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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/init.h>
44 #include <linux/err.h>
45 #include <linux/bug.h>
46 #include <linux/kernel.h>
47 #include <linux/module.h>
48 #include <linux/spinlock.h>
49 #include <linux/compiler.h>
50 #include <linux/types.h>
51 #include <linux/errno.h>
52 #include <linux/log2.h>
53 #include <linux/ioport.h>
54 #include <linux/io.h>
55 #include <linux/gpio/driver.h>
56 #include <linux/slab.h>
57 #include <linux/bitops.h>
58 #include <linux/platform_device.h>
59 #include <linux/mod_devicetable.h>
60 #include <linux/of.h>
61 #include <linux/of_device.h>
62 
bgpio_write8(void __iomem * reg,unsigned long data)63 static void bgpio_write8(void __iomem *reg, unsigned long data)
64 {
65 	writeb(data, reg);
66 }
67 
bgpio_read8(void __iomem * reg)68 static unsigned long bgpio_read8(void __iomem *reg)
69 {
70 	return readb(reg);
71 }
72 
bgpio_write16(void __iomem * reg,unsigned long data)73 static void bgpio_write16(void __iomem *reg, unsigned long data)
74 {
75 	writew(data, reg);
76 }
77 
bgpio_read16(void __iomem * reg)78 static unsigned long bgpio_read16(void __iomem *reg)
79 {
80 	return readw(reg);
81 }
82 
bgpio_write32(void __iomem * reg,unsigned long data)83 static void bgpio_write32(void __iomem *reg, unsigned long data)
84 {
85 	writel(data, reg);
86 }
87 
bgpio_read32(void __iomem * reg)88 static unsigned long bgpio_read32(void __iomem *reg)
89 {
90 	return readl(reg);
91 }
92 
93 #if BITS_PER_LONG >= 64
bgpio_write64(void __iomem * reg,unsigned long data)94 static void bgpio_write64(void __iomem *reg, unsigned long data)
95 {
96 	writeq(data, reg);
97 }
98 
bgpio_read64(void __iomem * reg)99 static unsigned long bgpio_read64(void __iomem *reg)
100 {
101 	return readq(reg);
102 }
103 #endif /* BITS_PER_LONG >= 64 */
104 
bgpio_write16be(void __iomem * reg,unsigned long data)105 static void bgpio_write16be(void __iomem *reg, unsigned long data)
106 {
107 	iowrite16be(data, reg);
108 }
109 
bgpio_read16be(void __iomem * reg)110 static unsigned long bgpio_read16be(void __iomem *reg)
111 {
112 	return ioread16be(reg);
113 }
114 
bgpio_write32be(void __iomem * reg,unsigned long data)115 static void bgpio_write32be(void __iomem *reg, unsigned long data)
116 {
117 	iowrite32be(data, reg);
118 }
119 
bgpio_read32be(void __iomem * reg)120 static unsigned long bgpio_read32be(void __iomem *reg)
121 {
122 	return ioread32be(reg);
123 }
124 
bgpio_line2mask(struct gpio_chip * gc,unsigned int line)125 static unsigned long bgpio_line2mask(struct gpio_chip *gc, unsigned int line)
126 {
127 	if (gc->be_bits)
128 		return BIT(gc->bgpio_bits - 1 - line);
129 	return BIT(line);
130 }
131 
bgpio_get_set(struct gpio_chip * gc,unsigned int gpio)132 static int bgpio_get_set(struct gpio_chip *gc, unsigned int gpio)
133 {
134 	unsigned long pinmask = bgpio_line2mask(gc, gpio);
135 	bool dir = !!(gc->bgpio_dir & pinmask);
136 
137 	if (dir)
138 		return !!(gc->read_reg(gc->reg_set) & pinmask);
139 	else
140 		return !!(gc->read_reg(gc->reg_dat) & pinmask);
141 }
142 
143 /*
144  * This assumes that the bits in the GPIO register are in native endianness.
