gpio_keys_polled.c

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/*
 *  Driver for buttons on GPIO lines not capable of generating interrupts
 *
 *  Copyright (C) 2007-2010 Gabor Juhos <[email protected]>
 *  Copyright (C) 2010 Nuno Goncalves <[email protected]>
 *
 *  This file was based on: /drivers/input/misc/cobalt_btns.c
 *  Copyright (C) 2007 Yoichi Yuasa <[email protected]>
 *
 *  also was based on: /drivers/input/keyboard/gpio_keys.c
 *  Copyright 2005 Phil Blundell
 *
 *  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/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/input-polldev.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/gpio_keys.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>

#define DRV_NAME    "gpio-keys-polled"

struct gpio_keys_button_data {
    int last_state;
    int count;
    int threshold;
    int can_sleep;
};

struct gpio_keys_polled_dev {
    struct input_polled_dev *poll_dev;
    struct device *dev;
    const struct gpio_keys_platform_data *pdata;
    struct gpio_keys_button_data data[0];
};

static void gpio_keys_polled_check_state(struct input_dev *input,
                     struct gpio_keys_button *button,
                     struct gpio_keys_button_data *bdata)
{
    int state;

    if (bdata->can_sleep)
        state = !!gpio_get_value_cansleep(button->gpio);
    else
        state = !!gpio_get_value(button->gpio);

    if (state != bdata->last_state) {
        unsigned int type = button->type ?: EV_KEY;

        input_event(input, type, button->code,
                !!(state ^ button->active_low));
        input_sync(input);
        bdata->count = 0;
        bdata->last_state = state;
    }
}

static void gpio_keys_polled_poll(struct input_polled_dev *dev)
{
    struct gpio_keys_polled_dev *bdev = dev->private;
    const struct gpio_keys_platform_data *pdata = bdev->pdata;
    struct input_dev *input = dev->input;
    int i;

    for (i = 0; i < pdata->nbuttons; i++) {
        struct gpio_keys_button_data *bdata = &bdev->data[i];

        if (bdata->count < bdata->threshold)
            bdata->count++;
        else
            gpio_keys_polled_check_state(input, &pdata->buttons[i],
                             bdata);
    }
}

static void gpio_keys_polled_open(struct input_polled_dev *dev)
{
    struct gpio_keys_polled_dev *bdev = dev->private;
    const struct gpio_keys_platform_data *pdata = bdev->pdata;

    if (pdata->enable)
        pdata->enable(bdev->dev);
}

static void gpio_keys_polled_close(struct input_polled_dev *dev)
{
    struct gpio_keys_polled_dev *bdev = dev->private;
    const struct gpio_keys_platform_data *pdata = bdev->pdata;

    if (pdata->disable)
        pdata->disable(bdev->dev);
}

#ifdef CONFIG_OF
static struct gpio_keys_platform_data * __devinit
gpio_keys_polled_get_devtree_pdata(struct device *dev)
{
    struct device_node *node, *pp;
    struct gpio_keys_platform_data *pdata;
    struct gpio_keys_button *button;
    int error;
    int nbuttons;
    int i;

    node = dev->of_node;
    if (!node)
        return NULL;

    nbuttons = of_get_child_count(node);
    if (nbuttons == 0)
        return NULL;

    pdata = kzalloc(sizeof(*pdata) + nbuttons * (sizeof *button),
            GFP_KERNEL);
    if (!pdata) {
        error = -ENOMEM;
        goto err_out;
    }

    pdata->buttons = (struct gpio_keys_button *)(pdata + 1);
    pdata->nbuttons = nbuttons;

    pdata->rep = !!of_get_property(node, "autorepeat", NULL);
    of_property_read_u32(node, "poll-interval", &pdata->poll_interval);

    i = 0;
    for_each_child_of_node(node, pp) {
        enum of_gpio_flags flags;

        if (!of_find_property(pp, "gpios", NULL)) {
            pdata->nbuttons--;
            dev_warn(dev, "Found button without gpios\n");
            continue;
        }

        button = &pdata->buttons[i++];

        button->gpio = of_get_gpio_flags(pp, 0, &flags);
        button->active_low = flags & OF_GPIO_ACTIVE_LOW;

        if (of_property_read_u32(pp, "linux,code", &button->code)) {
            dev_err(dev, "Button without keycode: 0x%x\n",
                button->gpio);
            error = -EINVAL;
            goto err_free_pdata;
        }

        button->desc = of_get_property(pp, "label", NULL);

        if (of_property_read_u32(pp, "linux,input-type", &button->type))
            button->type = EV_KEY;

        button->wakeup = !!of_get_property(pp, "gpio-key,wakeup", NULL);

        if (of_property_read_u32(pp, "debounce-interval",
                     &button->debounce_interval))
            button->debounce_interval = 5;
    }

    if (pdata->nbuttons == 0) {
        error = -EINVAL;
        goto err_free_pdata;
    }

    return pdata;

err_free_pdata:
    kfree(pdata);
err_out:
    return ERR_PTR(error);
}

static struct of_device_id gpio_keys_polled_of_match[] = {
    { .compatible = "gpio-keys-polled", },
    { },
};
MODULE_DEVICE_TABLE(of, gpio_keys_polled_of_match);

