xref: /openbmc/linux/drivers/gpio/gpio-max732x.c (revision 9cfc5c90)
1 /*
2  *  MAX732x I2C Port Expander with 8/16 I/O
3  *
4  *  Copyright (C) 2007 Marvell International Ltd.
5  *  Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
6  *  Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
7  *  Copyright (C) 2015 Linus Walleij <linus.walleij@linaro.org>
8  *
9  *  Derived from drivers/gpio/pca953x.c
10  *
11  *  This program is free software; you can redistribute it and/or modify
12  *  it under the terms of the GNU General Public License as published by
13  *  the Free Software Foundation; version 2 of the License.
14  */
15 
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/slab.h>
19 #include <linux/string.h>
20 #include <linux/gpio/driver.h>
21 #include <linux/interrupt.h>
22 #include <linux/i2c.h>
23 #include <linux/i2c/max732x.h>
24 #include <linux/of.h>
25 
26 
27 /*
28  * Each port of MAX732x (including MAX7319) falls into one of the
29  * following three types:
30  *
31  *   - Push Pull Output
32  *   - Input
33  *   - Open Drain I/O
34  *
35  * designated by 'O', 'I' and 'P' individually according to MAXIM's
36  * datasheets. 'I' and 'P' ports are interrupt capables, some with
37  * a dedicated interrupt mask.
38  *
39  * There are two groups of I/O ports, each group usually includes
40  * up to 8 I/O ports, and is accessed by a specific I2C address:
41  *
42  *   - Group A : by I2C address 0b'110xxxx
43  *   - Group B : by I2C address 0b'101xxxx
44  *
45  * where 'xxxx' is decided by the connections of pin AD2/AD0.  The
46  * address used also affects the initial state of output signals.
47  *
48  * Within each group of ports, there are five known combinations of
49  * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
50  * the detailed organization of these ports. Only Goup A is interrupt
51  * capable.
52  *
53  * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
54  * and GPIOs from GROUP_A are numbered before those from GROUP_B
55  * (if there are two groups).
56  *
57  * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
58  * they are not supported by this driver.
59  */
60 
61 #define PORT_NONE	0x0	/* '/' No Port */
62 #define PORT_OUTPUT	0x1	/* 'O' Push-Pull, Output Only */
63 #define PORT_INPUT	0x2	/* 'I' Input Only */
64 #define PORT_OPENDRAIN	0x3	/* 'P' Open-Drain, I/O */
65 
66 #define IO_4I4O		0x5AA5	/* O7 O6 I5 I4 I3 I2 O1 O0 */
67 #define IO_4P4O		0x5FF5	/* O7 O6 P5 P4 P3 P2 O1 O0 */
68 #define IO_8I		0xAAAA	/* I7 I6 I5 I4 I3 I2 I1 I0 */
69 #define IO_8P		0xFFFF	/* P7 P6 P5 P4 P3 P2 P1 P0 */
70 #define IO_8O		0x5555	/* O7 O6 O5 O4 O3 O2 O1 O0 */
71 
72 #define GROUP_A(x)	((x) & 0xffff)	/* I2C Addr: 0b'110xxxx */
73 #define GROUP_B(x)	((x) << 16)	/* I2C Addr: 0b'101xxxx */
74 
75 #define INT_NONE	0x0	/* No interrupt capability */
