xref: /linux/drivers/gpio/gpio-mmio.c (revision bfb921b2a9d5d1123d1d10b196a39db629ddef87)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Generic driver for memory-mapped GPIO controllers.
4  *
5  * Copyright 2008 MontaVista Software, Inc.
6  * Copyright 2008,2010 Anton Vorontsov <cbouatmailru@gmail.com>
7  *
8  * ....``.```~~~~````.`.`.`.`.```````'',,,.........`````......`.......
9  * ...``                                                         ```````..
10  * ..The simplest form of a GPIO controller that the driver supports is``
11  *  `.just a single "data" register, where GPIO state can be read and/or `
12  *    `,..written. ,,..``~~~~ .....``.`.`.~~.```.`.........``````.```````
13  *        `````````
14                                     ___
15 _/~~|___/~|   . ```~~~~~~       ___/___\___     ,~.`.`.`.`````.~~...,,,,...
16 __________|~$@~~~        %~    /o*o*o*o*o*o\   .. Implementing such a GPIO .
17 o        `                     ~~~~\___/~~~~    ` controller in FPGA is ,.`
18                                                  `....trivial..'~`.```.```
19  *                                                    ```````
20  *  .```````~~~~`..`.``.``.
21  * .  The driver supports  `...       ,..```.`~~~```````````````....````.``,,
22  * .   big-endian notation, just`.  .. A bit more sophisticated controllers ,
23  *  . register the device with -be`. .with a pair of set/clear-bit registers ,
24  *   `.. suffix.  ```~~`````....`.`   . affecting the data register and the .`
25  *     ``.`.``...```                  ```.. output pins are also supported.`
26  *                        ^^             `````.`````````.,``~``~``~~``````
27  *                                                   .                  ^^
28  *   ,..`.`.`...````````````......`.`.`.`.`.`..`.`.`..
29  * .. The expectation is that in at least some cases .    ,-~~~-,
30  *  .this will be used with roll-your-own ASIC/FPGA .`     \   /
31  *  .logic in Verilog or VHDL. ~~~`````````..`````~~`       \ /
32  *  ..````````......```````````                             \o_
33  *                                                           |
34  *                              ^^                          / \
35  *
36  *           ...`````~~`.....``.`..........``````.`.``.```........``.
37  *            `  8, 16, 32 and 64 bits registers are supported, and``.
38  *            . the number of GPIOs is determined by the width of   ~
39  *             .. the registers. ,............```.`.`..`.`.~~~.`.`.`~
40  *               `.......````.```
41  */
42 
43 #include <linux/bitops.h>
44 #include <linux/compiler.h>
45 #include <linux/err.h>
46 #include <linux/init.h>
47 #include <linux/io.h>
48 #include <linux/ioport.h>
49 #include <linux/log2.h>
50 #include <linux/mod_devicetable.h>
51 #include <linux/module.h>
52 #include <linux/platform_device.h>
53 #include <linux/property.h>
54 #include <linux/slab.h>
55 #include <linux/spinlock.h>
56 #include <linux/types.h>
57 
58 #include <linux/gpio/driver.h>
59 
60 #include "gpiolib.h"
61 
62 static void bgpio_write8(void __iomem *reg, unsigned long data)
63 {
64 	writeb(data, reg);
65 }
66 
67 static unsigned long bgpio_read8(void __iomem *reg)
68 {
69 	return readb(reg);
70 }
71 
72 static void bgpio_write16(void __iomem *reg, unsigned long data)
73 {
74 	writew(data, reg);
75 }
76 
77 static unsigned long bgpio_read16(void __iomem *reg)
78 {
79 	return readw(reg);
