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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/gpio/gpio-max732x.c
Initial import
Diffstat (limited to 'drivers/gpio/gpio-max732x.c')
-rw-r--r--drivers/gpio/gpio-max732x.c764
1 files changed, 764 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-max732x.c b/drivers/gpio/gpio-max732x.c
new file mode 100644
index 000000000..0fa4543c5
--- /dev/null
+++ b/drivers/gpio/gpio-max732x.c
@@ -0,0 +1,764 @@
+/*
+ * MAX732x I2C Port Expander with 8/16 I/O
+ *
+ * Copyright (C) 2007 Marvell International Ltd.
+ * Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
+ * Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
+ * Copyright (C) 2015 Linus Walleij <linus.walleij@linaro.org>
+ *
+ * Derived from drivers/gpio/pca953x.c
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/gpio/driver.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/i2c/max732x.h>
+#include <linux/of.h>
+
+
+/*
+ * Each port of MAX732x (including MAX7319) falls into one of the
+ * following three types:
+ *
+ * - Push Pull Output
+ * - Input
+ * - Open Drain I/O
+ *
+ * designated by 'O', 'I' and 'P' individually according to MAXIM's
+ * datasheets. 'I' and 'P' ports are interrupt capables, some with
+ * a dedicated interrupt mask.
+ *
+ * There are two groups of I/O ports, each group usually includes
+ * up to 8 I/O ports, and is accessed by a specific I2C address:
+ *
+ * - Group A : by I2C address 0b'110xxxx
+ * - Group B : by I2C address 0b'101xxxx
+ *
+ * where 'xxxx' is decided by the connections of pin AD2/AD0. The
+ * address used also affects the initial state of output signals.
+ *
+ * Within each group of ports, there are five known combinations of
+ * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
+ * the detailed organization of these ports. Only Goup A is interrupt
+ * capable.
+ *
+ * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
+ * and GPIOs from GROUP_A are numbered before those from GROUP_B
+ * (if there are two groups).
+ *
+ * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
+ * they are not supported by this driver.
+ */
+
+#define PORT_NONE 0x0 /* '/' No Port */
+#define PORT_OUTPUT 0x1 /* 'O' Push-Pull, Output Only */
+#define PORT_INPUT 0x2 /* 'I' Input Only */
+#define PORT_OPENDRAIN 0x3 /* 'P' Open-Drain, I/O */
+
+#define IO_4I4O 0x5AA5 /* O7 O6 I5 I4 I3 I2 O1 O0 */
+#define IO_4P4O 0x5FF5 /* O7 O6 P5 P4 P3 P2 O1 O0 */
+#define IO_8I 0xAAAA /* I7 I6 I5 I4 I3 I2 I1 I0 */
+#define IO_8P 0xFFFF /* P7 P6 P5 P4 P3 P2 P1 P0 */
+#define IO_8O 0x5555 /* O7 O6 O5 O4 O3 O2 O1 O0 */
+
+#define GROUP_A(x) ((x) & 0xffff) /* I2C Addr: 0b'110xxxx */
+#define GROUP_B(x) ((x) << 16) /* I2C Addr: 0b'101xxxx */
+
+#define INT_NONE 0x0 /* No interrupt capability */
+#define INT_NO_MASK 0x1 /* Has interrupts, no mask */
+#define INT_INDEP_MASK 0x2 /* Has interrupts, independent mask */
+#define INT_MERGED_MASK 0x3 /* Has interrupts, merged mask */
+
+#define INT_CAPS(x) (((uint64_t)(x)) << 32)
+
+enum {
+ MAX7319,
+ MAX7320,
+ MAX7321,
+ MAX7322,
+ MAX7323,
+ MAX7324,
+ MAX7325,
+ MAX7326,
+ MAX7327,
+};
+
+static uint64_t max732x_features[] = {
