ucb1400_ts.c

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/*
 *  Philips UCB1400 touchscreen driver
 *
 *  Author: Nicolas Pitre
 *  Created:    September 25, 2006
 *  Copyright:  MontaVista Software, Inc.
 *
 * Spliting done by: Marek Vasut <[email protected]>
 * If something doesn't work and it worked before spliting, e-mail me,
 * dont bother Nicolas please ;-)
 *
 * 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.
 *
 * This code is heavily based on ucb1x00-*.c copyrighted by Russell King
 * covering the UCB1100, UCB1200 and UCB1300..  Support for the UCB1400 has
 * been made separate from ucb1x00-core/ucb1x00-ts on Russell's request.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/ucb1400.h>

#define UCB1400_TS_POLL_PERIOD  10 /* ms */

static bool adcsync;
static int ts_delay = 55; /* us */
static int ts_delay_pressure;   /* us */

/* Switch to interrupt mode. */
static void ucb1400_ts_mode_int(struct ucb1400_ts *ucb)
{
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
            UCB_TS_CR_MODE_INT);
}

/*
 * Switch to pressure mode, and read pressure.  We don't need to wait
 * here, since both plates are being driven.
 */
static unsigned int ucb1400_ts_read_pressure(struct ucb1400_ts *ucb)
{
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);

    udelay(ts_delay_pressure);

    return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPY, adcsync);
}

/*
 * Switch to X position mode and measure Y plate.  We switch the plate
 * configuration in pressure mode, then switch to position mode.  This
 * gives a faster response time.  Even so, we need to wait about 55us
 * for things to stabilise.
 */
static unsigned int ucb1400_ts_read_xpos(struct ucb1400_ts *ucb)
{
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
            UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

    udelay(ts_delay);

    return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPY, adcsync);
}

/*
 * Switch to Y position mode and measure X plate.  We switch the plate
 * configuration in pressure mode, then switch to position mode.  This
 * gives a faster response time.  Even so, we need to wait about 55us
 * for things to stabilise.
 */
static int ucb1400_ts_read_ypos(struct ucb1400_ts *ucb)
{
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
            UCB_TS_CR_MODE_POS | UCB_TS_CR_BIAS_ENA);

    udelay(ts_delay);

    return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPX, adcsync);
}

/*
 * Switch to X plate resistance mode.  Set MX to ground, PX to
 * supply.  Measure current.
 */
static unsigned int ucb1400_ts_read_xres(struct ucb1400_ts *ucb)
{
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMX_GND | UCB_TS_CR_TSPX_POW |
            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
    return ucb1400_adc_read(ucb->ac97, 0, adcsync);
}

/*
 * Switch to Y plate resistance mode.  Set MY to ground, PY to
 * supply.  Measure current.
 */
static unsigned int ucb1400_ts_read_yres(struct ucb1400_ts *ucb)
{
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
            UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_POW |
            UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
    return ucb1400_adc_read(ucb->ac97, 0, adcsync);
}

static int ucb1400_ts_pen_up(struct ucb1400_ts *ucb)
{
    unsigned short val = ucb1400_reg_read(ucb->ac97, UCB_TS_CR);

    return val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW);
}

static void ucb1400_ts_irq_enable(struct ucb1400_ts *ucb)
{
    ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, UCB_IE_TSPX);
    ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);
    ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, UCB_IE_TSPX);
}

static void ucb1400_ts_irq_disable(struct ucb1400_ts *ucb)
{
    ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, 0);
}

static void ucb1400_ts_report_event(struct input_dev *idev, u16 pressure, u16 x, u16 y)
{
    input_report_abs(idev, ABS_X, x);
    input_report_abs(idev, ABS_Y, y);
    input_report_abs(idev, ABS_PRESSURE, pressure);
    input_report_key(idev, BTN_TOUCH, 1);
    input_sync(idev);
}

static void ucb1400_ts_event_release(struct input_dev *idev)
{
    input_report_abs(idev, ABS_PRESSURE, 0);
    input_report_key(idev, BTN_TOUCH, 0);
    input_sync(idev);
}

static void ucb1400_clear_pending_irq(struct ucb1400_ts *ucb)
{
    unsigned int isr;

    isr = ucb1400_reg_read(ucb->ac97, UCB_IE_STATUS);
    ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, isr);
    ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);

    if (isr & UCB_IE_TSPX)
        ucb1400_ts_irq_disable(ucb);
    else
        dev_dbg(&ucb->ts_idev->dev,
            "ucb1400: unexpected IE_STATUS = %#x\n", isr);
}