80 }
81 
82 static void bgpio_write32(void __iomem *reg, unsigned long data)
83 {
84 	writel(data, reg);
85 }
86 
87 static unsigned long bgpio_read32(void __iomem *reg)
88 {
89 	return readl(reg);
90 }
91 
92 #if BITS_PER_LONG >= 64
93 static void bgpio_write64(void __iomem *reg, unsigned long data)
94 {
95 	writeq(data, reg);
96 }
97 
98 static unsigned long bgpio_read64(void __iomem *reg)
99 {
100 	return readq(reg);
101 }
102 #endif /* BITS_PER_LONG >= 64 */
103 
104 static void bgpio_write16be(void __iomem *reg, unsigned long data)
105 {
106 	iowrite16be(data, reg);
107 }
108 
109 static unsigned long bgpio_read16be(void __iomem *reg)
110 {
111 	return ioread16be(reg);
112 }
113 
114 static void bgpio_write32be(void __iomem *reg, unsigned long data)
115 {
116 	iowrite32be(data, reg);
117 }
118 
119 static unsigned long bgpio_read32be(void __iomem *reg)
120 {
121 	return ioread32be(reg);
122 }
123 
124 static unsigned long bgpio_line2mask(struct gpio_chip *gc, unsigned int line)
125 {
126 	if (gc->be_bits)
127 		return BIT(gc->bgpio_bits - 1 - line);
128 	return BIT(line);
129 }
130 
131 static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)
132 {
133 	unsigned long pinmask = bgpio_line2mask(gc, gpio);
134 	bool dir = !!(gc->bgpio_dir & pinmask);
135 
136 	if (dir)
137 		return !!(gc->read_reg(gc->reg_set) & pinmask);
138 	else
139 		return !!(gc->read_reg(gc->reg_dat) & pinmask);
140 }
141 
142 /*
143  * This assumes that the bits in the GPIO register are in native endianness.
144  * We only assign the function pointer if we have that.
145  */
146 static int bgpio_get_set_multiple(struct gpio_chip *gc, unsigned long *mask,
147 				  unsigned long *bits)
148 {
149 	unsigned long get_mask = 0;
150 	unsigned long set_mask = 0;
151 
152 	/* Make sure we first clear any bits that are zero when we read the register */
153 	*bits &= ~*mask;
154 
155 	set_mask = *mask & gc->bgpio_dir;
156 	get_mask = *mask & ~gc->bgpio_dir;
157 
158 	if (set_mask)
159 		*bits |= gc->read_reg(gc->reg_set) & set_mask;
160 	if (get_mask)
161 		*bits |= gc->read_reg(gc->reg_dat) & get_mask;
162 
163 	return 0;
164 }
165 
166 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
167 {
168 	return !!(gc->read_reg(gc->reg_dat) & bgpio_line2mask(gc, gpio));
169 }
170 
171 /*
172  * This only works if the bits in the GPIO register are in native endianness.
173  */
174 static int bgpio_get_multiple(struct gpio_chip *gc, unsigned long *mask,
175 			      unsigned long *bits)
176 {
177 	/* Make sure we first clear any bits that are zero when we read the register */
178 	*bits &= ~*mask;
179 	*bits |= gc->read_reg(gc->reg_dat) & *mask;
180 	return 0;
181 }
182 
183 /*
184  * With big endian mirrored bit order it becomes more tedious.
185  */
186 static int bgpio_get_multiple_be(struct gpio_chip *gc, unsigned long *mask,
187 				 unsigned long *bits)
188 {
189 	unsigned long readmask = 0;
190 	unsigned long val;
191 	int bit;
192 
193 	/* Make sure we first clear any bits that are zero when we read the register */
194 	*bits &= ~*mask;
195 
196 	/* Create a mirrored mask */
197 	for_each_set_bit(bit, mask, gc->ngpio)
198 		readmask |= bgpio_line2mask(gc, bit);
199 
200 	/* Read the register */
201 	val = gc->read_reg(gc->reg_dat) & readmask;
202 
203 	/*
204 	 * Mirror the result into the "bits" result, this will give line 0
205 	 * in bit 0 ... line 31 in bit 31 for a 32bit register.
