pxa930_trkball.c

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/*
 * PXA930 track ball mouse driver
 *
 * Copyright (C) 2007 Marvell International Ltd.
 * 2008-02-28: Yong Yao <[email protected]>
 *             initial version
 *
 *  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/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/slab.h>

#include <mach/hardware.h>
#include <linux/platform_data/mouse-pxa930_trkball.h>

/* Trackball Controller Register Definitions */
#define TBCR        (0x000C)
#define TBCNTR      (0x0010)
#define TBSBC       (0x0014)

#define TBCR_TBRST  (1 << 1)
#define TBCR_TBSB   (1 << 10)

#define TBCR_Y_FLT(n)   (((n) & 0xf) << 6)
#define TBCR_X_FLT(n)   (((n) & 0xf) << 2)

#define TBCNTR_YM(n)    (((n) >> 24) & 0xff)
#define TBCNTR_YP(n)    (((n) >> 16) & 0xff)
#define TBCNTR_XM(n)    (((n) >> 8) & 0xff)
#define TBCNTR_XP(n)    ((n) & 0xff)

#define TBSBC_TBSBC (0x1)

struct pxa930_trkball {
    struct pxa930_trkball_platform_data *pdata;

    /* Memory Mapped Register */
    struct resource *mem;
    void __iomem *mmio_base;

    struct input_dev *input;
};

static irqreturn_t pxa930_trkball_interrupt(int irq, void *dev_id)
{
    struct pxa930_trkball *trkball = dev_id;
    struct input_dev *input = trkball->input;
    int tbcntr, x, y;

    /* According to the spec software must read TBCNTR twice:
     * if the read value is the same, the reading is valid
     */
    tbcntr = __raw_readl(trkball->mmio_base + TBCNTR);

    if (tbcntr == __raw_readl(trkball->mmio_base + TBCNTR)) {
        x = (TBCNTR_XP(tbcntr) - TBCNTR_XM(tbcntr)) / 2;
        y = (TBCNTR_YP(tbcntr) - TBCNTR_YM(tbcntr)) / 2;

        input_report_rel(input, REL_X, x);
        input_report_rel(input, REL_Y, y);
        input_sync(input);
    }

    __raw_writel(TBSBC_TBSBC, trkball->mmio_base + TBSBC);
    __raw_writel(0, trkball->mmio_base + TBSBC);

    return IRQ_HANDLED;
}

/* For TBCR, we need to wait for a while to make sure it has been modified. */
static int write_tbcr(struct pxa930_trkball *trkball, int v)
{
    int i = 100;

    __raw_writel(v, trkball->mmio_base + TBCR);

    while (--i) {
        if (__raw_readl(trkball->mmio_base + TBCR) == v)
            break;
        msleep(1);
    }

    if (i == 0) {
        pr_err("%s: timed out writing TBCR(%x)!\n", __func__, v);
        return -ETIMEDOUT;
    }

    return 0;
}

static void pxa930_trkball_config(struct pxa930_trkball *trkball)
{
    uint32_t tbcr;

    /* According to spec, need to write the filters of x,y to 0xf first! */
    tbcr = __raw_readl(trkball->mmio_base + TBCR);
    write_tbcr(trkball, tbcr | TBCR_X_FLT(0xf) | TBCR_Y_FLT(0xf));
    write_tbcr(trkball, TBCR_X_FLT(trkball->pdata->x_filter) |
                TBCR_Y_FLT(trkball->pdata->y_filter));

    /* According to spec, set TBCR_TBRST first, before clearing it! */
    tbcr = __raw_readl(trkball->mmio_base + TBCR);
    write_tbcr(trkball, tbcr | TBCR_TBRST);
    write_tbcr(trkball, tbcr & ~TBCR_TBRST);

