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1/*
2 * PCA953x 4/8/16 bit I/O ports
3 *
4 * Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
5 * Copyright (C) 2007 Marvell International Ltd.
6 *
7 * Derived from drivers/i2c/chips/pca9539.c
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; version 2 of the License.
12 */
13
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/gpio.h>
17#include <linux/interrupt.h>
18#include <linux/irq.h>
19#include <linux/i2c.h>
20#include <linux/i2c/pca953x.h>
21#include <linux/slab.h>
22#ifdef CONFIG_OF_GPIO
23#include <linux/of_platform.h>
24#endif
25
26#define PCA953X_INPUT 0
27#define PCA953X_OUTPUT 1
28#define PCA953X_INVERT 2
29#define PCA953X_DIRECTION 3
30
31#define PCA957X_IN 0
32#define PCA957X_INVRT 1
33#define PCA957X_BKEN 2
34#define PCA957X_PUPD 3
35#define PCA957X_CFG 4
36#define PCA957X_OUT 5
37#define PCA957X_MSK 6
38#define PCA957X_INTS 7
39
40#define PCA_GPIO_MASK 0x00FF
41#define PCA_INT 0x0100
42#define PCA953X_TYPE 0x1000
43#define PCA957X_TYPE 0x2000
44
45static const struct i2c_device_id pca953x_id[] = {
46 { "pca9534", 8 | PCA953X_TYPE | PCA_INT, },
47 { "pca9535", 16 | PCA953X_TYPE | PCA_INT, },
48 { "pca9536", 4 | PCA953X_TYPE, },
49 { "pca9537", 4 | PCA953X_TYPE | PCA_INT, },
50 { "pca9538", 8 | PCA953X_TYPE | PCA_INT, },
51 { "pca9539", 16 | PCA953X_TYPE | PCA_INT, },
52 { "pca9554", 8 | PCA953X_TYPE | PCA_INT, },
53 { "pca9555", 16 | PCA953X_TYPE | PCA_INT, },
54 { "pca9556", 8 | PCA953X_TYPE, },
55 { "pca9557", 8 | PCA953X_TYPE, },
56 { "pca9574", 8 | PCA957X_TYPE | PCA_INT, },
57 { "pca9575", 16 | PCA957X_TYPE | PCA_INT, },
58
59 { "max7310", 8 | PCA953X_TYPE, },
60 { "max7312", 16 | PCA953X_TYPE | PCA_INT, },
61 { "max7313", 16 | PCA953X_TYPE | PCA_INT, },
62 { "max7315", 8 | PCA953X_TYPE | PCA_INT, },
63 { "pca6107", 8 | PCA953X_TYPE | PCA_INT, },
64 { "tca6408", 8 | PCA953X_TYPE | PCA_INT, },
65 { "tca6416", 16 | PCA953X_TYPE | PCA_INT, },
66 /* NYET: { "tca6424", 24, }, */
67 { }
68};
69MODULE_DEVICE_TABLE(i2c, pca953x_id);
70
71struct pca953x_chip {
72 unsigned gpio_start;
73 uint16_t reg_output;
74 uint16_t reg_direction;
75 struct mutex i2c_lock;
76
77#ifdef CONFIG_GPIO_PCA953X_IRQ
78 struct mutex irq_lock;
79 uint16_t irq_mask;
80 uint16_t irq_stat;
81 uint16_t irq_trig_raise;
82 uint16_t irq_trig_fall;
83 int irq_base;
84#endif
85
86 struct i2c_client *client;
87 struct gpio_chip gpio_chip;
88 const char *const *names;
89 int chip_type;
90};
91
92static int pca953x_write_reg(struct pca953x_chip *chip, int reg, uint16_t val)
93{
94 int ret = 0;
95
96 if (chip->gpio_chip.ngpio <= 8)
97 ret = i2c_smbus_write_byte_data(chip->client, reg, val);
98 else {
99 switch (chip->chip_type) {
100 case PCA953X_TYPE:
101 ret = i2c_smbus_write_word_data(chip->client,
102 reg << 1, val);
103 break;
104 case PCA957X_TYPE:
105 ret = i2c_smbus_write_byte_data(chip->client, reg << 1,
106 val & 0xff);
107 if (ret < 0)
108 break;
109 ret = i2c_smbus_write_byte_data(chip->client,
110 (reg << 1) + 1,
111 (val & 0xff00) >> 8);
112 break;
113 }
114 }
115
116 if (ret < 0) {
117 dev_err(&chip->client->dev, "failed writing register\n");
118 return ret;
119 }
120
121 return 0;
122}
123
124static int pca953x_read_reg(struct pca953x_chip *chip, int reg, uint16_t *val)
125{
126 int ret;
127
128 if (chip->gpio_chip.ngpio <= 8)
129 ret = i2c_smbus_read_byte_data(chip->client, reg);
130 else
131 ret = i2c_smbus_read_word_data(chip->client, reg << 1);
132
133 if (ret < 0) {
134 dev_err(&chip->client->dev, "failed reading register\n");
135 return ret;
136 }
137
138 *val = (uint16_t)ret;
139 return 0;
140}
141
142static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
143{
144 struct pca953x_chip *chip;
145 uint16_t reg_val;
146 int ret, offset = 0;
147
148 chip = container_of(gc, struct pca953x_chip, gpio_chip);
149
150 mutex_lock(&chip->i2c_lock);
151 reg_val = chip->reg_direction | (1u << off);
152
153 switch (chip->chip_type) {
154 case PCA953X_TYPE:
155 offset = PCA953X_DIRECTION;
156 break;
157 case PCA957X_TYPE:
158 offset = PCA957X_CFG;
159 break;
160 }
161 ret = pca953x_write_reg(chip, offset, reg_val);
162 if (ret)
163 goto exit;
164
165 chip->reg_direction = reg_val;
166 ret = 0;
167exit:
168 mutex_unlock(&chip->i2c_lock);
169 return ret;
170}
171
172static int pca953x_gpio_direction_output(struct gpio_chip *gc,
173 unsigned off, int val)
174{
175 struct pca953x_chip *chip;
176 uint16_t reg_val;
177 int ret, offset = 0;
178
