xref: /openbmc/linux/drivers/gpio/gpio-max732x.c (revision 0e96cf7f)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  MAX732x I2C Port Expander with 8/16 I/O
4  *
5  *  Copyright (C) 2007 Marvell International Ltd.
6  *  Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
7  *  Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
8  *  Copyright (C) 2015 Linus Walleij <linus.walleij@linaro.org>
9  *
10  *  Derived from drivers/gpio/pca953x.c
11  */
12 
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/string.h>
17 #include <linux/gpio/driver.h>
18 #include <linux/interrupt.h>
19 #include <linux/i2c.h>
20 #include <linux/platform_data/max732x.h>
21 #include <linux/of.h>
22 
23 
24 /*
25  * Each port of MAX732x (including MAX7319) falls into one of the
26  * following three types:
27  *
28  *   - Push Pull Output
29  *   - Input
30  *   - Open Drain I/O
31  *
32  * designated by 'O', 'I' and 'P' individually according to MAXIM's
33  * datasheets. 'I' and 'P' ports are interrupt capables, some with
34  * a dedicated interrupt mask.
35  *
36  * There are two groups of I/O ports, each group usually includes
37  * up to 8 I/O ports, and is accessed by a specific I2C address:
38  *
39  *   - Group A : by I2C address 0b'110xxxx
40  *   - Group B : by I2C address 0b'101xxxx
41  *
42  * where 'xxxx' is decided by the connections of pin AD2/AD0.  The
43  * address used also affects the initial state of output signals.
44  *
45  * Within each group of ports, there are five known combinations of
46  * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
47  * the detailed organization of these ports. Only Goup A is interrupt
48  * capable.
49  *
50  * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
51  * and GPIOs from GROUP_A are numbered before those from GROUP_B
52  * (if there are two groups).
53  *
54  * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
55  * they are not supported by this driver.
56  */
57 
58 #define PORT_NONE	0x0	/* '/' No Port */
59 #define PORT_OUTPUT	0x1	/* 'O' Push-Pull, Output Only */
60 #define PORT_INPUT	0x2	/* 'I' Input Only */
61 #define PORT_OPENDRAIN	0x3	/* 'P' Open-Drain, I/O */
62 
63 #define IO_4I4O		0x5AA5	/* O7 O6 I5 I4 I3 I2 O1 O0 */
64 #define IO_4P4O		0x5FF5	/* O7 O6 P5 P4 P3 P2 O1 O0 */
65 #define IO_8I		0xAAAA	/* I7 I6 I5 I4 I3 I2 I1 I0 */
66 #define IO_8P		0xFFFF	/* P7 P6 P5 P4 P3 P2 P1 P0 */
67 #define IO_8O		0x5555	/* O7 O6 O5 O4 O3 O2 O1 O0 */
68 
69 #define GROUP_A(x)	((x) & 0xffff)	/* I2C Addr: 0b'110xxxx */
70 #define GROUP_B(x)	((x) << 16)	/* I2C Addr: 0b'101xxxx */
71 
72 #define INT_NONE	0x0	/* No interrupt capability */
73 #define INT_NO_MASK	0x1	/* Has interrupts, no mask */
74 #define INT_INDEP_MASK	0x2	/* Has interrupts, independent mask */
75 #define INT_MERGED_MASK 0x3	/* Has interrupts, merged mask */
76 
77 #define INT_CAPS(x)	(((uint64_t)(x)) << 32)
78 
79 enum {
80 	MAX7319,
81 	MAX7320,
82 	MAX7321,
83 	MAX7322,
84 	MAX7323,
85 	MAX7324,
86 	MAX7325,
87 	MAX7326,
88 	MAX7327,
89 };
90 
91 static uint64_t max732x_features[] = {
92 	[MAX7319] = GROUP_A(IO_8I) | INT_CAPS(INT_MERGED_MASK),
93 	[MAX7320] = GROUP_B(IO_8O),
94 	[MAX7321] = GROUP_A(IO_8P) | INT_CAPS(INT_NO_MASK),
95 	[MAX7322] = GROUP_A(IO_4I4O) | INT_CAPS(INT_MERGED_MASK),
96 	[MAX7323] = GROUP_A(IO_4P4O) | INT_CAPS(INT_INDEP_MASK),
97 	[MAX7324] = GROUP_A(IO_8I) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK),
98 	[MAX7325] = GROUP_A(IO_8P) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK),
