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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 .
 17o        `                     ~~~~\___/~~~~    ` 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
 62static void bgpio_write8(void __iomem *reg, unsigned long data)
 63{
 64	writeb(data, reg);
 65}
 66
 67static unsigned long bgpio_read8(void __iomem *reg)
 68{
 69	return readb(reg);
 70}
 71
 72static void bgpio_write16(void __iomem *reg, unsigned long data)
 73{
 74	writew(data, reg);
 75}
 76
 77static unsigned long bgpio_read16(void __iomem *reg)
 78{
 79	return readw(reg);
 80}
 81
 82static void bgpio_write32(void __iomem *reg, unsigned long data)
 83{
 84	writel(data, reg);
 85}
 86
 87static unsigned long bgpio_read32(void __iomem *reg)
 88{
 89	return readl(reg);
 90}
 91
 92#if BITS_PER_LONG >= 64
 93static void bgpio_write64(void __iomem *reg, unsigned long data)
 94{
 95	writeq(data, reg);
 96}
 97
 98static unsigned long bgpio_read64(void __iomem *reg)
 99{
100	return readq(reg);
101}
102#endif /* BITS_PER_LONG >= 64 */
103
104static void bgpio_write16be(void __iomem *reg, unsigned long data)
105{
106	iowrite16be(data, reg);
107}
108
109static unsigned long bgpio_read16be(void __iomem *reg)
110{
111	return ioread16be(reg);
112}
113
114static void bgpio_write32be(void __iomem *reg, unsigned long data)
115{
116	iowrite32be(data, reg);
117}
118
119static unsigned long bgpio_read32be(void __iomem *reg)
120{
121	return ioread32be(reg);
122}
123
124static 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
131static 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 */
146static 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
166static 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 */
174static 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 */
186static 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
213static void bgpio_set_none(struct gpio_chip *gc, unsigned int gpio, int val)
214{
215}
216
217static 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
234static 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
245static 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
262static 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
280static 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
300static 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
306static 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
312static 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
326static int bgpio_simple_dir_in(struct gpio_chip *gc, unsigned int gpio)
327{
328	return 0;
329}
330
331static int bgpio_dir_out_err(struct gpio_chip *gc, unsigned int gpio,
332				int val)
333{
334	return -EINVAL;
335}
336
337static 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
345static 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
363static 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
385static 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
401static 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
409static 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
417static 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 */
487static 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
538static 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
563static 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 */
598int 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
623	ret = bgpio_setup_io(gc, dat, set, clr, flags);
624	if (ret)
625		return ret;
626
627	ret = bgpio_setup_accessors(dev, gc, flags & BGPIOF_BIG_ENDIAN_BYTE_ORDER);
628	if (ret)
629		return ret;
630
631	ret = bgpio_setup_direction(gc, dirout, dirin, flags);
632	if (ret)
633		return ret;
634
635	gc->bgpio_data = gc->read_reg(gc->reg_dat);
636	if (gc->set == bgpio_set_set &&
637			!(flags & BGPIOF_UNREADABLE_REG_SET))
638		gc->bgpio_data = gc->read_reg(gc->reg_set);
639
640	if (flags & BGPIOF_UNREADABLE_REG_DIR)
641		gc->bgpio_dir_unreadable = true;
642
643	/*
644	 * Inspect hardware to find initial direction setting.
645	 */
646	if ((gc->reg_dir_out || gc->reg_dir_in) &&
647	    !(flags & BGPIOF_UNREADABLE_REG_DIR)) {
648		if (gc->reg_dir_out)
649			gc->bgpio_dir = gc->read_reg(gc->reg_dir_out);
650		else if (gc->reg_dir_in)
651			gc->bgpio_dir = ~gc->read_reg(gc->reg_dir_in);
652		/*
653		 * If we have two direction registers, synchronise
654		 * input setting to output setting, the library
655		 * can not handle a line being input and output at
656		 * the same time.