145  * We only assign the function pointer if we have that.
146  */
bgpio_get_set_multiple(struct gpio_chip * gc,unsigned long * mask,unsigned long * bits)147 static int bgpio_get_set_multiple(struct gpio_chip *gc, unsigned long *mask,
148 				  unsigned long *bits)
149 {
150 	unsigned long get_mask = 0;
151 	unsigned long set_mask = 0;
152 
153 	/* Make sure we first clear any bits that are zero when we read the register */
154 	*bits &= ~*mask;
155 
156 	set_mask = *mask & gc->bgpio_dir;
157 	get_mask = *mask & ~gc->bgpio_dir;
158 
159 	if (set_mask)
160 		*bits |= gc->read_reg(gc->reg_set) & set_mask;
161 	if (get_mask)
162 		*bits |= gc->read_reg(gc->reg_dat) & get_mask;
163 
164 	return 0;
165 }
166 
bgpio_get(struct gpio_chip * gc,unsigned int gpio)167 static int bgpio_get(struct gpio_chip *gc, unsigned int gpio)
168 {
169 	return !!(gc->read_reg(gc->reg_dat) & bgpio_line2mask(gc, gpio));
170 }
171 
172 /*
173  * This only works if the bits in the GPIO register are in native endianness.
174  */
bgpio_get_multiple(struct gpio_chip * gc,unsigned long * mask,unsigned long * bits)175 static int bgpio_get_multiple(struct gpio_chip *gc, unsigned long *mask,
176 			      unsigned long *bits)
177 {
178 	/* Make sure we first clear any bits that are zero when we read the register */
179 	*bits &= ~*mask;
180 	*bits |= gc->read_reg(gc->reg_dat) & *mask;
181 	return 0;
182 }
183 
184 /*
185  * With big endian mirrored bit order it becomes more tedious.
186  */
bgpio_get_multiple_be(struct gpio_chip * gc,unsigned long * mask,unsigned long * bits)187 static int bgpio_get_multiple_be(struct gpio_chip *gc, unsigned long *mask,
188 				 unsigned long *bits)
189 {
190 	unsigned long readmask = 0;
191 	unsigned long val;
192 	int bit;
193 
194 	/* Make sure we first clear any bits that are zero when we read the register */
195 	*bits &= ~*mask;
196 
197 	/* Create a mirrored mask */
198 	for_each_set_bit(bit, mask, gc->ngpio)
199 		readmask |= bgpio_line2mask(gc, bit);
200 
201 	/* Read the register */
202 	val = gc->read_reg(gc->reg_dat) & readmask;
203 
204 	/*
205 	 * Mirror the result into the "bits" result, this will give line 0
206 	 * in bit 0 ... line 31 in bit 31 for a 32bit register.
207 	 */
208 	for_each_set_bit(bit, &val, gc->ngpio)
209 		*bits |= bgpio_line2mask(gc, bit);
210 
211 	return 0;
212 }
213 
bgpio_set_none(struct gpio_chip * gc,unsigned int gpio,int val)214 static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)
215 {
216 }
217 
bgpio_set(struct gpio_chip * gc,unsigned int gpio,int val)218 static void bgpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
219 {
220 	unsigned long mask = bgpio_line2mask(gc, gpio);
221 	unsigned long flags;
222 
223 	spin_lock_irqsave(&gc->bgpio_lock, flags);
224 
225 	if (val)
226 		gc->bgpio_data |= mask;
227 	else
228 		gc->bgpio_data &= ~mask;
229 
230 	gc->write_reg(gc->reg_dat, gc->bgpio_data);
231 
232 	spin_unlock_irqrestore(&gc->bgpio_lock, flags);
233 }
234 
bgpio_set_with_clear(struct gpio_chip * gc,unsigned int gpio,int val)235 static void bgpio_set_with_clear(struct gpio_chip *gc, unsigned int gpio,
236 				 int val)
237 {
238 	unsigned long mask = bgpio_line2mask(gc, gpio);