76 #define INT_NO_MASK	0x1	/* Has interrupts, no mask */
77 #define INT_INDEP_MASK	0x2	/* Has interrupts, independent mask */
78 #define INT_MERGED_MASK 0x3	/* Has interrupts, merged mask */
79 
80 #define INT_CAPS(x)	(((uint64_t)(x)) << 32)
81 
82 enum {
83 	MAX7319,
84 	MAX7320,
85 	MAX7321,
86 	MAX7322,
87 	MAX7323,
88 	MAX7324,
89 	MAX7325,
90 	MAX7326,
91 	MAX7327,
92 };
93 
94 static uint64_t max732x_features[] = {
95 	[MAX7319] = GROUP_A(IO_8I) | INT_CAPS(INT_MERGED_MASK),
96 	[MAX7320] = GROUP_B(IO_8O),
97 	[MAX7321] = GROUP_A(IO_8P) | INT_CAPS(INT_NO_MASK),
98 	[MAX7322] = GROUP_A(IO_4I4O) | INT_CAPS(INT_MERGED_MASK),
99 	[MAX7323] = GROUP_A(IO_4P4O) | INT_CAPS(INT_INDEP_MASK),
100 	[MAX7324] = GROUP_A(IO_8I) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK),
101 	[MAX7325] = GROUP_A(IO_8P) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK),
102 	[MAX7326] = GROUP_A(IO_4I4O) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK),
103 	[MAX7327] = GROUP_A(IO_4P4O) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK),
104 };
105 
106 static const struct i2c_device_id max732x_id[] = {
107 	{ "max7319", MAX7319 },
108 	{ "max7320", MAX7320 },
109 	{ "max7321", MAX7321 },
110 	{ "max7322", MAX7322 },
111 	{ "max7323", MAX7323 },
112 	{ "max7324", MAX7324 },
113 	{ "max7325", MAX7325 },
114 	{ "max7326", MAX7326 },
115 	{ "max7327", MAX7327 },
116 	{ },
117 };
118 MODULE_DEVICE_TABLE(i2c, max732x_id);
119 
120 #ifdef CONFIG_OF
121 static const struct of_device_id max732x_of_table[] = {
122 	{ .compatible = "maxim,max7319" },
123 	{ .compatible = "maxim,max7320" },
124 	{ .compatible = "maxim,max7321" },
125 	{ .compatible = "maxim,max7322" },
126 	{ .compatible = "maxim,max7323" },
127 	{ .compatible = "maxim,max7324" },
128 	{ .compatible = "maxim,max7325" },
129 	{ .compatible = "maxim,max7326" },
130 	{ .compatible = "maxim,max7327" },
131 	{ }
132 };
133 MODULE_DEVICE_TABLE(of, max732x_of_table);
134 #endif
135 
136 struct max732x_chip {
137 	struct gpio_chip gpio_chip;
138 
139 	struct i2c_client *client;	/* "main" client */
140 	struct i2c_client *client_dummy;
141 	struct i2c_client *client_group_a;
142 	struct i2c_client *client_group_b;
143 
144 	unsigned int	mask_group_a;
145 	unsigned int	dir_input;
146 	unsigned int	dir_output;
147 
148 	struct mutex	lock;
149 	uint8_t		reg_out[2];
150 
151 #ifdef CONFIG_GPIO_MAX732X_IRQ
152 	struct mutex		irq_lock;
153 	uint8_t			irq_mask;
154 	uint8_t			irq_mask_cur;
155 	uint8_t			irq_trig_raise;
156 	uint8_t			irq_trig_fall;
157 	uint8_t			irq_features;
158 #endif
159 };
160 
161 static inline struct max732x_chip *to_max732x(struct gpio_chip *gc)
162 {
163 	return container_of(gc, struct max732x_chip, gpio_chip);
164 }
165 
166 static int max732x_writeb(struct max732x_chip *chip, int group_a, uint8_t val)
167 {
168 	struct i2c_client *client;