    __raw_writel(TBSBC_TBSBC, trkball->mmio_base + TBSBC);
    __raw_writel(0, trkball->mmio_base + TBSBC);

    pr_debug("%s: final TBCR=%x!\n", __func__,
         __raw_readl(trkball->mmio_base + TBCR));
}

static int pxa930_trkball_open(struct input_dev *dev)
{
    struct pxa930_trkball *trkball = input_get_drvdata(dev);

    pxa930_trkball_config(trkball);

    return 0;
}

static void pxa930_trkball_disable(struct pxa930_trkball *trkball)
{
    uint32_t tbcr = __raw_readl(trkball->mmio_base + TBCR);

    /* Held in reset, gate the 32-KHz input clock off */
    write_tbcr(trkball, tbcr | TBCR_TBRST);
}

static void pxa930_trkball_close(struct input_dev *dev)
{
    struct pxa930_trkball *trkball = input_get_drvdata(dev);

    pxa930_trkball_disable(trkball);
}

static int __devinit pxa930_trkball_probe(struct platform_device *pdev)
{
    struct pxa930_trkball *trkball;
    struct input_dev *input;
    struct resource *res;
    int irq, error;

    irq = platform_get_irq(pdev, 0);
    if (irq < 0) {
        dev_err(&pdev->dev, "failed to get trkball irq\n");
        return -ENXIO;
    }

    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        dev_err(&pdev->dev, "failed to get register memory\n");
        return -ENXIO;
    }

    trkball = kzalloc(sizeof(struct pxa930_trkball), GFP_KERNEL);
    if (!trkball)
        return -ENOMEM;

    trkball->pdata = pdev->dev.platform_data;
    if (!trkball->pdata) {
        dev_err(&pdev->dev, "no platform data defined\n");
        error = -EINVAL;
        goto failed;
    }

    trkball->mmio_base = ioremap_nocache(res->start, resource_size(res));
    if (!trkball->mmio_base) {
        dev_err(&pdev->dev, "failed to ioremap registers\n");
        error = -ENXIO;
        goto failed;
    }

    /* held the module in reset, will be enabled in open() */
    pxa930_trkball_disable(trkball);

    error = request_irq(irq, pxa930_trkball_interrupt, 0,
                pdev->name, trkball);
    if (error) {
        dev_err(&pdev->dev, "failed to request irq: %d\n", error);
        goto failed_free_io;
    }

    platform_set_drvdata(pdev, trkball);

    input = input_allocate_device();
    if (!input) {
        dev_err(&pdev->dev, "failed to allocate input device\n");
        error = -ENOMEM;
        goto failed_free_irq;
    }

    input->name = pdev->name;
    input->id.bustype = BUS_HOST;
    input->open = pxa930_trkball_open;
    input->close = pxa930_trkball_close;
    input->dev.parent = &pdev->dev;
    input_set_drvdata(input, trkball);

    trkball->input = input;

    input_set_capability(input, EV_REL, REL_X);
    input_set_capability(input, EV_REL, REL_Y);

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

    return 0;

failed_free_input:
    input_free_device(input);
failed_free_irq:
    free_irq(irq, trkball);
failed_free_io:
    iounmap(trkball->mmio_base);
failed:
    kfree(trkball);
    return error;
}

static int __devexit pxa930_trkball_remove(struct platform_device *pdev)
{
    struct pxa930_trkball *trkball = platform_get_drvdata(pdev);
    int irq = platform_get_irq(pdev, 0);

    input_unregister_device(trkball->input);
    free_irq(irq, trkball);
    iounmap(trkball->mmio_base);
    kfree(trkball);

    return 0;
}

static struct platform_driver pxa930_trkball_driver = {
    .driver     = {
        .name   = "pxa930-trkball",
    },
    .probe      = pxa930_trkball_probe,
    .remove     = __devexit_p(pxa930_trkball_remove),
};
module_platform_driver(pxa930_trkball_driver);

MODULE_AUTHOR("Yong Yao <[email protected]>");
MODULE_DESCRIPTION("PXA930 Trackball Mouse Driver");
MODULE_LICENSE("GPL");