206 	 */
207 	for_each_set_bit(bit, &val, gc->ngpio)
208 		*bits |= bgpio_line2mask(gc, bit);
209 
210 	return 0;
211 }
212 
213 static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)
214 {
215 }
216 
217 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
218 {
219 	unsigned long mask = bgpio_line2mask(gc, gpio);
220 	unsigned long flags;
221 
222 	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
223 
224 	if (val)
225 		gc->bgpio_data |= mask;
226 	else
227 		gc->bgpio_data &= ~mask;
228 
229 	gc->write_reg(gc->reg_dat, gc->bgpio_data);
230 
231 	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
232 }
233 
234 static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
235 				 int val)
236 {
237 	unsigned long mask = bgpio_line2mask(gc, gpio);
238 
239 	if (val)
240 		gc->write_reg(gc->reg_set, mask);
241 	else
242 		gc->write_reg(gc->reg_clr, mask);
243 }
244 
245 static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
246 {
247 	unsigned long mask = bgpio_line2mask(gc, gpio);
248 	unsigned long flags;
249 
250 	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
251 
252 	if (val)
253 		gc->bgpio_data |= mask;
254 	else
255 		gc->bgpio_data &= ~mask;
256 
257 	gc->write_reg(gc->reg_set, gc->bgpio_data);
258 
259 	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
260 }
261 
262 static void bgpio_multiple_get_masks(struct gpio_chip *gc,
263 				     unsigned long *mask, unsigned long *bits,
264 				     unsigned long *set_mask,
265 				     unsigned long *clear_mask)
266 {
267 	int i;
268 
269 	*set_mask = 0;
270 	*clear_mask = 0;
271 
272 	for_each_set_bit(i, mask, gc->bgpio_bits) {
273 		if (test_bit(i, bits))
274 			*set_mask |= bgpio_line2mask(gc, i);
275 		else
276 			*clear_mask |= bgpio_line2mask(gc, i);
277 	}
278 }
279 
280 static void bgpio_set_multiple_single_reg(struct gpio_chip *gc,
281 					  unsigned long *mask,
282 					  unsigned long *bits,
283 					  void __iomem *reg)
284 {
285 	unsigned long flags;
286 	unsigned long set_mask, clear_mask;
287 
288 	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
289 
290 	bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);
291 
292 	gc->bgpio_data |= set_mask;
293 	gc->bgpio_data &= ~clear_mask;
294 
295 	gc->write_reg(reg, gc->bgpio_data);
296 
297 	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
298 }
299 
300 static void bgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
301 			       unsigned long *bits)
302 {
303 	bgpio_set_multiple_single_reg(gc, mask, bits, gc->reg_dat);
304 }
305 
306 static void bgpio_set_multiple_set(struct gpio_chip *gc, unsigned long *mask,
307 				   unsigned long *bits)
308 {
309 	bgpio_set_multiple_single_reg(gc, mask, bits, gc->reg_set);
310 }
311 
312 static void bgpio_set_multiple_with_clear(struct gpio_chip *gc,
313 					  unsigned long *mask,
314 					  unsigned long *bits)
315 {
316 	unsigned long set_mask, clear_mask;
317 
318 	bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);
319 
320 	if (set_mask)
321 		gc->write_reg(gc->reg_set, set_mask);
322 	if (clear_mask)
323 		gc->write_reg(gc->reg_clr, clear_mask);
324 }
325 
326 static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
327 {
328 	return 0;
329 }
330 
331 static int bgpio_dir_out_err(struct gpio_chip *gc, unsigned int gpio,
332 				int val)
333 {
334 	return -EINVAL;
335 }
336 
337 static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
338 				int val)
339 {
340 	gc->set(gc, gpio, val);
341 
342 	return 0;
343 }
344 
345 static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
346 {
347 	unsigned long flags;
348 
349 	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
350 
351 	gc->bgpio_dir &= ~bgpio_line2mask(gc, gpio);
352 
353 	if (gc->reg_dir_in)
354 		gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
355 	if (gc->reg_dir_out)
