xref: /openbmc/linux/drivers/gpio/gpio-max732x.c (revision 5b394b2d)
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/platform_data/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 int max732x_writeb(struct max732x_chip *chip, int group_a, uint8_t val)
162 {
163 	struct i2c_client *client;
164 	int ret;
165 
166 	client = group_a ? chip->client_group_a : chip->client_group_b;
167 	ret = i2c_smbus_write_byte(client, val);
168 	if (ret < 0) {
169 		dev_err(&client->dev, "failed writing\n");
170 		return ret;
171 	}
172 
173 	return 0;
174 }
175 
176 static int max732x_readb(struct max732x_chip *chip, int group_a, uint8_t *val)
177 {
178 	struct i2c_client *client;
179 	int ret;
180 
181 	client = group_a ? chip->client_group_a : chip->client_group_b;
182 	ret = i2c_smbus_read_byte(client);
183 	if (ret < 0) {
184 		dev_err(&client->dev, "failed reading\n");
185 		return ret;
186 	}
187 
188 	*val = (uint8_t)ret;
189 	return 0;
190 }
191 
192 static inline int is_group_a(struct max732x_chip *chip, unsigned off)
193 {
194 	return (1u << off) & chip->mask_group_a;
195 }
196 
197 static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
198 {
199 	struct max732x_chip *chip = gpiochip_get_data(gc);
200 	uint8_t reg_val;
201 	int ret;
202 
203 	ret = max732x_readb(chip, is_group_a(chip, off), &reg_val);
204 	if (ret < 0)
205 		return ret;
206 
207 	return !!(reg_val & (1u << (off & 0x7)));
208 }
209 
210 static void max732x_gpio_set_mask(struct gpio_chip *gc, unsigned off, int mask,
211 				  int val)
212 {
213 	struct max732x_chip *chip = gpiochip_get_data(gc);
214 	uint8_t reg_out;
215 	int ret;
216 
217 	mutex_lock(&chip->lock);
218 
219 	reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
220 	reg_out = (reg_out & ~mask) | (val & mask);
221 
222 	ret = max732x_writeb(chip, is_group_a(chip, off), reg_out);
223 	if (ret < 0)
224 		goto out;
225 
226 	/* update the shadow register then */
227 	if (off > 7)
228 		chip->reg_out[1] = reg_out;
229 	else
230 		chip->reg_out[0] = reg_out;
231 out:
232 	mutex_unlock(&chip->lock);
233 }
234 
235 static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
236 {
237 	unsigned base = off & ~0x7;
238 	uint8_t mask = 1u << (off & 0x7);
239 
240 	max732x_gpio_set_mask(gc, base, mask, val << (off & 0x7));
241 }
242 
243 static void max732x_gpio_set_multiple(struct gpio_chip *gc,
244 				      unsigned long *mask, unsigned long *bits)
245 {
246 	unsigned mask_lo = mask[0] & 0xff;
247 	unsigned mask_hi = (mask[0] >> 8) & 0xff;
248 
249 	if (mask_lo)
250 		max732x_gpio_set_mask(gc, 0, mask_lo, bits[0] & 0xff);
251 	if (mask_hi)
252 		max732x_gpio_set_mask(gc, 8, mask_hi, (bits[0] >> 8) & 0xff);
253 }
254 
255 static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
256 {
257 	struct max732x_chip *chip = gpiochip_get_data(gc);
258 	unsigned int mask = 1u << off;
259 
260 	if ((mask & chip->dir_input) == 0) {
261 		dev_dbg(&chip->client->dev, "%s port %d is output only\n",
262 			chip->client->name, off);
263 		return -EACCES;
264 	}
265 
266 	/*
267 	 * Open-drain pins must be set to high impedance (which is
268 	 * equivalent to output-high) to be turned into an input.
