/*
 * TI Palma series PMIC's GPIO driver.
 *
 * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
 *
 * Author: Laxman Dewangan <ldewangan@nvidia.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <linux/gpio/driver.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/mfd/palmas.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>

struct palmas_gpio {
        struct gpio_chip gpio_chip;
        struct palmas *palmas;
};

struct palmas_device_data {
        int ngpio;
};

static int palmas_gpio_get(struct gpio_chip *gc, unsigned offset)
{
        struct palmas_gpio *pg = gpiochip_get_data(gc);
        struct palmas *palmas = pg->palmas;
        unsigned int val;
        int ret;
        unsigned int reg;
        int gpio16 = (offset/8);

        offset %= 8;
        reg = (gpio16) ? PALMAS_GPIO_DATA_DIR2 : PALMAS_GPIO_DATA_DIR;

        ret = palmas_read(palmas, PALMAS_GPIO_BASE, reg, &val);
        if (ret < 0) {
                dev_err(gc->parent, "Reg 0x%02x read failed, %d\n", reg, ret);
                return ret;
        }

        if (val & BIT(offset))
                reg = (gpio16) ? PALMAS_GPIO_DATA_OUT2 : PALMAS_GPIO_DATA_OUT;
        else
                reg = (gpio16) ? PALMAS_GPIO_DATA_IN2 : PALMAS_GPIO_DATA_IN;

        ret = palmas_read(palmas, PALMAS_GPIO_BASE, reg, &val);
        if (ret < 0) {
                dev_err(gc->parent, "Reg 0x%02x read failed, %d\n", reg, ret);
                return ret;
        }
        return !!(val & BIT(offset));
}

static void palmas_gpio_set(struct gpio_chip *gc, unsigned offset,
                        int value)
{
        struct palmas_gpio *pg = gpiochip_get_data(gc);
        struct palmas *palmas = pg->palmas;
        int ret;
        unsigned int reg;
        int gpio16 = (offset/8);

        offset %= 8;
        if (gpio16)
                reg = (value) ?
                        PALMAS_GPIO_SET_DATA_OUT2 : PALMAS_GPIO_CLEAR_DATA_OUT2;
        else
                reg = (value) ?
                        PALMAS_GPIO_SET_DATA_OUT : PALMAS_GPIO_CLEAR_DATA_OUT;

        ret = palmas_write(palmas, PALMAS_GPIO_BASE, reg, BIT(offset));
        if (ret < 0)
                dev_err(gc->parent, "Reg 0x%02x write failed, %d\n", reg, ret);
}

static int palmas_gpio_output(struct gpio_chip *gc, unsigned offset,
                                int value)
{
        struct palmas_gpio *pg = gpiochip_get_data(gc);
        struct palmas *palmas = pg->palmas;
        int ret;
        unsigned int reg;
        int gpio16 = (offset/8);

        offset %= 8;
        reg = (gpio16) ? PALMAS_GPIO_DATA_DIR2 : PALMAS_GPIO_DATA_DIR;

        /* Set the initial value */
        palmas_gpio_set(gc, offset, value);

        ret = palmas_update_bits(palmas, PALMAS_GPIO_BASE, reg,
                                BIT(offset), BIT(offset));
        if (ret < 0)
                dev_err(gc->parent, "Reg 0x%02x update failed, %d\n", reg,
                        ret);
        return ret;
}

static int palmas_gpio_input(struct gpio_chip *gc, unsigned offset)
{
        struct palmas_gpio *pg = gpiochip_get_data(gc);
        struct palmas *palmas = pg->palmas;
        int ret;
        unsigned int reg;
        int gpio16 = (offset/8);

        offset %= 8;
        reg = (gpio16) ? PALMAS_GPIO_DATA_DIR2 : PALMAS_GPIO_DATA_DIR;

        ret = palmas_update_bits(palmas, PALMAS_GPIO_BASE, reg, BIT(offset), 0);
        if (ret < 0)
                dev_err(gc->parent, "Reg 0x%02x update failed, %d\n", reg,
                        ret);
        return ret;
}

static int palmas_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
{
        struct palmas_gpio *pg = gpiochip_get_data(gc);
        struct palmas *palmas = pg->palmas;

        return palmas_irq_get_virq(palmas, PALMAS_GPIO_0_IRQ + offset);
}

static const struct palmas_device_data palmas_dev_data = {
        .ngpio = 8,
};

static const struct palmas_device_data tps80036_dev_data = {
        .ngpio = 16,
};

static const struct of_device_id of_palmas_gpio_match[] = {
        { .compatible = "ti,palmas-gpio", .data = &palmas_dev_data,},
        { .compatible = "ti,tps65913-gpio", .data = &palmas_dev_data,},
        { .compatible = "ti,tps65914-gpio", .data = &palmas_dev_data,},
        { .compatible = "ti,tps80036-gpio", .data = &tps80036_dev_data,},
        { },
};

static int palmas_gpio_probe(struct platform_device *pdev)
{
        struct palmas *palmas = dev_get_drvdata(pdev->dev.parent);
        struct palmas_platform_data *palmas_pdata;
        struct palmas_gpio *palmas_gpio;
        int ret;
        const struct palmas_device_data *dev_data;

        dev_data = of_device_get_match_data(&pdev->dev);
        if (!dev_data)
                dev_data = &palmas_dev_data;

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

        palmas_gpio->palmas = palmas;
        palmas_gpio->gpio_chip.owner = THIS_MODULE;
        palmas_gpio->gpio_chip.label = dev_name(&pdev->dev);
        palmas_gpio->gpio_chip.ngpio = dev_data->ngpio;
        palmas_gpio->gpio_chip.can_sleep = true;
        palmas_gpio->gpio_chip.direction_input = palmas_gpio_input;
        palmas_gpio->gpio_chip.direction_output = palmas_gpio_output;
        palmas_gpio->gpio_chip.to_irq = palmas_gpio_to_irq;
        palmas_gpio->gpio_chip.set      = palmas_gpio_set;
        palmas_gpio->gpio_chip.get      = palmas_gpio_get;
        palmas_gpio->gpio_chip.parent = &pdev->dev;
#ifdef CONFIG_OF_GPIO
        palmas_gpio->gpio_chip.of_node = pdev->dev.of_node;
#endif
        palmas_pdata = dev_get_platdata(palmas->dev);
        if (palmas_pdata && palmas_pdata->gpio_base)
                palmas_gpio->gpio_chip.base = palmas_pdata->gpio_base;
        else
                palmas_gpio->gpio_chip.base = -1;

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

        platform_set_drvdata(pdev, palmas_gpio);
        return ret;
}

static struct platform_driver palmas_gpio_driver = {
        .driver.name    = "palmas-gpio",
        .driver.of_match_table = of_palmas_gpio_match,
        .probe          = palmas_gpio_probe,
};

static int __init palmas_gpio_init(void)
{
        return platform_driver_register(&palmas_gpio_driver);
}
subsys_initcall(palmas_gpio_init);