+ [MAX7319] = GROUP_A(IO_8I) | INT_CAPS(INT_MERGED_MASK),
+ [MAX7320] = GROUP_B(IO_8O),
+ [MAX7321] = GROUP_A(IO_8P) | INT_CAPS(INT_NO_MASK),
+ [MAX7322] = GROUP_A(IO_4I4O) | INT_CAPS(INT_MERGED_MASK),
+ [MAX7323] = GROUP_A(IO_4P4O) | INT_CAPS(INT_INDEP_MASK),
+ [MAX7324] = GROUP_A(IO_8I) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK),
+ [MAX7325] = GROUP_A(IO_8P) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK),
+ [MAX7326] = GROUP_A(IO_4I4O) | GROUP_B(IO_8O) | INT_CAPS(INT_MERGED_MASK),
+ [MAX7327] = GROUP_A(IO_4P4O) | GROUP_B(IO_8O) | INT_CAPS(INT_NO_MASK),
+};
+
+static const struct i2c_device_id max732x_id[] = {
+ { "max7319", MAX7319 },
+ { "max7320", MAX7320 },
+ { "max7321", MAX7321 },
+ { "max7322", MAX7322 },
+ { "max7323", MAX7323 },
+ { "max7324", MAX7324 },
+ { "max7325", MAX7325 },
+ { "max7326", MAX7326 },
+ { "max7327", MAX7327 },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, max732x_id);
+
+#ifdef CONFIG_OF
+static const struct of_device_id max732x_of_table[] = {
+ { .compatible = "maxim,max7319" },
+ { .compatible = "maxim,max7320" },
+ { .compatible = "maxim,max7321" },
+ { .compatible = "maxim,max7322" },
+ { .compatible = "maxim,max7323" },
+ { .compatible = "maxim,max7324" },
+ { .compatible = "maxim,max7325" },
+ { .compatible = "maxim,max7326" },
+ { .compatible = "maxim,max7327" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, max732x_of_table);
+#endif
+
+struct max732x_chip {
+ struct gpio_chip gpio_chip;
+
+ struct i2c_client *client; /* "main" client */
+ struct i2c_client *client_dummy;
+ struct i2c_client *client_group_a;
+ struct i2c_client *client_group_b;
+
+ unsigned int mask_group_a;
+ unsigned int dir_input;
+ unsigned int dir_output;
+
+ struct mutex lock;
+ uint8_t reg_out[2];
+
+#ifdef CONFIG_GPIO_MAX732X_IRQ
+ struct mutex irq_lock;
+ uint8_t irq_mask;
+ uint8_t irq_mask_cur;
+ uint8_t irq_trig_raise;
+ uint8_t irq_trig_fall;
+ uint8_t irq_features;
+#endif
+};
+
+static inline struct max732x_chip *to_max732x(struct gpio_chip *gc)
+{
+ return container_of(gc, struct max732x_chip, gpio_chip);
+}
+
+static int max732x_writeb(struct max732x_chip *chip, int group_a, uint8_t val)
+{
+ struct i2c_client *client;
+ int ret;
+
+ client = group_a ? chip->client_group_a : chip->client_group_b;
+ ret = i2c_smbus_write_byte(client, val);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed writing\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int max732x_readb(struct max732x_chip *chip, int group_a, uint8_t *val)
+{
+ struct i2c_client *client;
+ int ret;
+
+ client = group_a ? chip->client_group_a : chip->client_group_b;
+ ret = i2c_smbus_read_byte(client);
+ if (ret < 0) {
+ dev_err(&client->dev, "failed reading\n");
+ return ret;
+ }
+
+ *val = (uint8_t)ret;
+ return 0;
+}
+
+static inline int is_group_a(struct max732x_chip *chip, unsigned off)
+{
+ return (1u << off) & chip->mask_group_a;
+}
+
+static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
+{
+ struct max732x_chip *chip = to_max732x(gc);
+ uint8_t reg_val;
+ int ret;
+
+ ret = max732x_readb(chip, is_group_a(chip, off), &reg_val);
+ if (ret < 0)
+ return 0;
+
+ return reg_val & (1u << (off & 0x7));
