// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * gpiolib support for Wolfson Arizona class devices
 *
 * Copyright 2012 Wolfson Microelectronics PLC.
 *
 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 */

#include <linux/gpio/driver.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>

#include <linux/mfd/arizona/core.h>
#include <linux/mfd/arizona/pdata.h>
#include <linux/mfd/arizona/registers.h>

struct arizona_gpio {
        struct arizona *arizona;
        struct gpio_chip gpio_chip;
};

static int arizona_gpio_direction_in(struct gpio_chip *chip, unsigned offset)
{
        struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
        struct arizona *arizona = arizona_gpio->arizona;
        bool persistent = gpiochip_line_is_persistent(chip, offset);
        bool change;
        int ret;

        ret = regmap_update_bits_check(arizona->regmap,
                                       ARIZONA_GPIO1_CTRL + offset,
                                       ARIZONA_GPN_DIR, ARIZONA_GPN_DIR,
                                       &change);
        if (ret < 0)
                return ret;

        if (change && persistent) {
                pm_runtime_put_autosuspend(chip->parent);
        }

        return 0;
}

static int arizona_gpio_get(struct gpio_chip *chip, unsigned offset)
{
        struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
        struct arizona *arizona = arizona_gpio->arizona;
        unsigned int reg, val;
        int ret;

        reg = ARIZONA_GPIO1_CTRL + offset;
        ret = regmap_read(arizona->regmap, reg, &val);
        if (ret < 0)
                return ret;

        /* Resume to read actual registers for input pins */
        if (val & ARIZONA_GPN_DIR) {
                ret = pm_runtime_get_sync(chip->parent);
                if (ret < 0) {
                        dev_err(chip->parent, "Failed to resume: %d\n", ret);
                        pm_runtime_put_autosuspend(chip->parent);
                        return ret;
                }

                /* Register is cached, drop it to ensure a physical read */
                ret = regcache_drop_region(arizona->regmap, reg, reg);
                if (ret < 0) {
                        dev_err(chip->parent, "Failed to drop cache: %d\n",
                                ret);
                        pm_runtime_put_autosuspend(chip->parent);
                        return ret;
                }

                ret = regmap_read(arizona->regmap, reg, &val);
                if (ret < 0) {
                        pm_runtime_put_autosuspend(chip->parent);
                        return ret;
                }

                pm_runtime_put_autosuspend(chip->parent);
        }

        if (val & ARIZONA_GPN_LVL)
                return 1;
        else
                return 0;
}

static int arizona_gpio_direction_out(struct gpio_chip *chip,
                                     unsigned offset, int value)
{
        struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
        struct arizona *arizona = arizona_gpio->arizona;
        bool persistent = gpiochip_line_is_persistent(chip, offset);
        unsigned int val;
        int ret;

        ret = regmap_read(arizona->regmap, ARIZONA_GPIO1_CTRL + offset, &val);
        if (ret < 0)
                return ret;

        if ((val & ARIZONA_GPN_DIR) && persistent) {
                ret = pm_runtime_get_sync(chip->parent);
                if (ret < 0) {
                        dev_err(chip->parent, "Failed to resume: %d\n", ret);
                        pm_runtime_put(chip->parent);
                        return ret;
                }
        }

        if (value)
                value = ARIZONA_GPN_LVL;

        return regmap_update_bits(arizona->regmap, ARIZONA_GPIO1_CTRL + offset,
                                  ARIZONA_GPN_DIR | ARIZONA_GPN_LVL, value);
}

static int arizona_gpio_set(struct gpio_chip *chip, unsigned int offset,
                            int value)
{
        struct arizona_gpio *arizona_gpio = gpiochip_get_data(chip);
        struct arizona *arizona = arizona_gpio->arizona;

        if (value)
                value = ARIZONA_GPN_LVL;

        return regmap_update_bits(arizona->regmap, ARIZONA_GPIO1_CTRL + offset,
                                  ARIZONA_GPN_LVL, value);
}

static const struct gpio_chip template_chip = {
        .label                  = "arizona",
        .owner                  = THIS_MODULE,
        .direction_input        = arizona_gpio_direction_in,
        .get                    = arizona_gpio_get,
        .direction_output       = arizona_gpio_direction_out,
        .set                    = arizona_gpio_set,
        .can_sleep              = true,
};

static int arizona_gpio_probe(struct platform_device *pdev)
{
        struct arizona *arizona = dev_get_drvdata(pdev->dev.parent);
        struct arizona_pdata *pdata = &arizona->pdata;
        struct arizona_gpio *arizona_gpio;
        int ret;

        device_set_node(&pdev->dev, dev_fwnode(pdev->dev.parent));

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

        arizona_gpio->arizona = arizona;
        arizona_gpio->gpio_chip = template_chip;
        arizona_gpio->gpio_chip.parent = &pdev->dev;

        switch (arizona->type) {
        case WM5102:
        case WM5110:
        case WM8280:
        case WM8997:
        case WM8998:
        case WM1814:
                arizona_gpio->gpio_chip.ngpio = 5;
                break;
        case WM1831:
        case CS47L24:
                arizona_gpio->gpio_chip.ngpio = 2;
                break;
        default:
                dev_err(&pdev->dev, "Unknown chip variant %d\n",
                        arizona->type);
                return -EINVAL;
        }

        if (pdata->gpio_base)
                arizona_gpio->gpio_chip.base = pdata->gpio_base;
        else
                arizona_gpio->gpio_chip.base = -1;

        pm_runtime_enable(&pdev->dev);

        ret = devm_gpiochip_add_data(&pdev->dev, &arizona_gpio->gpio_chip,
                                     arizona_gpio);
        if (ret < 0) {
                pm_runtime_disable(&pdev->dev);
                dev_err(&pdev->dev, "Could not register gpiochip, %d\n",
                        ret);
                return ret;
        }

        return 0;
}

static struct platform_driver arizona_gpio_driver = {
        .driver.name    = "arizona-gpio",
        .probe          = arizona_gpio_probe,
};

module_platform_driver(arizona_gpio_driver);

MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
MODULE_DESCRIPTION("GPIO interface for Arizona devices");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:arizona-gpio");