gpio-twl4030.c

Go to the documentation of this file.

/*
 * 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 <[email protected]>
 *
 * 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.
 */


static struct gpio_chip twl_gpiochip;
static int twl4030_gpio_base;
static int twl4030_gpio_irq_base;

/* 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

/* Data structures */
static DEFINE_MUTEX(gpio_lock);

/* store usage of each GPIO. - each bit represents one GPIO */
static unsigned int gpio_usage_count;

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

/*
 * 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 (use TWL4030_MODULE_{LED,PWMA,PWMB}))
 * PWMs A and B are dedicated to LEDs A and B, respectively.
 */

#define TWL4030_LED_LEDEN   0x0

/* 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 TWL4030_PWMx_PWMxON 0x0
#define TWL4030_PWMx_PWMxOFF    0x1

#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;     /* protected by gpio_lock */

/* 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;

    mutex_lock(&gpio_lock);
    if (value)
        cached_leden &= ~mask;
    else
        cached_leden |= mask;
    status = twl_i2c_write_u8(TWL4030_MODULE_LED, cached_leden,
            TWL4030_LED_LEDEN);
    mutex_unlock(&gpio_lock);
}

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;

    mutex_lock(&gpio_lock);
    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);
    }
    mutex_unlock(&gpio_lock);
    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;

    if (unlikely((gpio >= TWL4030_GPIO_MAX)
        || !(gpio_usage_count & BIT(gpio))))
        return -EPERM;

    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)
{
    int status = 0;

    mutex_lock(&gpio_lock);

    /* 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  module = TWL4030_MODULE_PWMA;

        offset -= TWL4030_GPIO_MAX;
        if (offset) {
            ledclr_mask <<= 1;
            module = TWL4030_MODULE_PWMB;
        }

        /* initialize PWM to always-drive */
        status = twl_i2c_write_u8(module, 0x7f,
                TWL4030_PWMx_PWMxOFF);
        if (status < 0)
            goto done;
        status = twl_i2c_write_u8(module, 0x7f,
                TWL4030_PWMx_PWMxON);
        if (status < 0)
            goto done;

        /* init LED to not-driven (high) */
        module = TWL4030_MODULE_LED;
        status = twl_i2c_read_u8(module, &cached_leden,
                TWL4030_LED_LEDEN);
        if (status < 0)
            goto done;
        cached_leden &= ~ledclr_mask;
        status = twl_i2c_write_u8(module, cached_leden,
                TWL4030_LED_LEDEN);
        if (status < 0)
            goto done;

        status = 0;
        goto done;
    }

    /* on first use, turn GPIO module "on" */
    if (!gpio_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);
    }

    if (!status)
        gpio_usage_count |= (0x1 << offset);

done:
    mutex_unlock(&gpio_lock);
    return status;
}

static void twl_free(struct gpio_chip *chip, unsigned offset)
{
    if (offset >= TWL4030_GPIO_MAX) {
        twl4030_led_set_value(offset - TWL4030_GPIO_MAX, 1);
        return;
    }

    mutex_lock(&gpio_lock);

    gpio_usage_count &= ~BIT(offset);

    /* on last use, switch off GPIO module */
    if (!gpio_usage_count)
        gpio_twl4030_write(REG_GPIO_CTRL, 0x0);

    mutex_unlock(&gpio_lock);
}

static int twl_direction_in(struct gpio_chip *chip, unsigned offset)
{
    return (offset < TWL4030_GPIO_MAX)
        ? twl4030_set_gpio_direction(offset, 1)
        : -EINVAL;
}

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

    if (offset < TWL4030_GPIO_MAX)
        status = twl4030_get_gpio_datain(offset);
    else if (offset == TWL4030_GPIO_MAX)
        status = cached_leden & LEDEN_LEDAON;
    else
        status = cached_leden & LEDEN_LEDBON;
    return (status < 0) ? 0 : status;
}

static int twl_direction_out(struct gpio_chip *chip, unsigned offset, int value)
{
    if (offset < TWL4030_GPIO_MAX) {
        twl4030_set_gpio_dataout(offset, value);
        return twl4030_set_gpio_direction(offset, 0);
    } else {
        twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value);
        return 0;
    }
}

static void twl_set(struct gpio_chip *chip, unsigned offset, int value)
{
    if (offset < TWL4030_GPIO_MAX)
        twl4030_set_gpio_dataout(offset, value);
    else
        twl4030_led_set_value(offset - TWL4030_GPIO_MAX, value);
}

static int twl_to_irq(struct gpio_chip *chip, unsigned offset)
{
    return (twl4030_gpio_irq_base && (offset < TWL4030_GPIO_MAX))
        ? (twl4030_gpio_irq_base + offset)
        : -EINVAL;
}

static struct gpio_chip twl_gpiochip = {
    .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 __devinit gpio_twl4030_pulls(u32 ups, u32 downs)
{
    u8      message[6];
    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 = 1; i < 6; 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 __devinit gpio_twl4030_debounce(u32 debounce, u8 mmc_cd)
{
    u8      message[4];

    /* 30 msec of debouncing is always used for MMC card detect,
     * and is optional for everything else.
     */
    message[1] = (debounce & 0xff) | (mmc_cd & 0x03);
    debounce >>= 8;
    message[2] = (debounce & 0xff);
    debounce >>= 8;
    message[3] = (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 __devinit 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;
    int ret, irq_base;

    /* 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;

    twl4030_gpio_irq_base = irq_base;

no_irqs:
    twl_gpiochip.base = -1;
    twl_gpiochip.ngpio = TWL4030_GPIO_MAX;
    twl_gpiochip.dev = &pdev->dev;

    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)
        twl_gpiochip.ngpio += 2;

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

    twl4030_gpio_base = twl_gpiochip.base;

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

        status = pdata->setup(&pdev->dev,
                twl4030_gpio_base, TWL4030_GPIO_MAX);
        if (status)
            dev_dbg(&pdev->dev, "setup --> %d\n", status);
    }

out:
    return ret;
}

/* Cannot use __devexit 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;
    int status;

    if (pdata && pdata->teardown) {
        status = pdata->teardown(&pdev->dev,
                twl4030_gpio_base, TWL4030_GPIO_MAX);
        if (status) {
            dev_dbg(&pdev->dev, "teardown --> %d\n", status);
            return status;
        }
    }

    status = gpiochip_remove(&twl_gpiochip);
    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");