gpio-ab8500.c

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/*
 * Copyright (C) ST-Ericsson SA 2011
 *
 * Author: BIBEK BASU <[email protected]>
 * License terms: GNU General Public License (GPL) version 2
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/mfd/ab8500.h>
#include <linux/mfd/abx500.h>
#include <linux/mfd/ab8500/gpio.h>

/*
 * GPIO registers offset
 * Bank: 0x10
 */
#define AB8500_GPIO_SEL1_REG    0x00
#define AB8500_GPIO_SEL2_REG    0x01
#define AB8500_GPIO_SEL3_REG    0x02
#define AB8500_GPIO_SEL4_REG    0x03
#define AB8500_GPIO_SEL5_REG    0x04
#define AB8500_GPIO_SEL6_REG    0x05

#define AB8500_GPIO_DIR1_REG    0x10
#define AB8500_GPIO_DIR2_REG    0x11
#define AB8500_GPIO_DIR3_REG    0x12
#define AB8500_GPIO_DIR4_REG    0x13
#define AB8500_GPIO_DIR5_REG    0x14
#define AB8500_GPIO_DIR6_REG    0x15

#define AB8500_GPIO_OUT1_REG    0x20
#define AB8500_GPIO_OUT2_REG    0x21
#define AB8500_GPIO_OUT3_REG    0x22
#define AB8500_GPIO_OUT4_REG    0x23
#define AB8500_GPIO_OUT5_REG    0x24
#define AB8500_GPIO_OUT6_REG    0x25

#define AB8500_GPIO_PUD1_REG    0x30
#define AB8500_GPIO_PUD2_REG    0x31
#define AB8500_GPIO_PUD3_REG    0x32
#define AB8500_GPIO_PUD4_REG    0x33
#define AB8500_GPIO_PUD5_REG    0x34
#define AB8500_GPIO_PUD6_REG    0x35

#define AB8500_GPIO_IN1_REG 0x40
#define AB8500_GPIO_IN2_REG 0x41
#define AB8500_GPIO_IN3_REG 0x42
#define AB8500_GPIO_IN4_REG 0x43
#define AB8500_GPIO_IN5_REG 0x44
#define AB8500_GPIO_IN6_REG 0x45
#define AB8500_GPIO_ALTFUN_REG  0x45
#define ALTFUN_REG_INDEX    6
#define AB8500_NUM_GPIO     42
#define AB8500_NUM_VIR_GPIO_IRQ 16

enum ab8500_gpio_action {
    NONE,
    STARTUP,
    SHUTDOWN,
    MASK,
    UNMASK
};

struct ab8500_gpio {
    struct gpio_chip chip;
    struct ab8500 *parent;
    struct device *dev;
    struct mutex lock;
    u32 irq_base;
    enum ab8500_gpio_action irq_action;
    u16 rising;
    u16 falling;
};
static inline struct ab8500_gpio *to_ab8500_gpio(struct gpio_chip *chip)
{
    return container_of(chip, struct ab8500_gpio, chip);
}

static int ab8500_gpio_set_bits(struct gpio_chip *chip, u8 reg,
                    unsigned offset, int val)
{
    struct ab8500_gpio *ab8500_gpio = to_ab8500_gpio(chip);
    u8 pos = offset % 8;
    int ret;

    reg = reg + (offset / 8);
    ret = abx500_mask_and_set_register_interruptible(ab8500_gpio->dev,
                AB8500_MISC, reg, 1 << pos, val << pos);
    if (ret < 0)
        dev_err(ab8500_gpio->dev, "%s write failed\n", __func__);
    return ret;
}
static int ab8500_gpio_get(struct gpio_chip *chip, unsigned offset)
{
    struct ab8500_gpio *ab8500_gpio = to_ab8500_gpio(chip);
    u8 mask = 1 << (offset % 8);
    u8 reg = AB8500_GPIO_OUT1_REG + (offset / 8);
    int ret;
    u8 data;
    ret = abx500_get_register_interruptible(ab8500_gpio->dev, AB8500_MISC,
                        reg, &data);
    if (ret < 0) {
        dev_err(ab8500_gpio->dev, "%s read failed\n", __func__);
        return ret;
    }
    return (data & mask) >> (offset % 8);
}