179 chip = container_of(gc, struct pca953x_chip, gpio_chip);
180
181 mutex_lock(&chip->i2c_lock);
182 /* set output level */
183 if (val)
184 reg_val = chip->reg_output | (1u << off);
185 else
186 reg_val = chip->reg_output & ~(1u << off);
187
188 switch (chip->chip_type) {
189 case PCA953X_TYPE:
190 offset = PCA953X_OUTPUT;
191 break;
192 case PCA957X_TYPE:
193 offset = PCA957X_OUT;
194 break;
195 }
196 ret = pca953x_write_reg(chip, offset, reg_val);
197 if (ret)
198 goto exit;
199
200 chip->reg_output = reg_val;
201
202 /* then direction */
203 reg_val = chip->reg_direction & ~(1u << off);
204 switch (chip->chip_type) {
205 case PCA953X_TYPE:
206 offset = PCA953X_DIRECTION;
207 break;
208 case PCA957X_TYPE:
209 offset = PCA957X_CFG;
210 break;
211 }
212 ret = pca953x_write_reg(chip, offset, reg_val);
213 if (ret)
214 goto exit;
215
216 chip->reg_direction = reg_val;
217 ret = 0;
218exit:
219 mutex_unlock(&chip->i2c_lock);
220 return ret;
221}
222
223static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
224{
225 struct pca953x_chip *chip;
226 uint16_t reg_val;
227 int ret, offset = 0;
228
229 chip = container_of(gc, struct pca953x_chip, gpio_chip);
230
231 mutex_lock(&chip->i2c_lock);
232 switch (chip->chip_type) {
233 case PCA953X_TYPE:
234 offset = PCA953X_INPUT;
235 break;
236 case PCA957X_TYPE:
237 offset = PCA957X_IN;
238 break;
239 }
240 ret = pca953x_read_reg(chip, offset, ®_val);
241 mutex_unlock(&chip->i2c_lock);
242 if (ret < 0) {
243 /* NOTE: diagnostic already emitted; that's all we should
244 * do unless gpio_*_value_cansleep() calls become different
245 * from their nonsleeping siblings (and report faults).
246 */
247 return 0;
248 }
249
250 return (reg_val & (1u << off)) ? 1 : 0;
251}
252
253static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
254{
255 struct pca953x_chip *chip;
256 uint16_t reg_val;
257 int ret, offset = 0;
258
259 chip = container_of(gc, struct pca953x_chip, gpio_chip);
260
261 mutex_lock(&chip->i2c_lock);
262 if (val)
263 reg_val = chip->reg_output | (1u << off);
264 else
265 reg_val = chip->reg_output & ~(1u << off);
266
267 switch (chip->chip_type) {
268 case PCA953X_TYPE:
269 offset = PCA953X_OUTPUT;
270 break;
271 case PCA957X_TYPE:
272 offset = PCA957X_OUT;
273 break;
274 }
275 ret = pca953x_write_reg(chip, offset, reg_val);
276 if (ret)
277 goto exit;
278
279 chip->reg_output = reg_val;
280exit:
281 mutex_unlock(&chip->i2c_lock);
282}
283
284static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
285{
286 struct gpio_chip *gc;
287
288 gc = &chip->gpio_chip;
289
290 gc->direction_input = pca953x_gpio_direction_input;
291 gc->direction_output = pca953x_gpio_direction_output;
292 gc->get = pca953x_gpio_get_value;
293 gc->set = pca953x_gpio_set_value;
294 gc->can_sleep = 1;
295
296 gc->base = chip->gpio_start;
297 gc->ngpio = gpios;
298 gc->label = chip->client->name;
299 gc->dev = &chip->client->dev;
300 gc->owner = THIS_MODULE;
301 gc->names = chip->names;
302}
303
304#ifdef CONFIG_GPIO_PCA953X_IRQ
305static int pca953x_gpio_to_irq(struct gpio_chip *gc, unsigned off)
306{
307 struct pca953x_chip *chip;
308
309 chip = container_of(gc, struct pca953x_chip, gpio_chip);
310 return chip->irq_base + off;
311}
312
313static void pca953x_irq_mask(struct irq_data *d)
314{
315 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
316
317 chip->irq_mask &= ~(1 << (d->irq - chip->irq_base));
318}
319
320static void pca953x_irq_unmask(struct irq_data *d)
321{
322 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
323
324 chip->irq_mask |= 1 << (d->irq - chip->irq_base);
325}
326
327static void pca953x_irq_bus_lock(struct irq_data *d)
328{
329 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
330
331 mutex_lock(&chip->irq_lock);
332}
333
334static void pca953x_irq_bus_sync_unlock(struct irq_data *d)
335{
336 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
337 uint16_t new_irqs;
338 uint16_t level;
339
340 /* Look for any newly setup interrupt */
341 new_irqs = chip->irq_trig_fall | chip->irq_trig_raise;
342 new_irqs &= ~chip->reg_direction;
343
344 while (new_irqs) {
345 level = __ffs(new_irqs);
346 pca953x_gpio_direction_input(&chip->gpio_chip, level);
347 new_irqs &= ~(1 << level);
348 }
349
350 mutex_unlock(&chip->irq_lock);
351}
352
353static int pca953x_irq_set_type(struct irq_data *d, unsigned int type)
354{
355 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
356 uint16_t level = d->irq - chip->irq_base;
357 uint16_t mask = 1 << level;
358
359 if (!(type & IRQ_TYPE_EDGE_BOTH)) {