99 	[MAX7326] = GROUP_A(IO_4I4O) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK),
100 	[MAX7327] = GROUP_A(IO_4P4O) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK),
101 };
102 
103 static const struct i2c_device_id max732x_id[] = {
104 	{ "max7319", MAX7319 },
105 	{ "max7320", MAX7320 },
106 	{ "max7321", MAX7321 },
107 	{ "max7322", MAX7322 },
108 	{ "max7323", MAX7323 },
109 	{ "max7324", MAX7324 },
110 	{ "max7325", MAX7325 },
111 	{ "max7326", MAX7326 },
112 	{ "max7327", MAX7327 },
113 	{ },
114 };
115 MODULE_DEVICE_TABLE(i2c, max732x_id);
116 
117 #ifdef CONFIG_OF
118 static const struct of_device_id max732x_of_table[] = {
119 	{ .compatible = "maxim,max7319" },
120 	{ .compatible = "maxim,max7320" },
121 	{ .compatible = "maxim,max7321" },
122 	{ .compatible = "maxim,max7322" },
123 	{ .compatible = "maxim,max7323" },
124 	{ .compatible = "maxim,max7324" },
125 	{ .compatible = "maxim,max7325" },
126 	{ .compatible = "maxim,max7326" },
127 	{ .compatible = "maxim,max7327" },
128 	{ }
129 };
130 MODULE_DEVICE_TABLE(of, max732x_of_table);
131 #endif
132 
133 struct max732x_chip {
134 	struct gpio_chip gpio_chip;
135 
136 	struct i2c_client *client;	/* "main" client */
137 	struct i2c_client *client_dummy;
138 	struct i2c_client *client_group_a;
139 	struct i2c_client *client_group_b;
140 
141 	unsigned int	mask_group_a;
142 	unsigned int	dir_input;
143 	unsigned int	dir_output;
144 
145 	struct mutex	lock;
146 	uint8_t		reg_out[2];
147 
148 #ifdef CONFIG_GPIO_MAX732X_IRQ
149 	struct mutex		irq_lock;
150 	uint8_t			irq_mask;
151 	uint8_t			irq_mask_cur;
152 	uint8_t			irq_trig_raise;
153 	uint8_t			irq_trig_fall;
154 	uint8_t			irq_features;
155 #endif
156 };
157 
158 static int max732x_writeb(struct max732x_chip *chip, int group_a, uint8_t val)
159 {
160 	struct i2c_client *client;
161 	int ret;
162 
163 	client = group_a ? chip->client_group_a : chip->client_group_b;
164 	ret = i2c_smbus_write_byte(client, val);
165 	if (ret < 0) {
166 		dev_err(&client->dev, "failed writing\n");
167 		return ret;
168 	}
169 
170 	return 0;
171 }
172 
173 static int max732x_readb(struct max732x_chip *chip, int group_a, uint8_t *val)
174 {
175 	struct i2c_client *client;
176 	int ret;
177 
178 	client = group_a ? chip->client_group_a : chip->client_group_b;
179 	ret = i2c_smbus_read_byte(client);
180 	if (ret < 0) {
181 		dev_err(&client->dev, "failed reading\n");
182 		return ret;
183 	}
184 
185 	*val = (uint8_t)ret;
186 	return 0;
187 }
188 
189 static inline int is_group_a(struct max732x_chip *chip, unsigned off)
190 {
191 	return (1u << off) & chip->mask_group_a;
192 }
193 
194 static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
195 {
196 	struct max732x_chip *chip = gpiochip_get_data(gc);
197 	uint8_t reg_val;
198 	int ret;
199 
200 	ret = max732x_readb(chip, is_group_a(chip, off), &reg_val);
201 	if (ret < 0)
202 		return ret;
203 
204 	return !!(reg_val & (1u << (off & 0x7)));
205 }
206 
207 static void max732x_gpio_set_mask(struct gpio_chip *gc, unsigned off, int mask,
208 				  int val)
209 {
210 	struct max732x_chip *chip = gpiochip_get_data(gc);
211 	uint8_t reg_out;
212 	int ret;
213 
214 	mutex_lock(&chip->lock);
215 
216 	reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
217 	reg_out = (reg_out & ~mask) | (val & mask);
218 
219 	ret = max732x_writeb(chip, is_group_a(chip, off), reg_out);
220 	if (ret < 0)
221 		goto out;
222 
223 	/* update the shadow register then */
224 	if (off > 7)
225 		chip->reg_out[1] = reg_out;
226 	else