+}
+
+static void max732x_gpio_set_mask(struct gpio_chip *gc, unsigned off, int mask,
+ int val)
+{
+ struct max732x_chip *chip = to_max732x(gc);
+ uint8_t reg_out;
+ int ret;
+
+ mutex_lock(&chip->lock);
+
+ reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
+ reg_out = (reg_out & ~mask) | (val & mask);
+
+ ret = max732x_writeb(chip, is_group_a(chip, off), reg_out);
+ if (ret < 0)
+ goto out;
+
+ /* update the shadow register then */
+ if (off > 7)
+ chip->reg_out[1] = reg_out;
+ else
+ chip->reg_out[0] = reg_out;
+out:
+ mutex_unlock(&chip->lock);
+}
+
+static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
+{
+ unsigned base = off & ~0x7;
+ uint8_t mask = 1u << (off & 0x7);
+
+ max732x_gpio_set_mask(gc, base, mask, val << (off & 0x7));
+}
+
+static void max732x_gpio_set_multiple(struct gpio_chip *gc,
+ unsigned long *mask, unsigned long *bits)
+{
+ unsigned mask_lo = mask[0] & 0xff;
+ unsigned mask_hi = (mask[0] >> 8) & 0xff;
+
+ if (mask_lo)
+ max732x_gpio_set_mask(gc, 0, mask_lo, bits[0] & 0xff);
+ if (mask_hi)
+ max732x_gpio_set_mask(gc, 8, mask_hi, (bits[0] >> 8) & 0xff);
+}
+
+static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
+{
+ struct max732x_chip *chip = to_max732x(gc);
+ unsigned int mask = 1u << off;
+
+ if ((mask & chip->dir_input) == 0) {
+ dev_dbg(&chip->client->dev, "%s port %d is output only\n",
+ chip->client->name, off);
+ return -EACCES;
+ }
+
+ /*
+ * Open-drain pins must be set to high impedance (which is
+ * equivalent to output-high) to be turned into an input.
+ */
+ if ((mask & chip->dir_output))
+ max732x_gpio_set_value(gc, off, 1);
+
+ return 0;
+}
+
+static int max732x_gpio_direction_output(struct gpio_chip *gc,
+ unsigned off, int val)
+{
+ struct max732x_chip *chip = to_max732x(gc);
+ unsigned int mask = 1u << off;
+
+ if ((mask & chip->dir_output) == 0) {
+ dev_dbg(&chip->client->dev, "%s port %d is input only\n",
+ chip->client->name, off);
+ return -EACCES;
+ }
+
+ max732x_gpio_set_value(gc, off, val);
+ return 0;
+}
+
+#ifdef CONFIG_GPIO_MAX732X_IRQ
+static int max732x_writew(struct max732x_chip *chip, uint16_t val)
+{
+ int ret;
+
+ val = cpu_to_le16(val);
+
+ ret = i2c_master_send(chip->client_group_a, (char *)&val, 2);
+ if (ret < 0) {
+ dev_err(&chip->client_group_a->dev, "failed writing\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int max732x_readw(struct max732x_chip *chip, uint16_t *val)
+{
+ int ret;
+
+ ret = i2c_master_recv(chip->client_group_a, (char *)val, 2);
+ if (ret < 0) {
+ dev_err(&chip->client_group_a->dev, "failed reading\n");
+ return ret;
+ }
+
+ *val = le16_to_cpu(*val);
+ return 0;
+}
+
+static void max732x_irq_update_mask(struct max732x_chip *chip)
+{
+ uint16_t msg;
+
+ if (chip->irq_mask == chip->irq_mask_cur)
+ return;
+
+ chip->irq_mask = chip->irq_mask_cur;
+
+ if (chip->irq_features == INT_NO_MASK)
+ return;
+
+ mutex_lock(&chip->lock);
+
+ switch (chip->irq_features) {
+ case INT_INDEP_MASK:
+ msg = (chip->irq_mask << 8) | chip->reg_out[0];
+ max732x_writew(chip, msg);
+ break;
+
+ case INT_MERGED_MASK:
+ msg = chip->irq_mask | chip->reg_out[0];
+ max732x_writeb(chip, 1, (uint8_t)msg);
+ break;