356 		gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
357 
358 	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
359 
360 	return 0;
361 }
362 
363 static int bgpio_get_dir(struct gpio_chip *gc, unsigned int gpio)
364 {
365 	/* Return 0 if output, 1 if input */
366 	if (gc->bgpio_dir_unreadable) {
367 		if (gc->bgpio_dir & bgpio_line2mask(gc, gpio))
368 			return GPIO_LINE_DIRECTION_OUT;
369 		return GPIO_LINE_DIRECTION_IN;
370 	}
371 
372 	if (gc->reg_dir_out) {
373 		if (gc->read_reg(gc->reg_dir_out) & bgpio_line2mask(gc, gpio))
374 			return GPIO_LINE_DIRECTION_OUT;
375 		return GPIO_LINE_DIRECTION_IN;
376 	}
377 
378 	if (gc->reg_dir_in)
379 		if (!(gc->read_reg(gc->reg_dir_in) & bgpio_line2mask(gc, gpio)))
380 			return GPIO_LINE_DIRECTION_OUT;
381 
382 	return GPIO_LINE_DIRECTION_IN;
383 }
384 
385 static void bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
386 {
387 	unsigned long flags;
388 
389 	raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
390 
391 	gc->bgpio_dir |= bgpio_line2mask(gc, gpio);
392 
393 	if (gc->reg_dir_in)
394 		gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
395 	if (gc->reg_dir_out)
396 		gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
397 
398 	raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
399 }
400 
401 static int bgpio_dir_out_dir_first(struct gpio_chip *gc, unsigned int gpio,
402 				   int val)
403 {
404 	bgpio_dir_out(gc, gpio, val);
405 	gc->set(gc, gpio, val);
406 	return 0;
407 }
408 
409 static int bgpio_dir_out_val_first(struct gpio_chip *gc, unsigned int gpio,
410 				   int val)
411 {
412 	gc->set(gc, gpio, val);
413 	bgpio_dir_out(gc, gpio, val);
414 	return 0;
415 }
416 
417 static int bgpio_setup_accessors(struct device *dev,
418 				 struct gpio_chip *gc,
419 				 bool byte_be)
420 {
421 
422 	switch (gc->bgpio_bits) {
423 	case 8:
424 		gc->read_reg	= bgpio_read8;
425 		gc->write_reg	= bgpio_write8;
426 		break;
427 	case 16:
428 		if (byte_be) {
429 			gc->read_reg	= bgpio_read16be;
430 			gc->write_reg	= bgpio_write16be;
431 		} else {
432 			gc->read_reg	= bgpio_read16;
433 			gc->write_reg	= bgpio_write16;
434 		}
435 		break;
436 	case 32:
437 		if (byte_be) {
438 			gc->read_reg	= bgpio_read32be;
439 			gc->write_reg	= bgpio_write32be;
440 		} else {
441 			gc->read_reg	= bgpio_read32;
442 			gc->write_reg	= bgpio_write32;
443 		}
444 		break;
445 #if BITS_PER_LONG >= 64
446 	case 64:
447 		if (byte_be) {
448 			dev_err(dev,
449 				"64 bit big endian byte order unsupported\n");
450 			return -EINVAL;
451 		} else {
452 			gc->read_reg	= bgpio_read64;
453 			gc->write_reg	= bgpio_write64;
454 		}
455 		break;
456 #endif /* BITS_PER_LONG >= 64 */
457 	default:
458 		dev_err(dev, "unsupported data width %u bits\n", gc->bgpio_bits);
459 		return -EINVAL;
460 	}
461 
462 	return 0;
463 }
464 
465 /*
466  * Create the device and allocate the resources.  For setting GPIO's there are
467  * three supported configurations:
468  *
469  *	- single input/output register resource (named "dat").
470  *	- set/clear pair (named "set" and "clr").
471  *	- single output register resource and single input resource ("set" and
472  *	dat").
473  *
474  * For the single output register, this drives a 1 by setting a bit and a zero
475  * by clearing a bit.  For the set clr pair, this drives a 1 by setting a bit
476  * in the set register and clears it by setting a bit in the clear register.
477  * The configuration is detected by which resources are present.
478  *
479  * For setting the GPIO direction, there are three supported configurations:
480  *
481  *	- simple bidirection GPIO that requires no configuration.
482  *	- an output direction register (named "dirout") where a 1 bit
483  *	indicates the GPIO is an output.
484  *	- an input direction register (named "dirin") where a 1 bit indicates
485  *	the GPIO is an input.