360 dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
361 d->irq, type);
362 return -EINVAL;
363 }
364
365 if (type & IRQ_TYPE_EDGE_FALLING)
366 chip->irq_trig_fall |= mask;
367 else
368 chip->irq_trig_fall &= ~mask;
369
370 if (type & IRQ_TYPE_EDGE_RISING)
371 chip->irq_trig_raise |= mask;
372 else
373 chip->irq_trig_raise &= ~mask;
374
375 return 0;
376}
377
378static struct irq_chip pca953x_irq_chip = {
379 .name = "pca953x",
380 .irq_mask = pca953x_irq_mask,
381 .irq_unmask = pca953x_irq_unmask,
382 .irq_bus_lock = pca953x_irq_bus_lock,
383 .irq_bus_sync_unlock = pca953x_irq_bus_sync_unlock,
384 .irq_set_type = pca953x_irq_set_type,
385};
386
387static uint16_t pca953x_irq_pending(struct pca953x_chip *chip)
388{
389 uint16_t cur_stat;
390 uint16_t old_stat;
391 uint16_t pending;
392 uint16_t trigger;
393 int ret, offset = 0;
394
395 switch (chip->chip_type) {
396 case PCA953X_TYPE:
397 offset = PCA953X_INPUT;
398 break;
399 case PCA957X_TYPE:
400 offset = PCA957X_IN;
401 break;
402 }
403 ret = pca953x_read_reg(chip, offset, &cur_stat);
404 if (ret)
405 return 0;
406
407 /* Remove output pins from the equation */
408 cur_stat &= chip->reg_direction;
409
410 old_stat = chip->irq_stat;
411 trigger = (cur_stat ^ old_stat) & chip->irq_mask;
412
413 if (!trigger)
414 return 0;
415
416 chip->irq_stat = cur_stat;
417
418 pending = (old_stat & chip->irq_trig_fall) |
419 (cur_stat & chip->irq_trig_raise);
420 pending &= trigger;
421
422 return pending;
423}
424
425static irqreturn_t pca953x_irq_handler(int irq, void *devid)
426{
427 struct pca953x_chip *chip = devid;
428 uint16_t pending;
429 uint16_t level;
430
431 pending = pca953x_irq_pending(chip);
432
433 if (!pending)
434 return IRQ_HANDLED;
435
436 do {
437 level = __ffs(pending);
438 handle_nested_irq(level + chip->irq_base);
439
440 pending &= ~(1 << level);
441 } while (pending);
442
443 return IRQ_HANDLED;
444}
445
446static int pca953x_irq_setup(struct pca953x_chip *chip,
447 const struct i2c_device_id *id,
448 int irq_base)
449{
450 struct i2c_client *client = chip->client;
451 int ret, offset = 0;
452
453 if (irq_base != -1
454 && (id->driver_data & PCA_INT)) {
455 int lvl;
456
457 switch (chip->chip_type) {
458 case PCA953X_TYPE:
459 offset = PCA953X_INPUT;
460 break;
461 case PCA957X_TYPE:
462 offset = PCA957X_IN;
463 break;
464 }
465 ret = pca953x_read_reg(chip, offset, &chip->irq_stat);
466 if (ret)
467 goto out_failed;
468
469 /*
470 * There is no way to know which GPIO line generated the
471 * interrupt. We have to rely on the previous read for
472 * this purpose.
473 */
474 chip->irq_stat &= chip->reg_direction;
475 mutex_init(&chip->irq_lock);
476
477 chip->irq_base = irq_alloc_descs(-1, irq_base, chip->gpio_chip.ngpio, -1);
478 if (chip->irq_base < 0)
479 goto out_failed;
480
481 for (lvl = 0; lvl < chip->gpio_chip.ngpio; lvl++) {
482 int irq = lvl + chip->irq_base;
483
484 irq_clear_status_flags(irq, IRQ_NOREQUEST);
485 irq_set_chip_data(irq, chip);
486 irq_set_chip(irq, &pca953x_irq_chip);
487 irq_set_nested_thread(irq, true);
488#ifdef CONFIG_ARM
489 set_irq_flags(irq, IRQF_VALID);
490#else
491 irq_set_noprobe(irq);
492#endif
493 }
494
495 ret = request_threaded_irq(client->irq,
496 NULL,
497 pca953x_irq_handler,
498 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
499 dev_name(&client->dev), chip);
500 if (ret) {
501 dev_err(&client->dev, "failed to request irq %d\n",
502 client->irq);
503 goto out_failed;
504 }
505
506 chip->gpio_chip.to_irq = pca953x_gpio_to_irq;
507 }
508
509 return 0;
510
511out_failed:
512 chip->irq_base = -1;
513 return ret;
514}
515
516static void pca953x_irq_teardown(struct pca953x_chip *chip)
517{
518 if (chip->irq_base != -1) {
519 irq_free_descs(chip->irq_base, chip->gpio_chip.ngpio);
520 free_irq(chip->client->irq, chip);
521 }
522}
523#else /* CONFIG_GPIO_PCA953X_IRQ */
524static int pca953x_irq_setup(struct pca953x_chip *chip,
525 const struct i2c_device_id *id,
526 int irq_base)
527{
528 struct i2c_client *client = chip->client;
529
530 if (irq_base != -1 && (id->driver_data & PCA_INT))
531 dev_warn(&client->dev, "interrupt support not compiled in\n");
532
533 return 0;
534}
535
536static void pca953x_irq_teardown(struct pca953x_chip *chip)
537{
538}
539#endif
540
541/*
542 * Handlers for alternative sources of platform_data
543 */
544#ifdef CONFIG_OF_GPIO
545/*
546 * Translate OpenFirmware node properties into platform_data
547 * WARNING: This is DEPRECATED and will be removed eventually!