269 	 */
270 	if ((mask & chip->dir_output))
271 		max732x_gpio_set_value(gc, off, 1);
272 
273 	return 0;
274 }
275 
276 static int max732x_gpio_direction_output(struct gpio_chip *gc,
277 		unsigned off, int val)
278 {
279 	struct max732x_chip *chip = gpiochip_get_data(gc);
280 	unsigned int mask = 1u << off;
281 
282 	if ((mask & chip->dir_output) == 0) {
283 		dev_dbg(&chip->client->dev, "%s port %d is input only\n",
284 			chip->client->name, off);
285 		return -EACCES;
286 	}
287 
288 	max732x_gpio_set_value(gc, off, val);
289 	return 0;
290 }
291 
292 #ifdef CONFIG_GPIO_MAX732X_IRQ
293 static int max732x_writew(struct max732x_chip *chip, uint16_t val)
294 {
295 	int ret;
296 
297 	val = cpu_to_le16(val);
298 
299 	ret = i2c_master_send(chip->client_group_a, (char *)&val, 2);
300 	if (ret < 0) {
301 		dev_err(&chip->client_group_a->dev, "failed writing\n");
302 		return ret;
303 	}
304 
305 	return 0;
306 }
307 
308 static int max732x_readw(struct max732x_chip *chip, uint16_t *val)
309 {
310 	int ret;
311 
312 	ret = i2c_master_recv(chip->client_group_a, (char *)val, 2);
313 	if (ret < 0) {
314 		dev_err(&chip->client_group_a->dev, "failed reading\n");
315 		return ret;
316 	}
317 
318 	*val = le16_to_cpu(*val);
319 	return 0;
320 }
321 
322 static void max732x_irq_update_mask(struct max732x_chip *chip)
323 {
324 	uint16_t msg;
325 
326 	if (chip->irq_mask == chip->irq_mask_cur)
327 		return;
328 
329 	chip->irq_mask = chip->irq_mask_cur;
330 
331 	if (chip->irq_features == INT_NO_MASK)
332 		return;
333 
334 	mutex_lock(&chip->lock);
335 
336 	switch (chip->irq_features) {
337 	case INT_INDEP_MASK:
338 		msg = (chip->irq_mask << 8) | chip->reg_out[0];
339 		max732x_writew(chip, msg);
340 		break;
341 
342 	case INT_MERGED_MASK:
343 		msg = chip->irq_mask | chip->reg_out[0];
344 		max732x_writeb(chip, 1, (uint8_t)msg);
345 		break;
346 	}
347 
348 	mutex_unlock(&chip->lock);
349 }
350 
351 static void max732x_irq_mask(struct irq_data *d)
352 {
353 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
354 	struct max732x_chip *chip = gpiochip_get_data(gc);
355 
356 	chip->irq_mask_cur &= ~(1 << d->hwirq);
357 }
358 
359 static void max732x_irq_unmask(struct irq_data *d)
360 {
361 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
362 	struct max732x_chip *chip = gpiochip_get_data(gc);
363 
364 	chip->irq_mask_cur |= 1 << d->hwirq;
365 }
366 
367 static void max732x_irq_bus_lock(struct irq_data *d)
368 {
369 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
370 	struct max732x_chip *chip = gpiochip_get_data(gc);
371 
372 	mutex_lock(&chip->irq_lock);
373 	chip->irq_mask_cur = chip->irq_mask;
374 }
375 
376 static void max732x_irq_bus_sync_unlock(struct irq_data *d)
377 {
378 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
379 	struct max732x_chip *chip = gpiochip_get_data(gc);
380 	uint16_t new_irqs;
381 	uint16_t level;
382 
383 	max732x_irq_update_mask(chip);
384 
385 	new_irqs = chip->irq_trig_fall | chip->irq_trig_raise;
386 	while (new_irqs) {
387 		level = __ffs(new_irqs);
388 		max732x_gpio_direction_input(&chip->gpio_chip, level);
389 		new_irqs &= ~(1 << level);
390 	}
391 
392 	mutex_unlock(&chip->irq_lock);
393 }
394 
395 static int max732x_irq_set_type(struct irq_data *d, unsigned int type)
396 {
397 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
