wm831x-on.c

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#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#include <linux/mfd/wm831x/core.h>

struct wm831x_on {
    struct input_dev *dev;
    struct delayed_work work;
    struct wm831x *wm831x;
};

/*
 * The chip gives us an interrupt when the ON pin is asserted but we
 * then need to poll to see when the pin is deasserted.
 */
static void wm831x_poll_on(struct work_struct *work)
{
    struct wm831x_on *wm831x_on = container_of(work, struct wm831x_on,
                           work.work);
    struct wm831x *wm831x = wm831x_on->wm831x;
    int poll, ret;

    ret = wm831x_reg_read(wm831x, WM831X_ON_PIN_CONTROL);
    if (ret >= 0) {
        poll = !(ret & WM831X_ON_PIN_STS);

        input_report_key(wm831x_on->dev, KEY_POWER, poll);
        input_sync(wm831x_on->dev);
    } else {
        dev_err(wm831x->dev, "Failed to read ON status: %d\n", ret);
        poll = 1;
    }

    if (poll)
        schedule_delayed_work(&wm831x_on->work, 100);
}

static irqreturn_t wm831x_on_irq(int irq, void *data)
{
    struct wm831x_on *wm831x_on = data;

    schedule_delayed_work(&wm831x_on->work, 0);

    return IRQ_HANDLED;
}

static int __devinit wm831x_on_probe(struct platform_device *pdev)
{
    struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
    struct wm831x_on *wm831x_on;
    int irq = wm831x_irq(wm831x, platform_get_irq(pdev, 0));
    int ret;

    wm831x_on = kzalloc(sizeof(struct wm831x_on), GFP_KERNEL);
    if (!wm831x_on) {
        dev_err(&pdev->dev, "Can't allocate data\n");
        return -ENOMEM;
    }

    wm831x_on->wm831x = wm831x;
    INIT_DELAYED_WORK(&wm831x_on->work, wm831x_poll_on);

    wm831x_on->dev = input_allocate_device();
    if (!wm831x_on->dev) {
        dev_err(&pdev->dev, "Can't allocate input dev\n");
        ret = -ENOMEM;
        goto err;
    }

    wm831x_on->dev->evbit[0] = BIT_MASK(EV_KEY);
    wm831x_on->dev->keybit[BIT_WORD(KEY_POWER)] = BIT_MASK(KEY_POWER);
    wm831x_on->dev->name = "wm831x_on";
    wm831x_on->dev->phys = "wm831x_on/input0";
    wm831x_on->dev->dev.parent = &pdev->dev;

    ret = request_threaded_irq(irq, NULL, wm831x_on_irq,
                   IRQF_TRIGGER_RISING, "wm831x_on",
                   wm831x_on);
    if (ret < 0) {
        dev_err(&pdev->dev, "Unable to request IRQ: %d\n", ret);
        goto err_input_dev;
    }
    ret = input_register_device(wm831x_on->dev);
    if (ret) {
        dev_dbg(&pdev->dev, "Can't register input device: %d\n", ret);
        goto err_irq;
    }

    platform_set_drvdata(pdev, wm831x_on);

    return 0;

err_irq:
    free_irq(irq, wm831x_on);
err_input_dev:
    input_free_device(wm831x_on->dev);
err:
    kfree(wm831x_on);
    return ret;
}

static int __devexit wm831x_on_remove(struct platform_device *pdev)
{
    struct wm831x_on *wm831x_on = platform_get_drvdata(pdev);
    int irq = platform_get_irq(pdev, 0);

    free_irq(irq, wm831x_on);
    cancel_delayed_work_sync(&wm831x_on->work);
    input_unregister_device(wm831x_on->dev);
    kfree(wm831x_on);

    return 0;
}

static struct platform_driver wm831x_on_driver = {
    .probe      = wm831x_on_probe,
    .remove     = __devexit_p(wm831x_on_remove),
    .driver     = {
        .name   = "wm831x-on",
        .owner  = THIS_MODULE,
    },
};
module_platform_driver(wm831x_on_driver);

MODULE_ALIAS("platform:wm831x-on");
MODULE_DESCRIPTION("WM831x ON pin");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Mark Brown <[email protected]>");