169 	int ret;
170 
171 	client = group_a ? chip->client_group_a : chip->client_group_b;
172 	ret = i2c_smbus_write_byte(client, val);
173 	if (ret < 0) {
174 		dev_err(&client->dev, "failed writing\n");
175 		return ret;
176 	}
177 
178 	return 0;
179 }
180 
181 static int max732x_readb(struct max732x_chip *chip, int group_a, uint8_t *val)
182 {
183 	struct i2c_client *client;
184 	int ret;
185 
186 	client = group_a ? chip->client_group_a : chip->client_group_b;
187 	ret = i2c_smbus_read_byte(client);
188 	if (ret < 0) {
189 		dev_err(&client->dev, "failed reading\n");
190 		return ret;
191 	}
192 
193 	*val = (uint8_t)ret;
194 	return 0;
195 }
196 
197 static inline int is_group_a(struct max732x_chip *chip, unsigned off)
198 {
199 	return (1u << off) & chip->mask_group_a;
200 }
201 
202 static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
203 {
204 	struct max732x_chip *chip = to_max732x(gc);
205 	uint8_t reg_val;
206 	int ret;
207 
208 	ret = max732x_readb(chip, is_group_a(chip, off), &reg_val);
209 	if (ret < 0)
210 		return 0;
211 
212 	return reg_val & (1u << (off & 0x7));
213 }
214 
215 static void max732x_gpio_set_mask(struct gpio_chip *gc, unsigned off, int mask,
216 				  int val)
217 {
218 	struct max732x_chip *chip = to_max732x(gc);
219 	uint8_t reg_out;
220 	int ret;
221 
222 	mutex_lock(&chip->lock);
223 
224 	reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
225 	reg_out = (reg_out & ~mask) | (val & mask);
226 
227 	ret = max732x_writeb(chip, is_group_a(chip, off), reg_out);
228 	if (ret < 0)
229 		goto out;
230 
231 	/* update the shadow register then */
232 	if (off > 7)
233 		chip->reg_out[1] = reg_out;
234 	else
235 		chip->reg_out[0] = reg_out;
236 out:
237 	mutex_unlock(&chip->lock);
238 }
239 
240 static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
241 {
242 	unsigned base = off & ~0x7;
243 	uint8_t mask = 1u << (off & 0x7);
244 
245 	max732x_gpio_set_mask(gc, base, mask, val << (off & 0x7));
246 }
247 
248 static void max732x_gpio_set_multiple(struct gpio_chip *gc,
249 				      unsigned long *mask, unsigned long *bits)
250 {
251 	unsigned mask_lo = mask[0] & 0xff;
252 	unsigned mask_hi = (mask[0] >> 8) & 0xff;
253 
254 	if (mask_lo)
255 		max732x_gpio_set_mask(gc, 0, mask_lo, bits[0] & 0xff);
256 	if (mask_hi)
257 		max732x_gpio_set_mask(gc, 8, mask_hi, (bits[0] >> 8) & 0xff);
258 }
259 
260 static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
261 {
262 	struct max732x_chip *chip = to_max732x(gc);
263 	unsigned int mask = 1u << off;
264 
265 	if ((mask & chip->dir_input) == 0) {
266 		dev_dbg(&chip->client->dev, "%s port %d is output only\n",
267 			chip->client->name, off);
268 		return -EACCES;
269 	}
270 
271 	/*
272 	 * Open-drain pins must be set to high impedance (which is
273 	 * equivalent to output-high) to be turned into an input.
