gpio.c

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/*
 * SuperH Pin Function Controller GPIO driver.
 *
 * Copyright (C) 2008 Magnus Damm
 * Copyright (C) 2009 - 2012 Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#define pr_fmt(fmt) "sh_pfc " KBUILD_MODNAME ": " fmt

#include <linux/init.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/sh_pfc.h>

struct sh_pfc_chip {
    struct sh_pfc       *pfc;
    struct gpio_chip    gpio_chip;
};

static struct sh_pfc_chip *gpio_to_pfc_chip(struct gpio_chip *gc)
{
    return container_of(gc, struct sh_pfc_chip, gpio_chip);
}

static struct sh_pfc *gpio_to_pfc(struct gpio_chip *gc)
{
    return gpio_to_pfc_chip(gc)->pfc;
}

static int sh_gpio_request(struct gpio_chip *gc, unsigned offset)
{
    return pinctrl_request_gpio(offset);
}

static void sh_gpio_free(struct gpio_chip *gc, unsigned offset)
{
    pinctrl_free_gpio(offset);
}

static void sh_gpio_set_value(struct sh_pfc *pfc, unsigned gpio, int value)
{
    struct pinmux_data_reg *dr = NULL;
    int bit = 0;

    if (!pfc || sh_pfc_get_data_reg(pfc, gpio, &dr, &bit) != 0)
        BUG();
    else
        sh_pfc_write_bit(dr, bit, value);
}

static int sh_gpio_get_value(struct sh_pfc *pfc, unsigned gpio)
{
    struct pinmux_data_reg *dr = NULL;
    int bit = 0;

    if (!pfc || sh_pfc_get_data_reg(pfc, gpio, &dr, &bit) != 0)
        return -EINVAL;

    return sh_pfc_read_bit(dr, bit);
}

static int sh_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
{
    return pinctrl_gpio_direction_input(offset);
}

static int sh_gpio_direction_output(struct gpio_chip *gc, unsigned offset,
                    int value)
{
    sh_gpio_set_value(gpio_to_pfc(gc), offset, value);

    return pinctrl_gpio_direction_output(offset);
}

static int sh_gpio_get(struct gpio_chip *gc, unsigned offset)
{
    return sh_gpio_get_value(gpio_to_pfc(gc), offset);
}

static void sh_gpio_set(struct gpio_chip *gc, unsigned offset, int value)
{
    sh_gpio_set_value(gpio_to_pfc(gc), offset, value);
}

static int sh_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
{
    struct sh_pfc *pfc = gpio_to_pfc(gc);
    pinmux_enum_t enum_id;
    pinmux_enum_t *enum_ids;
    int i, k, pos;

    pos = 0;
    enum_id = 0;
    while (1) {
        pos = sh_pfc_gpio_to_enum(pfc, offset, pos, &enum_id);
        if (pos <= 0 || !enum_id)
            break;

        for (i = 0; i < pfc->gpio_irq_size; i++) {
            enum_ids = pfc->gpio_irq[i].enum_ids;
            for (k = 0; enum_ids[k]; k++) {
                if (enum_ids[k] == enum_id)
                    return pfc->gpio_irq[i].irq;
            }
        }
    }

    return -ENOSYS;
}

static void sh_pfc_gpio_setup(struct sh_pfc_chip *chip)
{
    struct sh_pfc *pfc = chip->pfc;
    struct gpio_chip *gc = &chip->gpio_chip;

    gc->request = sh_gpio_request;
    gc->free = sh_gpio_free;
    gc->direction_input = sh_gpio_direction_input;
    gc->get = sh_gpio_get;
    gc->direction_output = sh_gpio_direction_output;
    gc->set = sh_gpio_set;
    gc->to_irq = sh_gpio_to_irq;

    WARN_ON(pfc->first_gpio != 0); /* needs testing */

    gc->label = pfc->name;
    gc->owner = THIS_MODULE;
    gc->base = pfc->first_gpio;
    gc->ngpio = (pfc->last_gpio - pfc->first_gpio) + 1;
}

int sh_pfc_register_gpiochip(struct sh_pfc *pfc)
{
    struct sh_pfc_chip *chip;
    int ret;

    chip = kzalloc(sizeof(struct sh_pfc_chip), GFP_KERNEL);
    if (unlikely(!chip))
        return -ENOMEM;

    chip->pfc = pfc;

    sh_pfc_gpio_setup(chip);

    ret = gpiochip_add(&chip->gpio_chip);
    if (unlikely(ret < 0))
        kfree(chip);

    pr_info("%s handling gpio %d -> %d\n",
        pfc->name, pfc->first_gpio, pfc->last_gpio);

    return ret;
}
EXPORT_SYMBOL_GPL(sh_pfc_register_gpiochip);

static int sh_pfc_gpio_match(struct gpio_chip *gc, void *data)
{
    return !!strstr(gc->label, data);
}

static int __devinit sh_pfc_gpio_probe(struct platform_device *pdev)
{
    struct sh_pfc_chip *chip;
    struct gpio_chip *gc;

    gc = gpiochip_find("_pfc", sh_pfc_gpio_match);
    if (unlikely(!gc)) {
        pr_err("Cant find gpio chip\n");
        return -ENODEV;
    }

    chip = gpio_to_pfc_chip(gc);
    platform_set_drvdata(pdev, chip);

    pr_info("attaching to GPIO chip %s\n", chip->pfc->name);

    return 0;
}

static int __devexit sh_pfc_gpio_remove(struct platform_device *pdev)
{
    struct sh_pfc_chip *chip = platform_get_drvdata(pdev);
    int ret;

    ret = gpiochip_remove(&chip->gpio_chip);
    if (unlikely(ret < 0))
        return ret;

    kfree(chip);
    return 0;
}

static struct platform_driver sh_pfc_gpio_driver = {
    .probe      = sh_pfc_gpio_probe,
    .remove     = __devexit_p(sh_pfc_gpio_remove),
    .driver     = {
        .name   = KBUILD_MODNAME,
        .owner  = THIS_MODULE,
    },
};

static struct platform_device sh_pfc_gpio_device = {
    .name       = KBUILD_MODNAME,
    .id     = -1,
};

static int __init sh_pfc_gpio_init(void)
{
    int rc;

    rc = platform_driver_register(&sh_pfc_gpio_driver);
    if (likely(!rc)) {
        rc = platform_device_register(&sh_pfc_gpio_device);
        if (unlikely(rc))
            platform_driver_unregister(&sh_pfc_gpio_driver);
    }

    return rc;
}

static void __exit sh_pfc_gpio_exit(void)
{
    platform_device_unregister(&sh_pfc_gpio_device);
    platform_driver_unregister(&sh_pfc_gpio_driver);
}

module_init(sh_pfc_gpio_init);
module_exit(sh_pfc_gpio_exit);

MODULE_AUTHOR("Magnus Damm, Paul Mundt");
MODULE_DESCRIPTION("GPIO driver for SuperH pin function controller");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:pfc-gpio");