/*
 * A restriction with interrupts exists when using the ucb1400, as
 * the codec read/write routines may sleep while waiting for codec
 * access completion and uses semaphores for access control to the
 * AC97 bus. Therefore the driver is forced to use threaded interrupt
 * handler.
 */
static irqreturn_t ucb1400_irq(int irqnr, void *devid)
{
    struct ucb1400_ts *ucb = devid;
    unsigned int x, y, p;
    bool penup;

    if (unlikely(irqnr != ucb->irq))
        return IRQ_NONE;

    ucb1400_clear_pending_irq(ucb);

    /* Start with a small delay before checking pendown state */
    msleep(UCB1400_TS_POLL_PERIOD);

    while (!ucb->stopped && !(penup = ucb1400_ts_pen_up(ucb))) {

        ucb1400_adc_enable(ucb->ac97);
        x = ucb1400_ts_read_xpos(ucb);
        y = ucb1400_ts_read_ypos(ucb);
        p = ucb1400_ts_read_pressure(ucb);
        ucb1400_adc_disable(ucb->ac97);

        ucb1400_ts_report_event(ucb->ts_idev, p, x, y);

        wait_event_timeout(ucb->ts_wait, ucb->stopped,
                   msecs_to_jiffies(UCB1400_TS_POLL_PERIOD));
    }

    ucb1400_ts_event_release(ucb->ts_idev);

    if (!ucb->stopped) {
        /* Switch back to interrupt mode. */
        ucb1400_ts_mode_int(ucb);
        ucb1400_ts_irq_enable(ucb);
    }

    return IRQ_HANDLED;
}

static void ucb1400_ts_stop(struct ucb1400_ts *ucb)
{
    /* Signal IRQ thread to stop polling and disable the handler. */
    ucb->stopped = true;
    mb();
    wake_up(&ucb->ts_wait);
    disable_irq(ucb->irq);

    ucb1400_ts_irq_disable(ucb);
    ucb1400_reg_write(ucb->ac97, UCB_TS_CR, 0);
}

/* Must be called with ts->lock held */
static void ucb1400_ts_start(struct ucb1400_ts *ucb)
{
    /* Tell IRQ thread that it may poll the device. */
    ucb->stopped = false;
    mb();

    ucb1400_ts_mode_int(ucb);
    ucb1400_ts_irq_enable(ucb);

    enable_irq(ucb->irq);
}

static int ucb1400_ts_open(struct input_dev *idev)
{
    struct ucb1400_ts *ucb = input_get_drvdata(idev);

    ucb1400_ts_start(ucb);

    return 0;
}

static void ucb1400_ts_close(struct input_dev *idev)
{
    struct ucb1400_ts *ucb = input_get_drvdata(idev);

    ucb1400_ts_stop(ucb);
}

#ifndef NO_IRQ
#define NO_IRQ  0
#endif

/*
 * Try to probe our interrupt, rather than relying on lots of
 * hard-coded machine dependencies.
 */
static int __devinit ucb1400_ts_detect_irq(struct ucb1400_ts *ucb,
                       struct platform_device *pdev)
{
    unsigned long mask, timeout;

    mask = probe_irq_on();

    /* Enable the ADC interrupt. */
    ucb1400_reg_write(ucb->ac97, UCB_IE_RIS, UCB_IE_ADC);
    ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, UCB_IE_ADC);
    ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0xffff);
    ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);

    /* Cause an ADC interrupt. */
    ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, UCB_ADC_ENA);
    ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, UCB_ADC_ENA | UCB_ADC_START);

    /* Wait for the conversion to complete. */
    timeout = jiffies + HZ/2;
    while (!(ucb1400_reg_read(ucb->ac97, UCB_ADC_DATA) &
                        UCB_ADC_DAT_VALID)) {
        cpu_relax();
        if (time_after(jiffies, timeout)) {
            dev_err(&pdev->dev, "timed out in IRQ probe\n");
            probe_irq_off(mask);
            return -ENODEV;
        }
    }
    ucb1400_reg_write(ucb->ac97, UCB_ADC_CR, 0);

    /* Disable and clear interrupt. */
    ucb1400_reg_write(ucb->ac97, UCB_IE_RIS, 0);
    ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, 0);
    ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0xffff);
    ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);

    /* Read triggered interrupt. */
    ucb->irq = probe_irq_off(mask);
    if (ucb->irq < 0 || ucb->irq == NO_IRQ)
        return -ENODEV;

    return 0;
}

static int __devinit ucb1400_ts_probe(struct platform_device *pdev)
{
    struct ucb1400_ts *ucb = pdev->dev.platform_data;
    int error, x_res, y_res;
    u16 fcsr;

    ucb->ts_idev = input_allocate_device();
    if (!ucb->ts_idev) {
        error = -ENOMEM;
        goto err;
    }

