LXR linux/drivers/gpio/gpio-tpic2810.c

   1/*
   2 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
   3 *      Andrew F. Davis <afd@ti.com>
   4 *
   5 * This program is free software; you can redistribute it and/or
   6 * modify it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 *
   9 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  10 * kind, whether expressed or implied; without even the implied warranty
  11 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License version 2 for more details.
  13 */
  14
  15#include <linux/gpio/driver.h>
  16#include <linux/i2c.h>
  17#include <linux/module.h>
  18#include <linux/mutex.h>
  19
  20#define TPIC2810_WS_COMMAND 0x44
  21
  22/**
  23 * struct tpic2810 - GPIO driver data
  24 * @chip: GPIO controller chip
  25 * @client: I2C device pointer
  26 * @buffer: Buffer for device register
  27 * @lock: Protects write sequences
  28 */
  29struct tpic2810 {
  30        struct gpio_chip chip;
  31        struct i2c_client *client;
  32        u8 buffer;
  33        struct mutex lock;
  34};
  35
  36static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value);
  37
  38static int tpic2810_get_direction(struct gpio_chip *chip,
  39                                  unsigned offset)
  40{
  41        /* This device always output */
  42        return 0;
  43}
  44
  45static int tpic2810_direction_input(struct gpio_chip *chip,
  46                                    unsigned offset)
  47{
  48        /* This device is output only */
  49        return -EINVAL;
  50}
  51
  52static int tpic2810_direction_output(struct gpio_chip *chip,
  53                                     unsigned offset, int value)
  54{
  55        /* This device always output */
  56        tpic2810_set(chip, offset, value);
  57        return 0;
  58}
  59
  60static void tpic2810_set_mask_bits(struct gpio_chip *chip, u8 mask, u8 bits)
  61{
  62        struct tpic2810 *gpio = gpiochip_get_data(chip);
  63        u8 buffer;
  64        int err;
  65
  66        mutex_lock(&gpio->lock);
  67
  68        buffer = gpio->buffer & ~mask;
  69        buffer |= (mask & bits);
  70
  71        err = i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,
  72                                        buffer);
  73        if (!err)
  74                gpio->buffer = buffer;
  75
  76        mutex_unlock(&gpio->lock);
  77}
  78
  79static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value)
  80{
  81        tpic2810_set_mask_bits(chip, BIT(offset), value ? BIT(offset) : 0);
  82}
  83
  84static void tpic2810_set_multiple(struct gpio_chip *chip, unsigned long *mask,
  85                                  unsigned long *bits)
  86{
  87        tpic2810_set_mask_bits(chip, *mask, *bits);
  88}
  89
  90static struct gpio_chip template_chip = {
  91        .label                  = "tpic2810",
  92        .owner                  = THIS_MODULE,
  93        .get_direction          = tpic2810_get_direction,
  94        .direction_input        = tpic2810_direction_input,
  95        .direction_output       = tpic2810_direction_output,
  96        .set                    = tpic2810_set,
  97        .set_multiple           = tpic2810_set_multiple,
  98        .base                   = -1,
  99        .ngpio                  = 8,
 100        .can_sleep              = true,
 101};
 102
 103static const struct of_device_id tpic2810_of_match_table[] = {
 104        { .compatible = "ti,tpic2810" },
 105        { /* sentinel */ }
 106};
 107MODULE_DEVICE_TABLE(of, tpic2810_of_match_table);
 108
 109static int tpic2810_probe(struct i2c_client *client,
 110                          const struct i2c_device_id *id)
 111{
 112        struct tpic2810 *gpio;
 113        int ret;
 114
 115        gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
 116        if (!gpio)
 117                return -ENOMEM;
 118
 119        i2c_set_clientdata(client, gpio);
 120
 121        gpio->chip = template_chip;
 122        gpio->chip.parent = &client->dev;
 123
 124        gpio->client = client;
 125
 126        mutex_init(&gpio->lock);
 127
 128        ret = gpiochip_add_data(&gpio->chip, gpio);
 129        if (ret < 0) {
 130                dev_err(&client->dev, "Unable to register gpiochip\n");
 131                return ret;
 132        }
 133
 134        return 0;
 135}
 136
 137static int tpic2810_remove(struct i2c_client *client)
 138{
 139        struct tpic2810 *gpio = i2c_get_clientdata(client);
 140
 141        gpiochip_remove(&gpio->chip);
 142
 143        return 0;
 144}
 145
 146static const struct i2c_device_id tpic2810_id_table[] = {
 147        { "tpic2810", },
 148        { /* sentinel */ }
 149};
 150MODULE_DEVICE_TABLE(i2c, tpic2810_id_table);
 151
 152static struct i2c_driver tpic2810_driver = {
 153        .driver = {
 154                .name = "tpic2810",
 155                .of_match_table = tpic2810_of_match_table,
 156        },
 157        .probe = tpic2810_probe,
 158        .remove = tpic2810_remove,
 159        .id_table = tpic2810_id_table,
 160};
 161module_i2c_driver(tpic2810_driver);
 162
 163MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
 164MODULE_DESCRIPTION("TPIC2810 8-Bit LED Driver GPIO Driver");
 165MODULE_LICENSE("GPL v2");
 166