227 		chip->reg_out[0] = reg_out;
228 out:
229 	mutex_unlock(&chip->lock);
230 }
231 
232 static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
233 {
234 	unsigned base = off & ~0x7;
235 	uint8_t mask = 1u << (off & 0x7);
236 
237 	max732x_gpio_set_mask(gc, base, mask, val << (off & 0x7));
238 }
239 
240 static void max732x_gpio_set_multiple(struct gpio_chip *gc,
241 				      unsigned long *mask, unsigned long *bits)
242 {
243 	unsigned mask_lo = mask[0] & 0xff;
244 	unsigned mask_hi = (mask[0] >> 8) & 0xff;
245 
246 	if (mask_lo)
247 		max732x_gpio_set_mask(gc, 0, mask_lo, bits[0] & 0xff);
248 	if (mask_hi)
249 		max732x_gpio_set_mask(gc, 8, mask_hi, (bits[0] >> 8) & 0xff);
250 }
251 
252 static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
253 {
254 	struct max732x_chip *chip = gpiochip_get_data(gc);
255 	unsigned int mask = 1u << off;
256 
257 	if ((mask & chip->dir_input) == 0) {
258 		dev_dbg(&chip->client->dev, "%s port %d is output only\n",
259 			chip->client->name, off);
260 		return -EACCES;
261 	}
262 
263 	/*
264 	 * Open-drain pins must be set to high impedance (which is
265 	 * equivalent to output-high) to be turned into an input.
266 	 */
267 	if ((mask & chip->dir_output))
268 		max732x_gpio_set_value(gc, off, 1);
269 
270 	return 0;
271 }
272 
273 static int max732x_gpio_direction_output(struct gpio_chip *gc,
274 		unsigned off, int val)
275 {
276 	struct max732x_chip *chip = gpiochip_get_data(gc);
277 	unsigned int mask = 1u << off;
278 
279 	if ((mask & chip->dir_output) == 0) {
280 		dev_dbg(&chip->client->dev, "%s port %d is input only\n",
281 			chip->client->name, off);
282 		return -EACCES;
283 	}
284 
285 	max732x_gpio_set_value(gc, off, val);
286 	return 0;
287 }
288 
289 #ifdef CONFIG_GPIO_MAX732X_IRQ
290 static int max732x_writew(struct max732x_chip *chip, uint16_t val)
291 {
292 	int ret;
293 
294 	val = cpu_to_le16(val);
295 
296 	ret = i2c_master_send(chip->client_group_a, (char *)&val, 2);
297 	if (ret < 0) {
298 		dev_err(&chip->client_group_a->dev, "failed writing\n");
299 		return ret;
300 	}
301 
302 	return 0;
303 }
304 
305 static int max732x_readw(struct max732x_chip *chip, uint16_t *val)
306 {
307 	int ret;
308 
309 	ret = i2c_master_recv(chip->client_group_a, (char *)val, 2);
310 	if (ret < 0) {
311 		dev_err(&chip->client_group_a->dev, "failed reading\n");
312 		return ret;
313 	}
314 
315 	*val = le16_to_cpu(*val);
316 	return 0;
317 }
318 
319 static void max732x_irq_update_mask(struct max732x_chip *chip)
320 {
321 	uint16_t msg;
322 
323 	if (chip->irq_mask == chip->irq_mask_cur)
324 		return;
325 
326 	chip->irq_mask = chip->irq_mask_cur;
327 
328 	if (chip->irq_features == INT_NO_MASK)
329 		return;
330 
331 	mutex_lock(&chip->lock);
332 
333 	switch (chip->irq_features) {
334 	case INT_INDEP_MASK:
335 		msg = (chip->irq_mask << 8) | chip->reg_out[0];
336 		max732x_writew(chip, msg);
337 		break;
338 
339 	case INT_MERGED_MASK:
340 		msg = chip->irq_mask | chip->reg_out[0];
341 		max732x_writeb(chip, 1, (uint8_t)msg);
342 		break;
343 	}
344 
345 	mutex_unlock(&chip->lock);
346 }
347 
348 static void max732x_irq_mask(struct irq_data *d)
349 {
350 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
351 	struct max732x_chip *chip = gpiochip_get_data(gc);
352 
353 	chip->irq_mask_cur &= ~(1 << d->hwirq);
354 }
355 
356 static void max732x_irq_unmask(struct irq_data *d)
357 {
358 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
359 	struct max732x_chip *chip = gpiochip_get_data(gc);