548 */
549void
550pca953x_get_alt_pdata(struct i2c_client *client, int *gpio_base, int *invert)
551{
552 struct device_node *node;
553 const __be32 *val;
554 int size;
555
556 node = client->dev.of_node;
557 if (node == NULL)
558 return;
559
560 *gpio_base = -1;
561 val = of_get_property(node, "linux,gpio-base", &size);
562 WARN(val, "%s: device-tree property 'linux,gpio-base' is deprecated!", __func__);
563 if (val) {
564 if (size != sizeof(*val))
565 dev_warn(&client->dev, "%s: wrong linux,gpio-base\n",
566 node->full_name);
567 else
568 *gpio_base = be32_to_cpup(val);
569 }
570
571 val = of_get_property(node, "polarity", NULL);
572 WARN(val, "%s: device-tree property 'polarity' is deprecated!", __func__);
573 if (val)
574 *invert = *val;
575}
576#else
577void
578pca953x_get_alt_pdata(struct i2c_client *client, int *gpio_base, int *invert)
579{
580 *gpio_base = -1;
581}
582#endif
583
584static int __devinit device_pca953x_init(struct pca953x_chip *chip, int invert)
585{
586 int ret;
587
588 ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
589 if (ret)
590 goto out;
591
592 ret = pca953x_read_reg(chip, PCA953X_DIRECTION,
593 &chip->reg_direction);
594 if (ret)
595 goto out;
596
597 /* set platform specific polarity inversion */
598 ret = pca953x_write_reg(chip, PCA953X_INVERT, invert);
599 if (ret)
600 goto out;
601 return 0;
602out:
603 return ret;
604}
605
606static int __devinit device_pca957x_init(struct pca953x_chip *chip, int invert)
607{
608 int ret;
609 uint16_t val = 0;
610
611 /* Let every port in proper state, that could save power */
612 pca953x_write_reg(chip, PCA957X_PUPD, 0x0);
613 pca953x_write_reg(chip, PCA957X_CFG, 0xffff);
614 pca953x_write_reg(chip, PCA957X_OUT, 0x0);
615
616 ret = pca953x_read_reg(chip, PCA957X_IN, &val);
617 if (ret)
618 goto out;
619 ret = pca953x_read_reg(chip, PCA957X_OUT, &chip->reg_output);
620 if (ret)
621 goto out;
622 ret = pca953x_read_reg(chip, PCA957X_CFG, &chip->reg_direction);
623 if (ret)
624 goto out;
625
626 /* set platform specific polarity inversion */
627 pca953x_write_reg(chip, PCA957X_INVRT, invert);
628
629 /* To enable register 6, 7 to controll pull up and pull down */
630 pca953x_write_reg(chip, PCA957X_BKEN, 0x202);
631
632 return 0;
633out:
634 return ret;
635}
636
637static int __devinit pca953x_probe(struct i2c_client *client,
638 const struct i2c_device_id *id)
639{
640 struct pca953x_platform_data *pdata;
641 struct pca953x_chip *chip;
642 int irq_base=0, invert=0;
643 int ret = 0;
644
645 chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
646 if (chip == NULL)
647 return -ENOMEM;
648
649 pdata = client->dev.platform_data;
650 if (pdata) {
651 irq_base = pdata->irq_base;
652 chip->gpio_start = pdata->gpio_base;
653 invert = pdata->invert;
654 chip->names = pdata->names;
655 } else {
656 pca953x_get_alt_pdata(client, &chip->gpio_start, &invert);
657#ifdef CONFIG_OF_GPIO
658 /* If I2C node has no interrupts property, disable GPIO interrupts */
659 if (of_find_property(client->dev.of_node, "interrupts", NULL) == NULL)
660 irq_base = -1;
661#endif
662 }
663
664 chip->client = client;
665
666 chip->chip_type = id->driver_data & (PCA953X_TYPE | PCA957X_TYPE);
667
668 mutex_init(&chip->i2c_lock);
669
670 /* initialize cached registers from their original values.
671 * we can't share this chip with another i2c master.
672 */
673 pca953x_setup_gpio(chip, id->driver_data & PCA_GPIO_MASK);
674
675 if (chip->chip_type == PCA953X_TYPE)
676 device_pca953x_init(chip, invert);
677 else if (chip->chip_type == PCA957X_TYPE)
678 device_pca957x_init(chip, invert);
679 else
680 goto out_failed;
681
682 ret = pca953x_irq_setup(chip, id, irq_base);
683 if (ret)
684 goto out_failed;
685
686 ret = gpiochip_add(&chip->gpio_chip);
687 if (ret)
688 goto out_failed_irq;
689
690 if (pdata && pdata->setup) {
691 ret = pdata->setup(client, chip->gpio_chip.base,
692 chip->gpio_chip.ngpio, pdata->context);
693 if (ret < 0)
694 dev_warn(&client->dev, "setup failed, %d\n", ret);
695 }
696
697 i2c_set_clientdata(client, chip);
698 return 0;
699
700out_failed_irq:
701 pca953x_irq_teardown(chip);
702out_failed:
703 kfree(chip);
704 return ret;
705}
706
707static int pca953x_remove(struct i2c_client *client)
708{
709 struct pca953x_platform_data *pdata = client->dev.platform_data;
710 struct pca953x_chip *chip = i2c_get_clientdata(client);
711 int ret = 0;
712
713 if (pdata && pdata->teardown) {
714 ret = pdata->teardown(client, chip->gpio_chip.base,
715 chip->gpio_chip.ngpio, pdata->context);
716 if (ret < 0) {
717 dev_err(&client->dev, "%s failed, %d\n",
718 "teardown", ret);
719 return ret;
720 }
721 }
722
723 ret = gpiochip_remove(&chip->gpio_chip);
724 if (ret) {
725 dev_err(&client->dev, "%s failed, %d\n",
726 "gpiochip_remove()", ret);
727 return ret;
728 }
729
730 pca953x_irq_teardown(chip);
731 kfree(chip);
732 return 0;
733}
734
735static struct i2c_driver pca953x_driver = {
736 .driver = {
737 .name = "pca953x",
738 },
739 .probe = pca953x_probe,
740 .remove = pca953x_remove,
741 .id_table = pca953x_id,
742};
743
744static int __init pca953x_init(void)
745{
746 return i2c_add_driver(&pca953x_driver);
747}
748/* register after i2c postcore initcall and before
749 * subsys initcalls that may rely on these GPIOs
750 */
751subsys_initcall(pca953x_init);
752
753static void __exit pca953x_exit(void)
754{
755 i2c_del_driver(&pca953x_driver);
756}
757module_exit(pca953x_exit);
758
759MODULE_AUTHOR("eric miao <eric.miao@marvell.com>");
760MODULE_DESCRIPTION("GPIO expander driver for PCA953x");
761MODULE_LICENSE("GPL");
1/*
2 * PCA953x 4/8/16 bit I/O ports
3 *
4 * Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com>
5 * Copyright (C) 2007 Marvell International Ltd.
6 *
7 * Derived from drivers/i2c/chips/pca9539.c
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; version 2 of the License.