274 	 */
275 	if ((mask & chip->dir_output))
276 		max732x_gpio_set_value(gc, off, 1);
277 
278 	return 0;
279 }
280 
281 static int max732x_gpio_direction_output(struct gpio_chip *gc,
282 		unsigned off, int val)
283 {
284 	struct max732x_chip *chip = to_max732x(gc);
285 	unsigned int mask = 1u << off;
286 
287 	if ((mask & chip->dir_output) == 0) {
288 		dev_dbg(&chip->client->dev, "%s port %d is input only\n",
289 			chip->client->name, off);
290 		return -EACCES;
291 	}
292 
293 	max732x_gpio_set_value(gc, off, val);
294 	return 0;
295 }
296 
297 #ifdef CONFIG_GPIO_MAX732X_IRQ
298 static int max732x_writew(struct max732x_chip *chip, uint16_t val)
299 {
300 	int ret;
301 
302 	val = cpu_to_le16(val);
303 
304 	ret = i2c_master_send(chip->client_group_a, (char *)&val, 2);
305 	if (ret < 0) {
306 		dev_err(&chip->client_group_a->dev, "failed writing\n");
307 		return ret;
308 	}
309 
310 	return 0;
311 }
312 
313 static int max732x_readw(struct max732x_chip *chip, uint16_t *val)
314 {
315 	int ret;
316 
317 	ret = i2c_master_recv(chip->client_group_a, (char *)val, 2);
318 	if (ret < 0) {
319 		dev_err(&chip->client_group_a->dev, "failed reading\n");
320 		return ret;
321 	}
322 
323 	*val = le16_to_cpu(*val);
324 	return 0;
325 }
326 
327 static void max732x_irq_update_mask(struct max732x_chip *chip)
328 {
329 	uint16_t msg;
330 
331 	if (chip->irq_mask == chip->irq_mask_cur)
332 		return;
333 
334 	chip->irq_mask = chip->irq_mask_cur;
335 
336 	if (chip->irq_features == INT_NO_MASK)
337 		return;
338 
339 	mutex_lock(&chip->lock);
340 
341 	switch (chip->irq_features) {
342 	case INT_INDEP_MASK:
343 		msg = (chip->irq_mask << 8) | chip->reg_out[0];
344 		max732x_writew(chip, msg);
345 		break;
346 
347 	case INT_MERGED_MASK:
348 		msg = chip->irq_mask | chip->reg_out[0];
349 		max732x_writeb(chip, 1, (uint8_t)msg);
350 		break;
351 	}
352 
353 	mutex_unlock(&chip->lock);
354 }
355 
356 static void max732x_irq_mask(struct irq_data *d)
357 {
358 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
359 	struct max732x_chip *chip = to_max732x(gc);
360 
361 	chip->irq_mask_cur &= ~(1 << d->hwirq);
362 }
363 
364 static void max732x_irq_unmask(struct irq_data *d)
365 {
366 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
367 	struct max732x_chip *chip = to_max732x(gc);
368 
369 	chip->irq_mask_cur |= 1 << d->hwirq;
370 }
371 
372 static void max732x_irq_bus_lock(struct irq_data *d)
373 {
374 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
375 	struct max732x_chip *chip = to_max732x(gc);
376 
377 	mutex_lock(&chip->irq_lock);
378 	chip->irq_mask_cur = chip->irq_mask;
379 }
380 
381 static void max732x_irq_bus_sync_unlock(struct irq_data *d)
382 {
383 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
384 	struct max732x_chip *chip = to_max732x(gc);
385 	uint16_t new_irqs;
386 	uint16_t level;
387 
388 	max732x_irq_update_mask(chip);
389 
390 	new_irqs = chip->irq_trig_fall | chip->irq_trig_raise;
391 	while (new_irqs) {
392 		level = __ffs(new_irqs);
393 		max732x_gpio_direction_input(&chip->gpio_chip, level);
394 		new_irqs &= ~(1 << level);
395 	}
396 
397 	mutex_unlock(&chip->irq_lock);
398 }
399 
400 static int max732x_irq_set_type(struct irq_data *d, unsigned int type)
401 {
402 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
