linux-imx

/*

 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/

 *  Andrew F. Davis <afd@ti.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether expressed or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License version 2 for more details.

 */

​

#include <linux/gpio/driver.h>

#include <linux/i2c.h>

#include <linux/module.h>

#include <linux/mutex.h>

​

#define TPIC2810_WS_COMMAND 0x44

​

/**

 * struct tpic2810 - GPIO driver data

 * @chip: GPIO controller chip

 * @client: I2C device pointer

 * @buffer: Buffer for device register

 * @lock: Protects write sequences

 */

struct tpic2810 {

    struct gpio_chip chip;

    struct i2c_client *client;

    u8 buffer;

    struct mutex lock;

};

​

static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value);

​

static int tpic2810_get_direction(struct gpio_chip *chip,

                  unsigned offset)

{

    /* This device always output */

    return 0;

}

​

static int tpic2810_direction_input(struct gpio_chip *chip,

                    unsigned offset)

{

    /* This device is output only */

    return -EINVAL;

}

​

static int tpic2810_direction_output(struct gpio_chip *chip,

                     unsigned offset, int value)

{

    /* This device always output */

    tpic2810_set(chip, offset, value);

    return 0;

}

​

static void tpic2810_set_mask_bits(struct gpio_chip *chip, u8 mask, u8 bits)

{

    struct tpic2810 *gpio = gpiochip_get_data(chip);

    u8 buffer;

    int err;

​

    mutex_lock(&gpio->lock);

​

    buffer = gpio->buffer & ~mask;

    buffer |= (mask & bits);

​

    err = i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,

                    buffer);

    if (!err)

        gpio->buffer = buffer;

​

    mutex_unlock(&gpio->lock);

}

​

static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value)

{

    tpic2810_set_mask_bits(chip, BIT(offset), value ? BIT(offset) : 0);

}

​

static void tpic2810_set_multiple(struct gpio_chip *chip, unsigned long *mask,

                  unsigned long *bits)

{

    tpic2810_set_mask_bits(chip, *mask, *bits);

}

​

static const struct gpio_chip template_chip = {

    .label          = "tpic2810",

    .owner          = THIS_MODULE,