2 * Generic driver for memory-mapped GPIO controllers.
4 * Copyright 2008 MontaVista Software, Inc.
5 * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License as published by the
9 * Free Software Foundation; either version 2 of the License, or (at your
10 * option) any later version.
12 * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......
14 * ..The simplest form of a GPIO controller that the driver supports is``
15 * `.just a single "data" register, where GPIO state can be read and/or `
16 * `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
19 _/~~|___/~| . ```~~~~~~ ___/___\___ ,~.`.`.`.`````.~~...,,,,...
20 __________|~$@~~~ %~ /o*o*o*o*o*o\ .. Implementing such a GPIO .
21 o ` ~~~~\___/~~~~ ` controller in FPGA is ,.`
22 `....trivial..'~`.```.```
24 * .```````~~~~`..`.``.``.
25 * . The driver supports `... ,..```.`~~~```````````````....````.``,,
26 * . big-endian notation, just`. .. A bit more sophisticated controllers ,
27 * . register the device with -be`. .with a pair of set/clear-bit registers ,
28 * `.. suffix. ```~~`````....`.` . affecting the data register and the .`
29 * ``.`.``...``` ```.. output pins are also supported.`
30 * ^^ `````.`````````.,``~``~``~~``````
32 * ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..
33 * .. The expectation is that in at least some cases . ,-~~~-,
34 * .this will be used with roll-your-own ASIC/FPGA .` \ /
35 * .logic in Verilog or VHDL. ~~~`````````..`````~~` \ /
36 * ..````````......``````````` \o_
40 * ...`````~~`.....``.`..........``````.`.``.```........``.
41 * ` 8, 16, 32 and 64 bits registers are supported, and``.
42 * . the number of GPIOs is determined by the width of ~
43 * .. the registers. ,............```.`.`..`.`.~~~.`.`.`~
47 #include <linux/init.h>
48 #include <linux/err.h>
49 #include <linux/bug.h>
50 #include <linux/kernel.h>
51 #include <linux/module.h>
52 #include <linux/spinlock.h>
53 #include <linux/compiler.h>
54 #include <linux/types.h>
55 #include <linux/errno.h>
56 #include <linux/log2.h>
57 #include <linux/ioport.h>
59 #include <linux/gpio.h>
60 #include <linux/slab.h>
61 #include <linux/platform_device.h>
62 #include <linux/mod_devicetable.h>
63 #include <linux/basic_mmio_gpio.h>
65 static void bgpio_write8(void __iomem *reg, unsigned long data)
70 static unsigned long bgpio_read8(void __iomem *reg)
75 static void bgpio_write16(void __iomem *reg, unsigned long data)
80 static unsigned long bgpio_read16(void __iomem *reg)
85 static void bgpio_write32(void __iomem *reg, unsigned long data)
90 static unsigned long bgpio_read32(void __iomem *reg)
95 #if BITS_PER_LONG >= 64
96 static void bgpio_write64(void __iomem *reg, unsigned long data)
101 static unsigned long bgpio_read64(void __iomem *reg)
105 #endif /* BITS_PER_LONG >= 64 */
107 static void bgpio_write16be(void __iomem *reg, unsigned long data)
109 iowrite16be(data, reg);
112 static unsigned long bgpio_read16be(void __iomem *reg)
114 return ioread16be(reg);
117 static void bgpio_write32be(void __iomem *reg, unsigned long data)
119 iowrite32be(data, reg);
122 static unsigned long bgpio_read32be(void __iomem *reg)
124 return ioread32be(reg);
127 static unsigned long bgpio_pin2mask(struct bgpio_chip *bgc, unsigned int pin)
132 static unsigned long bgpio_pin2mask_be(struct bgpio_chip *bgc,
135 return 1 << (bgc->bits - 1 - pin);
