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 inline struct max732x_chip *to_max732x(struct gpio_chip *gc)
162{
163	return container_of(gc, struct max732x_chip, gpio_chip);
164}
165
166static 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
181static 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
197static inline int is_group_a(struct max732x_chip *chip, unsigned off)
198{
199	return (1u << off) & chip->mask_group_a;
200}
201
202static 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
215static 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;
236out:
237	mutex_unlock(&chip->lock);
238}
239
240static 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
248static 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
260static 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
281static 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
298static 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
313static 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
327static 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
356static 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
364static 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
372static 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
381static 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
400static 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
432static 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};
440
441static uint8_t max732x_irq_pending(struct max732x_chip *chip)
442{
443	uint8_t cur_stat;
444	uint8_t old_stat;
445	uint8_t trigger;
446	uint8_t pending;
447	uint16_t status;
448	int ret;
449
450	ret = max732x_readw(chip, &status);
451	if (ret)
452		return 0;
453
454	trigger = status >> 8;
455	trigger &= chip->irq_mask;
456
457	if (!trigger)
458		return 0;
459
460	cur_stat = status & 0xFF;
461	cur_stat &= chip->irq_mask;
462
463	old_stat = cur_stat ^ trigger;
464
465	pending = (old_stat & chip->irq_trig_fall) |
466		  (cur_stat & chip->irq_trig_raise);
467	pending &= trigger;
468
469	return pending;
470}
471
472static irqreturn_t max732x_irq_handler(int irq, void *devid)
473{
474	struct max732x_chip *chip = devid;
475	uint8_t pending;
476	uint8_t level;
477
478	pending = max732x_irq_pending(chip);
479
480	if (!pending)
481		return IRQ_HANDLED;
482
483	do {
484		level = __ffs(pending);
485		handle_nested_irq(irq_find_mapping(chip->gpio_chip.irqdomain,
486						   level));
487
488		pending &= ~(1 << level);
489	} while (pending);
490
491	return IRQ_HANDLED;
492}
493
494static int max732x_irq_setup(struct max732x_chip *chip,
495			     const struct i2c_device_id *id)
496{
497	struct i2c_client *client = chip->client;
498	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
499	int has_irq = max732x_features[id->driver_data] >> 32;
500	int irq_base = 0;
501	int ret;
502
503	if (((pdata && pdata->irq_base) || client->irq)
504			&& has_irq != INT_NONE) {
505		if (pdata)
506			irq_base = pdata->irq_base;
507		chip->irq_features = has_irq;
508		mutex_init(&chip->irq_lock);
509
510		ret = devm_request_threaded_irq(&client->dev,
511					client->irq,
512					NULL,
513					max732x_irq_handler,
514					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
515					dev_name(&client->dev), chip);
516		if (ret) {
517			dev_err(&client->dev, "failed to request irq %d\n",
518				client->irq);
519			return ret;
520		}
521		ret =  gpiochip_irqchip_add(&chip->gpio_chip,
522					    &max732x_irq_chip,
523					    irq_base,
524					    handle_edge_irq,
525					    IRQ_TYPE_NONE);
526		if (ret) {
527			dev_err(&client->dev,
528				"could not connect irqchip to gpiochip\n");
529			return ret;
530		}
531		gpiochip_set_chained_irqchip(&chip->gpio_chip,
532					     &max732x_irq_chip,
533					     client->irq,
534					     NULL);
535	}
536
537	return 0;
538}
539
540#else /* CONFIG_GPIO_MAX732X_IRQ */
541static int max732x_irq_setup(struct max732x_chip *chip,
542			     const struct i2c_device_id *id)
543{
544	struct i2c_client *client = chip->client;
545	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
546	int has_irq = max732x_features[id->driver_data] >> 32;
547
548	if (((pdata && pdata->irq_base) || client->irq) && has_irq != INT_NONE)
549		dev_warn(&client->dev, "interrupt support not compiled in\n");
550
551	return 0;
552}
553#endif
554
555static int max732x_setup_gpio(struct max732x_chip *chip,
556					const struct i2c_device_id *id,
557					unsigned gpio_start)
558{
559	struct gpio_chip *gc = &chip->gpio_chip;
560	uint32_t id_data = (uint32_t)max732x_features[id->driver_data];
561	int i, port = 0;
562
563	for (i = 0; i < 16; i++, id_data >>= 2) {
564		unsigned int mask = 1 << port;
565
566		switch (id_data & 0x3) {
567		case PORT_OUTPUT:
568			chip->dir_output |= mask;
569			break;
570		case PORT_INPUT:
571			chip->dir_input |= mask;