239 
240 	if (val)
241 		gc->write_reg(gc->reg_set, mask);
242 	else
243 		gc->write_reg(gc->reg_clr, mask);
244 }
245 
bgpio_set_set(struct gpio_chip * gc,unsigned int gpio,int val)246 static void bgpio_set_set(struct gpio_chip *gc, unsigned int gpio, int val)
247 {
248 	unsigned long mask = bgpio_line2mask(gc, gpio);
249 	unsigned long flags;
250 
251 	spin_lock_irqsave(&gc->bgpio_lock, flags);
252 
253 	if (val)
254 		gc->bgpio_data |= mask;
255 	else
256 		gc->bgpio_data &= ~mask;
257 
258 	gc->write_reg(gc->reg_set, gc->bgpio_data);
259 
260 	spin_unlock_irqrestore(&gc->bgpio_lock, flags);
261 }
262 
bgpio_multiple_get_masks(struct gpio_chip * gc,unsigned long * mask,unsigned long * bits,unsigned long * set_mask,unsigned long * clear_mask)263 static void bgpio_multiple_get_masks(struct gpio_chip *gc,
264 				     unsigned long *mask, unsigned long *bits,
265 				     unsigned long *set_mask,
266 				     unsigned long *clear_mask)
267 {
268 	int i;
269 
270 	*set_mask = 0;
271 	*clear_mask = 0;
272 
273 	for_each_set_bit(i, mask, gc->bgpio_bits) {
274 		if (test_bit(i, bits))
275 			*set_mask |= bgpio_line2mask(gc, i);
276 		else
277 			*clear_mask |= bgpio_line2mask(gc, i);
278 	}
279 }
280 
bgpio_set_multiple_single_reg(struct gpio_chip * gc,unsigned long * mask,unsigned long * bits,void __iomem * reg)281 static void bgpio_set_multiple_single_reg(struct gpio_chip *gc,
282 					  unsigned long *mask,
283 					  unsigned long *bits,
284 					  void __iomem *reg)
285 {
286 	unsigned long flags;
287 	unsigned long set_mask, clear_mask;
288 
289 	spin_lock_irqsave(&gc->bgpio_lock, flags);
290 
291 	bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);
292 
293 	gc->bgpio_data |= set_mask;
294 	gc->bgpio_data &= ~clear_mask;
295 
296 	gc->write_reg(reg, gc->bgpio_data);
297 
298 	spin_unlock_irqrestore(&gc->bgpio_lock, flags);
299 }
300 
bgpio_set_multiple(struct gpio_chip * gc,unsigned long * mask,unsigned long * bits)301 static void bgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
302 			       unsigned long *bits)
303 {
304 	bgpio_set_multiple_single_reg(gc, mask, bits, gc->reg_dat);
305 }
306 
bgpio_set_multiple_set(struct gpio_chip * gc,unsigned long * mask,unsigned long * bits)307 static void bgpio_set_multiple_set(struct gpio_chip *gc, unsigned long *mask,
308 				   unsigned long *bits)
309 {
310 	bgpio_set_multiple_single_reg(gc, mask, bits, gc->reg_set);
311 }
312 
bgpio_set_multiple_with_clear(struct gpio_chip * gc,unsigned long * mask,unsigned long * bits)313 static void bgpio_set_multiple_with_clear(struct gpio_chip *gc,
314 					  unsigned long *mask,
315 					  unsigned long *bits)
316 {
317 	unsigned long set_mask, clear_mask;
318 
319 	bgpio_multiple_get_masks(gc, mask, bits, &set_mask, &clear_mask);
320 
321 	if (set_mask)
322 		gc->write_reg(gc->reg_set, set_mask);
323 	if (clear_mask)
324 		gc->write_reg(gc->reg_clr, clear_mask);
325 }
326 
bgpio_simple_dir_in(struct gpio_chip * gc,unsigned int gpio)327 static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
328 {
329 	return 0;
330 }
331 
