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
 82enum {
 83	MAX7319,
 84	MAX7320,
 85	MAX7321,
 86	MAX7322,
 87	MAX7323,
 88	MAX7324,
 89	MAX7325,
 90	MAX7326,
 91	MAX7327,
 92};
 93
 94static 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
106static 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};
118MODULE_DEVICE_TABLE(i2c, max732x_id);
119
120#ifdef CONFIG_OF
121static 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};
133MODULE_DEVICE_TABLE(of, max732x_of_table);
134#endif
135
136struct 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
161static 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
176static 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
192static inline int is_group_a(struct max732x_chip *chip, unsigned off)
193{
194	return (1u << off) & chip->mask_group_a;
195}
196
197static 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
210static 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;
231out:
232	mutex_unlock(&chip->lock);
233}
234
235static 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
243static 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
255static 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
276static 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
293static 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
308static 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
322static 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
351static 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
359static 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
367static 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
376static 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
395static 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
427static 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
435static 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
445static 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
476static 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.irqdomain,
490						   level));
491
492		pending &= ~(1 << level);
493	} while (pending);
494
495	return IRQ_HANDLED;
496}
497
498static 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(&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_chained_irqchip(&chip->gpio_chip,
534					     &max732x_irq_chip,
535					     client->irq,
536					     NULL);
537	}
538
539	return 0;
540}
541
542#else /* CONFIG_GPIO_MAX732X_IRQ */
543static int max732x_irq_setup(struct max732x_chip *chip,
544			     const struct i2c_device_id *id)
545{
546	struct i2c_client *client = chip->client;
547	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
548	int has_irq = max732x_features[id->driver_data] >> 32;
549
550	if (((pdata && pdata->irq_base) || client->irq) && has_irq != INT_NONE)
551		dev_warn(&client->dev, "interrupt support not compiled in\n");
552
553	return 0;
554}
555#endif
556
557static int max732x_setup_gpio(struct max732x_chip *chip,
558					const struct i2c_device_id *id,
559					unsigned gpio_start)
560{
561	struct gpio_chip *gc = &chip->gpio_chip;
562	uint32_t id_data = (uint32_t)max732x_features[id->driver_data];
563	int i, port = 0;
564
565	for (i = 0; i < 16; i++, id_data >>= 2) {
566		unsigned int mask = 1 << port;
567
568		switch (id_data & 0x3) {
569		case PORT_OUTPUT:
570			chip->dir_output |= mask;
571			break;
572		case PORT_INPUT:
573			chip->dir_input |= mask;
574			break;
575		case PORT_OPENDRAIN:
576			chip->dir_output |= mask;
577			chip->dir_input |= mask;
578			break;
579		default:
580			continue;
581		}
582
583		if (i < 8)
584			chip->mask_group_a |= mask;
585		port++;
586	}
587
588	if (chip->dir_input)
589		gc->direction_input = max732x_gpio_direction_input;
590	if (chip->dir_output) {
591		gc->direction_output = max732x_gpio_direction_output;
592		gc->set = max732x_gpio_set_value;
593		gc->set_multiple = max732x_gpio_set_multiple;
594	}
595	gc->get = max732x_gpio_get_value;
596	gc->can_sleep = true;
597
598	gc->base = gpio_start;
599	gc->ngpio = port;
600	gc->label = chip->client->name;
601	gc->parent = &chip->client->dev;
602	gc->owner = THIS_MODULE;
603
604	return port;
605}
606
