bfin_rotary.c

Go to the documentation of this file.

/*
 * Rotary counter driver for Analog Devices Blackfin Processors
 *
 * Copyright 2008-2009 Analog Devices Inc.
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/slab.h>

#include <asm/portmux.h>
#include <asm/bfin_rotary.h>

static const u16 per_cnt[] = {
    P_CNT_CUD,
    P_CNT_CDG,
    P_CNT_CZM,
    0
};

struct bfin_rot {
    struct input_dev *input;
    int irq;
    unsigned int up_key;
    unsigned int down_key;
    unsigned int button_key;
    unsigned int rel_code;
    unsigned short cnt_config;
    unsigned short cnt_imask;
    unsigned short cnt_debounce;
};

static void report_key_event(struct input_dev *input, int keycode)
{
    /* simulate a press-n-release */
    input_report_key(input, keycode, 1);
    input_sync(input);
    input_report_key(input, keycode, 0);
    input_sync(input);
}

static void report_rotary_event(struct bfin_rot *rotary, int delta)
{
    struct input_dev *input = rotary->input;

    if (rotary->up_key) {
        report_key_event(input,
                 delta > 0 ? rotary->up_key : rotary->down_key);
    } else {
        input_report_rel(input, rotary->rel_code, delta);
        input_sync(input);
    }
}

static irqreturn_t bfin_rotary_isr(int irq, void *dev_id)
{
    struct platform_device *pdev = dev_id;
    struct bfin_rot *rotary = platform_get_drvdata(pdev);
    int delta;

    switch (bfin_read_CNT_STATUS()) {

    case ICII:
        break;

    case UCII:
    case DCII:
        delta = bfin_read_CNT_COUNTER();
        if (delta)
            report_rotary_event(rotary, delta);
        break;

    case CZMII:
        report_key_event(rotary->input, rotary->button_key);
        break;

    default:
        break;
    }

    bfin_write_CNT_COMMAND(W1LCNT_ZERO);    /* Clear COUNTER */
    bfin_write_CNT_STATUS(-1);  /* Clear STATUS */

    return IRQ_HANDLED;
}

static int __devinit bfin_rotary_probe(struct platform_device *pdev)
{
    struct bfin_rotary_platform_data *pdata = pdev->dev.platform_data;
    struct bfin_rot *rotary;
    struct input_dev *input;
    int error;

    /* Basic validation */
    if ((pdata->rotary_up_key && !pdata->rotary_down_key) ||
        (!pdata->rotary_up_key && pdata->rotary_down_key)) {
        return -EINVAL;
    }

    error = peripheral_request_list(per_cnt, dev_name(&pdev->dev));
    if (error) {
        dev_err(&pdev->dev, "requesting peripherals failed\n");
        return error;
    }

    rotary = kzalloc(sizeof(struct bfin_rot), GFP_KERNEL);
    input = input_allocate_device();
    if (!rotary || !input) {
        error = -ENOMEM;
        goto out1;
    }

    rotary->input = input;

    rotary->up_key = pdata->rotary_up_key;
    rotary->down_key = pdata->rotary_down_key;
    rotary->button_key = pdata->rotary_button_key;
    rotary->rel_code = pdata->rotary_rel_code;

    error = rotary->irq = platform_get_irq(pdev, 0);
    if (error < 0)
        goto out1;

    input->name = pdev->name;
    input->phys = "bfin-rotary/input0";
    input->dev.parent = &pdev->dev;

    input_set_drvdata(input, rotary);

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

    if (rotary->up_key) {
        __set_bit(EV_KEY, input->evbit);
        __set_bit(rotary->up_key, input->keybit);
        __set_bit(rotary->down_key, input->keybit);
    } else {
        __set_bit(EV_REL, input->evbit);
        __set_bit(rotary->rel_code, input->relbit);
    }

    if (rotary->button_key) {
        __set_bit(EV_KEY, input->evbit);
        __set_bit(rotary->button_key, input->keybit);
    }

    error = request_irq(rotary->irq, bfin_rotary_isr,
                0, dev_name(&pdev->dev), pdev);
    if (error) {
        dev_err(&pdev->dev,
            "unable to claim irq %d; error %d\n",
            rotary->irq, error);
        goto out1;
    }

    error = input_register_device(input);
    if (error) {
        dev_err(&pdev->dev,
            "unable to register input device (%d)\n", error);
        goto out2;
    }

    if (pdata->rotary_button_key)
        bfin_write_CNT_IMASK(CZMIE);

    if (pdata->mode & ROT_DEBE)
        bfin_write_CNT_DEBOUNCE(pdata->debounce & DPRESCALE);

    if (pdata->mode)
        bfin_write_CNT_CONFIG(bfin_read_CNT_CONFIG() |
                    (pdata->mode & ~CNTE));

    bfin_write_CNT_IMASK(bfin_read_CNT_IMASK() | UCIE | DCIE);
    bfin_write_CNT_CONFIG(bfin_read_CNT_CONFIG() | CNTE);

    platform_set_drvdata(pdev, rotary);
    device_init_wakeup(&pdev->dev, 1);

    return 0;

out2:
    free_irq(rotary->irq, pdev);
out1:
    input_free_device(input);
    kfree(rotary);
    peripheral_free_list(per_cnt);

    return error;
}

static int __devexit bfin_rotary_remove(struct platform_device *pdev)
{
    struct bfin_rot *rotary = platform_get_drvdata(pdev);

    bfin_write_CNT_CONFIG(0);
    bfin_write_CNT_IMASK(0);

    free_irq(rotary->irq, pdev);
    input_unregister_device(rotary->input);
    peripheral_free_list(per_cnt);

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

    return 0;
}

#ifdef CONFIG_PM
static int bfin_rotary_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct bfin_rot *rotary = platform_get_drvdata(pdev);

    rotary->cnt_config = bfin_read_CNT_CONFIG();
    rotary->cnt_imask = bfin_read_CNT_IMASK();
    rotary->cnt_debounce = bfin_read_CNT_DEBOUNCE();

    if (device_may_wakeup(&pdev->dev))
        enable_irq_wake(rotary->irq);

    return 0;
}

static int bfin_rotary_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct bfin_rot *rotary = platform_get_drvdata(pdev);

    bfin_write_CNT_DEBOUNCE(rotary->cnt_debounce);
    bfin_write_CNT_IMASK(rotary->cnt_imask);
    bfin_write_CNT_CONFIG(rotary->cnt_config & ~CNTE);

    if (device_may_wakeup(&pdev->dev))
        disable_irq_wake(rotary->irq);

    if (rotary->cnt_config & CNTE)
        bfin_write_CNT_CONFIG(rotary->cnt_config);

    return 0;
}

static const struct dev_pm_ops bfin_rotary_pm_ops = {
    .suspend    = bfin_rotary_suspend,
    .resume     = bfin_rotary_resume,
};
#endif

static struct platform_driver bfin_rotary_device_driver = {
    .probe      = bfin_rotary_probe,
    .remove     = __devexit_p(bfin_rotary_remove),
    .driver     = {
        .name   = "bfin-rotary",
        .owner  = THIS_MODULE,
#ifdef CONFIG_PM
        .pm = &bfin_rotary_pm_ops,
#endif
    },
};
module_platform_driver(bfin_rotary_device_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Michael Hennerich <[email protected]>");
MODULE_DESCRIPTION("Rotary Counter driver for Blackfin Processors");
MODULE_ALIAS("platform:bfin-rotary");