bgpio_dir_out_err(struct gpio_chip * gc,unsigned int gpio,int val)332 static int bgpio_dir_out_err(struct gpio_chip *gc, unsigned int gpio,
333 				int val)
334 {
335 	return -EINVAL;
336 }
337 
bgpio_simple_dir_out(struct gpio_chip * gc,unsigned int gpio,int val)338 static int bgpio_simple_dir_out(struct gpio_chip *gc, unsigned int gpio,
339 				int val)
340 {
341 	gc->set(gc, gpio, val);
342 
343 	return 0;
344 }
345 
bgpio_dir_in(struct gpio_chip * gc,unsigned int gpio)346 static int bgpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
347 {
348 	unsigned long flags;
349 
350 	spin_lock_irqsave(&gc->bgpio_lock, flags);
351 
352 	gc->bgpio_dir &= ~bgpio_line2mask(gc, gpio);
353 
354 	if (gc->reg_dir_in)
355 		gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
356 	if (gc->reg_dir_out)
357 		gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
358 
359 	spin_unlock_irqrestore(&gc->bgpio_lock, flags);
360 
361 	return 0;
362 }
363 
bgpio_get_dir(struct gpio_chip * gc,unsigned int gpio)364 static int bgpio_get_dir(struct gpio_chip *gc, unsigned int gpio)
365 {
366 	/* Return 0 if output, 1 if input */
367 	if (gc->bgpio_dir_unreadable) {
368 		if (gc->bgpio_dir & bgpio_line2mask(gc, gpio))
369 			return GPIO_LINE_DIRECTION_OUT;
370 		return GPIO_LINE_DIRECTION_IN;
371 	}
372 
373 	if (gc->reg_dir_out) {
374 		if (gc->read_reg(gc->reg_dir_out) & bgpio_line2mask(gc, gpio))
375 			return GPIO_LINE_DIRECTION_OUT;
376 		return GPIO_LINE_DIRECTION_IN;
377 	}
378 
379 	if (gc->reg_dir_in)
380 		if (!(gc->read_reg(gc->reg_dir_in) & bgpio_line2mask(gc, gpio)))
381 			return GPIO_LINE_DIRECTION_OUT;
382 
383 	return GPIO_LINE_DIRECTION_IN;
384 }
385 
bgpio_dir_out(struct gpio_chip * gc,unsigned int gpio,int val)386 static void bgpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
387 {
388 	unsigned long flags;
389 
390 	spin_lock_irqsave(&gc->bgpio_lock, flags);
391 
392 	gc->bgpio_dir |= bgpio_line2mask(gc, gpio);
393 
394 	if (gc->reg_dir_in)
395 		gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
396 	if (gc->reg_dir_out)
397 		gc->write_reg(gc->reg_dir_out, gc->bgpio_dir);
398 
399 	spin_unlock_irqrestore(&gc->bgpio_lock, flags);
400 }
401 
bgpio_dir_out_dir_first(struct gpio_chip * gc,unsigned int gpio,int val)402 static int bgpio_dir_out_dir_first(struct gpio_chip *gc, unsigned int gpio,
403 				   int val)
404 {
405 	bgpio_dir_out(gc, gpio, val);
406 	gc->set(gc, gpio, val);
407 	return 0;
408 }
409 
bgpio_dir_out_val_first(struct gpio_chip * gc,unsigned int gpio,int val)410 static int bgpio_dir_out_val_first(struct gpio_chip *gc, unsigned int gpio,
411 				   int val)
412 {
413 	gc->set(gc, gpio, val);
414 	bgpio_dir_out(gc, gpio, val);
415 	return 0;
416 }
417 
bgpio_setup_accessors(struct device * dev,struct gpio_chip * gc,bool byte_be)418 static int bgpio_setup_accessors(struct device *dev,
419 				 struct gpio_chip *gc,
420 				 bool byte_be)
421 {
422 
423 	switch (gc->bgpio_bits) {
424 	case 8:
425 		gc->read_reg	= bgpio_read8;
426 		gc->write_reg	= bgpio_write8;
427 		break;
428 	case 16:
429 		if (byte_be) {
430 			gc->read_reg	= bgpio_read16be;
431 			gc->write_reg	= bgpio_write16be;
432 		} else {
433 			gc->read_reg	= bgpio_read16;
434 			gc->write_reg	= bgpio_write16;
