/*
 * GPIO driver for Analog Devices ADP5520 MFD PMICs
 *
 * Copyright 2009 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mfd/adp5520.h>

#include <linux/gpio.h>

struct adp5520_gpio {
        struct device *master;
        struct gpio_chip gpio_chip;
        unsigned char lut[ADP5520_MAXGPIOS];
        unsigned long output;
};

static int adp5520_gpio_get_value(struct gpio_chip *chip, unsigned off)
{
        struct adp5520_gpio *dev;
        uint8_t reg_val;

        dev = container_of(chip, struct adp5520_gpio, gpio_chip);

        /*
         * There are dedicated registers for GPIO IN/OUT.
         * Make sure we return the right value, even when configured as output
         */

        if (test_bit(off, &dev->output))
                adp5520_read(dev->master, ADP5520_GPIO_OUT, &reg_val);
        else
                adp5520_read(dev->master, ADP5520_GPIO_IN, &reg_val);

        return !!(reg_val & dev->lut[off]);
}

static void adp5520_gpio_set_value(struct gpio_chip *chip,
                unsigned off, int val)
{
        struct adp5520_gpio *dev;
        dev = container_of(chip, struct adp5520_gpio, gpio_chip);

        if (val)
                adp5520_set_bits(dev->master, ADP5520_GPIO_OUT, dev->lut[off]);
        else
                adp5520_clr_bits(dev->master, ADP5520_GPIO_OUT, dev->lut[off]);
}

static int adp5520_gpio_direction_input(struct gpio_chip *chip, unsigned off)
{
        struct adp5520_gpio *dev;
        dev = container_of(chip, struct adp5520_gpio, gpio_chip);

        clear_bit(off, &dev->output);

        return adp5520_clr_bits(dev->master, ADP5520_GPIO_CFG_2,
                                dev->lut[off]);
}

static int adp5520_gpio_direction_output(struct gpio_chip *chip,
                unsigned off, int val)
{
        struct adp5520_gpio *dev;
        int ret = 0;
        dev = container_of(chip, struct adp5520_gpio, gpio_chip);

        set_bit(off, &dev->output);

        if (val)
                ret |= adp5520_set_bits(dev->master, ADP5520_GPIO_OUT,
                                        dev->lut[off]);
        else
                ret |= adp5520_clr_bits(dev->master, ADP5520_GPIO_OUT,
                                        dev->lut[off]);

        ret |= adp5520_set_bits(dev->master, ADP5520_GPIO_CFG_2,
                                        dev->lut[off]);

        return ret;
}

static int __devinit adp5520_gpio_probe(struct platform_device *pdev)
{
        struct adp5520_gpio_platform_data *pdata = pdev->dev.platform_data;
        struct adp5520_gpio *dev;
        struct gpio_chip *gc;
        int ret, i, gpios;
        unsigned char ctl_mask = 0;

        if (pdata == NULL) {
                dev_err(&pdev->dev, "missing platform data\n");
                return -ENODEV;
        }

        if (pdev->id != ID_ADP5520) {
                dev_err(&pdev->dev, "only ADP5520 supports GPIO\n");
                return -ENODEV;
        }

        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
        if (dev == NULL) {
                dev_err(&pdev->dev, "failed to alloc memory\n");
                return -ENOMEM;
        }

        dev->master = pdev->dev.parent;

        for (gpios = 0, i = 0; i < ADP5520_MAXGPIOS; i++)
                if (pdata->gpio_en_mask & (1 << i))
                        dev->lut[gpios++] = 1 << i;

        if (gpios < 1) {
                ret = -EINVAL;
                goto err;
        }

        gc = &dev->gpio_chip;
        gc->direction_input  = adp5520_gpio_direction_input;
        gc->direction_output = adp5520_gpio_direction_output;
        gc->get = adp5520_gpio_get_value;
        gc->set = adp5520_gpio_set_value;
        gc->can_sleep = 1;

        gc->base = pdata->gpio_start;
        gc->ngpio = gpios;
        gc->label = pdev->name;
        gc->owner = THIS_MODULE;

        ret = adp5520_clr_bits(dev->master, ADP5520_GPIO_CFG_1,
                pdata->gpio_en_mask);

        if (pdata->gpio_en_mask & ADP5520_GPIO_C3)
                ctl_mask |= ADP5520_C3_MODE;

        if (pdata->gpio_en_mask & ADP5520_GPIO_R3)
                ctl_mask |= ADP5520_R3_MODE;

        if (ctl_mask)
                ret = adp5520_set_bits(dev->master, ADP5520_LED_CONTROL,
                        ctl_mask);

        ret |= adp5520_set_bits(dev->master, ADP5520_GPIO_PULLUP,
                pdata->gpio_pullup_mask);

        if (ret) {
                dev_err(&pdev->dev, "failed to write\n");
                goto err;
        }

        ret = gpiochip_add(&dev->gpio_chip);
        if (ret)
                goto err;

        platform_set_drvdata(pdev, dev);
        return 0;

err:
        kfree(dev);
        return ret;
}

static int __devexit adp5520_gpio_remove(struct platform_device *pdev)
{
        struct adp5520_gpio *dev;
        int ret;

        dev = platform_get_drvdata(pdev);
        ret = gpiochip_remove(&dev->gpio_chip);
        if (ret) {
                dev_err(&pdev->dev, "%s failed, %d\n",
                                "gpiochip_remove()", ret);
                return ret;
        }

        kfree(dev);
        return 0;
}

static struct platform_driver adp5520_gpio_driver = {
        .driver = {
                .name   = "adp5520-gpio",
                .owner  = THIS_MODULE,
        },
        .probe          = adp5520_gpio_probe,
        .remove         = __devexit_p(adp5520_gpio_remove),
};

static int __init adp5520_gpio_init(void)
{
        return platform_driver_register(&adp5520_gpio_driver);
}
module_init(adp5520_gpio_init);

static void __exit adp5520_gpio_exit(void)
{
        platform_driver_unregister(&adp5520_gpio_driver);
}
module_exit(adp5520_gpio_exit);

MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("GPIO ADP5520 Driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:adp5520-gpio");