138 static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)
140 struct bgpio_chip *bgc = to_bgpio_chip(gc);
141 unsigned long pinmask = bgc->pin2mask(bgc, gpio);
143 if (bgc->dir & pinmask)
144 return bgc->read_reg(bgc->reg_set) & pinmask;
146 return bgc->read_reg(bgc->reg_dat) & pinmask;
149 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
151 struct bgpio_chip *bgc = to_bgpio_chip(gc);
153 return !!(bgc->read_reg(bgc->reg_dat) & bgc->pin2mask(bgc, gpio));
156 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
158 struct bgpio_chip *bgc = to_bgpio_chip(gc);
159 unsigned long mask = bgc->pin2mask(bgc, gpio);
162 spin_lock_irqsave(&bgc->lock, flags);
169 bgc->write_reg(bgc->reg_dat, bgc->data);
171 spin_unlock_irqrestore(&bgc->lock, flags);
174 static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
177 struct bgpio_chip *bgc = to_bgpio_chip(gc);
178 unsigned long mask = bgc->pin2mask(bgc, gpio);
181 bgc->write_reg(bgc->reg_set, mask);
183 bgc->write_reg(bgc->reg_clr, mask);
186 static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
188 struct bgpio_chip *bgc = to_bgpio_chip(gc);
189 unsigned long mask = bgc->pin2mask(bgc, gpio);
192 spin_lock_irqsave(&bgc->lock, flags);
199 bgc->write_reg(bgc->reg_set, bgc->data);
201 spin_unlock_irqrestore(&bgc->lock, flags);
204 static void bgpio_multiple_get_masks(struct bgpio_chip *bgc,
205 unsigned long *mask, unsigned long *bits,
206 unsigned long *set_mask,
207 unsigned long *clear_mask)
214 for (i = 0; i < bgc->bits; i++) {
217 if (__test_and_clear_bit(i, mask)) {
218 if (test_bit(i, bits))
219 *set_mask |= bgc->pin2mask(bgc, i);
221 *clear_mask |= bgc->pin2mask(bgc, i);
226 static void bgpio_set_multiple_single_reg(struct bgpio_chip *bgc,
232 unsigned long set_mask, clear_mask;
234 spin_lock_irqsave(&bgc->lock, flags);
236 bgpio_multiple_get_masks(bgc, mask, bits, &set_mask, &clear_mask);
238 bgc->data |= set_mask;
239 bgc->data &= ~clear_mask;
241 bgc->write_reg(reg, bgc->data);
243 spin_unlock_irqrestore(&bgc->lock, flags);
246 static void bgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
249 struct bgpio_chip *bgc = to_bgpio_chip(gc);
251 bgpio_set_multiple_single_reg(bgc, mask, bits, bgc->reg_dat);
254 static void bgpio_set_multiple_set(struct gpio_chip *gc, unsigned long *mask,
257 struct bgpio_chip *bgc = to_bgpio_chip(gc);
259 bgpio_set_multiple_single_reg(bgc, mask, bits, bgc->reg_set);
262 static void bgpio_set_multiple_with_clear(struct gpio_chip *gc,
266 struct bgpio_chip *bgc = to_bgpio_chip(gc);
267 unsigned long set_mask, clear_mask;
269 bgpio_multiple_get_masks(bgc, mask, bits, &set_mask, &clear_mask);
272 bgc->write_reg(bgc->reg_set, set_mask);
274 bgc->write_reg(bgc->reg_clr, clear_mask);
277 static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
282 static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
285 gc->set(gc, gpio, val);
290 static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
292 struct bgpio_chip *bgc = to_bgpio_chip(gc);
295 spin_lock_irqsave(&bgc->lock, flags);
297 bgc->dir &= ~bgc->pin2mask(bgc, gpio);
298 bgc->write_reg(bgc->reg_dir, bgc->dir);
300 spin_unlock_irqrestore(&bgc->lock, flags);
305 static int bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
307 struct bgpio_chip *bgc = to_bgpio_chip(gc);
310 gc->set(gc, gpio, val);
312 spin_lock_irqsave(&bgc->lock, flags);
