pxa930_rotary.c

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/*
 * Driver for the enhanced rotary controller on pxa930 and pxa935
 *
 * 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/interrupt.h>
#include <linux/input.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>

#include <linux/platform_data/keyboard-pxa930_rotary.h>

#define SBCR    (0x04)
#define ERCR    (0x0c)

#define SBCR_ERSB   (1 << 5)

struct pxa930_rotary {
    struct input_dev    *input_dev;
    void __iomem        *mmio_base;
    int         last_ercr;

    struct pxa930_rotary_platform_data *pdata;
};

static void clear_sbcr(struct pxa930_rotary *r)
{
    uint32_t sbcr = __raw_readl(r->mmio_base + SBCR);

    __raw_writel(sbcr | SBCR_ERSB, r->mmio_base + SBCR);
    __raw_writel(sbcr & ~SBCR_ERSB, r->mmio_base + SBCR);
}

static irqreturn_t rotary_irq(int irq, void *dev_id)
{
    struct pxa930_rotary *r = dev_id;
    struct pxa930_rotary_platform_data *pdata = r->pdata;
    int ercr, delta, key;

    ercr = __raw_readl(r->mmio_base + ERCR) & 0xf;
    clear_sbcr(r);

    delta = ercr - r->last_ercr;
    if (delta == 0)
        return IRQ_HANDLED;

    r->last_ercr = ercr;

    if (pdata->up_key && pdata->down_key) {
        key = (delta > 0) ? pdata->up_key : pdata->down_key;
        input_report_key(r->input_dev, key, 1);
        input_sync(r->input_dev);
        input_report_key(r->input_dev, key, 0);
    } else
        input_report_rel(r->input_dev, pdata->rel_code, delta);

    input_sync(r->input_dev);

    return IRQ_HANDLED;
}

static int pxa930_rotary_open(struct input_dev *dev)
{
    struct pxa930_rotary *r = input_get_drvdata(dev);

    clear_sbcr(r);

    return 0;
}

static void pxa930_rotary_close(struct input_dev *dev)
{
    struct pxa930_rotary *r = input_get_drvdata(dev);

    clear_sbcr(r);
}

static int __devinit pxa930_rotary_probe(struct platform_device *pdev)
{
    struct pxa930_rotary_platform_data *pdata = pdev->dev.platform_data;
    struct pxa930_rotary *r;
    struct input_dev *input_dev;
    struct resource *res;
    int irq;
    int err;

    irq = platform_get_irq(pdev, 0);
    if (irq < 0) {
        dev_err(&pdev->dev, "no irq for rotary controller\n");
        return -ENXIO;
    }

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        dev_err(&pdev->dev, "no I/O memory defined\n");
        return -ENXIO;
    }

    if (!pdata) {
        dev_err(&pdev->dev, "no platform data defined\n");
        return -EINVAL;
    }

    r = kzalloc(sizeof(struct pxa930_rotary), GFP_KERNEL);
    if (!r)
        return -ENOMEM;

    r->mmio_base = ioremap_nocache(res->start, resource_size(res));
    if (r->mmio_base == NULL) {
        dev_err(&pdev->dev, "failed to remap IO memory\n");
        err = -ENXIO;
        goto failed_free;
    }

    r->pdata = pdata;
    platform_set_drvdata(pdev, r);

    /* allocate and register the input device */
    input_dev = input_allocate_device();
    if (!input_dev) {
        dev_err(&pdev->dev, "failed to allocate input device\n");
        err = -ENOMEM;
        goto failed_free_io;
    }

    input_dev->name = pdev->name;
    input_dev->id.bustype = BUS_HOST;
    input_dev->open = pxa930_rotary_open;
    input_dev->close = pxa930_rotary_close;
    input_dev->dev.parent = &pdev->dev;

    if (pdata->up_key && pdata->down_key) {
        __set_bit(pdata->up_key, input_dev->keybit);
        __set_bit(pdata->down_key, input_dev->keybit);
        __set_bit(EV_KEY, input_dev->evbit);
    } else {
        __set_bit(pdata->rel_code, input_dev->relbit);
        __set_bit(EV_REL, input_dev->evbit);
    }

    r->input_dev = input_dev;
    input_set_drvdata(input_dev, r);

    err = request_irq(irq, rotary_irq, 0,
            "enhanced rotary", r);
    if (err) {
        dev_err(&pdev->dev, "failed to request IRQ\n");
        goto failed_free_input;
    }

    err = input_register_device(input_dev);
    if (err) {
        dev_err(&pdev->dev, "failed to register input device\n");
        goto failed_free_irq;
    }

    return 0;

failed_free_irq:
    free_irq(irq, r);
failed_free_input:
    input_free_device(input_dev);
failed_free_io:
    iounmap(r->mmio_base);
failed_free:
    kfree(r);
    return err;
}

static int __devexit pxa930_rotary_remove(struct platform_device *pdev)
{
    struct pxa930_rotary *r = platform_get_drvdata(pdev);

    free_irq(platform_get_irq(pdev, 0), r);
    input_unregister_device(r->input_dev);
    iounmap(r->mmio_base);
    platform_set_drvdata(pdev, NULL);
    kfree(r);

    return 0;
}

static struct platform_driver pxa930_rotary_driver = {
    .driver     = {
        .name   = "pxa930-rotary",
        .owner  = THIS_MODULE,
    },
    .probe      = pxa930_rotary_probe,
    .remove     = __devexit_p(pxa930_rotary_remove),
};
module_platform_driver(pxa930_rotary_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Driver for PXA93x Enhanced Rotary Controller");
MODULE_AUTHOR("Yao Yong <[email protected]>");