435 		}
436 		break;
437 	case 32:
438 		if (byte_be) {
439 			gc->read_reg	= bgpio_read32be;
440 			gc->write_reg	= bgpio_write32be;
441 		} else {
442 			gc->read_reg	= bgpio_read32;
443 			gc->write_reg	= bgpio_write32;
444 		}
445 		break;
446 #if BITS_PER_LONG >= 64
447 	case 64:
448 		if (byte_be) {
449 			dev_err(dev,
450 				"64 bit big endian byte order unsupported\n");
451 			return -EINVAL;
452 		} else {
453 			gc->read_reg	= bgpio_read64;
454 			gc->write_reg	= bgpio_write64;
455 		}
456 		break;
457 #endif /* BITS_PER_LONG >= 64 */
458 	default:
459 		dev_err(dev, "unsupported data width %u bits\n", gc->bgpio_bits);
460 		return -EINVAL;
461 	}
462 
463 	return 0;
464 }
465 
466 /*
467  * Create the device and allocate the resources.  For setting GPIO's there are
468  * three supported configurations:
469  *
470  *	- single input/output register resource (named "dat").
471  *	- set/clear pair (named "set" and "clr").
472  *	- single output register resource and single input resource ("set" and
473  *	dat").
474  *
475  * For the single output register, this drives a 1 by setting a bit and a zero
476  * by clearing a bit.  For the set clr pair, this drives a 1 by setting a bit
477  * in the set register and clears it by setting a bit in the clear register.
478  * The configuration is detected by which resources are present.
479  *
480  * For setting the GPIO direction, there are three supported configurations:
481  *
482  *	- simple bidirection GPIO that requires no configuration.
483  *	- an output direction register (named "dirout") where a 1 bit
484  *	indicates the GPIO is an output.
485  *	- an input direction register (named "dirin") where a 1 bit indicates
486  *	the GPIO is an input.
487  */
bgpio_setup_io(struct gpio_chip * gc,void __iomem * dat,void __iomem * set,void __iomem * clr,unsigned long flags)488 static int bgpio_setup_io(struct gpio_chip *gc,
489 			  void __iomem *dat,
490 			  void __iomem *set,
491 			  void __iomem *clr,
492 			  unsigned long flags)
493 {
494 
495 	gc->reg_dat = dat;
496 	if (!gc->reg_dat)
497 		return -EINVAL;
498 
499 	if (set && clr) {
500 		gc->reg_set = set;
501 		gc->reg_clr = clr;
502 		gc->set = bgpio_set_with_clear;
503 		gc->set_multiple = bgpio_set_multiple_with_clear;
504 	} else if (set && !clr) {
505 		gc->reg_set = set;
506 		gc->set = bgpio_set_set;
507 		gc->set_multiple = bgpio_set_multiple_set;
508 	} else if (flags & BGPIOF_NO_OUTPUT) {
509 		gc->set = bgpio_set_none;
510 		gc->set_multiple = NULL;
511 	} else {
512 		gc->set = bgpio_set;
513 		gc->set_multiple = bgpio_set_multiple;
514 	}
515 
516 	if (!(flags & BGPIOF_UNREADABLE_REG_SET) &&
517 	    (flags & BGPIOF_READ_OUTPUT_REG_SET)) {
518 		gc->get = bgpio_get_set;
519 		if (!gc->be_bits)
520 			gc->get_multiple = bgpio_get_set_multiple;
521 		/*
522 		 * We deliberately avoid assigning the ->get_multiple() call
523 		 * for big endian mirrored registers which are ALSO reflecting
524 		 * their value in the set register when used as output. It is
525 		 * simply too much complexity, let the GPIO core fall back to
526 		 * reading each line individually in that fringe case.