+ }
+
+ mutex_unlock(&chip->lock);
+}
+
+static void max732x_irq_mask(struct irq_data *d)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+ struct max732x_chip *chip = to_max732x(gc);
+
+ chip->irq_mask_cur &= ~(1 << d->hwirq);
+}
+
+static void max732x_irq_unmask(struct irq_data *d)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+ struct max732x_chip *chip = to_max732x(gc);
+
+ chip->irq_mask_cur |= 1 << d->hwirq;
+}
+
+static void max732x_irq_bus_lock(struct irq_data *d)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+ struct max732x_chip *chip = to_max732x(gc);
+
+ mutex_lock(&chip->irq_lock);
+ chip->irq_mask_cur = chip->irq_mask;
+}
+
+static void max732x_irq_bus_sync_unlock(struct irq_data *d)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+ struct max732x_chip *chip = to_max732x(gc);
+ uint16_t new_irqs;
+ uint16_t level;
+
+ max732x_irq_update_mask(chip);
+
+ new_irqs = chip->irq_trig_fall | chip->irq_trig_raise;
+ while (new_irqs) {
+ level = __ffs(new_irqs);
+ max732x_gpio_direction_input(&chip->gpio_chip, level);
+ new_irqs &= ~(1 << level);
+ }
+
+ mutex_unlock(&chip->irq_lock);
+}
+
+static int max732x_irq_set_type(struct irq_data *d, unsigned int type)
+{
+ struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+ struct max732x_chip *chip = to_max732x(gc);
+ uint16_t off = d->hwirq;
+ uint16_t mask = 1 << off;
+
+ if (!(mask & chip->dir_input)) {
+ dev_dbg(&chip->client->dev, "%s port %d is output only\n",
+ chip->client->name, off);
+ return -EACCES;
+ }
+
+ if (!(type & IRQ_TYPE_EDGE_BOTH)) {
+ dev_err(&chip->client->dev, "irq %d: unsupported type %d\n",
+ d->irq, type);
+ return -EINVAL;
+ }
+
+ if (type & IRQ_TYPE_EDGE_FALLING)
+ chip->irq_trig_fall |= mask;
+ else
+ chip->irq_trig_fall &= ~mask;
+
+ if (type & IRQ_TYPE_EDGE_RISING)
+ chip->irq_trig_raise |= mask;
+ else
+ chip->irq_trig_raise &= ~mask;
+
+ return 0;
+}
+
+static struct irq_chip max732x_irq_chip = {
+ .name = "max732x",
+ .irq_mask = max732x_irq_mask,
+ .irq_unmask = max732x_irq_unmask,
+ .irq_bus_lock = max732x_irq_bus_lock,
+ .irq_bus_sync_unlock = max732x_irq_bus_sync_unlock,
+ .irq_set_type = max732x_irq_set_type,
+};
+
+static uint8_t max732x_irq_pending(struct max732x_chip *chip)
+{
+ uint8_t cur_stat;
+ uint8_t old_stat;
+ uint8_t trigger;
+ uint8_t pending;
+ uint16_t status;
+ int ret;
+
+ ret = max732x_readw(chip, &status);
+ if (ret)
+ return 0;
+
+ trigger = status >> 8;
+ trigger &= chip->irq_mask;
+
+ if (!trigger)
+ return 0;
+
+ cur_stat = status & 0xFF;
+ cur_stat &= chip->irq_mask;
+
+ old_stat = cur_stat ^ trigger;
+
+ pending = (old_stat & chip->irq_trig_fall) |
+ (cur_stat & chip->irq_trig_raise);
+ pending &= trigger;
+
+ return pending;
+}
+
+static irqreturn_t max732x_irq_handler(int irq, void *devid)
+{
+ struct max732x_chip *chip = devid;
+ uint8_t pending;
+ uint8_t level;
+
+ pending = max732x_irq_pending(chip);
+
+ if (!pending)
+ return IRQ_HANDLED;
+
+ do {
+ level = __ffs(pending);
+ handle_nested_irq(irq_find_mapping(chip->gpio_chip.irqdomain,
+ level));
+
+ pending &= ~(1 << level);
+ } while (pending);
+
+ return IRQ_HANDLED;
+}
+
+static int max732x_irq_setup(struct max732x_chip *chip,