572			break;
573		case PORT_OPENDRAIN:
574			chip->dir_output |= mask;
575			chip->dir_input |= mask;
576			break;
577		default:
578			continue;
579		}
580
581		if (i < 8)
582			chip->mask_group_a |= mask;
583		port++;
584	}
585
586	if (chip->dir_input)
587		gc->direction_input = max732x_gpio_direction_input;
588	if (chip->dir_output) {
589		gc->direction_output = max732x_gpio_direction_output;
590		gc->set = max732x_gpio_set_value;
591		gc->set_multiple = max732x_gpio_set_multiple;
592	}
593	gc->get = max732x_gpio_get_value;
594	gc->can_sleep = true;
595
596	gc->base = gpio_start;
597	gc->ngpio = port;
598	gc->label = chip->client->name;
599	gc->owner = THIS_MODULE;
600
601	return port;
602}
603
604static struct max732x_platform_data *of_gpio_max732x(struct device *dev)
605{
606	struct max732x_platform_data *pdata;
607
608	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
609	if (!pdata)
610		return NULL;
611
612	pdata->gpio_base = -1;
613
614	return pdata;
615}
616
617static int max732x_probe(struct i2c_client *client,
618				   const struct i2c_device_id *id)
619{
620	struct max732x_platform_data *pdata;
621	struct device_node *node;
622	struct max732x_chip *chip;
623	struct i2c_client *c;
624	uint16_t addr_a, addr_b;
625	int ret, nr_port;
626
627	pdata = dev_get_platdata(&client->dev);
628	node = client->dev.of_node;
629
630	if (!pdata && node)
631		pdata = of_gpio_max732x(&client->dev);
632
633	if (!pdata) {
634		dev_dbg(&client->dev, "no platform data\n");
635		return -EINVAL;
636	}
637
638	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
639	if (chip == NULL)
640		return -ENOMEM;
641	chip->client = client;
642
643	nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
644	chip->gpio_chip.dev = &client->dev;
645
646	addr_a = (client->addr & 0x0f) | 0x60;
647	addr_b = (client->addr & 0x0f) | 0x50;
648
649	switch (client->addr & 0x70) {
650	case 0x60:
651		chip->client_group_a = client;
652		if (nr_port > 8) {
653			c = i2c_new_dummy(client->adapter, addr_b);
654			chip->client_group_b = chip->client_dummy = c;
655		}
656		break;
657	case 0x50:
658		chip->client_group_b = client;
659		if (nr_port > 8) {
660			c = i2c_new_dummy(client->adapter, addr_a);
661			chip->client_group_a = chip->client_dummy = c;
662		}
663		break;
664	default:
665		dev_err(&client->dev, "invalid I2C address specified %02x\n",
666				client->addr);
667		ret = -EINVAL;
668		goto out_failed;
669	}
670
671	if (nr_port > 8 && !chip->client_dummy) {
672		dev_err(&client->dev,
673			"Failed to allocate second group I2C device\n");
674		ret = -ENODEV;
675		goto out_failed;
676	}
677
678	mutex_init(&chip->lock);
679
680	max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);
681	if (nr_port > 8)
682		max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]);
683
684	ret = gpiochip_add(&chip->gpio_chip);
685	if (ret)
686		goto out_failed;
687
688	ret = max732x_irq_setup(chip, id);
689	if (ret) {
690		gpiochip_remove(&chip->gpio_chip);
691		goto out_failed;
692	}
693
694	if (pdata && pdata->setup) {
695		ret = pdata->setup(client, chip->gpio_chip.base,
696				chip->gpio_chip.ngpio, pdata->context);
697		if (ret < 0)
698			dev_warn(&client->dev, "setup failed, %d\n", ret);
699	}
700
701	i2c_set_clientdata(client, chip);
702	return 0;
703
704out_failed:
705	if (chip->client_dummy)
706		i2c_unregister_device(chip->client_dummy);
707	return ret;
708}
709
710static int max732x_remove(struct i2c_client *client)
711{
712	struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
713	struct max732x_chip *chip = i2c_get_clientdata(client);
714
715	if (pdata && pdata->teardown) {
716		int ret;
717
718		ret = pdata->teardown(client, chip->gpio_chip.base,
719				chip->gpio_chip.ngpio, pdata->context);
720		if (ret < 0) {
721			dev_err(&client->dev, "%s failed, %d\n",
722					"teardown", ret);
723			return ret;
724		}
725	}
726
727	gpiochip_remove(&chip->gpio_chip);
728
729	/* unregister any dummy i2c_client */
730	if (chip->client_dummy)
731		i2c_unregister_device(chip->client_dummy);
732
733	return 0;
734}
735
736static struct i2c_driver max732x_driver = {
737	.driver = {
738		.name		= "max732x",
739		.owner		= THIS_MODULE,
740		.of_match_table	= of_match_ptr(max732x_of_table),
741	},
742	.probe		= max732x_probe,
743	.remove		= max732x_remove,
744	.id_table	= max732x_id,
745};
746
747static int __init max732x_init(void)
748{
749	return i2c_add_driver(&max732x_driver);
750}
751/* register after i2c postcore initcall and before
752 * subsys initcalls that may rely on these GPIOs
753 */
754subsys_initcall(max732x_init);
755
756static void __exit max732x_exit(void)
757{
758	i2c_del_driver(&max732x_driver);
759}
760module_exit(max732x_exit);
761
762MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
763MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
764MODULE_LICENSE("GPL");
765