314 bgc->dir |= bgc->pin2mask(bgc, gpio);
315 bgc->write_reg(bgc->reg_dir, bgc->dir);
317 spin_unlock_irqrestore(&bgc->lock, flags);
322 static int bgpio_dir_in_inv(struct gpio_chip *gc, unsigned int gpio)
324 struct bgpio_chip *bgc = to_bgpio_chip(gc);
327 spin_lock_irqsave(&bgc->lock, flags);
329 bgc->dir |= bgc->pin2mask(bgc, gpio);
330 bgc->write_reg(bgc->reg_dir, bgc->dir);
332 spin_unlock_irqrestore(&bgc->lock, flags);
337 static int bgpio_dir_out_inv(struct gpio_chip *gc, unsigned int gpio, int val)
339 struct bgpio_chip *bgc = to_bgpio_chip(gc);
342 gc->set(gc, gpio, val);
344 spin_lock_irqsave(&bgc->lock, flags);
346 bgc->dir &= ~bgc->pin2mask(bgc, gpio);
347 bgc->write_reg(bgc->reg_dir, bgc->dir);
349 spin_unlock_irqrestore(&bgc->lock, flags);
354 static int bgpio_setup_accessors(struct device *dev,
355 struct bgpio_chip *bgc,
362 bgc->read_reg = bgpio_read8;
363 bgc->write_reg = bgpio_write8;
367 bgc->read_reg = bgpio_read16be;
368 bgc->write_reg = bgpio_write16be;
370 bgc->read_reg = bgpio_read16;
371 bgc->write_reg = bgpio_write16;
376 bgc->read_reg = bgpio_read32be;
377 bgc->write_reg = bgpio_write32be;
379 bgc->read_reg = bgpio_read32;
380 bgc->write_reg = bgpio_write32;
383 #if BITS_PER_LONG >= 64
387 "64 bit big endian byte order unsupported\n");
390 bgc->read_reg = bgpio_read64;
391 bgc->write_reg = bgpio_write64;
394 #endif /* BITS_PER_LONG >= 64 */
396 dev_err(dev, "unsupported data width %u bits\n", bgc->bits);
400 bgc->pin2mask = bit_be ? bgpio_pin2mask_be : bgpio_pin2mask;
406 * Create the device and allocate the resources. For setting GPIO's there are
407 * three supported configurations:
409 * - single input/output register resource (named "dat").
410 * - set/clear pair (named "set" and "clr").
411 * - single output register resource and single input resource ("set" and
414 * For the single output register, this drives a 1 by setting a bit and a zero
415 * by clearing a bit. For the set clr pair, this drives a 1 by setting a bit
416 * in the set register and clears it by setting a bit in the clear register.
417 * The configuration is detected by which resources are present.
419 * For setting the GPIO direction, there are three supported configurations:
421 * - simple bidirection GPIO that requires no configuration.
422 * - an output direction register (named "dirout") where a 1 bit
423 * indicates the GPIO is an output.
424 * - an input direction register (named "dirin") where a 1 bit indicates
425 * the GPIO is an input.
427 static int bgpio_setup_io(struct bgpio_chip *bgc,
441 bgc->gc.set = bgpio_set_with_clear;
442 bgc->gc.set_multiple = bgpio_set_multiple_with_clear;
443 } else if (set && !clr) {
445 bgc->gc.set = bgpio_set_set;
446 bgc->gc.set_multiple = bgpio_set_multiple_set;
448 bgc->gc.set = bgpio_set;
449 bgc->gc.set_multiple = bgpio_set_multiple;
452 if (!(flags & BGPIOF_UNREADABLE_REG_SET) &&
453 (flags & BGPIOF_READ_OUTPUT_REG_SET))
454 bgc->gc.get = bgpio_get_set;
456 bgc->gc.get = bgpio_get;
461 static int bgpio_setup_direction(struct bgpio_chip *bgc,
462 void __iomem *dirout,
465 if (dirout && dirin) {
468 bgc->reg_dir = dirout;
469 bgc->gc.direction_output = bgpio_dir_out;
470 bgc->gc.direction_input = bgpio_dir_in;
472 bgc->reg_dir = dirin;
473 bgc->gc.direction_output = bgpio_dir_out_inv;
474 bgc->gc.direction_input = bgpio_dir_in_inv;