12 */
13
14#include <linux/module.h>
15#include <linux/init.h>
16#include <linux/gpio.h>
17#include <linux/interrupt.h>
18#include <linux/irq.h>
19#include <linux/i2c.h>
20#include <linux/i2c/pca953x.h>
21#include <linux/slab.h>
22#ifdef CONFIG_OF_GPIO
23#include <linux/of_platform.h>
24#endif
25
26#define PCA953X_INPUT 0
27#define PCA953X_OUTPUT 1
28#define PCA953X_INVERT 2
29#define PCA953X_DIRECTION 3
30
31#define REG_ADDR_AI 0x80
32
33#define PCA957X_IN 0
34#define PCA957X_INVRT 1
35#define PCA957X_BKEN 2
36#define PCA957X_PUPD 3
37#define PCA957X_CFG 4
38#define PCA957X_OUT 5
39#define PCA957X_MSK 6
40#define PCA957X_INTS 7
41
42#define PCA_GPIO_MASK 0x00FF
43#define PCA_INT 0x0100
44#define PCA953X_TYPE 0x1000
45#define PCA957X_TYPE 0x2000
46
47static const struct i2c_device_id pca953x_id[] = {
48 { "pca9534", 8 | PCA953X_TYPE | PCA_INT, },
49 { "pca9535", 16 | PCA953X_TYPE | PCA_INT, },
50 { "pca9536", 4 | PCA953X_TYPE, },
51 { "pca9537", 4 | PCA953X_TYPE | PCA_INT, },
52 { "pca9538", 8 | PCA953X_TYPE | PCA_INT, },
53 { "pca9539", 16 | PCA953X_TYPE | PCA_INT, },
54 { "pca9554", 8 | PCA953X_TYPE | PCA_INT, },
55 { "pca9555", 16 | PCA953X_TYPE | PCA_INT, },
56 { "pca9556", 8 | PCA953X_TYPE, },
57 { "pca9557", 8 | PCA953X_TYPE, },
58 { "pca9574", 8 | PCA957X_TYPE | PCA_INT, },
59 { "pca9575", 16 | PCA957X_TYPE | PCA_INT, },
60
61 { "max7310", 8 | PCA953X_TYPE, },
62 { "max7312", 16 | PCA953X_TYPE | PCA_INT, },
63 { "max7313", 16 | PCA953X_TYPE | PCA_INT, },
64 { "max7315", 8 | PCA953X_TYPE | PCA_INT, },
65 { "pca6107", 8 | PCA953X_TYPE | PCA_INT, },
66 { "tca6408", 8 | PCA953X_TYPE | PCA_INT, },
67 { "tca6416", 16 | PCA953X_TYPE | PCA_INT, },
68 { "tca6424", 24 | PCA953X_TYPE | PCA_INT, },
69 { }
70};
71MODULE_DEVICE_TABLE(i2c, pca953x_id);
72
73struct pca953x_chip {
74 unsigned gpio_start;
75 u32 reg_output;
76 u32 reg_direction;
77 struct mutex i2c_lock;
78
79#ifdef CONFIG_GPIO_PCA953X_IRQ
80 struct mutex irq_lock;
81 uint16_t irq_mask;
82 uint16_t irq_stat;
83 uint16_t irq_trig_raise;
84 uint16_t irq_trig_fall;
85 int irq_base;
86#endif
87
88 struct i2c_client *client;
89 struct gpio_chip gpio_chip;
90 const char *const *names;
91 int chip_type;
92};
93
94static int pca953x_write_reg(struct pca953x_chip *chip, int reg, u32 val)
95{
96 int ret = 0;
97
98 if (chip->gpio_chip.ngpio <= 8)
99 ret = i2c_smbus_write_byte_data(chip->client, reg, val);
100 else if (chip->gpio_chip.ngpio == 24) {
101 ret = i2c_smbus_write_word_data(chip->client,
102 (reg << 2) | REG_ADDR_AI,
103 val & 0xffff);
104 ret = i2c_smbus_write_byte_data(chip->client,
105 (reg << 2) + 2,
106 (val & 0xff0000) >> 16);
107 }
108 else {
109 switch (chip->chip_type) {
110 case PCA953X_TYPE:
111 ret = i2c_smbus_write_word_data(chip->client,
112 reg << 1, val);
113 break;
114 case PCA957X_TYPE:
115 ret = i2c_smbus_write_byte_data(chip->client, reg << 1,
116 val & 0xff);
117 if (ret < 0)
118 break;
119 ret = i2c_smbus_write_byte_data(chip->client,
120 (reg << 1) + 1,
121 (val & 0xff00) >> 8);
122 break;
123 }
124 }
125
126 if (ret < 0) {
127 dev_err(&chip->client->dev, "failed writing register\n");
128 return ret;
129 }
130
131 return 0;
132}
133
134static int pca953x_read_reg(struct pca953x_chip *chip, int reg, u32 *val)
135{
136 int ret;
137
138 if (chip->gpio_chip.ngpio <= 8)
139 ret = i2c_smbus_read_byte_data(chip->client, reg);
140 else if (chip->gpio_chip.ngpio == 24) {
141 ret = i2c_smbus_read_word_data(chip->client, reg << 2);
142 ret |= (i2c_smbus_read_byte_data(chip->client,
143 (reg << 2) + 2)<<16);
144 }
145 else
146 ret = i2c_smbus_read_word_data(chip->client, reg << 1);
147
148 if (ret < 0) {
149 dev_err(&chip->client->dev, "failed reading register\n");
150 return ret;
151 }
152
153 *val = (u32)ret;
154 return 0;
155}
156
157static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
158{
159 struct pca953x_chip *chip;
160 uint reg_val;
161 int ret, offset = 0;
162
163 chip = container_of(gc, struct pca953x_chip, gpio_chip);
164
165 mutex_lock(&chip->i2c_lock);
166 reg_val = chip->reg_direction | (1u << off);
167
168 switch (chip->chip_type) {
169 case PCA953X_TYPE:
170 offset = PCA953X_DIRECTION;
171 break;
172 case PCA957X_TYPE:
173 offset = PCA957X_CFG;
174 break;
175 }
176 ret = pca953x_write_reg(chip, offset, reg_val);
177 if (ret)
178 goto exit;
179
180 chip->reg_direction = reg_val;
181 ret = 0;
182exit:
183 mutex_unlock(&chip->i2c_lock);
184 return ret;
185}
186
187static int pca953x_gpio_direction_output(struct gpio_chip *gc,
188 unsigned off, int val)
189{
190 struct pca953x_chip *chip;