486  */
487 static int bgpio_setup_io(struct gpio_chip *gc,
488 			  void __iomem *dat,
489 			  void __iomem *set,
490 			  void __iomem *clr,
491 			  unsigned long flags)
492 {
493 
494 	gc->reg_dat = dat;
495 	if (!gc->reg_dat)
496 		return -EINVAL;
497 
498 	if (set && clr) {
499 		gc->reg_set = set;
500 		gc->reg_clr = clr;
501 		gc->set = bgpio_set_with_clear;
502 		gc->set_multiple = bgpio_set_multiple_with_clear;
503 	} else if (set && !clr) {
504 		gc->reg_set = set;
505 		gc->set = bgpio_set_set;
506 		gc->set_multiple = bgpio_set_multiple_set;
507 	} else if (flags & BGPIOF_NO_OUTPUT) {
508 		gc->set = bgpio_set_none;
509 		gc->set_multiple = NULL;
510 	} else {
511 		gc->set = bgpio_set;
512 		gc->set_multiple = bgpio_set_multiple;
513 	}
514 
515 	if (!(flags & BGPIOF_UNREADABLE_REG_SET) &&
516 	    (flags & BGPIOF_READ_OUTPUT_REG_SET)) {
517 		gc->get = bgpio_get_set;
518 		if (!gc->be_bits)
519 			gc->get_multiple = bgpio_get_set_multiple;
520 		/*
521 		 * We deliberately avoid assigning the ->get_multiple() call
522 		 * for big endian mirrored registers which are ALSO reflecting
523 		 * their value in the set register when used as output. It is
524 		 * simply too much complexity, let the GPIO core fall back to
525 		 * reading each line individually in that fringe case.
526 		 */
527 	} else {
528 		gc->get = bgpio_get;
529 		if (gc->be_bits)
530 			gc->get_multiple = bgpio_get_multiple_be;
531 		else
532 			gc->get_multiple = bgpio_get_multiple;
533 	}
534 
535 	return 0;
536 }
537 
538 static int bgpio_setup_direction(struct gpio_chip *gc,
539 				 void __iomem *dirout,
540 				 void __iomem *dirin,
541 				 unsigned long flags)
542 {
543 	if (dirout || dirin) {
544 		gc->reg_dir_out = dirout;
545 		gc->reg_dir_in = dirin;
546 		if (flags & BGPIOF_NO_SET_ON_INPUT)
547 			gc->direction_output = bgpio_dir_out_dir_first;
548 		else
549 			gc->direction_output = bgpio_dir_out_val_first;
550 		gc->direction_input = bgpio_dir_in;
551 		gc->get_direction = bgpio_get_dir;
552 	} else {
553 		if (flags & BGPIOF_NO_OUTPUT)
554 			gc->direction_output = bgpio_dir_out_err;
555 		else
556 			gc->direction_output = bgpio_simple_dir_out;
557 		gc->direction_input = bgpio_simple_dir_in;
558 	}
559 
560 	return 0;
561 }
562 
563 static int bgpio_request(struct gpio_chip *chip, unsigned gpio_pin)
564 {
565 	if (gpio_pin < chip->ngpio)
566 		return 0;
567 
568 	return -EINVAL;
569 }
570 
571 /**
572  * bgpio_init() - Initialize generic GPIO accessor functions
573  * @gc: the GPIO chip to set up
574  * @dev: the parent device of the new GPIO chip (compulsory)
575  * @sz: the size (width) of the MMIO registers in bytes, typically 1, 2 or 4
576  * @dat: MMIO address for the register to READ the value of the GPIO lines, it
577  *	is expected that a 1 in the corresponding bit in this register means the
578  *	line is asserted
579  * @set: MMIO address for the register to SET the value of the GPIO lines, it is
580  *	expected that we write the line with 1 in this register to drive the GPIO line
581  *	high.
582  * @clr: MMIO address for the register to CLEAR the value of the GPIO lines, it is
583  *	expected that we write the line with 1 in this register to drive the GPIO line
584  *	low. It is allowed to leave this address as NULL, in that case the SET register
585  *	will be assumed to also clear the GPIO lines, by actively writing the line
586  *	with 0.