    /* Only in case the IRQ line wasn't supplied, try detecting it */
    if (ucb->irq < 0) {
        error = ucb1400_ts_detect_irq(ucb, pdev);
        if (error) {
            dev_err(&pdev->dev, "IRQ probe failed\n");
            goto err_free_devs;
        }
    }
    dev_dbg(&pdev->dev, "found IRQ %d\n", ucb->irq);

    init_waitqueue_head(&ucb->ts_wait);

    input_set_drvdata(ucb->ts_idev, ucb);

    ucb->ts_idev->dev.parent    = &pdev->dev;
    ucb->ts_idev->name      = "UCB1400 touchscreen interface";
    ucb->ts_idev->id.vendor     = ucb1400_reg_read(ucb->ac97,
                        AC97_VENDOR_ID1);
    ucb->ts_idev->id.product    = ucb->id;
    ucb->ts_idev->open      = ucb1400_ts_open;
    ucb->ts_idev->close     = ucb1400_ts_close;
    ucb->ts_idev->evbit[0]      = BIT_MASK(EV_ABS) | BIT_MASK(EV_KEY);
    ucb->ts_idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

    /*
     * Enable ADC filter to prevent horrible jitter on Colibri.
     * This also further reduces jitter on boards where ADCSYNC
     * pin is connected.
     */
    fcsr = ucb1400_reg_read(ucb->ac97, UCB_FCSR);
    ucb1400_reg_write(ucb->ac97, UCB_FCSR, fcsr | UCB_FCSR_AVE);

    ucb1400_adc_enable(ucb->ac97);
    x_res = ucb1400_ts_read_xres(ucb);
    y_res = ucb1400_ts_read_yres(ucb);
    ucb1400_adc_disable(ucb->ac97);
    dev_dbg(&pdev->dev, "x/y = %d/%d\n", x_res, y_res);

    input_set_abs_params(ucb->ts_idev, ABS_X, 0, x_res, 0, 0);
    input_set_abs_params(ucb->ts_idev, ABS_Y, 0, y_res, 0, 0);
    input_set_abs_params(ucb->ts_idev, ABS_PRESSURE, 0, 0, 0, 0);

    ucb1400_ts_stop(ucb);

    error = request_threaded_irq(ucb->irq, NULL, ucb1400_irq,
                     IRQF_TRIGGER_RISING | IRQF_ONESHOT,
                     "UCB1400", ucb);
    if (error) {
        dev_err(&pdev->dev,
            "unable to grab irq%d: %d\n", ucb->irq, error);
        goto err_free_devs;
    }

    error = input_register_device(ucb->ts_idev);
    if (error)
        goto err_free_irq;

    return 0;

err_free_irq:
    free_irq(ucb->irq, ucb);
err_free_devs:
    input_free_device(ucb->ts_idev);
err:
    return error;
}

static int __devexit ucb1400_ts_remove(struct platform_device *pdev)
{
    struct ucb1400_ts *ucb = pdev->dev.platform_data;

    free_irq(ucb->irq, ucb);
    input_unregister_device(ucb->ts_idev);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int ucb1400_ts_suspend(struct device *dev)
{
    struct ucb1400_ts *ucb = dev->platform_data;
    struct input_dev *idev = ucb->ts_idev;

    mutex_lock(&idev->mutex);

    if (idev->users)
        ucb1400_ts_start(ucb);

    mutex_unlock(&idev->mutex);
    return 0;
}

static int ucb1400_ts_resume(struct device *dev)
{
    struct ucb1400_ts *ucb = dev->platform_data;
    struct input_dev *idev = ucb->ts_idev;

    mutex_lock(&idev->mutex);

    if (idev->users)
        ucb1400_ts_stop(ucb);

    mutex_unlock(&idev->mutex);
    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(ucb1400_ts_pm_ops,
             ucb1400_ts_suspend, ucb1400_ts_resume);

static struct platform_driver ucb1400_ts_driver = {
    .probe  = ucb1400_ts_probe,
    .remove = __devexit_p(ucb1400_ts_remove),
    .driver = {
        .name   = "ucb1400_ts",
        .owner  = THIS_MODULE,
        .pm = &ucb1400_ts_pm_ops,
    },
};
module_platform_driver(ucb1400_ts_driver);

module_param(adcsync, bool, 0444);
MODULE_PARM_DESC(adcsync, "Synchronize touch readings with ADCSYNC pin.");

module_param(ts_delay, int, 0444);
MODULE_PARM_DESC(ts_delay, "Delay between panel setup and"
                " position read. Default = 55us.");

module_param(ts_delay_pressure, int, 0444);
MODULE_PARM_DESC(ts_delay_pressure,
        "delay between panel setup and pressure read."
        "  Default = 0us.");

MODULE_DESCRIPTION("Philips UCB1400 touchscreen driver");
MODULE_LICENSE("GPL");