diff options
Diffstat (limited to 'drivers/gpio/gpio-max732x.c')
| -rw-r--r-- | drivers/gpio/gpio-max732x.c | 714 |
1 files changed, 714 insertions, 0 deletions
diff --git a/drivers/gpio/gpio-max732x.c b/drivers/gpio/gpio-max732x.c new file mode 100644 index 0000000..9504120 --- /dev/null +++ b/drivers/gpio/gpio-max732x.c @@ -0,0 +1,714 @@ +/* + * 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> + * + * 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.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/i2c.h> +#include <linux/i2c/max732x.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); + +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; + int irq_base; + 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 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; + uint8_t reg_val; + int ret; + + chip = container_of(gc, struct max732x_chip, gpio_chip); + + ret = max732x_readb(chip, is_group_a(chip, off), ®_val); + if (ret < 0) + return 0; + + return reg_val & (1u << (off & 0x7)); +} + +static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val) +{ + struct max732x_chip *chip; + uint8_t reg_out, mask = 1u << (off & 0x7); + int ret; + + chip = container_of(gc, struct max732x_chip, gpio_chip); + + mutex_lock(&chip->lock); + + reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0]; + reg_out = (val) ? reg_out | mask : reg_out & ~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 int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off) +{ + struct max732x_chip *chip; + unsigned int mask = 1u << off; + + chip = container_of(gc, struct max732x_chip, gpio_chip); + + 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; + unsigned int mask = 1u << off; + + chip = container_of(gc, struct max732x_chip, gpio_chip); + + 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 int max732x_gpio_to_irq(struct gpio_chip *gc, unsigned off) +{ + struct max732x_chip *chip; + + chip = container_of(gc, struct max732x_chip, gpio_chip); + return chip->irq_base + off; +} + +static void max732x_irq_mask(struct irq_data *d) +{ + struct max732x_chip *chip = irq_data_get_irq_chip_data(d); + + chip->irq_mask_cur &= ~(1 << (d->irq - chip->irq_base)); +} + +static void max732x_irq_unmask(struct irq_data *d) +{ + struct max732x_chip *chip = irq_data_get_irq_chip_data(d); + + chip->irq_mask_cur |= 1 << (d->irq - chip->irq_base); +} + +static void max732x_irq_bus_lock(struct irq_data *d) +{ + struct max732x_chip *chip = irq_data_get_irq_chip_data(d); + + mutex_lock(&chip->irq_lock); + chip->irq_mask_cur = chip->irq_mask; +} + +static void max732x_irq_bus_sync_unlock(struct irq_data *d) +{ + struct max732x_chip *chip = irq_data_get_irq_chip_data(d); + + max732x_irq_update_mask(chip); + mutex_unlock(&chip->irq_lock); +} + +static int max732x_irq_set_type(struct irq_data *d, unsigned int type) +{ + struct max732x_chip *chip = irq_data_get_irq_chip_data(d); + uint16_t off = d->irq - chip->irq_base; + 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 max732x_gpio_direction_input(&chip->gpio_chip, off); +} + +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(level + chip->irq_base); + + 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 = client->dev.platform_data; + int has_irq = max732x_features[id->driver_data] >> 32; + int ret; + + if (pdata->irq_base && has_irq != INT_NONE) { + int lvl; + + chip->irq_base = pdata->irq_base; + chip->irq_features = has_irq; + mutex_init(&chip->irq_lock); + + for (lvl = 0; lvl < chip->gpio_chip.ngpio; lvl++) { + int irq = lvl + chip->irq_base; + + if (!(chip->dir_input & (1 << lvl))) + continue; + + irq_set_chip_data(irq, chip); + irq_set_chip_and_handler(irq, &max732x_irq_chip, + handle_edge_irq); + irq_set_nested_thread(irq, 1); +#ifdef CONFIG_ARM + set_irq_flags(irq, IRQF_VALID); +#else + irq_set_noprobe(irq); +#endif + } + + ret = request_threaded_irq(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); + goto out_failed; + } + + chip->gpio_chip.to_irq = max732x_gpio_to_irq; + } + + return 0; + +out_failed: + chip->irq_base = 0; + return ret; +} + +static void max732x_irq_teardown(struct max732x_chip *chip) +{ + if (chip->irq_base) + free_irq(chip->client->irq, chip); +} +#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 = client->dev.platform_data; + int has_irq = max732x_features[id->driver_data] >> 32; + + if (pdata->irq_base && has_irq != INT_NONE) + dev_warn(&client->dev, "interrupt support not compiled in\n"); + + return 0; +} + +static void max732x_irq_teardown(struct max732x_chip *chip) +{ +} +#endif + +static int __devinit 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->get = max732x_gpio_get_value; + gc->can_sleep = 1; + + gc->base = gpio_start; + gc->ngpio = port; + gc->label = chip->client->name; + gc->owner = THIS_MODULE; + + return port; +} + +static int __devinit max732x_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct max732x_platform_data *pdata; + struct max732x_chip *chip; + struct i2c_client *c; + uint16_t addr_a, addr_b; + int ret, nr_port; + + pdata = client->dev.platform_data; + if (pdata == NULL) { + dev_dbg(&client->dev, "no platform data\n"); + return -EINVAL; + } + + chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL); + if (chip == NULL) + return -ENOMEM; + chip->client = client; + + nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base); + + 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; + } + + 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 = max732x_irq_setup(chip, id); + if (ret) + goto out_failed; + + ret = gpiochip_add(&chip->gpio_chip); + if (ret) + goto out_failed; + + if (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: + max732x_irq_teardown(chip); + kfree(chip); + return ret; +} + +static int __devexit max732x_remove(struct i2c_client *client) +{ + struct max732x_platform_data *pdata = client->dev.platform_data; + struct max732x_chip *chip = i2c_get_clientdata(client); + int ret; + + if (pdata->teardown) { + 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; + } + } + + ret = gpiochip_remove(&chip->gpio_chip); + if (ret) { + dev_err(&client->dev, "%s failed, %d\n", + "gpiochip_remove()", ret); + return ret; + } + + max732x_irq_teardown(chip); + + /* unregister any dummy i2c_client */ + if (chip->client_dummy) + i2c_unregister_device(chip->client_dummy); + + kfree(chip); + return 0; +} + +static struct i2c_driver max732x_driver = { + .driver = { + .name = "max732x", + .owner = THIS_MODULE, + }, + .probe = max732x_probe, + .remove = __devexit_p(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"); |