398 	struct max732x_chip *chip = gpiochip_get_data(gc);
399 	uint16_t off = d->hwirq;
400 	uint16_t mask = 1 << off;
401 
402 	if (!(mask & chip->dir_input)) {
403 		dev_dbg(&chip->client->dev, "%s port %d is output only\n",
404 			chip->client->name, off);
405 		return -EACCES;
406 	}
407 
408 	if (!(type & IRQ_TYPE_EDGE_BOTH)) {
409 		dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
410 			d->irq, type);
411 		return -EINVAL;
412 	}
413 
414 	if (type & IRQ_TYPE_EDGE_FALLING)
415 		chip->irq_trig_fall |= mask;
416 	else
417 		chip->irq_trig_fall &= ~mask;
418 
419 	if (type & IRQ_TYPE_EDGE_RISING)
420 		chip->irq_trig_raise |= mask;
421 	else
422 		chip->irq_trig_raise &= ~mask;
423 
424 	return 0;
425 }
426 
427 static int max732x_irq_set_wake(struct irq_data *data, unsigned int on)
428 {
429 	struct max732x_chip *chip = irq_data_get_irq_chip_data(data);
430 
431 	irq_set_irq_wake(chip->client->irq, on);
432 	return 0;
433 }
434 
435 static struct irq_chip max732x_irq_chip = {
436 	.name			= "max732x",
437 	.irq_mask		= max732x_irq_mask,
438 	.irq_unmask		= max732x_irq_unmask,
439 	.irq_bus_lock		= max732x_irq_bus_lock,
440 	.irq_bus_sync_unlock	= max732x_irq_bus_sync_unlock,
441 	.irq_set_type		= max732x_irq_set_type,
442 	.irq_set_wake		= max732x_irq_set_wake,
443 };
444 
445 static uint8_t max732x_irq_pending(struct max732x_chip *chip)
446 {
447 	uint8_t cur_stat;
448 	uint8_t old_stat;
449 	uint8_t trigger;
450 	uint8_t pending;
451 	uint16_t status;
452 	int ret;
453 
454 	ret = max732x_readw(chip, &status);
455 	if (ret)
456 		return 0;
457 
458 	trigger = status >> 8;
459 	trigger &= chip->irq_mask;
460 
461 	if (!trigger)
462 		return 0;
463 
464 	cur_stat = status & 0xFF;
465 	cur_stat &= chip->irq_mask;
466 
467 	old_stat = cur_stat ^ trigger;
468 
469 	pending = (old_stat & chip->irq_trig_fall) |
470 		  (cur_stat & chip->irq_trig_raise);
471 	pending &= trigger;
472 
473 	return pending;
474 }
475 
476 static irqreturn_t max732x_irq_handler(int irq, void *devid)
477 {
478 	struct max732x_chip *chip = devid;
479 	uint8_t pending;
480 	uint8_t level;
481 
482 	pending = max732x_irq_pending(chip);
483 
484 	if (!pending)
485 		return IRQ_HANDLED;
486 
487 	do {
488 		level = __ffs(pending);
489 		handle_nested_irq(irq_find_mapping(chip->gpio_chip.irq.domain,
490 						   level));
491 
492 		pending &= ~(1 << level);
493 	} while (pending);
494 
495 	return IRQ_HANDLED;
496 }
497 
498 static int max732x_irq_setup(struct max732x_chip *chip,
499 			     const struct i2c_device_id *id)
500 {
501 	struct i2c_client *client = chip->client;
502 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
503 	int has_irq = max732x_features[id->driver_data] >> 32;
504 	int irq_base = 0;
505 	int ret;
506 
507 	if (((pdata && pdata->irq_base) || client->irq)
508 			&& has_irq != INT_NONE) {
509 		if (pdata)
510 			irq_base = pdata->irq_base;
511 		chip->irq_features = has_irq;
512 		mutex_init(&chip->irq_lock);
513 
514 		ret = devm_request_threaded_irq(&client->dev, client->irq,
515 				NULL, max732x_irq_handler, IRQF_ONESHOT |
516 				IRQF_TRIGGER_FALLING | IRQF_SHARED,
517 				dev_name(&client->dev), chip);
518 		if (ret) {
519 			dev_err(&client->dev, "failed to request irq %d\n",
520 				client->irq);
521 			return ret;
522 		}
523 		ret =  gpiochip_irqchip_add_nested(&chip->gpio_chip,
