stmpe-ts.c

Go to the documentation of this file.

/* STMicroelectronics STMPE811 Touchscreen Driver
 *
 * (C) 2010 Luotao Fu <[email protected]>
 * All rights reserved.
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/workqueue.h>

#include <linux/mfd/stmpe.h>

/* Register layouts and functionalities are identical on all stmpexxx variants
 * with touchscreen controller
 */
#define STMPE_REG_INT_STA       0x0B
#define STMPE_REG_ADC_CTRL1     0x20
#define STMPE_REG_ADC_CTRL2     0x21
#define STMPE_REG_TSC_CTRL      0x40
#define STMPE_REG_TSC_CFG       0x41
#define STMPE_REG_FIFO_TH       0x4A
#define STMPE_REG_FIFO_STA      0x4B
#define STMPE_REG_FIFO_SIZE     0x4C
#define STMPE_REG_TSC_DATA_XYZ      0x52
#define STMPE_REG_TSC_FRACTION_Z    0x56
#define STMPE_REG_TSC_I_DRIVE       0x58

#define OP_MOD_XYZ          0

#define STMPE_TSC_CTRL_TSC_EN       (1<<0)

#define STMPE_FIFO_STA_RESET        (1<<0)

#define STMPE_IRQ_TOUCH_DET     0

#define SAMPLE_TIME(x)          ((x & 0xf) << 4)
#define MOD_12B(x)          ((x & 0x1) << 3)
#define REF_SEL(x)          ((x & 0x1) << 1)
#define ADC_FREQ(x)         (x & 0x3)
#define AVE_CTRL(x)         ((x & 0x3) << 6)
#define DET_DELAY(x)            ((x & 0x7) << 3)
#define SETTLING(x)         (x & 0x7)
#define FRACTION_Z(x)           (x & 0x7)
#define I_DRIVE(x)          (x & 0x1)
#define OP_MODE(x)          ((x & 0x7) << 1)

#define STMPE_TS_NAME           "stmpe-ts"
#define XY_MASK             0xfff

struct stmpe_touch {
    struct stmpe *stmpe;
    struct input_dev *idev;
    struct delayed_work work;
    struct device *dev;
    u8 sample_time;
    u8 mod_12b;
    u8 ref_sel;
    u8 adc_freq;
    u8 ave_ctrl;
    u8 touch_det_delay;
    u8 settling;
    u8 fraction_z;
    u8 i_drive;
};

static int __stmpe_reset_fifo(struct stmpe *stmpe)
{
    int ret;

    ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
            STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
    if (ret)
        return ret;

    return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
            STMPE_FIFO_STA_RESET, 0);
}

static void stmpe_work(struct work_struct *work)
{
    int int_sta;
    u32 timeout = 40;

    struct stmpe_touch *ts =
        container_of(work, struct stmpe_touch, work.work);

    int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);

    /*
     * touch_det sometimes get desasserted or just get stuck. This appears
     * to be a silicon bug, We still have to clearify this with the
     * manufacture. As a workaround We release the key anyway if the
     * touch_det keeps coming in after 4ms, while the FIFO contains no value
     * during the whole time.
     */
    while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
        timeout--;
        int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
        udelay(100);
    }

    /* reset the FIFO before we report release event */
    __stmpe_reset_fifo(ts->stmpe);

    input_report_abs(ts->idev, ABS_PRESSURE, 0);
    input_sync(ts->idev);
}

static irqreturn_t stmpe_ts_handler(int irq, void *data)
{
    u8 data_set[4];
    int x, y, z;
    struct stmpe_touch *ts = data;

    /*
     * Cancel scheduled polling for release if we have new value
     * available. Wait if the polling is already running.
     */
    cancel_delayed_work_sync(&ts->work);

    /*
     * The FIFO sometimes just crashes and stops generating interrupts. This
     * appears to be a silicon bug. We still have to clearify this with
     * the manufacture. As a workaround we disable the TSC while we are
     * collecting data and flush the FIFO after reading
     */
    stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
                STMPE_TSC_CTRL_TSC_EN, 0);

    stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);

    x = (data_set[0] << 4) | (data_set[1] >> 4);
    y = ((data_set[1] & 0xf) << 8) | data_set[2];
    z = data_set[3];

    input_report_abs(ts->idev, ABS_X, x);
    input_report_abs(ts->idev, ABS_Y, y);
    input_report_abs(ts->idev, ABS_PRESSURE, z);
    input_sync(ts->idev);