+ const struct i2c_device_id *id)
+{
+ struct i2c_client *client = chip->client;
+ struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
+ int has_irq = max732x_features[id->driver_data] >> 32;
+ int irq_base = 0;
+ int ret;
+
+ if (((pdata && pdata->irq_base) || client->irq)
+ && has_irq != INT_NONE) {
+ if (pdata)
+ irq_base = pdata->irq_base;
+ chip->irq_features = has_irq;
+ mutex_init(&chip->irq_lock);
+
+ ret = devm_request_threaded_irq(&client->dev,
+ client->irq,
+ NULL,
+ max732x_irq_handler,
+ IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+ dev_name(&client->dev), chip);
+ if (ret) {
+ dev_err(&client->dev, "failed to request irq %d\n",
+ client->irq);
+ return ret;
+ }
+ ret = gpiochip_irqchip_add(&chip->gpio_chip,
+ &max732x_irq_chip,
+ irq_base,
+ handle_edge_irq,
+ IRQ_TYPE_NONE);
+ if (ret) {
+ dev_err(&client->dev,
+ "could not connect irqchip to gpiochip\n");
+ return ret;
+ }
+ gpiochip_set_chained_irqchip(&chip->gpio_chip,
+ &max732x_irq_chip,
+ client->irq,
+ NULL);
+ }
+
+ return 0;
+}
+
+#else /* CONFIG_GPIO_MAX732X_IRQ */
+static int max732x_irq_setup(struct max732x_chip *chip,
+ const struct i2c_device_id *id)
+{
+ struct i2c_client *client = chip->client;
+ struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
+ int has_irq = max732x_features[id->driver_data] >> 32;
+
+ if (((pdata && pdata->irq_base) || client->irq) && has_irq != INT_NONE)
+ dev_warn(&client->dev, "interrupt support not compiled in\n");
+
+ return 0;
+}
+#endif
+
+static int max732x_setup_gpio(struct max732x_chip *chip,
+ const struct i2c_device_id *id,
+ unsigned gpio_start)
+{
+ struct gpio_chip *gc = &chip->gpio_chip;
+ uint32_t id_data = (uint32_t)max732x_features[id->driver_data];
+ int i, port = 0;
+
+ for (i = 0; i < 16; i++, id_data >>= 2) {
+ unsigned int mask = 1 << port;
+
+ switch (id_data & 0x3) {
+ case PORT_OUTPUT:
+ chip->dir_output |= mask;
+ break;
+ case PORT_INPUT:
+ chip->dir_input |= mask;
+ break;
+ case PORT_OPENDRAIN:
+ chip->dir_output |= mask;
+ chip->dir_input |= mask;
+ break;
+ default:
+ continue;
+ }
+
+ if (i < 8)
+ chip->mask_group_a |= mask;
+ port++;
+ }
+
+ if (chip->dir_input)
+ gc->direction_input = max732x_gpio_direction_input;
+ if (chip->dir_output) {
+ gc->direction_output = max732x_gpio_direction_output;
+ gc->set = max732x_gpio_set_value;
+ gc->set_multiple = max732x_gpio_set_multiple;
+ }
+ gc->get = max732x_gpio_get_value;
+ gc->can_sleep = true;
+
+ gc->base = gpio_start;
+ gc->ngpio = port;
+ gc->label = chip->client->name;
+ gc->owner = THIS_MODULE;
+
+ return port;
+}
+
+static struct max732x_platform_data *of_gpio_max732x(struct device *dev)
+{
+ struct max732x_platform_data *pdata;
+
+ pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
+ if (!pdata)
+ return NULL;
+
+ pdata->gpio_base = -1;
+
+ return pdata;
+}
+
+static int max732x_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ struct max732x_platform_data *pdata;
+ struct device_node *node;
+ struct max732x_chip *chip;
+ struct i2c_client *c;
+ uint16_t addr_a, addr_b;
+ int ret, nr_port;
+
+ pdata = dev_get_platdata(&client->dev);
+ node = client->dev.of_node;
+