360 
361 	chip->irq_mask_cur |= 1 << d->hwirq;
362 }
363 
364 static void max732x_irq_bus_lock(struct irq_data *d)
365 {
366 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
367 	struct max732x_chip *chip = gpiochip_get_data(gc);
368 
369 	mutex_lock(&chip->irq_lock);
370 	chip->irq_mask_cur = chip->irq_mask;
371 }
372 
373 static void max732x_irq_bus_sync_unlock(struct irq_data *d)
374 {
375 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
376 	struct max732x_chip *chip = gpiochip_get_data(gc);
377 	uint16_t new_irqs;
378 	uint16_t level;
379 
380 	max732x_irq_update_mask(chip);
381 
382 	new_irqs = chip->irq_trig_fall | chip->irq_trig_raise;
383 	while (new_irqs) {
384 		level = __ffs(new_irqs);
385 		max732x_gpio_direction_input(&chip->gpio_chip, level);
386 		new_irqs &= ~(1 << level);
387 	}
388 
389 	mutex_unlock(&chip->irq_lock);
390 }
391 
392 static int max732x_irq_set_type(struct irq_data *d, unsigned int type)
393 {
394 	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
395 	struct max732x_chip *chip = gpiochip_get_data(gc);
396 	uint16_t off = d->hwirq;
397 	uint16_t mask = 1 << off;
398 
399 	if (!(mask & chip->dir_input)) {
400 		dev_dbg(&chip->client->dev, "%s port %d is output only\n",
401 			chip->client->name, off);
402 		return -EACCES;
403 	}
404 
405 	if (!(type & IRQ_TYPE_EDGE_BOTH)) {
406 		dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
407 			d->irq, type);
408 		return -EINVAL;
409 	}
410 
411 	if (type & IRQ_TYPE_EDGE_FALLING)
412 		chip->irq_trig_fall |= mask;
413 	else
414 		chip->irq_trig_fall &= ~mask;
415 
416 	if (type & IRQ_TYPE_EDGE_RISING)
417 		chip->irq_trig_raise |= mask;
418 	else
419 		chip->irq_trig_raise &= ~mask;
420 
421 	return 0;
422 }
423 
424 static int max732x_irq_set_wake(struct irq_data *data, unsigned int on)
425 {
426 	struct max732x_chip *chip = irq_data_get_irq_chip_data(data);
427 
428 	irq_set_irq_wake(chip->client->irq, on);
429 	return 0;
430 }
431 
432 static struct irq_chip max732x_irq_chip = {
433 	.name			= "max732x",
434 	.irq_mask		= max732x_irq_mask,
435 	.irq_unmask		= max732x_irq_unmask,
436 	.irq_bus_lock		= max732x_irq_bus_lock,
437 	.irq_bus_sync_unlock	= max732x_irq_bus_sync_unlock,
438 	.irq_set_type		= max732x_irq_set_type,
439 	.irq_set_wake		= max732x_irq_set_wake,
440 };
441 
442 static uint8_t max732x_irq_pending(struct max732x_chip *chip)
443 {
444 	uint8_t cur_stat;
445 	uint8_t old_stat;
446 	uint8_t trigger;
447 	uint8_t pending;
448 	uint16_t status;
449 	int ret;
450 
451 	ret = max732x_readw(chip, &status);
452 	if (ret)
453 		return 0;
454 
455 	trigger = status >> 8;
456 	trigger &= chip->irq_mask;
457 
458 	if (!trigger)
459 		return 0;
460 
461 	cur_stat = status & 0xFF;
462 	cur_stat &= chip->irq_mask;
463 
464 	old_stat = cur_stat ^ trigger;
465 
466 	pending = (old_stat & chip->irq_trig_fall) |
467 		  (cur_stat & chip->irq_trig_raise);
468 	pending &= trigger;
469 
470 	return pending;
471 }
472 
473 static irqreturn_t max732x_irq_handler(int irq, void *devid)
474 {
475 	struct max732x_chip *chip = devid;
476 	uint8_t pending;
477 	uint8_t level;
478 
479 	pending = max732x_irq_pending(chip);
480 
481 	if (!pending)
482 		return IRQ_HANDLED;
483 
484 	do {
485 		level = __ffs(pending);
486 		handle_nested_irq(irq_find_mapping(chip->gpio_chip.irq.domain,
487 						   level));
488 
489 		pending &= ~(1 << level);
490 	} while (pending);
491 
492 	return IRQ_HANDLED;
493 }
494 
495 static int max732x_irq_setup(struct max732x_chip *chip,