527 		 */
528 	} else {
529 		gc->get = bgpio_get;
530 		if (gc->be_bits)
531 			gc->get_multiple = bgpio_get_multiple_be;
532 		else
533 			gc->get_multiple = bgpio_get_multiple;
534 	}
535 
536 	return 0;
537 }
538 
bgpio_setup_direction(struct gpio_chip * gc,void __iomem * dirout,void __iomem * dirin,unsigned long flags)539 static int bgpio_setup_direction(struct gpio_chip *gc,
540 				 void __iomem *dirout,
541 				 void __iomem *dirin,
542 				 unsigned long flags)
543 {
544 	if (dirout || dirin) {
545 		gc->reg_dir_out = dirout;
546 		gc->reg_dir_in = dirin;
547 		if (flags & BGPIOF_NO_SET_ON_INPUT)
548 			gc->direction_output = bgpio_dir_out_dir_first;
549 		else
550 			gc->direction_output = bgpio_dir_out_val_first;
551 		gc->direction_input = bgpio_dir_in;
552 		gc->get_direction = bgpio_get_dir;
553 	} else {
554 		if (flags & BGPIOF_NO_OUTPUT)
555 			gc->direction_output = bgpio_dir_out_err;
556 		else
557 			gc->direction_output = bgpio_simple_dir_out;
558 		gc->direction_input = bgpio_simple_dir_in;
559 	}
560 
561 	return 0;
562 }
563 
bgpio_request(struct gpio_chip * chip,unsigned gpio_pin)564 static int bgpio_request(struct gpio_chip *chip, unsigned gpio_pin)
565 {
566 	if (gpio_pin < chip->ngpio)
567 		return 0;
568 
569 	return -EINVAL;
570 }
571 
572 /**
573  * bgpio_init() - Initialize generic GPIO accessor functions
574  * @gc: the GPIO chip to set up
575  * @dev: the parent device of the new GPIO chip (compulsory)
576  * @sz: the size (width) of the MMIO registers in bytes, typically 1, 2 or 4
577  * @dat: MMIO address for the register to READ the value of the GPIO lines, it
578  *	is expected that a 1 in the corresponding bit in this register means the
579  *	line is asserted
580  * @set: MMIO address for the register to SET the value of the GPIO lines, it is
581  *	expected that we write the line with 1 in this register to drive the GPIO line
582  *	high.
583  * @clr: MMIO address for the register to CLEAR the value of the GPIO lines, it is
584  *	expected that we write the line with 1 in this register to drive the GPIO line
585  *	low. It is allowed to leave this address as NULL, in that case the SET register
586  *	will be assumed to also clear the GPIO lines, by actively writing the line
587  *	with 0.
588  * @dirout: MMIO address for the register to set the line as OUTPUT. It is assumed
589  *	that setting a line to 1 in this register will turn that line into an
590  *	output line. Conversely, setting the line to 0 will turn that line into
591  *	an input.
592  * @dirin: MMIO address for the register to set this line as INPUT. It is assumed
593  *	that setting a line to 1 in this register will turn that line into an
594  *	input line. Conversely, setting the line to 0 will turn that line into
595  *	an output.
596  * @flags: Different flags that will affect the behaviour of the device, such as
597  *	endianness etc.
