto out_master_free;
516 ssp->dmach = dma_request_slave_channel(&pdev->dev, "rx-tx");
518 dev_err(ssp->dev, "Failed to request DMA\n");
520 goto out_master_free;
523 ret = clk_prepare_enable(ssp->clk);
525 goto out_dma_release;
527 clk_set_rate(ssp->clk, clk_freq);
529 ret = stmp_reset_block(ssp->base);
531 goto out_disable_clk;
533 platform_set_drvdata(pdev, master);
535 ret = spi_register_master(master);
537 dev_err(&pdev->dev, "Cannot register SPI master, %d\n", ret);
538 goto out_disable_clk;
544 clk_disable_unprepare(ssp->clk);
546 dma_release_channel(ssp->dmach);
548 spi_master_put(master);
552 static int mxs_spi_remove(struct platform_device *pdev)
554 struct spi_master *master;
558 master = spi_master_get(platform_get_drvdata(pdev));
559 spi = spi_master_get_devdata(master);
562 spi_unregister_master(master);
563 clk_disable_unprepare(ssp->clk);
564 dma_release_channel(ssp->dmach);
565 spi_master_put(master);
570 static struct platform_driver mxs_spi_driver = {
571 .probe = mxs_spi_probe,
572 .remove = mxs_spi_remove,
575 .owner = THIS_MODULE,
576 .of_match_table = mxs_spi_dt_ids,
580 module_platform_driver(mxs_spi_driver);
582 MODULE_AUTHOR("Marek Vasut <marex@denx.de>");
583 MODULE_DESCRIPTION("MXS SPI master driver");
584 MODULE_LICENSE("GPL");
585 MODULE_ALIAS("platform:mxs-spi");