pcap_ts.c

Go to the documentation of this file.

/*
 * Driver for Motorola PCAP2 touchscreen as found in the EZX phone platform.
 *
 *  Copyright (C) 2006 Harald Welte <[email protected]>
 *  Copyright (C) 2009 Daniel Ribeiro <[email protected]>
 *
 *  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/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/pm.h>
#include <linux/timer.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/mfd/ezx-pcap.h>

struct pcap_ts {
    struct pcap_chip *pcap;
    struct input_dev *input;
    struct delayed_work work;
    u16 x, y;
    u16 pressure;
    u8 read_state;
};

#define SAMPLE_DELAY    20 /* msecs */

#define X_AXIS_MIN  0
#define X_AXIS_MAX  1023
#define Y_AXIS_MAX  X_AXIS_MAX
#define Y_AXIS_MIN  X_AXIS_MIN
#define PRESSURE_MAX    X_AXIS_MAX
#define PRESSURE_MIN    X_AXIS_MIN

static void pcap_ts_read_xy(void *data, u16 res[2])
{
    struct pcap_ts *pcap_ts = data;

    switch (pcap_ts->read_state) {
    case PCAP_ADC_TS_M_PRESSURE:
        /* pressure reading is unreliable */
        if (res[0] > PRESSURE_MIN && res[0] < PRESSURE_MAX)
            pcap_ts->pressure = res[0];
        pcap_ts->read_state = PCAP_ADC_TS_M_XY;
        schedule_delayed_work(&pcap_ts->work, 0);
        break;
    case PCAP_ADC_TS_M_XY:
        pcap_ts->y = res[0];
        pcap_ts->x = res[1];
        if (pcap_ts->x <= X_AXIS_MIN || pcap_ts->x >= X_AXIS_MAX ||
            pcap_ts->y <= Y_AXIS_MIN || pcap_ts->y >= Y_AXIS_MAX) {
            /* pen has been released */
            input_report_abs(pcap_ts->input, ABS_PRESSURE, 0);
            input_report_key(pcap_ts->input, BTN_TOUCH, 0);

            pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
            schedule_delayed_work(&pcap_ts->work, 0);
        } else {
            /* pen is touching the screen */
            input_report_abs(pcap_ts->input, ABS_X, pcap_ts->x);
            input_report_abs(pcap_ts->input, ABS_Y, pcap_ts->y);
            input_report_key(pcap_ts->input, BTN_TOUCH, 1);
            input_report_abs(pcap_ts->input, ABS_PRESSURE,
                        pcap_ts->pressure);

            /* switch back to pressure read mode */
            pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
            schedule_delayed_work(&pcap_ts->work,
                    msecs_to_jiffies(SAMPLE_DELAY));
        }
        input_sync(pcap_ts->input);
        break;
    default:
        dev_warn(&pcap_ts->input->dev,
                "pcap_ts: Warning, unhandled read_state %d\n",
                pcap_ts->read_state);
        break;
    }
}

static void pcap_ts_work(struct work_struct *work)
{
    struct delayed_work *dw = container_of(work, struct delayed_work, work);
    struct pcap_ts *pcap_ts = container_of(dw, struct pcap_ts, work);
    u8 ch[2];

    pcap_set_ts_bits(pcap_ts->pcap,
            pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);

    if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY)
        return;

    /* start adc conversion */
    ch[0] = PCAP_ADC_CH_TS_X1;
    ch[1] = PCAP_ADC_CH_TS_Y1;
    pcap_adc_async(pcap_ts->pcap, PCAP_ADC_BANK_1, 0, ch,
                        pcap_ts_read_xy, pcap_ts);
}

static irqreturn_t pcap_ts_event_touch(int pirq, void *data)
{
    struct pcap_ts *pcap_ts = data;

    if (pcap_ts->read_state == PCAP_ADC_TS_M_STANDBY) {
        pcap_ts->read_state = PCAP_ADC_TS_M_PRESSURE;
        schedule_delayed_work(&pcap_ts->work, 0);
    }
    return IRQ_HANDLED;
}

static int pcap_ts_open(struct input_dev *dev)
{
    struct pcap_ts *pcap_ts = input_get_drvdata(dev);

    pcap_ts->read_state = PCAP_ADC_TS_M_STANDBY;
    schedule_delayed_work(&pcap_ts->work, 0);