598  */
bgpio_init(struct gpio_chip * gc,struct device * dev,unsigned long sz,void __iomem * dat,void __iomem * set,void __iomem * clr,void __iomem * dirout,void __iomem * dirin,unsigned long flags)599 int bgpio_init(struct gpio_chip *gc, struct device *dev,
600 	       unsigned long sz, void __iomem *dat, void __iomem *set,
601 	       void __iomem *clr, void __iomem *dirout, void __iomem *dirin,
602 	       unsigned long flags)
603 {
604 	int ret;
605 
606 	if (!is_power_of_2(sz))
607 		return -EINVAL;
608 
609 	gc->bgpio_bits = sz * 8;
610 	if (gc->bgpio_bits > BITS_PER_LONG)
611 		return -EINVAL;
612 
613 	spin_lock_init(&gc->bgpio_lock);
614 	gc->parent = dev;
615 	gc->label = dev_name(dev);
616 	gc->base = -1;
617 	gc->ngpio = gc->bgpio_bits;
618 	gc->request = bgpio_request;
619 	gc->be_bits = !!(flags & BGPIOF_BIG_ENDIAN);
620 
621 	ret = bgpio_setup_io(gc, dat, set, clr, flags);
622 	if (ret)
623 		return ret;
624 
625 	ret = bgpio_setup_accessors(dev, gc, flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
626 	if (ret)
627 		return ret;
628 
629 	ret = bgpio_setup_direction(gc, dirout, dirin, flags);
630 	if (ret)
631 		return ret;
632 
633 	gc->bgpio_data = gc->read_reg(gc->reg_dat);
634 	if (gc->set == bgpio_set_set &&
635 			!(flags & BGPIOF_UNREADABLE_REG_SET))
636 		gc->bgpio_data = gc->read_reg(gc->reg_set);
637 
638 	if (flags & BGPIOF_UNREADABLE_REG_DIR)
639 		gc->bgpio_dir_unreadable = true;
640 
641 	/*
642 	 * Inspect hardware to find initial direction setting.
643 	 */
644 	if ((gc->reg_dir_out || gc->reg_dir_in) &&
645 	    !(flags & BGPIOF_UNREADABLE_REG_DIR)) {
646 		if (gc->reg_dir_out)
647 			gc->bgpio_dir = gc->read_reg(gc->reg_dir_out);
648 		else if (gc->reg_dir_in)
649 			gc->bgpio_dir = ~gc->read_reg(gc->reg_dir_in);
650 		/*
651 		 * If we have two direction registers, synchronise
652 		 * input setting to output setting, the library
653 		 * can not handle a line being input and output at
654 		 * the same time.
655 		 */
656 		if (gc->reg_dir_out && gc->reg_dir_in)
657 			gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
658 	}
659 
660 	return ret;
661 }
662 EXPORT_SYMBOL_GPL(bgpio_init);
663 
664 #if IS_ENABLED(CONFIG_GPIO_GENERIC_PLATFORM)
665 
bgpio_map(struct platform_device * pdev,const char * name,resource_size_t sane_sz)666 static void __iomem *bgpio_map(struct platform_device *pdev,
667 			       const char *name,
668 			       resource_size_t sane_sz)
669 {
670 	struct resource *r;
671 	resource_size_t sz;
672 
673 	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
674 	if (!r)
675 		return NULL;
676 
677 	sz = resource_size(r);
678 	if (sz != sane_sz)
679 		return IOMEM_ERR_PTR(-EINVAL);
680 
681 	return devm_ioremap_resource(&pdev->dev, r);
682 }
683 
684 #ifdef CONFIG_OF
685 static const struct of_device_id bgpio_of_match[] = {
686 	{ .compatible = "brcm,bcm6345-gpio" },
687 	{ .compatible = "wd,mbl-gpio" },
688 	{ .compatible = "ni,169445-nand-gpio" },
689 	{ }
690 };
691 MODULE_DEVICE_TABLE(of, bgpio_of_match);
692 
bgpio_parse_dt(struct platform_device * pdev,unsigned long * flags)693 static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
694 					  unsigned long *flags)
695 {
696 	struct bgpio_pdata *pdata;
697 
