linux/drivers/gpio/pca9539.c

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/*
* 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/pca9539.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, &reg_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");