static void ab8500_gpio_set(struct gpio_chip *chip, unsigned offset, int val)
{
    struct ab8500_gpio *ab8500_gpio = to_ab8500_gpio(chip);
    int ret;
    /* Write the data */
    ret = ab8500_gpio_set_bits(chip, AB8500_GPIO_OUT1_REG, offset, 1);
    if (ret < 0)
        dev_err(ab8500_gpio->dev, "%s write failed\n", __func__);
}

static int ab8500_gpio_direction_output(struct gpio_chip *chip, unsigned offset,
                    int val)
{
    int ret;
    /* set direction as output */
    ret = ab8500_gpio_set_bits(chip, AB8500_GPIO_DIR1_REG, offset, 1);
    if (ret < 0)
        return ret;
    /* disable pull down */
    ret = ab8500_gpio_set_bits(chip, AB8500_GPIO_PUD1_REG, offset, 1);
    if (ret < 0)
        return ret;
    /* set the output as 1 or 0 */
    return ab8500_gpio_set_bits(chip, AB8500_GPIO_OUT1_REG, offset, val);

}

static int ab8500_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
    /* set the register as input */
    return ab8500_gpio_set_bits(chip, AB8500_GPIO_DIR1_REG, offset, 0);
}

static int ab8500_gpio_to_irq(struct gpio_chip *chip, unsigned offset)
{
    /*
     * Only some GPIOs are interrupt capable, and they are
     * organized in discontiguous clusters:
     *
     *  GPIO6 to GPIO13
     *  GPIO24 and GPIO25
     *  GPIO36 to GPIO41
     */
    static struct ab8500_gpio_irq_cluster {
        int start;
        int end;
    } clusters[] = {
        {.start = 6,  .end = 13},
        {.start = 24, .end = 25},
        {.start = 36, .end = 41},
    };
    struct ab8500_gpio *ab8500_gpio = to_ab8500_gpio(chip);
    int base = ab8500_gpio->irq_base;
    int i;

    for (i = 0; i < ARRAY_SIZE(clusters); i++) {
        struct ab8500_gpio_irq_cluster *cluster = &clusters[i];

        if (offset >= cluster->start && offset <= cluster->end)
            return base + offset - cluster->start;

        /* Advance by the number of gpios in this cluster */
        base += cluster->end - cluster->start + 1;
    }

    return -EINVAL;
}

static struct gpio_chip ab8500gpio_chip = {
    .label          = "ab8500_gpio",
    .owner          = THIS_MODULE,
    .direction_input    = ab8500_gpio_direction_input,
    .get            = ab8500_gpio_get,
    .direction_output   = ab8500_gpio_direction_output,
    .set            = ab8500_gpio_set,
    .to_irq         = ab8500_gpio_to_irq,
};

static unsigned int irq_to_rising(unsigned int irq)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    int offset = irq - ab8500_gpio->irq_base;
    int new_irq = offset +  AB8500_INT_GPIO6R
            + ab8500_gpio->parent->irq_base;
    return new_irq;
}

static unsigned int irq_to_falling(unsigned int irq)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    int offset = irq - ab8500_gpio->irq_base;
    int new_irq = offset +  AB8500_INT_GPIO6F
            +  ab8500_gpio->parent->irq_base;
    return new_irq;

}

static unsigned int rising_to_irq(unsigned int irq, void *dev)
{
    struct ab8500_gpio *ab8500_gpio = dev;
    int offset = irq - AB8500_INT_GPIO6R
            - ab8500_gpio->parent->irq_base ;
    int new_irq = offset + ab8500_gpio->irq_base;
    return new_irq;
}

static unsigned int falling_to_irq(unsigned int irq, void *dev)
{
    struct ab8500_gpio *ab8500_gpio = dev;
    int offset = irq - AB8500_INT_GPIO6F
            - ab8500_gpio->parent->irq_base ;
    int new_irq = offset + ab8500_gpio->irq_base;
    return new_irq;