698 	if (!of_match_device(bgpio_of_match, &pdev->dev))
699 		return NULL;
700 
701 	pdata = devm_kzalloc(&pdev->dev, sizeof(struct bgpio_pdata),
702 			     GFP_KERNEL);
703 	if (!pdata)
704 		return ERR_PTR(-ENOMEM);
705 
706 	pdata->base = -1;
707 
708 	if (of_device_is_big_endian(pdev->dev.of_node))
709 		*flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER;
710 
711 	if (of_property_read_bool(pdev->dev.of_node, "no-output"))
712 		*flags |= BGPIOF_NO_OUTPUT;
713 
714 	return pdata;
715 }
716 #else
bgpio_parse_dt(struct platform_device * pdev,unsigned long * flags)717 static struct bgpio_pdata *bgpio_parse_dt(struct platform_device *pdev,
718 					  unsigned long *flags)
719 {
720 	return NULL;
721 }
722 #endif /* CONFIG_OF */
723 
bgpio_pdev_probe(struct platform_device * pdev)724 static int bgpio_pdev_probe(struct platform_device *pdev)
725 {
726 	struct device *dev = &pdev->dev;
727 	struct resource *r;
728 	void __iomem *dat;
729 	void __iomem *set;
730 	void __iomem *clr;
731 	void __iomem *dirout;
732 	void __iomem *dirin;
733 	unsigned long sz;
734 	unsigned long flags = 0;
735 	int err;
736 	struct gpio_chip *gc;
737 	struct bgpio_pdata *pdata;
738 
739 	pdata = bgpio_parse_dt(pdev, &flags);
740 	if (IS_ERR(pdata))
741 		return PTR_ERR(pdata);
742 
743 	if (!pdata) {
744 		pdata = dev_get_platdata(dev);
745 		flags = pdev->id_entry->driver_data;
746 	}
747 
748 	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
749 	if (!r)
750 		return -EINVAL;
751 
752 	sz = resource_size(r);
753 
754 	dat = bgpio_map(pdev, "dat", sz);
755 	if (IS_ERR(dat))
756 		return PTR_ERR(dat);
757 
758 	set = bgpio_map(pdev, "set", sz);
759 	if (IS_ERR(set))
760 		return PTR_ERR(set);
761 
762 	clr = bgpio_map(pdev, "clr", sz);
763 	if (IS_ERR(clr))
764 		return PTR_ERR(clr);
765 
766 	dirout = bgpio_map(pdev, "dirout", sz);
767 	if (IS_ERR(dirout))
768 		return PTR_ERR(dirout);
769 
770 	dirin = bgpio_map(pdev, "dirin", sz);
771 	if (IS_ERR(dirin))
772 		return PTR_ERR(dirin);
773 
774 	gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
775 	if (!gc)
776 		return -ENOMEM;
777 
778 	err = bgpio_init(gc, dev, sz, dat, set, clr, dirout, dirin, flags);
779 	if (err)
780 		return err;
781 
782 	if (pdata) {
783 		if (pdata->label)
784 			gc->label = pdata->label;
785 		gc->base = pdata->base;
786 		if (pdata->ngpio > 0)
787 			gc->ngpio = pdata->ngpio;
788 	}
789 
790 	platform_set_drvdata(pdev, gc);
791 
792 	return devm_gpiochip_add_data(&pdev->dev, gc, NULL);
793 }
794 
795 static const struct platform_device_id bgpio_id_table[] = {
796 	{
797 		.name		= "basic-mmio-gpio",
798 		.driver_data	= 0,
799 	}, {
800 		.name		= "basic-mmio-gpio-be",
801 		.driver_data	= BGPIOF_BIG_ENDIAN,
802 	},
803 	{ }
804 };
805 MODULE_DEVICE_TABLE(platform, bgpio_id_table);
806 
807 static struct platform_driver bgpio_driver = {
808 	.driver = {
809 		.name = "basic-mmio-gpio",
810 		.of_match_table = of_match_ptr(bgpio_of_match),
811 	},
812 	.id_table = bgpio_id_table,
813 	.probe = bgpio_pdev_probe,
814 };
815 
816 module_platform_driver(bgpio_driver);
817 
818 #endif /* CONFIG_GPIO_GENERIC_PLATFORM */
819 
820 MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
821 MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
822 MODULE_LICENSE("GPL");
823