LXR linux/drivers/gpio/gpio-pca9570.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Driver for PCA9570 I2C GPO expander
   4 *
   5 * Copyright (C) 2020 Sungbo Eo <mans0n@gorani.run>
   6 *
   7 * Based on gpio-tpic2810.c
   8 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
   9 *      Andrew F. Davis <afd@ti.com>
  10 */
  11
  12#include <linux/gpio/driver.h>
  13#include <linux/i2c.h>
  14#include <linux/module.h>
  15#include <linux/mutex.h>
  16#include <linux/property.h>
  17
  18/**
  19 * struct pca9570 - GPIO driver data
  20 * @chip: GPIO controller chip
  21 * @lock: Protects write sequences
  22 * @out: Buffer for device register
  23 */
  24struct pca9570 {
  25        struct gpio_chip chip;
  26        struct mutex lock;
  27        u8 out;
  28};
  29
  30static int pca9570_read(struct pca9570 *gpio, u8 *value)
  31{
  32        struct i2c_client *client = to_i2c_client(gpio->chip.parent);
  33        int ret;
  34
  35        ret = i2c_smbus_read_byte(client);
  36        if (ret < 0)
  37                return ret;
  38
  39        *value = ret;
  40        return 0;
  41}
  42
  43static int pca9570_write(struct pca9570 *gpio, u8 value)
  44{
  45        struct i2c_client *client = to_i2c_client(gpio->chip.parent);
  46
  47        return i2c_smbus_write_byte(client, value);
  48}
  49
  50static int pca9570_get_direction(struct gpio_chip *chip,
  51                                 unsigned offset)
  52{
  53        /* This device always output */
  54        return GPIO_LINE_DIRECTION_OUT;
  55}
  56
  57static int pca9570_get(struct gpio_chip *chip, unsigned offset)
  58{
  59        struct pca9570 *gpio = gpiochip_get_data(chip);
  60        u8 buffer;
  61        int ret;
  62
  63        ret = pca9570_read(gpio, &buffer);
  64        if (ret)
  65                return ret;
  66
  67        return !!(buffer & BIT(offset));
  68}
  69
  70static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value)
  71{
  72        struct pca9570 *gpio = gpiochip_get_data(chip);
  73        u8 buffer;
  74        int ret;
  75
  76        mutex_lock(&gpio->lock);
  77
  78        buffer = gpio->out;
  79        if (value)
  80                buffer |= BIT(offset);
  81        else
  82                buffer &= ~BIT(offset);
  83
  84        ret = pca9570_write(gpio, buffer);
  85        if (ret)
  86                goto out;
  87
  88        gpio->out = buffer;
  89
  90out:
  91        mutex_unlock(&gpio->lock);
  92}
  93
  94static int pca9570_probe(struct i2c_client *client)
  95{
  96        struct pca9570 *gpio;
  97
  98        gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
  99        if (!gpio)
 100                return -ENOMEM;
 101
 102        gpio->chip.label = client->name;
 103        gpio->chip.parent = &client->dev;
 104        gpio->chip.owner = THIS_MODULE;
 105        gpio->chip.get_direction = pca9570_get_direction;
 106        gpio->chip.get = pca9570_get;
 107        gpio->chip.set = pca9570_set;
 108        gpio->chip.base = -1;
 109        gpio->chip.ngpio = (uintptr_t)device_get_match_data(&client->dev);
 110        gpio->chip.can_sleep = true;
 111
 112        mutex_init(&gpio->lock);
 113
 114        /* Read the current output level */
 115        pca9570_read(gpio, &gpio->out);
 116
 117        i2c_set_clientdata(client, gpio);
 118
 119        return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
 120}
 121
 122static const struct i2c_device_id pca9570_id_table[] = {
 123        { "pca9570", 4 },
 124        { /* sentinel */ }
 125};
 126MODULE_DEVICE_TABLE(i2c, pca9570_id_table);
 127
 128static const struct of_device_id pca9570_of_match_table[] = {
 129        { .compatible = "nxp,pca9570", .data = (void *)4 },
 130        { /* sentinel */ }
 131};
 132MODULE_DEVICE_TABLE(of, pca9570_of_match_table);
 133
 134static struct i2c_driver pca9570_driver = {
 135        .driver = {
 136                .name = "pca9570",
 137                .of_match_table = pca9570_of_match_table,
 138        },
 139        .probe_new = pca9570_probe,
 140        .id_table = pca9570_id_table,
 141};
 142module_i2c_driver(pca9570_driver);
 143
 144MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
 145MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
 146MODULE_LICENSE("GPL v2");
 147