// SPDX-License-Identifier: GPL-2.0-only
// Copyright (C) 2018 ROHM Semiconductors

#include <linux/gpio/driver.h>
#include <linux/mfd/rohm-bd71828.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#define GPIO_OUT_REG(off) (BD71828_REG_GPIO_CTRL1 + (off))
#define HALL_GPIO_OFFSET 3

struct bd71828_gpio {
        struct regmap *regmap;
        struct device *dev;
        struct gpio_chip gpio;
};

static int bd71828_gpio_set(struct gpio_chip *chip, unsigned int offset,
                            int value)
{
        struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);
        u8 val = (value) ? BD71828_GPIO_OUT_HI : BD71828_GPIO_OUT_LO;

        /*
         * The HALL input pin can only be used as input. If this is the pin
         * we are dealing with - then we are done
         */
        if (offset == HALL_GPIO_OFFSET)
                return 0;

        return regmap_update_bits(bdgpio->regmap, GPIO_OUT_REG(offset),
                                  BD71828_GPIO_OUT_MASK, val);
}

static int bd71828_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
        int ret;
        unsigned int val;
        struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);

        if (offset == HALL_GPIO_OFFSET)
                ret = regmap_read(bdgpio->regmap, BD71828_REG_IO_STAT,
                                  &val);
        else
                ret = regmap_read(bdgpio->regmap, GPIO_OUT_REG(offset),
                                  &val);
        if (!ret)
                ret = (val & BD71828_GPIO_OUT_MASK);

        return ret;
}

static int bd71828_gpio_set_config(struct gpio_chip *chip, unsigned int offset,
                                   unsigned long config)
{
        struct bd71828_gpio *bdgpio = gpiochip_get_data(chip);

        if (offset == HALL_GPIO_OFFSET)
                return -ENOTSUPP;

        switch (pinconf_to_config_param(config)) {
        case PIN_CONFIG_DRIVE_OPEN_DRAIN:
                return regmap_update_bits(bdgpio->regmap,
                                          GPIO_OUT_REG(offset),
                                          BD71828_GPIO_DRIVE_MASK,
                                          BD71828_GPIO_OPEN_DRAIN);
        case PIN_CONFIG_DRIVE_PUSH_PULL:
                return regmap_update_bits(bdgpio->regmap,
                                          GPIO_OUT_REG(offset),
                                          BD71828_GPIO_DRIVE_MASK,
                                          BD71828_GPIO_PUSH_PULL);
        default:
                break;
        }
        return -ENOTSUPP;
}

static int bd71828_get_direction(struct gpio_chip *chip, unsigned int offset)
{
        /*
         * Pin usage is selected by OTP data. We can't read it runtime. Hence
         * we trust that if the pin is not excluded by "gpio-reserved-ranges"
         * the OTP configuration is set to OUT. (Other pins but HALL input pin
         * on BD71828 can't really be used for general purpose input - input
         * states are used for specific cases like regulator control or
         * PMIC_ON_REQ.
         */
        if (offset == HALL_GPIO_OFFSET)
                return GPIO_LINE_DIRECTION_IN;

        return GPIO_LINE_DIRECTION_OUT;
}

static int bd71828_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct bd71828_gpio *bdgpio;

        bdgpio = devm_kzalloc(dev, sizeof(*bdgpio), GFP_KERNEL);
        if (!bdgpio)
                return -ENOMEM;

        bdgpio->dev = dev;
        bdgpio->gpio.parent = dev->parent;
        bdgpio->gpio.label = "bd71828-gpio";
        bdgpio->gpio.owner = THIS_MODULE;
        bdgpio->gpio.get_direction = bd71828_get_direction;
        bdgpio->gpio.set_config = bd71828_gpio_set_config;
        bdgpio->gpio.can_sleep = true;
        bdgpio->gpio.get = bd71828_gpio_get;
        bdgpio->gpio.set = bd71828_gpio_set;
        bdgpio->gpio.base = -1;

        /*
         * See if we need some implementation to mark some PINs as
         * not controllable based on DT info or if core can handle
         * "gpio-reserved-ranges" and exclude them from control
         */
        bdgpio->gpio.ngpio = 4;
        bdgpio->regmap = dev_get_regmap(dev->parent, NULL);
        if (!bdgpio->regmap)
                return -ENODEV;

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

static struct platform_driver bd71828_gpio = {
        .driver = {
                .name = "bd71828-gpio"
        },
        .probe = bd71828_probe,
};

module_platform_driver(bd71828_gpio);

MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>");
MODULE_DESCRIPTION("BD71828 voltage regulator driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:bd71828-gpio");