476 bgc->gc.direction_output = bgpio_simple_dir_out;
477 bgc->gc.direction_input = bgpio_simple_dir_in;
483 static int bgpio_request(struct gpio_chip *chip, unsigned gpio_pin)
485 if (gpio_pin < chip->ngpio)
491 int bgpio_remove(struct bgpio_chip *bgc)
493 gpiochip_remove(&bgc->gc);
496 EXPORT_SYMBOL_GPL(bgpio_remove);
498 int bgpio_init(struct bgpio_chip *bgc, struct device *dev,
499 unsigned long sz, void __iomem *dat, void __iomem *set,
500 void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
505 if (!is_power_of_2(sz))
509 if (bgc->bits > BITS_PER_LONG)
512 spin_lock_init(&bgc->lock);
514 bgc->gc.label = dev_name(dev);
516 bgc->gc.ngpio = bgc->bits;
517 bgc->gc.request = bgpio_request;
519 ret = bgpio_setup_io(bgc, dat, set, clr, flags);
523 ret = bgpio_setup_accessors(dev, bgc, flags & BGPIOF_BIG_ENDIAN,
524 flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
528 ret = bgpio_setup_direction(bgc, dirout, dirin);
532 bgc->data = bgc->read_reg(bgc->reg_dat);
533 if (bgc->gc.set == bgpio_set_set &&
534 !(flags & BGPIOF_UNREADABLE_REG_SET))
535 bgc->data = bgc->read_reg(bgc->reg_set);
536 if (bgc->reg_dir && !(flags & BGPIOF_UNREADABLE_REG_DIR))
537 bgc->dir = bgc->read_reg(bgc->reg_dir);
541 EXPORT_SYMBOL_GPL(bgpio_init);
543 #ifdef CONFIG_GPIO_GENERIC_PLATFORM
545 static void __iomem *bgpio_map(struct platform_device *pdev,
547 resource_size_t sane_sz,
550 struct device *dev = &pdev->dev;
552 resource_size_t start;
558 r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
562 sz = resource_size(r);
569 if (!devm_request_mem_region(dev, start, sz, r->name)) {
574 ret = devm_ioremap(dev, start, sz);
583 static int bgpio_pdev_probe(struct platform_device *pdev)
585 struct device *dev = &pdev->dev;
590 void __iomem *dirout;
593 unsigned long flags = pdev->id_entry->driver_data;
595 struct bgpio_chip *bgc;
596 struct bgpio_pdata *pdata = dev_get_platdata(dev);
598 r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
602 sz = resource_size(r);
604 dat = bgpio_map(pdev, "dat", sz, &err);
606 return err ? err : -EINVAL;
608 set = bgpio_map(pdev, "set", sz, &err);
612 clr = bgpio_map(pdev, "clr", sz, &err);
616 dirout = bgpio_map(pdev, "dirout", sz, &err);
620 dirin = bgpio_map(pdev, "dirin", sz, &err);
624 bgc = devm_kzalloc(&pdev->dev, sizeof(*bgc), GFP_KERNEL);
628 err = bgpio_init(bgc, dev, sz, dat, set, clr, dirout, dirin, flags);
634 bgc->gc.label = pdata->label;
635 bgc->gc.base = pdata->base;
636 if (pdata->ngpio > 0)
637 bgc->gc.ngpio = pdata->ngpio;
640 platform_set_drvdata(pdev, bgc);
642 return gpiochip_add(&bgc->gc);
645 static int bgpio_pdev_remove(struct platform_device *pdev)
647 struct bgpio_chip *bgc = platform_get_drvdata(pdev);
649 return bgpio_remove(bgc);
652 static const struct platform_device_id bgpio_id_table[] = {
654 .name = "basic-mmio-gpio",
657 .name = "basic-mmio-gpio-be",
658 .driver_data = BGPIOF_BIG_ENDIAN,
662 MODULE_DEVICE_TABLE(platform, bgpio_id_table);
664 static struct platform_driver bgpio_driver = {
666 .name = "basic-mmio-gpio",
668 .id_table = bgpio_id_table,
669 .probe = bgpio_pdev_probe,
670 .remove = bgpio_pdev_remove,
673 module_platform_driver(bgpio_driver);
675 #endif /* CONFIG_GPIO_GENERIC_PLATFORM */
677 MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
678 MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
679 MODULE_LICENSE("GPL");