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 #define SLG7XL45106_GPO_REG     0xDB
  19
  20 /**
  21  * struct pca9570_chip_data - GPIO platformdata
  22  * @ngpio: no of gpios
  23  * @command: Command to be sent
  24  */
  25 struct pca9570_chip_data {
  26         u16 ngpio;
  27         u32 command;
  28 };
  29
  30 /**
  31  * struct pca9570 - GPIO driver data
  32  * @chip: GPIO controller chip
  33  * @chip_data: GPIO controller platform data
  34  * @lock: Protects write sequences
  35  * @out: Buffer for device register
  36  */
  37 struct pca9570 {
  38         struct gpio_chip chip;
  39         const struct pca9570_chip_data *chip_data;
  40         struct mutex lock;
  41         u8 out;
  42 };
  43
  44 static int pca9570_read(struct pca9570 *gpio, u8 *value)
  45 {
  46         struct i2c_client *client = to_i2c_client(gpio->chip.parent);
  47         int ret;
  48
  49         if (gpio->chip_data->command != 0)
  50                 ret = i2c_smbus_read_byte_data(client, gpio->chip_data->command);
  51         else
  52                 ret = i2c_smbus_read_byte(client);
  53
  54         if (ret < 0)
  55                 return ret;
  56
  57         *value = ret;
  58         return 0;
  59 }
  60
  61 static int pca9570_write(struct pca9570 *gpio, u8 value)
  62 {
  63         struct i2c_client *client = to_i2c_client(gpio->chip.parent);
  64
  65         if (gpio->chip_data->command != 0)
  66                 return i2c_smbus_write_byte_data(client, gpio->chip_data->command, value);
  67
  68         return i2c_smbus_write_byte(client, value);
  69 }
  70
  71 static int pca9570_get_direction(struct gpio_chip *chip,
  72                                  unsigned offset)
  73 {
  74         /* This device always output */
  75         return GPIO_LINE_DIRECTION_OUT;
  76 }
  77
  78 static int pca9570_get(struct gpio_chip *chip, unsigned offset)
  79 {
  80         struct pca9570 *gpio = gpiochip_get_data(chip);
  81         u8 buffer;
  82         int ret;
  83
  84         ret = pca9570_read(gpio, &buffer);
  85         if (ret)
  86                 return ret;
  87
  88         return !!(buffer & BIT(offset));
  89 }
  90
  91 static void pca9570_set(struct gpio_chip *chip, unsigned offset, int value)
  92 {
  93         struct pca9570 *gpio = gpiochip_get_data(chip);
  94         u8 buffer;
  95         int ret;
  96
  97         mutex_lock(&gpio->lock);
  98
  99         buffer = gpio->out;
 100         if (value)
 101                 buffer |= BIT(offset);
 102         else
 103                 buffer &= ~BIT(offset);
 104
 105         ret = pca9570_write(gpio, buffer);
 106         if (ret)
 107                 goto out;
 108
 109         gpio->out = buffer;
 110
 111 out:
 112         mutex_unlock(&gpio->lock);
 113 }
 114
 115 static int pca9570_probe(struct i2c_client *client)
 116 {
 117         struct pca9570 *gpio;
 118
 119         gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
 120         if (!gpio)
 121                 return -ENOMEM;
 122
 123         gpio->chip.label = client->name;
 124         gpio->chip.parent = &client->dev;
 125         gpio->chip.owner = THIS_MODULE;
 126         gpio->chip.get_direction = pca9570_get_direction;
 127         gpio->chip.get = pca9570_get;
 128         gpio->chip.set = pca9570_set;
 129         gpio->chip.base = -1;
 130         gpio->chip_data = device_get_match_data(&client->dev);
 131         gpio->chip.ngpio = gpio->chip_data->ngpio;
 132         gpio->chip.can_sleep = true;
 133
 134         mutex_init(&gpio->lock);
 135
 136         /* Read the current output level */
 137         pca9570_read(gpio, &gpio->out);
 138
 139         i2c_set_clientdata(client, gpio);
 140
 141         return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
 142 }
 143
 144 static const struct pca9570_chip_data pca9570_gpio = {
 145         .ngpio = 4,
 146 };
 147
 148 static const struct pca9570_chip_data pca9571_gpio = {
 149         .ngpio = 8,
 150 };
 151
 152 static const struct pca9570_chip_data slg7xl45106_gpio = {
 153         .ngpio = 8,
 154         .command = SLG7XL45106_GPO_REG,
 155 };
 156
 157 static const struct i2c_device_id pca9570_id_table[] = {
 158         { "pca9570", (kernel_ulong_t)&pca9570_gpio},
 159         { "pca9571", (kernel_ulong_t)&pca9571_gpio },
 160         { "slg7xl45106", (kernel_ulong_t)&slg7xl45106_gpio },
 161         { /* sentinel */ }
 162 };
 163 MODULE_DEVICE_TABLE(i2c, pca9570_id_table);
 164
 165 static const struct of_device_id pca9570_of_match_table[] = {
 166         { .compatible = "dlg,slg7xl45106", .data = &slg7xl45106_gpio},
 167         { .compatible = "nxp,pca9570", .data = &pca9570_gpio },
 168         { .compatible = "nxp,pca9571", .data = &pca9571_gpio },
 169         { /* sentinel */ }
 170 };
 171 MODULE_DEVICE_TABLE(of, pca9570_of_match_table);
 172
 173 static struct i2c_driver pca9570_driver = {
 174         .driver = {
 175                 .name = "pca9570",
 176                 .of_match_table = pca9570_of_match_table,
 177         },
 178         .probe = pca9570_probe,
 179         .id_table = pca9570_id_table,
 180 };
 181 module_i2c_driver(pca9570_driver);
 182
 183 MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
 184 MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
 185 MODULE_LICENSE("GPL v2");