587  * @dirout: MMIO address for the register to set the line as OUTPUT. It is assumed
588  *	that setting a line to 1 in this register will turn that line into an
589  *	output line. Conversely, setting the line to 0 will turn that line into
590  *	an input.
591  * @dirin: MMIO address for the register to set this line as INPUT. It is assumed
592  *	that setting a line to 1 in this register will turn that line into an
593  *	input line. Conversely, setting the line to 0 will turn that line into
594  *	an output.
595  * @flags: Different flags that will affect the behaviour of the device, such as
596  *	endianness etc.
597  */
598 int bgpio_init(struct gpio_chip *gc, struct device *dev,
599 	       unsigned long sz, void __iomem *dat, void __iomem *set,
600 	       void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
601 	       unsigned long flags)
602 {
603 	int ret;
604 
605 	if (!is_power_of_2(sz))
606 		return -EINVAL;
607 
608 	gc->bgpio_bits = sz * 8;
609 	if (gc->bgpio_bits > BITS_PER_LONG)
610 		return -EINVAL;
611 
612 	raw_spin_lock_init(&gc->bgpio_lock);
613 	gc->parent = dev;
614 	gc->label = dev_name(dev);
615 	gc->base = -1;
616 	gc->request = bgpio_request;
617 	gc->be_bits = !!(flags & BGPIOF_BIG_ENDIAN);
618 
619 	ret = gpiochip_get_ngpios(gc, dev);
620 	if (ret)
621 		gc->ngpio = gc->bgpio_bits;
622 	else
623 		gc->bgpio_bits = roundup_pow_of_two(round_up(gc->ngpio, 8));
624 
625 	ret = bgpio_setup_io(gc, dat, set, clr, flags);
626 	if (ret)
627 		return ret;
628 
629 	ret = bgpio_setup_accessors(dev, gc, flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
630 	if (ret)
631 		return ret;
632 
633 	ret = bgpio_setup_direction(gc, dirout, dirin, flags);
634 	if (ret)
635 		return ret;
636 
637 	gc->bgpio_data = gc->read_reg(gc->reg_dat);
638 	if (gc->set == bgpio_set_set &&
639 			!(flags & BGPIOF_UNREADABLE_REG_SET))
640 		gc->bgpio_data = gc->read_reg(gc->reg_set);
641 
642 	if (flags & BGPIOF_UNREADABLE_REG_DIR)
643 		gc->bgpio_dir_unreadable = true;
644 
645 	/*
646 	 * Inspect hardware to find initial direction setting.
647 	 */
648 	if ((gc->reg_dir_out || gc->reg_dir_in) &&
649 	    !(flags & BGPIOF_UNREADABLE_REG_DIR)) {
650 		if (gc->reg_dir_out)
651 			gc->bgpio_dir = gc->read_reg(gc->reg_dir_out);
652 		else if (gc->reg_dir_in)
653 			gc->bgpio_dir = ~gc->read_reg(gc->reg_dir_in);
654 		/*
655 		 * If we have two direction registers, synchronise
656 		 * input setting to output setting, the library
657 		 * can not handle a line being input and output at
658 		 * the same time.