}

/*
 * IRQ handler
 */

static irqreturn_t handle_rising(int irq, void *dev)
{

    handle_nested_irq(rising_to_irq(irq , dev));
    return IRQ_HANDLED;
}

static irqreturn_t handle_falling(int irq, void *dev)
{

    handle_nested_irq(falling_to_irq(irq, dev));
    return IRQ_HANDLED;
}

static void ab8500_gpio_irq_lock(unsigned int irq)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    mutex_lock(&ab8500_gpio->lock);
}

static void ab8500_gpio_irq_sync_unlock(unsigned int irq)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    int offset = irq - ab8500_gpio->irq_base;
    bool rising = ab8500_gpio->rising & BIT(offset);
    bool falling = ab8500_gpio->falling & BIT(offset);
    int ret;

    switch (ab8500_gpio->irq_action)    {
    case STARTUP:
        if (rising)
            ret = request_threaded_irq(irq_to_rising(irq),
                    NULL, handle_rising,
                    IRQF_TRIGGER_RISING,
                    "ab8500-gpio-r", ab8500_gpio);
        if (falling)
            ret = request_threaded_irq(irq_to_falling(irq),
                       NULL, handle_falling,
                       IRQF_TRIGGER_FALLING,
                       "ab8500-gpio-f", ab8500_gpio);
        break;
    case SHUTDOWN:
        if (rising)
            free_irq(irq_to_rising(irq), ab8500_gpio);
        if (falling)
            free_irq(irq_to_falling(irq), ab8500_gpio);
        break;
    case MASK:
        if (rising)
            disable_irq(irq_to_rising(irq));
        if (falling)
            disable_irq(irq_to_falling(irq));
        break;
    case UNMASK:
        if (rising)
            enable_irq(irq_to_rising(irq));
        if (falling)
            enable_irq(irq_to_falling(irq));
        break;
    case NONE:
        break;
    }
    ab8500_gpio->irq_action = NONE;
    ab8500_gpio->rising &= ~(BIT(offset));
    ab8500_gpio->falling &= ~(BIT(offset));
    mutex_unlock(&ab8500_gpio->lock);
}


static void ab8500_gpio_irq_mask(unsigned int irq)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    ab8500_gpio->irq_action = MASK;
}

static void ab8500_gpio_irq_unmask(unsigned int irq)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    ab8500_gpio->irq_action = UNMASK;
}

static int ab8500_gpio_irq_set_type(unsigned int irq, unsigned int type)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    int offset = irq - ab8500_gpio->irq_base;

    if (type == IRQ_TYPE_EDGE_BOTH) {
        ab8500_gpio->rising =  BIT(offset);
        ab8500_gpio->falling = BIT(offset);
    } else if (type == IRQ_TYPE_EDGE_RISING) {
        ab8500_gpio->rising =  BIT(offset);
    } else  {
        ab8500_gpio->falling = BIT(offset);
    }
    return 0;
}

unsigned int ab8500_gpio_irq_startup(unsigned int irq)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    ab8500_gpio->irq_action = STARTUP;
    return 0;
}

void ab8500_gpio_irq_shutdown(unsigned int irq)
{
    struct ab8500_gpio *ab8500_gpio = get_irq_chip_data(irq);
    ab8500_gpio->irq_action = SHUTDOWN;
}

static struct irq_chip ab8500_gpio_irq_chip = {
    .name           = "ab8500-gpio",
    .startup        = ab8500_gpio_irq_startup,
    .shutdown       = ab8500_gpio_irq_shutdown,
    .bus_lock       = ab8500_gpio_irq_lock,
    .bus_sync_unlock    = ab8500_gpio_irq_sync_unlock,
    .mask           = ab8500_gpio_irq_mask,
    .unmask         = ab8500_gpio_irq_unmask,
    .set_type       = ab8500_gpio_irq_set_type,
};

static int ab8500_gpio_irq_init(struct ab8500_gpio *ab8500_gpio)
{
    u32 base = ab8500_gpio->irq_base;
    int irq;

    for (irq = base; irq < base + AB8500_NUM_VIR_GPIO_IRQ ; irq++) {
        set_irq_chip_data(irq, ab8500_gpio);
        set_irq_chip_and_handler(irq, &ab8500_gpio_irq_chip,
                handle_simple_irq);
        set_irq_nested_thread(irq, 1);
#ifdef CONFIG_ARM
        set_irq_flags(irq, IRQF_VALID);
#else
        set_irq_noprobe(irq);
#endif
    }

    return 0;
}

static void ab8500_gpio_irq_remove(struct ab8500_gpio *ab8500_gpio)
{
    int base = ab8500_gpio->irq_base;
    int irq;

    for (irq = base; irq < base + AB8500_NUM_VIR_GPIO_IRQ; irq++) {
#ifdef CONFIG_ARM
        set_irq_flags(irq, 0);
#endif
        set_irq_chip_and_handler(irq, NULL, NULL);
        set_irq_chip_data(irq, NULL);
    }
}