191 uint reg_val;
192 int ret, offset = 0;
193
194 chip = container_of(gc, struct pca953x_chip, gpio_chip);
195
196 mutex_lock(&chip->i2c_lock);
197 /* set output level */
198 if (val)
199 reg_val = chip->reg_output | (1u << off);
200 else
201 reg_val = chip->reg_output & ~(1u << off);
202
203 switch (chip->chip_type) {
204 case PCA953X_TYPE:
205 offset = PCA953X_OUTPUT;
206 break;
207 case PCA957X_TYPE:
208 offset = PCA957X_OUT;
209 break;
210 }
211 ret = pca953x_write_reg(chip, offset, reg_val);
212 if (ret)
213 goto exit;
214
215 chip->reg_output = reg_val;
216
217 /* then direction */
218 reg_val = chip->reg_direction & ~(1u << off);
219 switch (chip->chip_type) {
220 case PCA953X_TYPE:
221 offset = PCA953X_DIRECTION;
222 break;
223 case PCA957X_TYPE:
224 offset = PCA957X_CFG;
225 break;
226 }
227 ret = pca953x_write_reg(chip, offset, reg_val);
228 if (ret)
229 goto exit;
230
231 chip->reg_direction = reg_val;
232 ret = 0;
233exit:
234 mutex_unlock(&chip->i2c_lock);
235 return ret;
236}
237
238static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
239{
240 struct pca953x_chip *chip;
241 u32 reg_val;
242 int ret, offset = 0;
243
244 chip = container_of(gc, struct pca953x_chip, gpio_chip);
245
246 mutex_lock(&chip->i2c_lock);
247 switch (chip->chip_type) {
248 case PCA953X_TYPE:
249 offset = PCA953X_INPUT;
250 break;
251 case PCA957X_TYPE:
252 offset = PCA957X_IN;
253 break;
254 }
255 ret = pca953x_read_reg(chip, offset, ®_val);
256 mutex_unlock(&chip->i2c_lock);
257 if (ret < 0) {
258 /* NOTE: diagnostic already emitted; that's all we should
259 * do unless gpio_*_value_cansleep() calls become different
260 * from their nonsleeping siblings (and report faults).
261 */
262 return 0;
263 }
264
265 return (reg_val & (1u << off)) ? 1 : 0;
266}
267
268static void pca953x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
269{
270 struct pca953x_chip *chip;
271 u32 reg_val;
272 int ret, offset = 0;
273
274 chip = container_of(gc, struct pca953x_chip, gpio_chip);
275
276 mutex_lock(&chip->i2c_lock);
277 if (val)
278 reg_val = chip->reg_output | (1u << off);
279 else
280 reg_val = chip->reg_output & ~(1u << off);
281
282 switch (chip->chip_type) {
283 case PCA953X_TYPE:
284 offset = PCA953X_OUTPUT;
285 break;
286 case PCA957X_TYPE:
287 offset = PCA957X_OUT;
288 break;
289 }
290 ret = pca953x_write_reg(chip, offset, reg_val);
291 if (ret)
292 goto exit;
293
294 chip->reg_output = reg_val;
295exit:
296 mutex_unlock(&chip->i2c_lock);
297}
298
299static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
300{
301 struct gpio_chip *gc;
302
303 gc = &chip->gpio_chip;
304
305 gc->direction_input = pca953x_gpio_direction_input;
306 gc->direction_output = pca953x_gpio_direction_output;
307 gc->get = pca953x_gpio_get_value;
308 gc->set = pca953x_gpio_set_value;
309 gc->can_sleep = 1;
310
311 gc->base = chip->gpio_start;
312 gc->ngpio = gpios;
313 gc->label = chip->client->name;
314 gc->dev = &chip->client->dev;
315 gc->owner = THIS_MODULE;
316 gc->names = chip->names;
317}
318
319#ifdef CONFIG_GPIO_PCA953X_IRQ
320static int pca953x_gpio_to_irq(struct gpio_chip *gc, unsigned off)
321{
322 struct pca953x_chip *chip;
323
324 chip = container_of(gc, struct pca953x_chip, gpio_chip);
325 return chip->irq_base + off;
326}
327
328static void pca953x_irq_mask(struct irq_data *d)
329{
330 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
331
332 chip->irq_mask &= ~(1 << (d->irq - chip->irq_base));
333}
334
335static void pca953x_irq_unmask(struct irq_data *d)
336{
337 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
338
339 chip->irq_mask |= 1 << (d->irq - chip->irq_base);
340}
341
342static void pca953x_irq_bus_lock(struct irq_data *d)
343{
344 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
345
346 mutex_lock(&chip->irq_lock);
347}
348
349static void pca953x_irq_bus_sync_unlock(struct irq_data *d)
350{
351 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
352 uint16_t new_irqs;
353 uint16_t level;
354
355 /* Look for any newly setup interrupt */
356 new_irqs = chip->irq_trig_fall | chip->irq_trig_raise;
357 new_irqs &= ~chip->reg_direction;
358
359 while (new_irqs) {
360 level = __ffs(new_irqs);
361 pca953x_gpio_direction_input(&chip->gpio_chip, level);
362 new_irqs &= ~(1 << level);
363 }
364
365 mutex_unlock(&chip->irq_lock);
366}
367
368static int pca953x_irq_set_type(struct irq_data *d, unsigned int type)
369{
370 struct pca953x_chip *chip = irq_data_get_irq_chip_data(d);
371 uint16_t level = d->irq - chip->irq_base;
372 uint16_t mask = 1 << level;
373