403 	struct max732x_chip *chip = to_max732x(gc);
404 	uint16_t off = d->hwirq;
405 	uint16_t mask = 1 << off;
406 
407 	if (!(mask & chip->dir_input)) {
408 		dev_dbg(&chip->client->dev, "%s port %d is output only\n",
409 			chip->client->name, off);
410 		return -EACCES;
411 	}
412 
413 	if (!(type & IRQ_TYPE_EDGE_BOTH)) {
414 		dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
415 			d->irq, type);
416 		return -EINVAL;
417 	}
418 
419 	if (type & IRQ_TYPE_EDGE_FALLING)
420 		chip->irq_trig_fall |= mask;
421 	else
422 		chip->irq_trig_fall &= ~mask;
423 
424 	if (type & IRQ_TYPE_EDGE_RISING)
425 		chip->irq_trig_raise |= mask;
426 	else
427 		chip->irq_trig_raise &= ~mask;
428 
429 	return 0;
430 }
431 
432 static int max732x_irq_set_wake(struct irq_data *data, unsigned int on)
433 {
434 	struct max732x_chip *chip = irq_data_get_irq_chip_data(data);
435 
436 	irq_set_irq_wake(chip->client->irq, on);
437 	return 0;
438 }
439 
440 static struct irq_chip max732x_irq_chip = {
441 	.name			= "max732x",
442 	.irq_mask		= max732x_irq_mask,
443 	.irq_unmask		= max732x_irq_unmask,
444 	.irq_bus_lock		= max732x_irq_bus_lock,
445 	.irq_bus_sync_unlock	= max732x_irq_bus_sync_unlock,
446 	.irq_set_type		= max732x_irq_set_type,
447 	.irq_set_wake		= max732x_irq_set_wake,
448 };
449 
450 static uint8_t max732x_irq_pending(struct max732x_chip *chip)
451 {
452 	uint8_t cur_stat;
453 	uint8_t old_stat;
454 	uint8_t trigger;
455 	uint8_t pending;
456 	uint16_t status;
457 	int ret;
458 
459 	ret = max732x_readw(chip, &status);
460 	if (ret)
461 		return 0;
462 
463 	trigger = status >> 8;
464 	trigger &= chip->irq_mask;
465 
466 	if (!trigger)
467 		return 0;
468 
469 	cur_stat = status & 0xFF;
470 	cur_stat &= chip->irq_mask;
471 
472 	old_stat = cur_stat ^ trigger;
473 
474 	pending = (old_stat & chip->irq_trig_fall) |
475 		  (cur_stat & chip->irq_trig_raise);
476 	pending &= trigger;
477 
478 	return pending;
479 }
480 
481 static irqreturn_t max732x_irq_handler(int irq, void *devid)
482 {
483 	struct max732x_chip *chip = devid;
484 	uint8_t pending;
485 	uint8_t level;
486 
487 	pending = max732x_irq_pending(chip);
488 
489 	if (!pending)
490 		return IRQ_HANDLED;
491 
492 	do {
493 		level = __ffs(pending);
494 		handle_nested_irq(irq_find_mapping(chip->gpio_chip.irqdomain,
495 						   level));
496 
497 		pending &= ~(1 << level);
498 	} while (pending);
499 
500 	return IRQ_HANDLED;
501 }
502 
503 static int max732x_irq_setup(struct max732x_chip *chip,
504 			     const struct i2c_device_id *id)
505 {
506 	struct i2c_client *client = chip->client;
507 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
508 	int has_irq = max732x_features[id->driver_data] >> 32;
509 	int irq_base = 0;
510 	int ret;
511 
512 	if (((pdata && pdata->irq_base) || client->irq)
513 			&& has_irq != INT_NONE) {
514 		if (pdata)
515 			irq_base = pdata->irq_base;
516 		chip->irq_features = has_irq;
517 		mutex_init(&chip->irq_lock);
518 
519 		ret = devm_request_threaded_irq(&client->dev, client->irq,
520 				NULL, max732x_irq_handler, IRQF_ONESHOT |
521 				IRQF_TRIGGER_FALLING | IRQF_SHARED,
522 				dev_name(&client->dev), chip);
523 		if (ret) {
524 			dev_err(&client->dev, "failed to request irq %d\n",
525 				client->irq);
526 			return ret;
527 		}
528 		ret =  gpiochip_irqchip_add(&chip->gpio_chip,
