/*
 * Access to GPIOs on TWL4030/TPS659x0 chips
 *
 * Copyright (C) 2006-2007 Texas Instruments, Inc.
 * Copyright (C) 2006 MontaVista Software, Inc.
 *
 * Code re-arranged and cleaned up by:
 *      Syed Mohammed Khasim <x0khasim@ti.com>
 *
 * Initial Code:
 *      Andy Lowe / Nishanth Menon
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that 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, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kthread.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/irqdomain.h>

#include <linux/i2c/twl.h>

/*
 * The GPIO "subchip" supports 18 GPIOs which can be configured as
 * inputs or outputs, with pullups or pulldowns on each pin.  Each
 * GPIO can trigger interrupts on either or both edges.
 *
 * GPIO interrupts can be fed to either of two IRQ lines; this is
 * intended to support multiple hosts.
 *
 * There are also two LED pins used sometimes as output-only GPIOs.
 */

/* genirq interfaces are not available to modules */
#ifdef MODULE
#define is_module()     true
#else
#define is_module()     false
#endif

/* GPIO_CTRL Fields */
#define MASK_GPIO_CTRL_GPIO0CD1         BIT(0)
#define MASK_GPIO_CTRL_GPIO1CD2         BIT(1)
#define MASK_GPIO_CTRL_GPIO_ON          BIT(2)

/* Mask for GPIO registers when aggregated into a 32-bit integer */
#define GPIO_32_MASK                    0x0003ffff

struct gpio_twl4030_priv {
        struct gpio_chip gpio_chip;
        struct mutex mutex;
        int irq_base;

        /* Bitfields for state caching */
        unsigned int usage_count;
        unsigned int direction;
        unsigned int out_state;
};

/*----------------------------------------------------------------------*/

static inline struct gpio_twl4030_priv *to_gpio_twl4030(struct gpio_chip *chip)
{
        return container_of(chip, struct gpio_twl4030_priv, gpio_chip);
}

/*
 * To configure TWL4030 GPIO module registers
 */
static inline int gpio_twl4030_write(u8 address, u8 data)
{
        return twl_i2c_write_u8(TWL4030_MODULE_GPIO, data, address);
}

/*----------------------------------------------------------------------*/

/*
 * LED register offsets from TWL_MODULE_LED base
 * PWMs A and B are dedicated to LEDs A and B, respectively.
 */

#define TWL4030_LED_LEDEN_REG   0x00
#define TWL4030_PWMAON_REG      0x01
#define TWL4030_PWMAOFF_REG     0x02
#define TWL4030_PWMBON_REG      0x03
#define TWL4030_PWMBOFF_REG     0x04

/* LEDEN bits */
#define LEDEN_LEDAON            BIT(0)
#define LEDEN_LEDBON            BIT(1)
#define LEDEN_LEDAEXT           BIT(2)
#define LEDEN_LEDBEXT           BIT(3)
#define LEDEN_LEDAPWM           BIT(4)
#define LEDEN_LEDBPWM           BIT(5)
#define LEDEN_PWM_LENGTHA       BIT(6)
#define LEDEN_PWM_LENGTHB       BIT(7)

#define PWMxON_LENGTH           BIT(7)

/*----------------------------------------------------------------------*/

/*
 * To read a TWL4030 GPIO module register
 */
static inline int gpio_twl4030_read(u8 address)
{
        u8 data;
        int ret = 0;

        ret = twl_i2c_read_u8(TWL4030_MODULE_GPIO, &data, address);
        return (ret < 0) ? ret : data;
}

/*----------------------------------------------------------------------*/

static u8 cached_leden;

/* The LED lines are open drain outputs ... a FET pulls to GND, so an
 * external pullup is needed.  We could also expose the integrated PWM
 * as a LED brightness control; we initialize it as "always on".
 */
static void twl4030_led_set_value(int led, int value)
{
        u8 mask = LEDEN_LEDAON | LEDEN_LEDAPWM;
        int status;

        if (led)
                mask <<= 1;

        if (value)
                cached_leden &= ~mask;
        else
                cached_leden |= mask;
        status = twl_i2c_write_u8(TWL4030_MODULE_LED, cached_leden,
                                  TWL4030_LED_LEDEN_REG);
}

static int twl4030_set_gpio_direction(int gpio, int is_input)
{
        u8 d_bnk = gpio >> 3;
        u8 d_msk = BIT(gpio & 0x7);
        u8 reg = 0;
        u8 base = REG_GPIODATADIR1 + d_bnk;
        int ret = 0;