524 						   &max732x_irq_chip,
525 						   irq_base,
526 						   handle_simple_irq,
527 						   IRQ_TYPE_NONE);
528 		if (ret) {
529 			dev_err(&client->dev,
530 				"could not connect irqchip to gpiochip\n");
531 			return ret;
532 		}
533 		gpiochip_set_nested_irqchip(&chip->gpio_chip,
534 					    &max732x_irq_chip,
535 					    client->irq);
536 	}
537 
538 	return 0;
539 }
540 
541 #else /* CONFIG_GPIO_MAX732X_IRQ */
542 static int max732x_irq_setup(struct max732x_chip *chip,
543 			     const struct i2c_device_id *id)
544 {
545 	struct i2c_client *client = chip->client;
546 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
547 	int has_irq = max732x_features[id->driver_data] >> 32;
548 
549 	if (((pdata && pdata->irq_base) || client->irq) && has_irq != INT_NONE)
550 		dev_warn(&client->dev, "interrupt support not compiled in\n");
551 
552 	return 0;
553 }
554 #endif
555 
556 static int max732x_setup_gpio(struct max732x_chip *chip,
557 					const struct i2c_device_id *id,
558 					unsigned gpio_start)
559 {
560 	struct gpio_chip *gc = &chip->gpio_chip;
561 	uint32_t id_data = (uint32_t)max732x_features[id->driver_data];
562 	int i, port = 0;
563 
564 	for (i = 0; i < 16; i++, id_data >>= 2) {
565 		unsigned int mask = 1 << port;
566 
567 		switch (id_data & 0x3) {
568 		case PORT_OUTPUT:
569 			chip->dir_output |= mask;
570 			break;
571 		case PORT_INPUT:
572 			chip->dir_input |= mask;
573 			break;
574 		case PORT_OPENDRAIN:
575 			chip->dir_output |= mask;
576 			chip->dir_input |= mask;
577 			break;
578 		default:
579 			continue;
580 		}
581 
582 		if (i < 8)
583 			chip->mask_group_a |= mask;
584 		port++;
585 	}
586 
587 	if (chip->dir_input)
588 		gc->direction_input = max732x_gpio_direction_input;
589 	if (chip->dir_output) {
590 		gc->direction_output = max732x_gpio_direction_output;
591 		gc->set = max732x_gpio_set_value;
592 		gc->set_multiple = max732x_gpio_set_multiple;
593 	}
594 	gc->get = max732x_gpio_get_value;
595 	gc->can_sleep = true;
596 
597 	gc->base = gpio_start;
598 	gc->ngpio = port;
599 	gc->label = chip->client->name;
600 	gc->parent = &chip->client->dev;
601 	gc->owner = THIS_MODULE;
602 
603 	return port;
604 }
605 
606 static struct max732x_platform_data *of_gpio_max732x(struct device *dev)
607 {
608 	struct max732x_platform_data *pdata;
609 
610 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
611 	if (!pdata)
612 		return NULL;
613 
614 	pdata->gpio_base = -1;
615 
616 	return pdata;
617 }
618 
619 static int max732x_probe(struct i2c_client *client,
620 				   const struct i2c_device_id *id)
621 {
622 	struct max732x_platform_data *pdata;
623 	struct device_node *node;
624 	struct max732x_chip *chip;
625 	struct i2c_client *c;
626 	uint16_t addr_a, addr_b;
627 	int ret, nr_port;
628 
629 	pdata = dev_get_platdata(&client->dev);
630 	node = client->dev.of_node;
631 
632 	if (!pdata && node)
633 		pdata = of_gpio_max732x(&client->dev);
634 
635 	if (!pdata) {
636 		dev_dbg(&client->dev, "no platform data\n");
637 		return -EINVAL;
638 	}
639 
640 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
641 	if (chip == NULL)
642 		return -ENOMEM;
643 	chip->client = client;
644 
645 	nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
646 	chip->gpio_chip.parent = &client->dev;
647 
648 	addr_a = (client->addr & 0x0f) | 0x60;