374 if (!(type & IRQ_TYPE_EDGE_BOTH)) {
375 dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
376 d->irq, type);
377 return -EINVAL;
378 }
379
380 if (type & IRQ_TYPE_EDGE_FALLING)
381 chip->irq_trig_fall |= mask;
382 else
383 chip->irq_trig_fall &= ~mask;
384
385 if (type & IRQ_TYPE_EDGE_RISING)
386 chip->irq_trig_raise |= mask;
387 else
388 chip->irq_trig_raise &= ~mask;
389
390 return 0;
391}
392
393static struct irq_chip pca953x_irq_chip = {
394 .name = "pca953x",
395 .irq_mask = pca953x_irq_mask,
396 .irq_unmask = pca953x_irq_unmask,
397 .irq_bus_lock = pca953x_irq_bus_lock,
398 .irq_bus_sync_unlock = pca953x_irq_bus_sync_unlock,
399 .irq_set_type = pca953x_irq_set_type,
400};
401
402static uint16_t pca953x_irq_pending(struct pca953x_chip *chip)
403{
404 u32 cur_stat;
405 uint16_t old_stat;
406 uint16_t pending;
407 uint16_t trigger;
408 int ret, offset = 0;
409
410 switch (chip->chip_type) {
411 case PCA953X_TYPE:
412 offset = PCA953X_INPUT;
413 break;
414 case PCA957X_TYPE:
415 offset = PCA957X_IN;
416 break;
417 }
418 ret = pca953x_read_reg(chip, offset, &cur_stat);
419 if (ret)
420 return 0;
421
422 /* Remove output pins from the equation */
423 cur_stat &= chip->reg_direction;
424
425 old_stat = chip->irq_stat;
426 trigger = (cur_stat ^ old_stat) & chip->irq_mask;
427
428 if (!trigger)
429 return 0;
430
431 chip->irq_stat = cur_stat;
432
433 pending = (old_stat & chip->irq_trig_fall) |
434 (cur_stat & chip->irq_trig_raise);
435 pending &= trigger;
436
437 return pending;
438}
439
440static irqreturn_t pca953x_irq_handler(int irq, void *devid)
441{
442 struct pca953x_chip *chip = devid;
443 uint16_t pending;
444 uint16_t level;
445
446 pending = pca953x_irq_pending(chip);
447
448 if (!pending)
449 return IRQ_HANDLED;
450
451 do {
452 level = __ffs(pending);
453 handle_nested_irq(level + chip->irq_base);
454
455 pending &= ~(1 << level);
456 } while (pending);
457
458 return IRQ_HANDLED;
459}
460
461static int pca953x_irq_setup(struct pca953x_chip *chip,
462 const struct i2c_device_id *id,
463 int irq_base)
464{
465 struct i2c_client *client = chip->client;
466 int ret, offset = 0;
467 u32 temporary;
468
469 if (irq_base != -1
470 && (id->driver_data & PCA_INT)) {
471 int lvl;
472
473 switch (chip->chip_type) {
474 case PCA953X_TYPE:
475 offset = PCA953X_INPUT;
476 break;
477 case PCA957X_TYPE:
478 offset = PCA957X_IN;
479 break;
480 }
481 ret = pca953x_read_reg(chip, offset, &temporary);
482 chip->irq_stat = temporary;
483 if (ret)
484 goto out_failed;
485
486 /*
487 * There is no way to know which GPIO line generated the
488 * interrupt. We have to rely on the previous read for
489 * this purpose.
490 */
491 chip->irq_stat &= chip->reg_direction;
492 mutex_init(&chip->irq_lock);
493
494 chip->irq_base = irq_alloc_descs(-1, irq_base, chip->gpio_chip.ngpio, -1);
495 if (chip->irq_base < 0)
496 goto out_failed;
497
498 for (lvl = 0; lvl < chip->gpio_chip.ngpio; lvl++) {
499 int irq = lvl + chip->irq_base;
500
501 irq_clear_status_flags(irq, IRQ_NOREQUEST);
502 irq_set_chip_data(irq, chip);
503 irq_set_chip(irq, &pca953x_irq_chip);
504 irq_set_nested_thread(irq, true);
505#ifdef CONFIG_ARM
506 set_irq_flags(irq, IRQF_VALID);
507#else
508 irq_set_noprobe(irq);
509#endif
510 }
511
512 ret = request_threaded_irq(client->irq,
513 NULL,
514 pca953x_irq_handler,
515 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
516 dev_name(&client->dev), chip);
517 if (ret) {
518 dev_err(&client->dev, "failed to request irq %d\n",
519 client->irq);
520 goto out_failed;
521 }
522
523 chip->gpio_chip.to_irq = pca953x_gpio_to_irq;
524 }
525
526 return 0;
527
528out_failed:
529 chip->irq_base = -1;
530 return ret;
531}
532
533static void pca953x_irq_teardown(struct pca953x_chip *chip)
534{
535 if (chip->irq_base != -1) {
536 irq_free_descs(chip->irq_base, chip->gpio_chip.ngpio);
537 free_irq(chip->client->irq, chip);
538 }
539}
540#else /* CONFIG_GPIO_PCA953X_IRQ */
541static int pca953x_irq_setup(struct pca953x_chip *chip,
542 const struct i2c_device_id *id,
543 int irq_base)
544{
545 struct i2c_client *client = chip->client;
546
547 if (irq_base != -1 && (id->driver_data & PCA_INT))
548 dev_warn(&client->dev, "interrupt support not compiled in\n");
549
550 return 0;
551}
552
553static void pca953x_irq_teardown(struct pca953x_chip *chip)
554{
555}
556#endif
557
558/*
559 * Handlers for alternative sources of platform_data
560 */
561#ifdef CONFIG_OF_GPIO
562/*
563 * Translate OpenFirmware node properties into platform_data
564 * WARNING: This is DEPRECATED and will be removed eventually!