496 			     const struct i2c_device_id *id)
497 {
498 	struct i2c_client *client = chip->client;
499 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
500 	int has_irq = max732x_features[id->driver_data] >> 32;
501 	int irq_base = 0;
502 	int ret;
503 
504 	if (((pdata && pdata->irq_base) || client->irq)
505 			&& has_irq != INT_NONE) {
506 		if (pdata)
507 			irq_base = pdata->irq_base;
508 		chip->irq_features = has_irq;
509 		mutex_init(&chip->irq_lock);
510 
511 		ret = devm_request_threaded_irq(&client->dev, client->irq,
512 				NULL, max732x_irq_handler, IRQF_ONESHOT |
513 				IRQF_TRIGGER_FALLING | IRQF_SHARED,
514 				dev_name(&client->dev), chip);
515 		if (ret) {
516 			dev_err(&client->dev, "failed to request irq %d\n",
517 				client->irq);
518 			return ret;
519 		}
520 		ret =  gpiochip_irqchip_add_nested(&chip->gpio_chip,
521 						   &max732x_irq_chip,
522 						   irq_base,
523 						   handle_simple_irq,
524 						   IRQ_TYPE_NONE);
525 		if (ret) {
526 			dev_err(&client->dev,
527 				"could not connect irqchip to gpiochip\n");
528 			return ret;
529 		}
530 		gpiochip_set_nested_irqchip(&chip->gpio_chip,
531 					    &max732x_irq_chip,
532 					    client->irq);
533 	}
534 
535 	return 0;
536 }
537 
538 #else /* CONFIG_GPIO_MAX732X_IRQ */
539 static int max732x_irq_setup(struct max732x_chip *chip,
540 			     const struct i2c_device_id *id)
541 {
542 	struct i2c_client *client = chip->client;
543 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
544 	int has_irq = max732x_features[id->driver_data] >> 32;
545 
546 	if (((pdata && pdata->irq_base) || client->irq) && has_irq != INT_NONE)
547 		dev_warn(&client->dev, "interrupt support not compiled in\n");
548 
549 	return 0;
550 }
551 #endif
552 
553 static int max732x_setup_gpio(struct max732x_chip *chip,
554 					const struct i2c_device_id *id,
555 					unsigned gpio_start)
556 {
557 	struct gpio_chip *gc = &chip->gpio_chip;
558 	uint32_t id_data = (uint32_t)max732x_features[id->driver_data];
559 	int i, port = 0;
560 
561 	for (i = 0; i < 16; i++, id_data >>= 2) {
562 		unsigned int mask = 1 << port;
563 
564 		switch (id_data & 0x3) {
565 		case PORT_OUTPUT:
566 			chip->dir_output |= mask;
567 			break;
568 		case PORT_INPUT:
569 			chip->dir_input |= mask;
570 			break;
571 		case PORT_OPENDRAIN:
572 			chip->dir_output |= mask;
573 			chip->dir_input |= mask;
574 			break;
575 		default:
576 			continue;
577 		}
578 
579 		if (i < 8)
580 			chip->mask_group_a |= mask;
581 		port++;
582 	}
583 
584 	if (chip->dir_input)
585 		gc->direction_input = max732x_gpio_direction_input;
586 	if (chip->dir_output) {
587 		gc->direction_output = max732x_gpio_direction_output;
588 		gc->set = max732x_gpio_set_value;
589 		gc->set_multiple = max732x_gpio_set_multiple;
590 	}
591 	gc->get = max732x_gpio_get_value;
592 	gc->can_sleep = true;
593 
594 	gc->base = gpio_start;
595 	gc->ngpio = port;
596 	gc->label = chip->client->name;
597 	gc->parent = &chip->client->dev;
598 	gc->owner = THIS_MODULE;
599 
600 	return port;
601 }
602 
603 static struct max732x_platform_data *of_gpio_max732x(struct device *dev)
604 {
605 	struct max732x_platform_data *pdata;
606 
607 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
608 	if (!pdata)
609 		return NULL;
610 
611 	pdata->gpio_base = -1;
612 
613 	return pdata;
614 }
615 
616 static int max732x_probe(struct i2c_client *client,
617 				   const struct i2c_device_id *id)
618 {
619 	struct max732x_platform_data *pdata;
620 	struct device_node *node;