659 		 */
660 		if (gc->reg_dir_out && gc->reg_dir_in)
661 			gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
662 	}
663 
664 	return ret;
665 }
666 EXPORT_SYMBOL_GPL(bgpio_init);
667 
668 #if IS_ENABLED(CONFIG_GPIO_GENERIC_PLATFORM)
669 
670 static void __iomem *bgpio_map(struct platform_device *pdev,
671 			       const char *name,
672 			       resource_size_t sane_sz)
673 {
674 	struct resource *r;
675 	resource_size_t sz;
676 
677 	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
678 	if (!r)
679 		return NULL;
680 
681 	sz = resource_size(r);
682 	if (sz != sane_sz)
683 		return IOMEM_ERR_PTR(-EINVAL);
684 
685 	return devm_ioremap_resource(&pdev->dev, r);
686 }
687 
688 static const struct of_device_id bgpio_of_match[] = {
689 	{ .compatible = "brcm,bcm6345-gpio" },
690 	{ .compatible = "wd,mbl-gpio" },
691 	{ .compatible = "ni,169445-nand-gpio" },
692 	{ }
693 };
694 MODULE_DEVICE_TABLE(of, bgpio_of_match);
695 
696 static struct bgpio_pdata *bgpio_parse_fw(struct device *dev, unsigned long *flags)
697 {
698 	struct bgpio_pdata *pdata;
699 
700 	if (!dev_fwnode(dev))
701 		return NULL;
702 
703 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
704 	if (!pdata)
705 		return ERR_PTR(-ENOMEM);
706 
707 	pdata->base = -1;
708 
709 	if (device_is_big_endian(dev))
710 		*flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER;
711 
712 	if (device_property_read_bool(dev, "no-output"))
713 		*flags |= BGPIOF_NO_OUTPUT;
714 
715 	return pdata;
716 }
717 
718 static int bgpio_pdev_probe(struct platform_device *pdev)
719 {
720 	struct device *dev = &pdev->dev;
721 	struct resource *r;
722 	void __iomem *dat;
723 	void __iomem *set;
724 	void __iomem *clr;
725 	void __iomem *dirout;
726 	void __iomem *dirin;
727 	unsigned long sz;
728 	unsigned long flags = 0;
729 	int err;
730 	struct gpio_chip *gc;
731 	struct bgpio_pdata *pdata;
732 
733 	pdata = bgpio_parse_fw(dev, &flags);
734 	if (IS_ERR(pdata))
735 		return PTR_ERR(pdata);
736 
737 	if (!pdata) {
738 		pdata = dev_get_platdata(dev);
739 		flags = pdev->id_entry->driver_data;
740 	}
741 
742 	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
743 	if (!r)
744 		return -EINVAL;
745 
746 	sz = resource_size(r);
747 
748 	dat = bgpio_map(pdev, "dat", sz);
749 	if (IS_ERR(dat))
750 		return PTR_ERR(dat);
751 
752 	set = bgpio_map(pdev, "set", sz);
753 	if (IS_ERR(set))
754 		return PTR_ERR(set);
755 
756 	clr = bgpio_map(pdev, "clr", sz);
757 	if (IS_ERR(clr))
758 		return PTR_ERR(clr);
759 
760 	dirout = bgpio_map(pdev, "dirout", sz);
761 	if (IS_ERR(dirout))
762 		return PTR_ERR(dirout);
763 
764 	dirin = bgpio_map(pdev, "dirin", sz);
765 	if (IS_ERR(dirin))
766 		return PTR_ERR(dirin);
767 
768 	gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
769 	if (!gc)
770 		return -ENOMEM;
771 
772 	err = bgpio_init(gc, dev, sz, dat, set, clr, dirout, dirin, flags);
773 	if (err)
774 		return err;
775 
776 	if (pdata) {
777 		if (pdata->label)
778 			gc->label = pdata->label;
779 		gc->base = pdata->base;
780 		if (pdata->ngpio > 0)
781 			gc->ngpio = pdata->ngpio;
782 	}
783 
784 	platform_set_drvdata(pdev, gc);
785 
786 	return devm_gpiochip_add_data(&pdev->dev, gc, NULL);
787 }
788 
789 static const struct platform_device_id bgpio_id_table[] = {
790 	{
791 		.name		= "basic-mmio-gpio",
792 		.driver_data	= 0,
793 	}, {
794 		.name		= "basic-mmio-gpio-be",
795 		.driver_data	= BGPIOF_BIG_ENDIAN,
796 	},
797 	{ }
798 };
799 MODULE_DEVICE_TABLE(platform, bgpio_id_table);
800 
801 static struct platform_driver bgpio_driver = {
802 	.driver = {
803 		.name = "basic-mmio-gpio",
804 		.of_match_table = bgpio_of_match,
805 	},
806 	.id_table = bgpio_id_table,
807 	.probe = bgpio_pdev_probe,
808 };
809 
810 module_platform_driver(bgpio_driver);
811 
812 #endif /* CONFIG_GPIO_GENERIC_PLATFORM */
813 
814 MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
815 MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
816 MODULE_LICENSE("GPL");
817