649 	addr_b = (client->addr & 0x0f) | 0x50;
650 
651 	switch (client->addr & 0x70) {
652 	case 0x60:
653 		chip->client_group_a = client;
654 		if (nr_port > 8) {
655 			c = i2c_new_dummy(client->adapter, addr_b);
656 			if (!c) {
657 				dev_err(&client->dev,
658 					"Failed to allocate I2C device\n");
659 				ret = -ENODEV;
660 				goto out_failed;
661 			}
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 			if (!c) {
670 				dev_err(&client->dev,
671 					"Failed to allocate I2C device\n");
672 				ret = -ENODEV;
673 				goto out_failed;
674 			}
675 			chip->client_group_a = chip->client_dummy = c;
676 		}
677 		break;
678 	default:
679 		dev_err(&client->dev, "invalid I2C address specified %02x\n",
680 				client->addr);
681 		ret = -EINVAL;
682 		goto out_failed;
683 	}
684 
685 	if (nr_port > 8 && !chip->client_dummy) {
686 		dev_err(&client->dev,
687 			"Failed to allocate second group I2C device\n");
688 		ret = -ENODEV;
689 		goto out_failed;
690 	}
691 
692 	mutex_init(&chip->lock);
693 
694 	ret = max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);
695 	if (ret)
696 		goto out_failed;
697 	if (nr_port > 8) {
698 		ret = max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]);
699 		if (ret)
700 			goto out_failed;
701 	}
702 
703 	ret = gpiochip_add_data(&chip->gpio_chip, chip);
704 	if (ret)
705 		goto out_failed;
706 
707 	ret = max732x_irq_setup(chip, id);
708 	if (ret) {
709 		gpiochip_remove(&chip->gpio_chip);
710 		goto out_failed;
711 	}
712 
713 	if (pdata && pdata->setup) {
714 		ret = pdata->setup(client, chip->gpio_chip.base,
715 				chip->gpio_chip.ngpio, pdata->context);
716 		if (ret < 0)
717 			dev_warn(&client->dev, "setup failed, %d\n", ret);
718 	}
719 
720 	i2c_set_clientdata(client, chip);
721 	return 0;
722 
723 out_failed:
724 	i2c_unregister_device(chip->client_dummy);
725 	return ret;
726 }
727 
728 static int max732x_remove(struct i2c_client *client)
729 {
730 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
731 	struct max732x_chip *chip = i2c_get_clientdata(client);
732 
733 	if (pdata && pdata->teardown) {
734 		int ret;
735 
736 		ret = pdata->teardown(client, chip->gpio_chip.base,
737 				chip->gpio_chip.ngpio, pdata->context);
738 		if (ret < 0) {
739 			dev_err(&client->dev, "%s failed, %d\n",
740 					"teardown", ret);
741 			return ret;
742 		}
743 	}
744 
745 	gpiochip_remove(&chip->gpio_chip);
746 
747 	/* unregister any dummy i2c_client */
748 	i2c_unregister_device(chip->client_dummy);
749 
750 	return 0;
751 }
752 
753 static struct i2c_driver max732x_driver = {
754 	.driver = {
755 		.name		= "max732x",
756 		.of_match_table	= of_match_ptr(max732x_of_table),
757 	},
758 	.probe		= max732x_probe,
759 	.remove		= max732x_remove,
760 	.id_table	= max732x_id,
761 };
762 
763 static int __init max732x_init(void)
764 {
765 	return i2c_add_driver(&max732x_driver);
766 }
767 /* register after i2c postcore initcall and before
768  * subsys initcalls that may rely on these GPIOs
769  */
770 subsys_initcall(max732x_init);
771 
772 static void __exit max732x_exit(void)
773 {
774 	i2c_del_driver(&max732x_driver);
775 }
776 module_exit(max732x_exit);
777 
778 MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
779 MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
780 MODULE_LICENSE("GPL");
781