529 					    &max732x_irq_chip,
530 					    irq_base,
531 					    handle_simple_irq,
532 					    IRQ_TYPE_NONE);
533 		if (ret) {
534 			dev_err(&client->dev,
535 				"could not connect irqchip to gpiochip\n");
536 			return ret;
537 		}
538 		gpiochip_set_chained_irqchip(&chip->gpio_chip,
539 					     &max732x_irq_chip,
540 					     client->irq,
541 					     NULL);
542 	}
543 
544 	return 0;
545 }
546 
547 #else /* CONFIG_GPIO_MAX732X_IRQ */
548 static int max732x_irq_setup(struct max732x_chip *chip,
549 			     const struct i2c_device_id *id)
550 {
551 	struct i2c_client *client = chip->client;
552 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
553 	int has_irq = max732x_features[id->driver_data] >> 32;
554 
555 	if (((pdata && pdata->irq_base) || client->irq) && has_irq != INT_NONE)
556 		dev_warn(&client->dev, "interrupt support not compiled in\n");
557 
558 	return 0;
559 }
560 #endif
561 
562 static int max732x_setup_gpio(struct max732x_chip *chip,
563 					const struct i2c_device_id *id,
564 					unsigned gpio_start)
565 {
566 	struct gpio_chip *gc = &chip->gpio_chip;
567 	uint32_t id_data = (uint32_t)max732x_features[id->driver_data];
568 	int i, port = 0;
569 
570 	for (i = 0; i < 16; i++, id_data >>= 2) {
571 		unsigned int mask = 1 << port;
572 
573 		switch (id_data & 0x3) {
574 		case PORT_OUTPUT:
575 			chip->dir_output |= mask;
576 			break;
577 		case PORT_INPUT:
578 			chip->dir_input |= mask;
579 			break;
580 		case PORT_OPENDRAIN:
581 			chip->dir_output |= mask;
582 			chip->dir_input |= mask;
583 			break;
584 		default:
585 			continue;
586 		}
587 
588 		if (i < 8)
589 			chip->mask_group_a |= mask;
590 		port++;
591 	}
592 
593 	if (chip->dir_input)
594 		gc->direction_input = max732x_gpio_direction_input;
595 	if (chip->dir_output) {
596 		gc->direction_output = max732x_gpio_direction_output;
597 		gc->set = max732x_gpio_set_value;
598 		gc->set_multiple = max732x_gpio_set_multiple;
599 	}
600 	gc->get = max732x_gpio_get_value;
601 	gc->can_sleep = true;
602 
603 	gc->base = gpio_start;
604 	gc->ngpio = port;
605 	gc->label = chip->client->name;
606 	gc->dev = &chip->client->dev;
607 	gc->owner = THIS_MODULE;
608 
609 	return port;
610 }
611 
612 static struct max732x_platform_data *of_gpio_max732x(struct device *dev)
613 {
614 	struct max732x_platform_data *pdata;
615 
616 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
617 	if (!pdata)
618 		return NULL;
619 
620 	pdata->gpio_base = -1;
621 
622 	return pdata;
623 }
624 
625 static int max732x_probe(struct i2c_client *client,
626 				   const struct i2c_device_id *id)
627 {
628 	struct max732x_platform_data *pdata;
629 	struct device_node *node;
630 	struct max732x_chip *chip;
631 	struct i2c_client *c;
632 	uint16_t addr_a, addr_b;
633 	int ret, nr_port;
634 
635 	pdata = dev_get_platdata(&client->dev);
636 	node = client->dev.of_node;
637 
638 	if (!pdata && node)
639 		pdata = of_gpio_max732x(&client->dev);
640 
641 	if (!pdata) {
642 		dev_dbg(&client->dev, "no platform data\n");
643 		return -EINVAL;
644 	}
645 
646 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
647 	if (chip == NULL)
648 		return -ENOMEM;
649 	chip->client = client;
650 
651 	nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
652 	chip->gpio_chip.dev = &client->dev;