static int __devinit ab8500_gpio_probe(struct platform_device *pdev)
{
    struct ab8500_platform_data *ab8500_pdata =
                dev_get_platdata(pdev->dev.parent);
    struct ab8500_gpio_platform_data *pdata;
    struct ab8500_gpio *ab8500_gpio;
    int ret;
    int i;

    pdata = ab8500_pdata->gpio;
    if (!pdata) {
        dev_err(&pdev->dev, "gpio platform data missing\n");
        return -ENODEV;
    }

    ab8500_gpio = kzalloc(sizeof(struct ab8500_gpio), GFP_KERNEL);
    if (ab8500_gpio == NULL) {
        dev_err(&pdev->dev, "failed to allocate memory\n");
        return -ENOMEM;
    }
    ab8500_gpio->dev = &pdev->dev;
    ab8500_gpio->parent = dev_get_drvdata(pdev->dev.parent);
    ab8500_gpio->chip = ab8500gpio_chip;
    ab8500_gpio->chip.ngpio = AB8500_NUM_GPIO;
    ab8500_gpio->chip.dev = &pdev->dev;
    ab8500_gpio->chip.base = pdata->gpio_base;
    ab8500_gpio->irq_base = pdata->irq_base;
    /* initialize the lock */
    mutex_init(&ab8500_gpio->lock);
    /*
     * AB8500 core will handle and clear the IRQ
     * configre GPIO based on config-reg value.
     * These values are for selecting the PINs as
     * GPIO or alternate function
     */
    for (i = AB8500_GPIO_SEL1_REG; i <= AB8500_GPIO_SEL6_REG; i++)  {
        ret = abx500_set_register_interruptible(ab8500_gpio->dev,
                AB8500_MISC, i,
                pdata->config_reg[i]);
        if (ret < 0)
            goto out_free;
    }
    ret = abx500_set_register_interruptible(ab8500_gpio->dev, AB8500_MISC,
                AB8500_GPIO_ALTFUN_REG,
                pdata->config_reg[ALTFUN_REG_INDEX]);
    if (ret < 0)
        goto out_free;

    ret = ab8500_gpio_irq_init(ab8500_gpio);
    if (ret)
        goto out_free;
    ret = gpiochip_add(&ab8500_gpio->chip);
    if (ret) {
        dev_err(&pdev->dev, "unable to add gpiochip: %d\n",
                ret);
        goto out_rem_irq;
    }
    platform_set_drvdata(pdev, ab8500_gpio);
    return 0;

out_rem_irq:
    ab8500_gpio_irq_remove(ab8500_gpio);
out_free:
    mutex_destroy(&ab8500_gpio->lock);
    kfree(ab8500_gpio);
    return ret;
}

/*
 * ab8500_gpio_remove() - remove Ab8500-gpio driver
 * @pdev :  Platform device registered
 */
static int __devexit ab8500_gpio_remove(struct platform_device *pdev)
{
    struct ab8500_gpio *ab8500_gpio = platform_get_drvdata(pdev);
    int ret;

    ret = gpiochip_remove(&ab8500_gpio->chip);
    if (ret < 0) {
        dev_err(ab8500_gpio->dev, "unable to remove gpiochip: %d\n",
            ret);
        return ret;
    }

    platform_set_drvdata(pdev, NULL);
    mutex_destroy(&ab8500_gpio->lock);
    kfree(ab8500_gpio);

    return 0;
}

static struct platform_driver ab8500_gpio_driver = {
    .driver = {
        .name = "ab8500-gpio",
        .owner = THIS_MODULE,
    },
    .probe = ab8500_gpio_probe,
    .remove = __devexit_p(ab8500_gpio_remove),
};

static int __init ab8500_gpio_init(void)
{
    return platform_driver_register(&ab8500_gpio_driver);
}
arch_initcall(ab8500_gpio_init);

static void __exit ab8500_gpio_exit(void)
{
    platform_driver_unregister(&ab8500_gpio_driver);
}
module_exit(ab8500_gpio_exit);

MODULE_AUTHOR("BIBEK BASU <[email protected]>");
MODULE_DESCRIPTION("Driver allows to use AB8500 unused pins to be used as GPIO");
MODULE_ALIAS("platform:ab8500-gpio");
MODULE_LICENSE("GPL v2");