        ret = gpio_twl4030_read(base);
        if (ret >= 0) {
                if (is_input)
                        reg = ret & ~d_msk;
                else
                        reg = ret | d_msk;

                ret = gpio_twl4030_write(base, reg);
        }
        return ret;
}

static int twl4030_set_gpio_dataout(int gpio, int enable)
{
        u8 d_bnk = gpio >> 3;
        u8 d_msk = BIT(gpio & 0x7);
        u8 base = 0;

        if (enable)
                base = REG_SETGPIODATAOUT1 + d_bnk;
        else
                base = REG_CLEARGPIODATAOUT1 + d_bnk;

        return gpio_twl4030_write(base, d_msk);
}

static int twl4030_get_gpio_datain(int gpio)
{
        u8 d_bnk = gpio >> 3;
        u8 d_off = gpio & 0x7;
        u8 base = 0;
        int ret = 0;

        base = REG_GPIODATAIN1 + d_bnk;
        ret = gpio_twl4030_read(base);
        if (ret > 0)
                ret = (ret >> d_off) & 0x1;

        return ret;
}

/*----------------------------------------------------------------------*/

static int twl_request(struct gpio_chip *chip, unsigned offset)
{
        struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
        int status = 0;

        mutex_lock(&priv->mutex);

        /* Support the two LED outputs as output-only GPIOs. */
        if (offset >= TWL4030_GPIO_MAX) {
                u8      ledclr_mask = LEDEN_LEDAON | LEDEN_LEDAEXT
                                | LEDEN_LEDAPWM | LEDEN_PWM_LENGTHA;
                u8      reg = TWL4030_PWMAON_REG;

                offset -= TWL4030_GPIO_MAX;
                if (offset) {
                        ledclr_mask <<= 1;
                        reg = TWL4030_PWMBON_REG;
                }

                /* initialize PWM to always-drive */
                /* Configure PWM OFF register first */
                status = twl_i2c_write_u8(TWL4030_MODULE_LED, 0x7f, reg + 1);
                if (status < 0)
                        goto done;

                /* Followed by PWM ON register */
                status = twl_i2c_write_u8(TWL4030_MODULE_LED, 0x7f, reg);
                if (status < 0)
                        goto done;

                /* init LED to not-driven (high) */
                status = twl_i2c_read_u8(TWL4030_MODULE_LED, &cached_leden,
                                         TWL4030_LED_LEDEN_REG);
                if (status < 0)
                        goto done;
                cached_leden &= ~ledclr_mask;
                status = twl_i2c_write_u8(TWL4030_MODULE_LED, cached_leden,
                                          TWL4030_LED_LEDEN_REG);
                if (status < 0)
                        goto done;

                status = 0;
                goto done;
        }

        /* on first use, turn GPIO module "on" */
        if (!priv->usage_count) {
                struct twl4030_gpio_platform_data *pdata;
                u8 value = MASK_GPIO_CTRL_GPIO_ON;

                /* optionally have the first two GPIOs switch vMMC1
                 * and vMMC2 power supplies based on card presence.
                 */
                pdata = chip->dev->platform_data;
                if (pdata)
                        value |= pdata->mmc_cd & 0x03;

                status = gpio_twl4030_write(REG_GPIO_CTRL, value);
        }

done:
        if (!status)
                priv->usage_count |= BIT(offset);

        mutex_unlock(&priv->mutex);
        return status;
}

static void twl_free(struct gpio_chip *chip, unsigned offset)
{
        struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);

        mutex_lock(&priv->mutex);
        if (offset >= TWL4030_GPIO_MAX) {
                twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1);
                goto out;
        }

        priv->usage_count &= ~BIT(offset);

        /* on last use, switch off GPIO module */
        if (!priv->usage_count)
                gpio_twl4030_write(REG_GPIO_CTRL, 0x0);

out:
        mutex_unlock(&priv->mutex);
}

static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
{
        struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
        int ret;

        mutex_lock(&priv->mutex);
        if (offset < TWL4030_GPIO_MAX)
                ret = twl4030_set_gpio_direction(offset, 1);
        else
                ret = -EINVAL;

        if (!ret)
                priv->direction &= ~BIT(offset);

        mutex_unlock(&priv->mutex);

        return ret;
}

static int twl_get(struct gpio_chip *chip, unsigned offset)
{
        struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
        int ret;
        int status = 0;

        mutex_lock(&priv->mutex);
        if (!(priv->usage_count & BIT(offset))) {
                ret = -EPERM;
                goto out;
        }

        if (priv->direction & BIT(offset))
                status = priv->out_state & BIT(offset);
        else
                status = twl4030_get_gpio_datain(offset);