607static struct max732x_platform_data *of_gpio_max732x(struct device *dev)
608{
609	struct max732x_platform_data *pdata;
610
611	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
612	if (!pdata)
613		return NULL;
614
615	pdata->gpio_base = -1;
616
617	return pdata;
618}
619
620static int max732x_probe(struct i2c_client *client,
621				   const struct i2c_device_id *id)
622{
623	struct max732x_platform_data *pdata;
624	struct device_node *node;
625	struct max732x_chip *chip;
626	struct i2c_client *c;
627	uint16_t addr_a, addr_b;
628	int ret, nr_port;
629
630	pdata = dev_get_platdata(&client->dev);
631	node = client->dev.of_node;
632
633	if (!pdata && node)
634		pdata = of_gpio_max732x(&client->dev);
635
636	if (!pdata) {
637		dev_dbg(&client->dev, "no platform data\n");
638		return -EINVAL;
639	}
640
641	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
642	if (chip == NULL)
643		return -ENOMEM;
644	chip->client = client;
645
646	nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
647	chip->gpio_chip.parent = &client->dev;
648
649	addr_a = (client->addr & 0x0f) | 0x60;
650	addr_b = (client->addr & 0x0f) | 0x50;
651
652	switch (client->addr & 0x70) {
653	case 0x60:
654		chip->client_group_a = client;
655		if (nr_port > 8) {
656			c = i2c_new_dummy(client->adapter, addr_b);
657			chip->client_group_b = chip->client_dummy = c;
658		}
659		break;
660	case 0x50:
661		chip->client_group_b = client;
662		if (nr_port > 8) {
663			c = i2c_new_dummy(client->adapter, addr_a);
664			chip->client_group_a = chip->client_dummy = c;
665		}
666		break;
667	default:
668		dev_err(&client->dev, "invalid I2C address specified %02x\n",
669				client->addr);
670		ret = -EINVAL;
671		goto out_failed;
672	}
673
674	if (nr_port > 8 && !chip->client_dummy) {
675		dev_err(&client->dev,
676			"Failed to allocate second group I2C device\n");
677		ret = -ENODEV;
678		goto out_failed;
679	}
680
681	mutex_init(&chip->lock);
682
683	ret = max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);
684	if (ret)
685		goto out_failed;
686	if (nr_port > 8) {
687		ret = max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]);
688		if (ret)
689			goto out_failed;
690	}
691
692	ret = gpiochip_add_data(&chip->gpio_chip, chip);
693	if (ret)
694		goto out_failed;
695
696	ret = max732x_irq_setup(chip, id);
697	if (ret) {
698		gpiochip_remove(&chip->gpio_chip);
699		goto out_failed;
700	}
701
702	if (pdata && pdata->setup) {
703		ret = pdata->setup(client, chip->gpio_chip.base,
704				chip->gpio_chip.ngpio, pdata->context);
705		if (ret < 0)
706			dev_warn(&client->dev, "setup failed, %d\n", ret);
707	}
708
709	i2c_set_clientdata(client, chip);
710	return 0;
711
712out_failed:
713	if (chip->client_dummy)
714		i2c_unregister_device(chip->client_dummy);
715	return ret;
716}
717
718static int max732x_remove(struct i2c_client *client)
719{
720	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
721	struct max732x_chip *chip = i2c_get_clientdata(client);
722
723	if (pdata && pdata->teardown) {
724		int ret;
725
726		ret = pdata->teardown(client, chip->gpio_chip.base,
727				chip->gpio_chip.ngpio, pdata->context);
728		if (ret < 0) {
729			dev_err(&client->dev, "%s failed, %d\n",
730					"teardown", ret);
731			return ret;
732		}
733	}
734
735	gpiochip_remove(&chip->gpio_chip);
736
737	/* unregister any dummy i2c_client */
738	if (chip->client_dummy)
739		i2c_unregister_device(chip->client_dummy);
740
741	return 0;
742}
743
744static struct i2c_driver max732x_driver = {
745	.driver = {
746		.name		= "max732x",
747		.of_match_table	= of_match_ptr(max732x_of_table),
748	},
749	.probe		= max732x_probe,
750	.remove		= max732x_remove,
751	.id_table	= max732x_id,
752};
753
754static int __init max732x_init(void)
755{
756	return i2c_add_driver(&max732x_driver);
757}
758/* register after i2c postcore initcall and before
759 * subsys initcalls that may rely on these GPIOs
760 */
761subsys_initcall(max732x_init);
762
763static void __exit max732x_exit(void)
764{
765	i2c_del_driver(&max732x_driver);
766}
767module_exit(max732x_exit);
768
769MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
770MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
771MODULE_LICENSE("GPL");