657		 */
658		if (gc->reg_dir_out && gc->reg_dir_in)
659			gc->write_reg(gc->reg_dir_in, ~gc->bgpio_dir);
660	}
661
662	return ret;
663}
664EXPORT_SYMBOL_GPL(bgpio_init);
665
666#if IS_ENABLED(CONFIG_GPIO_GENERIC_PLATFORM)
667
668static void __iomem *bgpio_map(struct platform_device *pdev,
669			       const char *name,
670			       resource_size_t sane_sz)
671{
672	struct resource *r;
673	resource_size_t sz;
674
675	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, name);
676	if (!r)
677		return NULL;
678
679	sz = resource_size(r);
680	if (sz != sane_sz)
681		return IOMEM_ERR_PTR(-EINVAL);
682
683	return devm_ioremap_resource(&pdev->dev, r);
684}
685
686static const struct of_device_id bgpio_of_match[] = {
687	{ .compatible = "brcm,bcm6345-gpio" },
688	{ .compatible = "wd,mbl-gpio" },
689	{ .compatible = "ni,169445-nand-gpio" },
690	{ }
691};
692MODULE_DEVICE_TABLE(of, bgpio_of_match);
693
694static struct bgpio_pdata *bgpio_parse_fw(struct device *dev, unsigned long *flags)
695{
696	struct bgpio_pdata *pdata;
697
698	if (!dev_fwnode(dev))
699		return NULL;
700
701	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
702	if (!pdata)
703		return ERR_PTR(-ENOMEM);
704
705	pdata->base = -1;
706
707	if (device_is_big_endian(dev))
708		*flags |= BGPIOF_BIG_ENDIAN_BYTE_ORDER;
709
710	if (device_property_read_bool(dev, "no-output"))
711		*flags |= BGPIOF_NO_OUTPUT;
712
713	return pdata;
714}
715
716static int bgpio_pdev_probe(struct platform_device *pdev)
717{
718	struct device *dev = &pdev->dev;
719	struct resource *r;
720	void __iomem *dat;
721	void __iomem *set;
722	void __iomem *clr;
723	void __iomem *dirout;
724	void __iomem *dirin;
725	unsigned long sz;
726	unsigned long flags = 0;
727	int err;
728	struct gpio_chip *gc;
729	struct bgpio_pdata *pdata;
730
731	pdata = bgpio_parse_fw(dev, &flags);
732	if (IS_ERR(pdata))
733		return PTR_ERR(pdata);
734
735	if (!pdata) {
736		pdata = dev_get_platdata(dev);
737		flags = pdev->id_entry->driver_data;
738	}
739
740	r = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dat");
741	if (!r)
742		return -EINVAL;
743
744	sz = resource_size(r);
745
746	dat = bgpio_map(pdev, "dat", sz);
747	if (IS_ERR(dat))
748		return PTR_ERR(dat);
749
750	set = bgpio_map(pdev, "set", sz);
751	if (IS_ERR(set))
752		return PTR_ERR(set);
753
754	clr = bgpio_map(pdev, "clr", sz);
755	if (IS_ERR(clr))
756		return PTR_ERR(clr);
757
758	dirout = bgpio_map(pdev, "dirout", sz);
759	if (IS_ERR(dirout))
760		return PTR_ERR(dirout);
761
762	dirin = bgpio_map(pdev, "dirin", sz);
763	if (IS_ERR(dirin))
764		return PTR_ERR(dirin);
765
766	gc = devm_kzalloc(&pdev->dev, sizeof(*gc), GFP_KERNEL);
767	if (!gc)
768		return -ENOMEM;
769
770	err = bgpio_init(gc, dev, sz, dat, set, clr, dirout, dirin, flags);
771	if (err)
772		return err;
773
774	if (pdata) {
775		if (pdata->label)
776			gc->label = pdata->label;
777		gc->base = pdata->base;
778		if (pdata->ngpio > 0)
779			gc->ngpio = pdata->ngpio;
780	}
781
782	platform_set_drvdata(pdev, gc);
783
784	return devm_gpiochip_add_data(&pdev->dev, gc, NULL);
785}
786
787static const struct platform_device_id bgpio_id_table[] = {
788	{
789		.name		= "basic-mmio-gpio",
790		.driver_data	= 0,
791	}, {
792		.name		= "basic-mmio-gpio-be",
793		.driver_data	= BGPIOF_BIG_ENDIAN,
794	},
795	{ }
796};
797MODULE_DEVICE_TABLE(platform, bgpio_id_table);
798
799static struct platform_driver bgpio_driver = {
800	.driver = {
801		.name = "basic-mmio-gpio",
802		.of_match_table = bgpio_of_match,
803	},
804	.id_table = bgpio_id_table,
805	.probe = bgpio_pdev_probe,
806};
807
808module_platform_driver(bgpio_driver);
809
810#endif /* CONFIG_GPIO_GENERIC_PLATFORM */
811
812MODULE_DESCRIPTION("Driver for basic memory-mapped GPIO controllers");
813MODULE_AUTHOR("Anton Vorontsov <cbouatmailru@gmail.com>");
814MODULE_LICENSE("GPL");