        ret = (status <= 0) ? 0 : 1;
out:
        mutex_unlock(&priv->mutex);
        return ret;
}

static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
{
        struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);

        mutex_lock(&priv->mutex);
        if (offset < TWL4030_GPIO_MAX)
                twl4030_set_gpio_dataout(offset, value);
        else
                twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value);

        if (value)
                priv->out_state |= BIT(offset);
        else
                priv->out_state &= ~BIT(offset);

        mutex_unlock(&priv->mutex);
}

static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
{
        struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);
        int ret = -EINVAL;

        mutex_lock(&priv->mutex);
        if (offset < TWL4030_GPIO_MAX)
                ret = twl4030_set_gpio_direction(offset, 0);

        priv->direction |= BIT(offset);
        mutex_unlock(&priv->mutex);

        twl_set(chip, offset, value);

        return ret;
}

static int twl_to_irq(struct gpio_chip *chip, unsigned offset)
{
        struct gpio_twl4030_priv *priv = to_gpio_twl4030(chip);

        return (priv->irq_base && (offset < TWL4030_GPIO_MAX))
                ? (priv->irq_base + offset)
                : -EINVAL;
}

static struct gpio_chip template_chip = {
        .label                  = "twl4030",
        .owner                  = THIS_MODULE,
        .request                = twl_request,
        .free                   = twl_free,
        .direction_input        = twl_direction_in,
        .get                    = twl_get,
        .direction_output       = twl_direction_out,
        .set                    = twl_set,
        .to_irq                 = twl_to_irq,
        .can_sleep              = 1,
};

/*----------------------------------------------------------------------*/

static int gpio_twl4030_pulls(u32 ups, u32 downs)
{
        u8              message[5];
        unsigned        i, gpio_bit;

        /* For most pins, a pulldown was enabled by default.
         * We should have data that's specific to this board.
         */
        for (gpio_bit = 1, i = 0; i < 5; i++) {
                u8              bit_mask;
                unsigned        j;

                for (bit_mask = 0, j = 0; j < 8; j += 2, gpio_bit <<= 1) {
                        if (ups & gpio_bit)
                                bit_mask |= 1 << (j + 1);
                        else if (downs & gpio_bit)
                                bit_mask |= 1 << (j + 0);
                }
                message[i] = bit_mask;
        }

        return twl_i2c_write(TWL4030_MODULE_GPIO, message,
                                REG_GPIOPUPDCTR1, 5);
}

static int gpio_twl4030_debounce(u32 debounce, u8 mmc_cd)
{
        u8              message[3];

        /* 30 msec of debouncing is always used for MMC card detect,
         * and is optional for everything else.
         */
        message[0] = (debounce & 0xff) | (mmc_cd & 0x03);
        debounce >>= 8;
        message[1] = (debounce & 0xff);
        debounce >>= 8;
        message[2] = (debounce & 0x03);

        return twl_i2c_write(TWL4030_MODULE_GPIO, message,
                                REG_GPIO_DEBEN1, 3);
}

static int gpio_twl4030_remove(struct platform_device *pdev);

static struct twl4030_gpio_platform_data *of_gpio_twl4030(struct device *dev)
{
        struct twl4030_gpio_platform_data *omap_twl_info;

        omap_twl_info = devm_kzalloc(dev, sizeof(*omap_twl_info), GFP_KERNEL);
        if (!omap_twl_info)
                return NULL;

        omap_twl_info->use_leds = of_property_read_bool(dev->of_node,
                        "ti,use-leds");

        of_property_read_u32(dev->of_node, "ti,debounce",
                             &omap_twl_info->debounce);
        of_property_read_u32(dev->of_node, "ti,mmc-cd",
                             (u32 *)&omap_twl_info->mmc_cd);
        of_property_read_u32(dev->of_node, "ti,pullups",
                             &omap_twl_info->pullups);
        of_property_read_u32(dev->of_node, "ti,pulldowns",
                             &omap_twl_info->pulldowns);

        return omap_twl_info;
}

static int gpio_twl4030_probe(struct platform_device *pdev)
{
        struct twl4030_gpio_platform_data *pdata = pdev->dev.platform_data;
        struct device_node *node = pdev->dev.of_node;
        struct gpio_twl4030_priv *priv;
        int ret, irq_base;

        priv = devm_kzalloc(&pdev->dev, sizeof(struct gpio_twl4030_priv),
                            GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        /* maybe setup IRQs */
        if (is_module()) {
                dev_err(&pdev->dev, "can't dispatch IRQs from modules\n");
                goto no_irqs;
        }