+ if (!pdata && node)
+ pdata = of_gpio_max732x(&client->dev);
+
+ if (!pdata) {
+ dev_dbg(&client->dev, "no platform data\n");
+ return -EINVAL;
+ }
+
+ chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
+ if (chip == NULL)
+ return -ENOMEM;
+ chip->client = client;
+
+ nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
+ chip->gpio_chip.dev = &client->dev;
+
+ addr_a = (client->addr & 0x0f) | 0x60;
+ addr_b = (client->addr & 0x0f) | 0x50;
+
+ switch (client->addr & 0x70) {
+ case 0x60:
+ chip->client_group_a = client;
+ if (nr_port > 8) {
+ c = i2c_new_dummy(client->adapter, addr_b);
+ chip->client_group_b = chip->client_dummy = c;
+ }
+ break;
+ case 0x50:
+ chip->client_group_b = client;
+ if (nr_port > 8) {
+ c = i2c_new_dummy(client->adapter, addr_a);
+ chip->client_group_a = chip->client_dummy = c;
+ }
+ break;
+ default:
+ dev_err(&client->dev, "invalid I2C address specified %02x\n",
+ client->addr);
+ ret = -EINVAL;
+ goto out_failed;
+ }
+
+ if (nr_port > 8 && !chip->client_dummy) {
+ dev_err(&client->dev,
+ "Failed to allocate second group I2C device\n");
+ ret = -ENODEV;
+ goto out_failed;
+ }
+
+ mutex_init(&chip->lock);
+
+ max732x_readb(chip, is_group_a(chip, 0), &chip->reg_out[0]);
+ if (nr_port > 8)
+ max732x_readb(chip, is_group_a(chip, 8), &chip->reg_out[1]);
+
+ ret = gpiochip_add(&chip->gpio_chip);
+ if (ret)
+ goto out_failed;
+
+ ret = max732x_irq_setup(chip, id);
+ if (ret) {
+ gpiochip_remove(&chip->gpio_chip);
+ goto out_failed;
+ }
+
+ if (pdata && pdata->setup) {
+ ret = pdata->setup(client, chip->gpio_chip.base,
+ chip->gpio_chip.ngpio, pdata->context);
+ if (ret < 0)
+ dev_warn(&client->dev, "setup failed, %d\n", ret);
+ }
+
+ i2c_set_clientdata(client, chip);
+ return 0;
+
+out_failed:
+ if (chip->client_dummy)
+ i2c_unregister_device(chip->client_dummy);
+ return ret;
+}
+
+static int max732x_remove(struct i2c_client *client)
+{
+ struct max732x_platform_data *pdata = dev_get_platdata(&client->dev);
+ struct max732x_chip *chip = i2c_get_clientdata(client);
+
+ if (pdata && pdata->teardown) {
+ int ret;
+
+ ret = pdata->teardown(client, chip->gpio_chip.base,
+ chip->gpio_chip.ngpio, pdata->context);
+ if (ret < 0) {
+ dev_err(&client->dev, "%s failed, %d\n",
+ "teardown", ret);
+ return ret;
+ }
+ }
+
+ gpiochip_remove(&chip->gpio_chip);
+
+ /* unregister any dummy i2c_client */
+ if (chip->client_dummy)
+ i2c_unregister_device(chip->client_dummy);
+
+ return 0;
+}
+
+static struct i2c_driver max732x_driver = {
+ .driver = {
+ .name = "max732x",
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(max732x_of_table),
+ },
+ .probe = max732x_probe,
+ .remove = max732x_remove,
+ .id_table = max732x_id,
+};
+
+static int __init max732x_init(void)
+{
+ return i2c_add_driver(&max732x_driver);
+}
+/* register after i2c postcore initcall and before
+ * subsys initcalls that may rely on these GPIOs
+ */
+subsys_initcall(max732x_init);
+
+static void __exit max732x_exit(void)
+{
+ i2c_del_driver(&max732x_driver);
+}
+module_exit(max732x_exit);
+
+MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
+MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
+MODULE_LICENSE("GPL");