653 
654 	addr_a = (client->addr & 0x0f) | 0x60;
655 	addr_b = (client->addr & 0x0f) | 0x50;
656 
657 	switch (client->addr & 0x70) {
658 	case 0x60:
659 		chip->client_group_a = client;
660 		if (nr_port > 8) {
661 			c = i2c_new_dummy(client->adapter, addr_b);
662 			chip->client_group_b = chip->client_dummy = c;
663 		}
664 		break;
665 	case 0x50:
666 		chip->client_group_b = client;
667 		if (nr_port > 8) {
668 			c = i2c_new_dummy(client->adapter, addr_a);
669 			chip->client_group_a = chip->client_dummy = c;
670 		}
671 		break;
672 	default:
673 		dev_err(&client->dev, "invalid I2C address specified %02x\n",
674 				client->addr);
675 		ret = -EINVAL;
676 		goto out_failed;
677 	}
678 
679 	if (nr_port > 8 && !chip->client_dummy) {
680 		dev_err(&client->dev,
681 			"Failed to allocate second group I2C device\n");
682 		ret = -ENODEV;
683 		goto out_failed;
684 	}
685 
686 	mutex_init(&chip->lock);
687 
688 	ret = max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);
689 	if (ret)
690 		goto out_failed;
691 	if (nr_port > 8) {
692 		ret = max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]);
693 		if (ret)
694 			goto out_failed;
695 	}
696 
697 	ret = gpiochip_add(&chip->gpio_chip);
698 	if (ret)
699 		goto out_failed;
700 
701 	ret = max732x_irq_setup(chip, id);
702 	if (ret) {
703 		gpiochip_remove(&chip->gpio_chip);
704 		goto out_failed;
705 	}
706 
707 	if (pdata && pdata->setup) {
708 		ret = pdata->setup(client, chip->gpio_chip.base,
709 				chip->gpio_chip.ngpio, pdata->context);
710 		if (ret < 0)
711 			dev_warn(&client->dev, "setup failed, %d\n", ret);
712 	}
713 
714 	i2c_set_clientdata(client, chip);
715 	return 0;
716 
717 out_failed:
718 	if (chip->client_dummy)
719 		i2c_unregister_device(chip->client_dummy);
720 	return ret;
721 }
722 
723 static int max732x_remove(struct i2c_client *client)
724 {
725 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
726 	struct max732x_chip *chip = i2c_get_clientdata(client);
727 
728 	if (pdata && pdata->teardown) {
729 		int ret;
730 
731 		ret = pdata->teardown(client, chip->gpio_chip.base,
732 				chip->gpio_chip.ngpio, pdata->context);
733 		if (ret < 0) {
734 			dev_err(&client->dev, "%s failed, %d\n",
735 					"teardown", ret);
736 			return ret;
737 		}
738 	}
739 
740 	gpiochip_remove(&chip->gpio_chip);
741 
742 	/* unregister any dummy i2c_client */
743 	if (chip->client_dummy)
744 		i2c_unregister_device(chip->client_dummy);
745 
746 	return 0;
747 }
748 
749 static struct i2c_driver max732x_driver = {
750 	.driver = {
751 		.name		= "max732x",
752 		.owner		= THIS_MODULE,
753 		.of_match_table	= of_match_ptr(max732x_of_table),
754 	},
755 	.probe		= max732x_probe,
756 	.remove		= max732x_remove,
757 	.id_table	= max732x_id,
758 };
759 
760 static int __init max732x_init(void)
761 {
762 	return i2c_add_driver(&max732x_driver);
763 }
764 /* register after i2c postcore initcall and before
765  * subsys initcalls that may rely on these GPIOs
766  */
767 subsys_initcall(max732x_init);
768 
769 static void __exit max732x_exit(void)
770 {
771 	i2c_del_driver(&max732x_driver);
772 }
773 module_exit(max732x_exit);
774 
775 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
776 MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
777 MODULE_LICENSE("GPL");
778