        irq_base = irq_alloc_descs(-1, 0, TWL4030_GPIO_MAX, 0);
        if (irq_base < 0) {
                dev_err(&pdev->dev, "Failed to alloc irq_descs\n");
                return irq_base;
        }

        irq_domain_add_legacy(node, TWL4030_GPIO_MAX, irq_base, 0,
                              &irq_domain_simple_ops, NULL);

        ret = twl4030_sih_setup(&pdev->dev, TWL4030_MODULE_GPIO, irq_base);
        if (ret < 0)
                return ret;

        priv->irq_base = irq_base;

no_irqs:
        priv->gpio_chip = template_chip;
        priv->gpio_chip.base = -1;
        priv->gpio_chip.ngpio = TWL4030_GPIO_MAX;
        priv->gpio_chip.dev = &pdev->dev;

        mutex_init(&priv->mutex);

        if (node)
                pdata = of_gpio_twl4030(&pdev->dev);

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

        /*
         * NOTE:  boards may waste power if they don't set pullups
         * and pulldowns correctly ... default for non-ULPI pins is
         * pulldown, and some other pins may have external pullups
         * or pulldowns.  Careful!
         */
        ret = gpio_twl4030_pulls(pdata->pullups, pdata->pulldowns);
        if (ret)
                dev_dbg(&pdev->dev, "pullups %.05x %.05x --> %d\n",
                        pdata->pullups, pdata->pulldowns, ret);

        ret = gpio_twl4030_debounce(pdata->debounce, pdata->mmc_cd);
        if (ret)
                dev_dbg(&pdev->dev, "debounce %.03x %.01x --> %d\n",
                        pdata->debounce, pdata->mmc_cd, ret);

        /*
         * NOTE: we assume VIBRA_CTL.VIBRA_EN, in MODULE_AUDIO_VOICE,
         * is (still) clear if use_leds is set.
         */
        if (pdata->use_leds)
                priv->gpio_chip.ngpio += 2;

        ret = gpiochip_add(&priv->gpio_chip);
        if (ret < 0) {
                dev_err(&pdev->dev, "could not register gpiochip, %d\n", ret);
                priv->gpio_chip.ngpio = 0;
                gpio_twl4030_remove(pdev);
                goto out;
        }

        platform_set_drvdata(pdev, priv);

        if (pdata && pdata->setup) {
                int status;

                status = pdata->setup(&pdev->dev, priv->gpio_chip.base,
                                      TWL4030_GPIO_MAX);
                if (status)
                        dev_dbg(&pdev->dev, "setup --> %d\n", status);
        }

out:
        return ret;
}

/* Cannot use as gpio_twl4030_probe() calls us */
static int gpio_twl4030_remove(struct platform_device *pdev)
{
        struct twl4030_gpio_platform_data *pdata = pdev->dev.platform_data;
        struct gpio_twl4030_priv *priv = platform_get_drvdata(pdev);
        int status;

        if (pdata && pdata->teardown) {
                status = pdata->teardown(&pdev->dev, priv->gpio_chip.base,
                                         TWL4030_GPIO_MAX);
                if (status) {
                        dev_dbg(&pdev->dev, "teardown --> %d\n", status);
                        return status;
                }
        }

        status = gpiochip_remove(&priv->gpio_chip);
        if (status < 0)
                return status;

        if (is_module())
                return 0;

        /* REVISIT no support yet for deregistering all the IRQs */
        WARN_ON(1);
        return -EIO;
}

static const struct of_device_id twl_gpio_match[] = {
        { .compatible = "ti,twl4030-gpio", },
        { },
};
MODULE_DEVICE_TABLE(of, twl_gpio_match);

/* Note:  this hardware lives inside an I2C-based multi-function device. */
MODULE_ALIAS("platform:twl4030_gpio");

static struct platform_driver gpio_twl4030_driver = {
        .driver = {
                .name   = "twl4030_gpio",
                .owner  = THIS_MODULE,
                .of_match_table = of_match_ptr(twl_gpio_match),
        },
        .probe          = gpio_twl4030_probe,
        .remove         = gpio_twl4030_remove,
};

static int __init gpio_twl4030_init(void)
{
        return platform_driver_register(&gpio_twl4030_driver);
}
subsys_initcall(gpio_twl4030_init);

static void __exit gpio_twl4030_exit(void)
{
        platform_driver_unregister(&gpio_twl4030_driver);
}
module_exit(gpio_twl4030_exit);

MODULE_AUTHOR("Texas Instruments, Inc.");
MODULE_DESCRIPTION("GPIO interface for TWL4030");
MODULE_LICENSE("GPL");