565 */
566static void
567pca953x_get_alt_pdata(struct i2c_client *client, int *gpio_base, int *invert)
568{
569 struct device_node *node;
570 const __be32 *val;
571 int size;
572
573 node = client->dev.of_node;
574 if (node == NULL)
575 return;
576
577 *gpio_base = -1;
578 val = of_get_property(node, "linux,gpio-base", &size);
579 WARN(val, "%s: device-tree property 'linux,gpio-base' is deprecated!", __func__);
580 if (val) {
581 if (size != sizeof(*val))
582 dev_warn(&client->dev, "%s: wrong linux,gpio-base\n",
583 node->full_name);
584 else
585 *gpio_base = be32_to_cpup(val);
586 }
587
588 val = of_get_property(node, "polarity", NULL);
589 WARN(val, "%s: device-tree property 'polarity' is deprecated!", __func__);
590 if (val)
591 *invert = *val;
592}
593#else
594static void
595pca953x_get_alt_pdata(struct i2c_client *client, int *gpio_base, int *invert)
596{
597 *gpio_base = -1;
598}
599#endif
600
601static int __devinit device_pca953x_init(struct pca953x_chip *chip, int invert)
602{
603 int ret;
604
605 ret = pca953x_read_reg(chip, PCA953X_OUTPUT, &chip->reg_output);
606 if (ret)
607 goto out;
608
609 ret = pca953x_read_reg(chip, PCA953X_DIRECTION,
610 &chip->reg_direction);
611 if (ret)
612 goto out;
613
614 /* set platform specific polarity inversion */
615 ret = pca953x_write_reg(chip, PCA953X_INVERT, invert);
616out:
617 return ret;
618}
619
620static int __devinit device_pca957x_init(struct pca953x_chip *chip, int invert)
621{
622 int ret;
623 u32 val = 0;
624
625 /* Let every port in proper state, that could save power */
626 pca953x_write_reg(chip, PCA957X_PUPD, 0x0);
627 pca953x_write_reg(chip, PCA957X_CFG, 0xffff);
628 pca953x_write_reg(chip, PCA957X_OUT, 0x0);
629
630 ret = pca953x_read_reg(chip, PCA957X_IN, &val);
631 if (ret)
632 goto out;
633 ret = pca953x_read_reg(chip, PCA957X_OUT, &chip->reg_output);
634 if (ret)
635 goto out;
636 ret = pca953x_read_reg(chip, PCA957X_CFG, &chip->reg_direction);
637 if (ret)
638 goto out;
639
640 /* set platform specific polarity inversion */
641 pca953x_write_reg(chip, PCA957X_INVRT, invert);
642
643 /* To enable register 6, 7 to controll pull up and pull down */
644 pca953x_write_reg(chip, PCA957X_BKEN, 0x202);
645
646 return 0;
647out:
648 return ret;
649}
650
651static int __devinit pca953x_probe(struct i2c_client *client,
652 const struct i2c_device_id *id)
653{
654 struct pca953x_platform_data *pdata;
655 struct pca953x_chip *chip;
656 int irq_base=0, invert=0;
657 int ret;
658
659 chip = kzalloc(sizeof(struct pca953x_chip), GFP_KERNEL);
660 if (chip == NULL)
661 return -ENOMEM;
662
663 pdata = client->dev.platform_data;
664 if (pdata) {
665 irq_base = pdata->irq_base;
666 chip->gpio_start = pdata->gpio_base;
667 invert = pdata->invert;
668 chip->names = pdata->names;
669 } else {
670 pca953x_get_alt_pdata(client, &chip->gpio_start, &invert);
671#ifdef CONFIG_OF_GPIO
672 /* If I2C node has no interrupts property, disable GPIO interrupts */
673 if (of_find_property(client->dev.of_node, "interrupts", NULL) == NULL)
674 irq_base = -1;
675#endif
676 }
677
678 chip->client = client;
679
680 chip->chip_type = id->driver_data & (PCA953X_TYPE | PCA957X_TYPE);
681
682 mutex_init(&chip->i2c_lock);
683
684 /* initialize cached registers from their original values.
685 * we can't share this chip with another i2c master.
686 */
687 pca953x_setup_gpio(chip, id->driver_data & PCA_GPIO_MASK);
688
689 if (chip->chip_type == PCA953X_TYPE)
690 ret = device_pca953x_init(chip, invert);
691 else
692 ret = device_pca957x_init(chip, invert);
693 if (ret)
694 goto out_failed;
695
696 ret = pca953x_irq_setup(chip, id, irq_base);
697 if (ret)
698 goto out_failed;
699
700 ret = gpiochip_add(&chip->gpio_chip);
701 if (ret)
702 goto out_failed_irq;
703
704 if (pdata && pdata->setup) {
705 ret = pdata->setup(client, chip->gpio_chip.base,
706 chip->gpio_chip.ngpio, pdata->context);
707 if (ret < 0)
708 dev_warn(&client->dev, "setup failed, %d\n", ret);
709 }
710
711 i2c_set_clientdata(client, chip);
712 return 0;
713
714out_failed_irq:
715 pca953x_irq_teardown(chip);
716out_failed:
717 kfree(chip);
718 return ret;
719}
720
721static int pca953x_remove(struct i2c_client *client)
722{
723 struct pca953x_platform_data *pdata = client->dev.platform_data;
724 struct pca953x_chip *chip = i2c_get_clientdata(client);
725 int ret = 0;
726
727 if (pdata && pdata->teardown) {
728 ret = pdata->teardown(client, chip->gpio_chip.base,
729 chip->gpio_chip.ngpio, pdata->context);
730 if (ret < 0) {
731 dev_err(&client->dev, "%s failed, %d\n",
732 "teardown", ret);
733 return ret;
734 }
735 }
736
737 ret = gpiochip_remove(&chip->gpio_chip);
738 if (ret) {
739 dev_err(&client->dev, "%s failed, %d\n",
740 "gpiochip_remove()", ret);
741 return ret;
742 }
743
744 pca953x_irq_teardown(chip);
745 kfree(chip);
746 return 0;
747}
748
749static struct i2c_driver pca953x_driver = {
750 .driver = {
751 .name = "pca953x",
752 },
753 .probe = pca953x_probe,
754 .remove = pca953x_remove,
755 .id_table = pca953x_id,
756};
757
758static int __init pca953x_init(void)
759{
760 return i2c_add_driver(&pca953x_driver);
761}
762/* register after i2c postcore initcall and before
763 * subsys initcalls that may rely on these GPIOs
764 */
765subsys_initcall(pca953x_init);
766
767static void __exit pca953x_exit(void)
768{
769 i2c_del_driver(&pca953x_driver);
770}
771module_exit(pca953x_exit);
772
773MODULE_AUTHOR("eric miao <eric.miao@marvell.com>");
774MODULE_DESCRIPTION("GPIO expander driver for PCA953x");
775MODULE_LICENSE("GPL");