// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for PCA9570 I2C GPO expander
 *
 * Copyright (C) 2020 Sungbo Eo <mans0n@gorani.run>
 *
 * Based on gpio-tpic2810.c
 * Copyright (C) 2015 Texas Instruments Incorporated - http://www.ti.com/
 *      Andrew F. Davis <afd@ti.com>
 */

#include <linux/bits.h>
#include <linux/cleanup.h>
#include <linux/device/devres.h>
#include <linux/errno.h>
#include <linux/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/property.h>
#include <linux/types.h>

#define SLG7XL45106_GPO_REG     0xDB

/**
 * struct pca9570_chip_data - GPIO platformdata
 * @ngpio: no of gpios
 * @command: Command to be sent
 */
struct pca9570_chip_data {
        u16 ngpio;
        u32 command;
};

/**
 * struct pca9570 - GPIO driver data
 * @chip: GPIO controller chip
 * @chip_data: GPIO controller platform data
 * @lock: Protects write sequences
 * @out: Buffer for device register
 */
struct pca9570 {
        struct gpio_chip chip;
        const struct pca9570_chip_data *chip_data;
        struct mutex lock;
        u8 out;
};

static int pca9570_read(struct pca9570 *gpio, u8 *value)
{
        struct i2c_client *client = to_i2c_client(gpio->chip.parent);
        int ret;

        if (gpio->chip_data->command != 0)
                ret = i2c_smbus_read_byte_data(client, gpio->chip_data->command);
        else
                ret = i2c_smbus_read_byte(client);

        if (ret < 0)
                return ret;

        *value = ret;
        return 0;
}

static int pca9570_write(struct pca9570 *gpio, u8 value)
{
        struct i2c_client *client = to_i2c_client(gpio->chip.parent);

        if (gpio->chip_data->command != 0)
                return i2c_smbus_write_byte_data(client, gpio->chip_data->command, value);

        return i2c_smbus_write_byte(client, value);
}

static int pca9570_get_direction(struct gpio_chip *chip,
                                 unsigned offset)
{
        /* This device always output */
        return GPIO_LINE_DIRECTION_OUT;
}

static int pca9570_get(struct gpio_chip *chip, unsigned offset)
{
        struct pca9570 *gpio = gpiochip_get_data(chip);
        u8 buffer;
        int ret;

        ret = pca9570_read(gpio, &buffer);
        if (ret)
                return ret;

        return !!(buffer & BIT(offset));
}

static int pca9570_set(struct gpio_chip *chip, unsigned int offset, int value)
{
        struct pca9570 *gpio = gpiochip_get_data(chip);
        u8 buffer;
        int ret;

        guard(mutex)(&gpio->lock);

        buffer = gpio->out;
        if (value)
                buffer |= BIT(offset);
        else
                buffer &= ~BIT(offset);

        ret = pca9570_write(gpio, buffer);
        if (ret)
                return ret;

        gpio->out = buffer;

        return 0;
}

static int pca9570_probe(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        struct pca9570 *gpio;
        int ret;

        gpio = devm_kzalloc(&client->dev, sizeof(*gpio), GFP_KERNEL);
        if (!gpio)
                return -ENOMEM;

        gpio->chip.label = client->name;
        gpio->chip.parent = &client->dev;
        gpio->chip.owner = THIS_MODULE;
        gpio->chip.get_direction = pca9570_get_direction;
        gpio->chip.get = pca9570_get;
        gpio->chip.set = pca9570_set;
        gpio->chip.base = -1;
        gpio->chip_data = device_get_match_data(&client->dev);
        gpio->chip.ngpio = gpio->chip_data->ngpio;
        gpio->chip.can_sleep = true;

        ret = devm_mutex_init(dev, &gpio->lock);
        if (ret)
                return ret;

        /* Read the current output level */
        pca9570_read(gpio, &gpio->out);

        i2c_set_clientdata(client, gpio);

        return devm_gpiochip_add_data(&client->dev, &gpio->chip, gpio);
}

static const struct pca9570_chip_data pca9570_gpio = {
        .ngpio = 4,
};

static const struct pca9570_chip_data pca9571_gpio = {
        .ngpio = 8,
};

static const struct pca9570_chip_data slg7xl45106_gpio = {
        .ngpio = 8,
        .command = SLG7XL45106_GPO_REG,
};

static const struct i2c_device_id pca9570_id_table[] = {
        { "pca9570", (kernel_ulong_t)&pca9570_gpio},
        { "pca9571", (kernel_ulong_t)&pca9571_gpio },
        { "slg7xl45106", (kernel_ulong_t)&slg7xl45106_gpio },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(i2c, pca9570_id_table);

static const struct of_device_id pca9570_of_match_table[] = {
        { .compatible = "dlg,slg7xl45106", .data = &slg7xl45106_gpio},
        { .compatible = "nxp,pca9570", .data = &pca9570_gpio },
        { .compatible = "nxp,pca9571", .data = &pca9571_gpio },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pca9570_of_match_table);

static struct i2c_driver pca9570_driver = {
        .driver = {
                .name = "pca9570",
                .of_match_table = pca9570_of_match_table,
        },
        .probe = pca9570_probe,
        .id_table = pca9570_id_table,
};
module_i2c_driver(pca9570_driver);

MODULE_AUTHOR("Sungbo Eo <mans0n@gorani.run>");
MODULE_DESCRIPTION("GPIO expander driver for PCA9570");
MODULE_LICENSE("GPL v2");