#else

static inline struct gpio_keys_platform_data *
gpio_keys_polled_get_devtree_pdata(struct device *dev)
{
    return NULL;
}
#endif

static int __devinit gpio_keys_polled_probe(struct platform_device *pdev)
{
    struct device *dev = &pdev->dev;
    const struct gpio_keys_platform_data *pdata = dev_get_platdata(dev);
    struct gpio_keys_polled_dev *bdev;
    struct input_polled_dev *poll_dev;
    struct input_dev *input;
    int error;
    int i;

    if (!pdata) {
        pdata = gpio_keys_polled_get_devtree_pdata(dev);
        if (IS_ERR(pdata))
            return PTR_ERR(pdata);
        if (!pdata) {
            dev_err(dev, "missing platform data\n");
            return -EINVAL;
        }
    }

    if (!pdata->poll_interval) {
        dev_err(dev, "missing poll_interval value\n");
        error = -EINVAL;
        goto err_free_pdata;
    }

    bdev = kzalloc(sizeof(struct gpio_keys_polled_dev) +
               pdata->nbuttons * sizeof(struct gpio_keys_button_data),
               GFP_KERNEL);
    if (!bdev) {
        dev_err(dev, "no memory for private data\n");
        error = -ENOMEM;
        goto err_free_pdata;
    }

    poll_dev = input_allocate_polled_device();
    if (!poll_dev) {
        dev_err(dev, "no memory for polled device\n");
        error = -ENOMEM;
        goto err_free_bdev;
    }

    poll_dev->private = bdev;
    poll_dev->poll = gpio_keys_polled_poll;
    poll_dev->poll_interval = pdata->poll_interval;
    poll_dev->open = gpio_keys_polled_open;
    poll_dev->close = gpio_keys_polled_close;

    input = poll_dev->input;

    input->evbit[0] = BIT(EV_KEY);
    input->name = pdev->name;
    input->phys = DRV_NAME"/input0";
    input->dev.parent = &pdev->dev;

    input->id.bustype = BUS_HOST;
    input->id.vendor = 0x0001;
    input->id.product = 0x0001;
    input->id.version = 0x0100;

    for (i = 0; i < pdata->nbuttons; i++) {
        struct gpio_keys_button *button = &pdata->buttons[i];
        struct gpio_keys_button_data *bdata = &bdev->data[i];
        unsigned int gpio = button->gpio;
        unsigned int type = button->type ?: EV_KEY;

        if (button->wakeup) {
            dev_err(dev, DRV_NAME " does not support wakeup\n");
            error = -EINVAL;
            goto err_free_gpio;
        }

        error = gpio_request(gpio,
                     button->desc ? button->desc : DRV_NAME);
        if (error) {
            dev_err(dev, "unable to claim gpio %u, err=%d\n",
                gpio, error);
            goto err_free_gpio;
        }

        error = gpio_direction_input(gpio);
        if (error) {
            dev_err(dev,
                "unable to set direction on gpio %u, err=%d\n",
                gpio, error);
            goto err_free_gpio;
        }

        bdata->can_sleep = gpio_cansleep(gpio);
        bdata->last_state = -1;
        bdata->threshold = DIV_ROUND_UP(button->debounce_interval,
                        pdata->poll_interval);

        input_set_capability(input, type, button->code);
    }

    bdev->poll_dev = poll_dev;
    bdev->dev = dev;
    bdev->pdata = pdata;
    platform_set_drvdata(pdev, bdev);

    error = input_register_polled_device(poll_dev);
    if (error) {
        dev_err(dev, "unable to register polled device, err=%d\n",
            error);
        goto err_free_gpio;
    }

    /* report initial state of the buttons */
    for (i = 0; i < pdata->nbuttons; i++)
        gpio_keys_polled_check_state(input, &pdata->buttons[i],
                         &bdev->data[i]);

    return 0;

err_free_gpio:
    while (--i >= 0)
        gpio_free(pdata->buttons[i].gpio);

    input_free_polled_device(poll_dev);

err_free_bdev:
    kfree(bdev);
    platform_set_drvdata(pdev, NULL);

err_free_pdata:
    /* If we have no platform_data, we allocated pdata dynamically.  */
    if (!dev_get_platdata(&pdev->dev))
        kfree(pdata);

    return error;
}

static int __devexit gpio_keys_polled_remove(struct platform_device *pdev)
{
    struct gpio_keys_polled_dev *bdev = platform_get_drvdata(pdev);
    const struct gpio_keys_platform_data *pdata = bdev->pdata;
    int i;

    input_unregister_polled_device(bdev->poll_dev);

    for (i = 0; i < pdata->nbuttons; i++)
        gpio_free(pdata->buttons[i].gpio);

    input_free_polled_device(bdev->poll_dev);

    /*
     * If we had no platform_data, we allocated pdata dynamically and
     * must free it here.
     */
    if (!dev_get_platdata(&pdev->dev))
        kfree(pdata);

    kfree(bdev);
    platform_set_drvdata(pdev, NULL);

    return 0;
}

static struct platform_driver gpio_keys_polled_driver = {
    .probe  = gpio_keys_polled_probe,
    .remove = __devexit_p(gpio_keys_polled_remove),
    .driver = {
        .name   = DRV_NAME,
        .owner  = THIS_MODULE,
        .of_match_table = of_match_ptr(gpio_keys_polled_of_match),
    },
};
module_platform_driver(gpio_keys_polled_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Gabor Juhos <[email protected]>");
MODULE_DESCRIPTION("Polled GPIO Buttons driver");
MODULE_ALIAS("platform:" DRV_NAME);