    return 0;
}

static void pcap_ts_close(struct input_dev *dev)
{
    struct pcap_ts *pcap_ts = input_get_drvdata(dev);

    cancel_delayed_work_sync(&pcap_ts->work);

    pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
    pcap_set_ts_bits(pcap_ts->pcap,
                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
}

static int __devinit pcap_ts_probe(struct platform_device *pdev)
{
    struct input_dev *input_dev;
    struct pcap_ts *pcap_ts;
    int err = -ENOMEM;

    pcap_ts = kzalloc(sizeof(*pcap_ts), GFP_KERNEL);
    if (!pcap_ts)
        return err;

    pcap_ts->pcap = dev_get_drvdata(pdev->dev.parent);
    platform_set_drvdata(pdev, pcap_ts);

    input_dev = input_allocate_device();
    if (!input_dev)
        goto fail;

    INIT_DELAYED_WORK(&pcap_ts->work, pcap_ts_work);

    pcap_ts->read_state = PCAP_ADC_TS_M_NONTS;
    pcap_set_ts_bits(pcap_ts->pcap,
                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);

    pcap_ts->input = input_dev;
    input_set_drvdata(input_dev, pcap_ts);

    input_dev->name = "pcap-touchscreen";
    input_dev->phys = "pcap_ts/input0";
    input_dev->id.bustype = BUS_HOST;
    input_dev->id.vendor = 0x0001;
    input_dev->id.product = 0x0002;
    input_dev->id.version = 0x0100;
    input_dev->dev.parent = &pdev->dev;
    input_dev->open = pcap_ts_open;
    input_dev->close = pcap_ts_close;

    input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
    input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
    input_set_abs_params(input_dev, ABS_X, X_AXIS_MIN, X_AXIS_MAX, 0, 0);
    input_set_abs_params(input_dev, ABS_Y, Y_AXIS_MIN, Y_AXIS_MAX, 0, 0);
    input_set_abs_params(input_dev, ABS_PRESSURE, PRESSURE_MIN,
                 PRESSURE_MAX, 0, 0);

    err = input_register_device(pcap_ts->input);
    if (err)
        goto fail_allocate;

    err = request_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS),
            pcap_ts_event_touch, 0, "Touch Screen", pcap_ts);
    if (err)
        goto fail_register;

    return 0;

fail_register:
    input_unregister_device(input_dev);
    goto fail;
fail_allocate:
    input_free_device(input_dev);
fail:
    kfree(pcap_ts);

    return err;
}

static int __devexit pcap_ts_remove(struct platform_device *pdev)
{
    struct pcap_ts *pcap_ts = platform_get_drvdata(pdev);

    free_irq(pcap_to_irq(pcap_ts->pcap, PCAP_IRQ_TS), pcap_ts);
    cancel_delayed_work_sync(&pcap_ts->work);

    input_unregister_device(pcap_ts->input);

    kfree(pcap_ts);

    return 0;
}

#ifdef CONFIG_PM
static int pcap_ts_suspend(struct device *dev)
{
    struct pcap_ts *pcap_ts = dev_get_drvdata(dev);

    pcap_set_ts_bits(pcap_ts->pcap, PCAP_ADC_TS_REF_LOWPWR);
    return 0;
}

static int pcap_ts_resume(struct device *dev)
{
    struct pcap_ts *pcap_ts = dev_get_drvdata(dev);

    pcap_set_ts_bits(pcap_ts->pcap,
                pcap_ts->read_state << PCAP_ADC_TS_M_SHIFT);
    return 0;
}

static const struct dev_pm_ops pcap_ts_pm_ops = {
    .suspend    = pcap_ts_suspend,
    .resume     = pcap_ts_resume,
};
#define PCAP_TS_PM_OPS (&pcap_ts_pm_ops)
#else
#define PCAP_TS_PM_OPS NULL
#endif

static struct platform_driver pcap_ts_driver = {
    .probe      = pcap_ts_probe,
    .remove     = __devexit_p(pcap_ts_remove),
    .driver     = {
        .name   = "pcap-ts",
        .owner  = THIS_MODULE,
        .pm = PCAP_TS_PM_OPS,
    },
};
module_platform_driver(pcap_ts_driver);

MODULE_DESCRIPTION("Motorola PCAP2 touchscreen driver");
MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pcap_ts");