621 	struct max732x_chip *chip;
622 	struct i2c_client *c;
623 	uint16_t addr_a, addr_b;
624 	int ret, nr_port;
625 
626 	pdata = dev_get_platdata(&client->dev);
627 	node = client->dev.of_node;
628 
629 	if (!pdata && node)
630 		pdata = of_gpio_max732x(&client->dev);
631 
632 	if (!pdata) {
633 		dev_dbg(&client->dev, "no platform data\n");
634 		return -EINVAL;
635 	}
636 
637 	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
638 	if (chip == NULL)
639 		return -ENOMEM;
640 	chip->client = client;
641 
642 	nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
643 	chip->gpio_chip.parent = &client->dev;
644 
645 	addr_a = (client->addr & 0x0f) | 0x60;
646 	addr_b = (client->addr & 0x0f) | 0x50;
647 
648 	switch (client->addr & 0x70) {
649 	case 0x60:
650 		chip->client_group_a = client;
651 		if (nr_port > 8) {
652 			c = i2c_new_dummy(client->adapter, addr_b);
653 			if (!c) {
654 				dev_err(&client->dev,
655 					"Failed to allocate I2C device\n");
656 				ret = -ENODEV;
657 				goto out_failed;
658 			}
659 			chip->client_group_b = chip->client_dummy = c;
660 		}
661 		break;
662 	case 0x50:
663 		chip->client_group_b = client;
664 		if (nr_port > 8) {
665 			c = i2c_new_dummy(client->adapter, addr_a);
666 			if (!c) {
667 				dev_err(&client->dev,
668 					"Failed to allocate I2C device\n");
669 				ret = -ENODEV;
670 				goto out_failed;
671 			}
672 			chip->client_group_a = chip->client_dummy = c;
673 		}
674 		break;
675 	default:
676 		dev_err(&client->dev, "invalid I2C address specified %02x\n",
677 				client->addr);
678 		ret = -EINVAL;
679 		goto out_failed;
680 	}
681 
682 	if (nr_port > 8 && !chip->client_dummy) {
683 		dev_err(&client->dev,
684 			"Failed to allocate second group I2C device\n");
685 		ret = -ENODEV;
686 		goto out_failed;
687 	}
688 
689 	mutex_init(&chip->lock);
690 
691 	ret = max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);
692 	if (ret)
693 		goto out_failed;
694 	if (nr_port > 8) {
695 		ret = max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]);
696 		if (ret)
697 			goto out_failed;
698 	}
699 
700 	ret = gpiochip_add_data(&chip->gpio_chip, chip);
701 	if (ret)
702 		goto out_failed;
703 
704 	ret = max732x_irq_setup(chip, id);
705 	if (ret) {
706 		gpiochip_remove(&chip->gpio_chip);
707 		goto out_failed;
708 	}
709 
710 	if (pdata && pdata->setup) {
711 		ret = pdata->setup(client, chip->gpio_chip.base,
712 				chip->gpio_chip.ngpio, pdata->context);
713 		if (ret < 0)
714 			dev_warn(&client->dev, "setup failed, %d\n", ret);
715 	}
716 
717 	i2c_set_clientdata(client, chip);
718 	return 0;
719 
720 out_failed:
721 	i2c_unregister_device(chip->client_dummy);
722 	return ret;
723 }
724 
725 static int max732x_remove(struct i2c_client *client)
726 {
727 	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
728 	struct max732x_chip *chip = i2c_get_clientdata(client);
729 
730 	if (pdata && pdata->teardown) {
731 		int ret;
732 
733 		ret = pdata->teardown(client, chip->gpio_chip.base,
734 				chip->gpio_chip.ngpio, pdata->context);
735 		if (ret < 0) {
736 			dev_err(&client->dev, "%s failed, %d\n",
737 					"teardown", ret);
738 			return ret;
739 		}
740 	}
741 
742 	gpiochip_remove(&chip->gpio_chip);
743 
744 	/* unregister any dummy i2c_client */
745 	i2c_unregister_device(chip->client_dummy);
746 
747 	return 0;
748 }
749 
750 static struct i2c_driver max732x_driver = {
751 	.driver = {
752 		.name		= "max732x",
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