diff options
Diffstat (limited to 'drivers/gpio/pca953x.c')
| -rw-r--r-- | drivers/gpio/pca953x.c | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/drivers/gpio/pca953x.c b/drivers/gpio/pca953x.c new file mode 100644 index 00000000000..7fae4e500df --- /dev/null +++ b/drivers/gpio/pca953x.c @@ -0,0 +1,271 @@ +/* + * pca9539.c - 16-bit I/O port with interrupt and reset + * + * Copyright (C) 2005 Ben Gardner <bgardner@wabtec.com> + * Copyright (C) 2007 Marvell International Ltd. + * + * Derived from drivers/i2c/chips/pca9539.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/i2c.h> +#include <linux/i2c/pca953x.h> + +#include <asm/gpio.h> + + +#define NR_PCA9539_GPIOS 16 + +#define PCA9539_INPUT 0 +#define PCA9539_OUTPUT 2 +#define PCA9539_INVERT 4 +#define PCA9539_DIRECTION 6 + +struct pca9539_chip { + unsigned gpio_start; + uint16_t reg_output; + uint16_t reg_direction; + + struct i2c_client *client; + struct gpio_chip gpio_chip; +}; + +/* NOTE: we can't currently rely on fault codes to come from SMBus + * calls, so we map all errors to EIO here and return zero otherwise. + */ +static int pca9539_write_reg(struct pca9539_chip *chip, int reg, uint16_t val) +{ + if (i2c_smbus_write_word_data(chip->client, reg, val) < 0) + return -EIO; + else + return 0; +} + +static int pca9539_read_reg(struct pca9539_chip *chip, int reg, uint16_t *val) +{ + int ret; + + ret = i2c_smbus_read_word_data(chip->client, reg); + if (ret < 0) { + dev_err(&chip->client->dev, "failed reading register\n"); + return -EIO; + } + + *val = (uint16_t)ret; + return 0; +} + +static int pca9539_gpio_direction_input(struct gpio_chip *gc, unsigned off) +{ + struct pca9539_chip *chip; + uint16_t reg_val; + int ret; + + chip = container_of(gc, struct pca9539_chip, gpio_chip); + + reg_val = chip->reg_direction | (1u << off); + ret = pca9539_write_reg(chip, PCA9539_DIRECTION, reg_val); + if (ret) + return ret; + + chip->reg_direction = reg_val; + return 0; +} + +static int pca9539_gpio_direction_output(struct gpio_chip *gc, + unsigned off, int val) +{ + struct pca9539_chip *chip; + uint16_t reg_val; + int ret; + + chip = container_of(gc, struct pca9539_chip, gpio_chip); + + /* set output level */ + if (val) + reg_val = chip->reg_output | (1u << off); + else + reg_val = chip->reg_output & ~(1u << off); + + ret = pca9539_write_reg(chip, PCA9539_OUTPUT, reg_val); + if (ret) + return ret; + + chip->reg_output = reg_val; + + /* then direction */ + reg_val = chip->reg_direction & ~(1u << off); + ret = pca9539_write_reg(chip, PCA9539_DIRECTION, reg_val); + if (ret) + return ret; + + chip->reg_direction = reg_val; + return 0; +} + +static int pca9539_gpio_get_value(struct gpio_chip *gc, unsigned off) +{ + struct pca9539_chip *chip; + uint16_t reg_val; + int ret; + + chip = container_of(gc, struct pca9539_chip, gpio_chip); + + ret = pca9539_read_reg(chip, PCA9539_INPUT, ®_val); + if (ret < 0) { + /* NOTE: diagnostic already emitted; that's all we should + * do unless gpio_*_value_cansleep() calls become different + * from their nonsleeping siblings (and report faults). + */ + return 0; + } + + return (reg_val & (1u << off)) ? 1 : 0; +} + +static void pca9539_gpio_set_value(struct gpio_chip *gc, unsigned off, int val) +{ + struct pca9539_chip *chip; + uint16_t reg_val; + int ret; + + chip = container_of(gc, struct pca9539_chip, gpio_chip); + + if (val) + reg_val = chip->reg_output | (1u << off); + else + reg_val = chip->reg_output & ~(1u << off); + + ret = pca9539_write_reg(chip, PCA9539_OUTPUT, reg_val); + if (ret) + return; + + chip->reg_output = reg_val; +} + +static int pca9539_init_gpio(struct pca9539_chip *chip) +{ + struct gpio_chip *gc; + + gc = &chip->gpio_chip; + + gc->direction_input = pca9539_gpio_direction_input; + gc->direction_output = pca9539_gpio_direction_output; + gc->get = pca9539_gpio_get_value; + gc->set = pca9539_gpio_set_value; + + gc->base = chip->gpio_start; + gc->ngpio = NR_PCA9539_GPIOS; + gc->label = "pca9539"; + + return gpiochip_add(gc); +} + +static int __devinit pca9539_probe(struct i2c_client *client) +{ + struct pca9539_platform_data *pdata; + struct pca9539_chip *chip; + int ret; + + pdata = client->dev.platform_data; + if (pdata == NULL) + return -ENODEV; + + chip = kzalloc(sizeof(struct pca9539_chip), GFP_KERNEL); + if (chip == NULL) + return -ENOMEM; + + chip->client = client; + + chip->gpio_start = pdata->gpio_base; + + /* initialize cached registers from their original values. + * we can't share this chip with another i2c master. + */ + ret = pca9539_read_reg(chip, PCA9539_OUTPUT, &chip->reg_output); + if (ret) + goto out_failed; + + ret = pca9539_read_reg(chip, PCA9539_DIRECTION, &chip->reg_direction); + if (ret) + goto out_failed; + + /* set platform specific polarity inversion */ + ret = pca9539_write_reg(chip, PCA9539_INVERT, pdata->invert); + if (ret) + goto out_failed; + + ret = pca9539_init_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: + kfree(chip); + return ret; +} + +static int pca9539_remove(struct i2c_client *client) +{ + struct pca9539_platform_data *pdata = client->dev.platform_data; + struct pca9539_chip *chip = i2c_get_clientdata(client); + int ret = 0; + + 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; + } + + kfree(chip); + return 0; +} + +static struct i2c_driver pca9539_driver = { + .driver = { + .name = "pca9539", + }, + .probe = pca9539_probe, + .remove = pca9539_remove, +}; + +static int __init pca9539_init(void) +{ + return i2c_add_driver(&pca9539_driver); +} +module_init(pca9539_init); + +static void __exit pca9539_exit(void) +{ + i2c_del_driver(&pca9539_driver); +} +module_exit(pca9539_exit); + +MODULE_AUTHOR("eric miao <eric.miao@marvell.com>"); +MODULE_DESCRIPTION("GPIO expander driver for PCA9539"); +MODULE_LICENSE("GPL"); |