// SPDX-License-Identifier: GPL-2.0
//
// Copyright (C) 2018 BayLibre SAS
// Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
//
// GPIO driver for MAXIM 77650/77651 charger/power-supply.

#include <linux/gpio/driver.h>
#include <linux/i2c.h>
#include <linux/mfd/max77650.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>

#define MAX77650_GPIO_DIR_MASK          BIT(0)
#define MAX77650_GPIO_INVAL_MASK        BIT(1)
#define MAX77650_GPIO_DRV_MASK          BIT(2)
#define MAX77650_GPIO_OUTVAL_MASK       BIT(3)
#define MAX77650_GPIO_DEBOUNCE_MASK     BIT(4)

#define MAX77650_GPIO_DIR_OUT           0x00
#define MAX77650_GPIO_DIR_IN            BIT(0)
#define MAX77650_GPIO_OUT_LOW           0x00
#define MAX77650_GPIO_OUT_HIGH          BIT(3)
#define MAX77650_GPIO_DRV_OPEN_DRAIN    0x00
#define MAX77650_GPIO_DRV_PUSH_PULL     BIT(2)
#define MAX77650_GPIO_DEBOUNCE          BIT(4)

#define MAX77650_GPIO_DIR_BITS(_reg) \
                ((_reg) & MAX77650_GPIO_DIR_MASK)
#define MAX77650_GPIO_INVAL_BITS(_reg) \
                (((_reg) & MAX77650_GPIO_INVAL_MASK) >> 1)

struct max77650_gpio_chip {
        struct regmap *map;
        struct gpio_chip gc;
        int irq;
};

static int max77650_gpio_direction_input(struct gpio_chip *gc,
                                         unsigned int offset)
{
        struct max77650_gpio_chip *chip = gpiochip_get_data(gc);

        return regmap_update_bits(chip->map,
                                  MAX77650_REG_CNFG_GPIO,
                                  MAX77650_GPIO_DIR_MASK,
                                  MAX77650_GPIO_DIR_IN);
}

static int max77650_gpio_direction_output(struct gpio_chip *gc,
                                          unsigned int offset, int value)
{
        struct max77650_gpio_chip *chip = gpiochip_get_data(gc);
        int mask, regval;

        mask = MAX77650_GPIO_DIR_MASK | MAX77650_GPIO_OUTVAL_MASK;
        regval = value ? MAX77650_GPIO_OUT_HIGH : MAX77650_GPIO_OUT_LOW;
        regval |= MAX77650_GPIO_DIR_OUT;

        return regmap_update_bits(chip->map,
                                  MAX77650_REG_CNFG_GPIO, mask, regval);
}

static int max77650_gpio_set_value(struct gpio_chip *gc,
                                   unsigned int offset, int value)
{
        struct max77650_gpio_chip *chip = gpiochip_get_data(gc);
        int regval;

        regval = value ? MAX77650_GPIO_OUT_HIGH : MAX77650_GPIO_OUT_LOW;

        return regmap_update_bits(chip->map, MAX77650_REG_CNFG_GPIO,
                                  MAX77650_GPIO_OUTVAL_MASK, regval);
}

static int max77650_gpio_get_value(struct gpio_chip *gc,
                                   unsigned int offset)
{
        struct max77650_gpio_chip *chip = gpiochip_get_data(gc);
        unsigned int val;
        int rv;

        rv = regmap_read(chip->map, MAX77650_REG_CNFG_GPIO, &val);
        if (rv)
                return rv;

        return MAX77650_GPIO_INVAL_BITS(val);
}

static int max77650_gpio_get_direction(struct gpio_chip *gc,
                                       unsigned int offset)
{
        struct max77650_gpio_chip *chip = gpiochip_get_data(gc);
        unsigned int val;
        int rv;

        rv = regmap_read(chip->map, MAX77650_REG_CNFG_GPIO, &val);
        if (rv)
                return rv;

        return MAX77650_GPIO_DIR_BITS(val);
}

static int max77650_gpio_set_config(struct gpio_chip *gc,
                                    unsigned int offset, unsigned long cfg)
{
        struct max77650_gpio_chip *chip = gpiochip_get_data(gc);

        switch (pinconf_to_config_param(cfg)) {
        case PIN_CONFIG_DRIVE_OPEN_DRAIN:
                return regmap_update_bits(chip->map,
                                          MAX77650_REG_CNFG_GPIO,
                                          MAX77650_GPIO_DRV_MASK,
                                          MAX77650_GPIO_DRV_OPEN_DRAIN);
        case PIN_CONFIG_DRIVE_PUSH_PULL:
                return regmap_update_bits(chip->map,
                                          MAX77650_REG_CNFG_GPIO,
                                          MAX77650_GPIO_DRV_MASK,
                                          MAX77650_GPIO_DRV_PUSH_PULL);
        case PIN_CONFIG_INPUT_DEBOUNCE:
                return regmap_update_bits(chip->map,
                                          MAX77650_REG_CNFG_GPIO,
                                          MAX77650_GPIO_DEBOUNCE_MASK,
                                          MAX77650_GPIO_DEBOUNCE);
        default:
                return -ENOTSUPP;
        }
}

static int max77650_gpio_to_irq(struct gpio_chip *gc, unsigned int offset)
{
        struct max77650_gpio_chip *chip = gpiochip_get_data(gc);

        return chip->irq;
}

static int max77650_gpio_probe(struct platform_device *pdev)
{
        struct max77650_gpio_chip *chip;
        struct device *dev, *parent;
        struct i2c_client *i2c;

        dev = &pdev->dev;
        parent = dev->parent;
        i2c = to_i2c_client(parent);

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

        chip->map = dev_get_regmap(parent, NULL);
        if (!chip->map)
                return -ENODEV;

        chip->irq = platform_get_irq_byname(pdev, "GPI");
        if (chip->irq < 0)
                return chip->irq;

        chip->gc.base = -1;
        chip->gc.ngpio = 1;
        chip->gc.label = i2c->name;
        chip->gc.parent = dev;
        chip->gc.owner = THIS_MODULE;
        chip->gc.can_sleep = true;

        chip->gc.direction_input = max77650_gpio_direction_input;
        chip->gc.direction_output = max77650_gpio_direction_output;
        chip->gc.set = max77650_gpio_set_value;
        chip->gc.get = max77650_gpio_get_value;
        chip->gc.get_direction = max77650_gpio_get_direction;
        chip->gc.set_config = max77650_gpio_set_config;
        chip->gc.to_irq = max77650_gpio_to_irq;

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

static struct platform_driver max77650_gpio_driver = {
        .driver = {
                .name = "max77650-gpio",
        },
        .probe = max77650_gpio_probe,
};
module_platform_driver(max77650_gpio_driver);

MODULE_DESCRIPTION("MAXIM 77650/77651 GPIO driver");
MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:max77650-gpio");