       /* flush the FIFO after we have read out our values. */
    __stmpe_reset_fifo(ts->stmpe);

    /* reenable the tsc */
    stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
            STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);

    /* start polling for touch_det to detect release */
    schedule_delayed_work(&ts->work, HZ / 50);

    return IRQ_HANDLED;
}

static int __devinit stmpe_init_hw(struct stmpe_touch *ts)
{
    int ret;
    u8 adc_ctrl1, adc_ctrl1_mask, tsc_cfg, tsc_cfg_mask;
    struct stmpe *stmpe = ts->stmpe;
    struct device *dev = ts->dev;

    ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
    if (ret) {
        dev_err(dev, "Could not enable clock for ADC and TS\n");
        return ret;
    }

    adc_ctrl1 = SAMPLE_TIME(ts->sample_time) | MOD_12B(ts->mod_12b) |
        REF_SEL(ts->ref_sel);
    adc_ctrl1_mask = SAMPLE_TIME(0xff) | MOD_12B(0xff) | REF_SEL(0xff);

    ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL1,
            adc_ctrl1_mask, adc_ctrl1);
    if (ret) {
        dev_err(dev, "Could not setup ADC\n");
        return ret;
    }

    ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL2,
            ADC_FREQ(0xff), ADC_FREQ(ts->adc_freq));
    if (ret) {
        dev_err(dev, "Could not setup ADC\n");
        return ret;
    }

    tsc_cfg = AVE_CTRL(ts->ave_ctrl) | DET_DELAY(ts->touch_det_delay) |
            SETTLING(ts->settling);
    tsc_cfg_mask = AVE_CTRL(0xff) | DET_DELAY(0xff) | SETTLING(0xff);

    ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
    if (ret) {
        dev_err(dev, "Could not config touch\n");
        return ret;
    }

    ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
            FRACTION_Z(0xff), FRACTION_Z(ts->fraction_z));
    if (ret) {
        dev_err(dev, "Could not config touch\n");
        return ret;
    }

    ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
            I_DRIVE(0xff), I_DRIVE(ts->i_drive));
    if (ret) {
        dev_err(dev, "Could not config touch\n");
        return ret;
    }

    /* set FIFO to 1 for single point reading */
    ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
    if (ret) {
        dev_err(dev, "Could not set FIFO\n");
        return ret;
    }

    ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
            OP_MODE(0xff), OP_MODE(OP_MOD_XYZ));
    if (ret) {
        dev_err(dev, "Could not set mode\n");
        return ret;
    }

    return 0;
}

static int stmpe_ts_open(struct input_dev *dev)
{
    struct stmpe_touch *ts = input_get_drvdata(dev);
    int ret = 0;

    ret = __stmpe_reset_fifo(ts->stmpe);
    if (ret)
        return ret;

    return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
            STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
}

static void stmpe_ts_close(struct input_dev *dev)
{
    struct stmpe_touch *ts = input_get_drvdata(dev);

    cancel_delayed_work_sync(&ts->work);

    stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
            STMPE_TSC_CTRL_TSC_EN, 0);
}

static int __devinit stmpe_input_probe(struct platform_device *pdev)
{
    struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
    struct stmpe_platform_data *pdata = stmpe->pdata;
    struct stmpe_touch *ts;
    struct input_dev *idev;
    struct stmpe_ts_platform_data *ts_pdata = NULL;
    int ret;
    int ts_irq;

    ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
    if (ts_irq < 0)
        return ts_irq;

    ts = kzalloc(sizeof(*ts), GFP_KERNEL);
    if (!ts) {
        ret = -ENOMEM;
        goto err_out;
    }

    idev = input_allocate_device();
    if (!idev) {
        ret = -ENOMEM;
        goto err_free_ts;
    }

    platform_set_drvdata(pdev, ts);
    ts->stmpe = stmpe;
    ts->idev = idev;
    ts->dev = &pdev->dev;

    if (pdata)
        ts_pdata = pdata->ts;

    if (ts_pdata) {
        ts->sample_time = ts_pdata->sample_time;
        ts->mod_12b = ts_pdata->mod_12b;
        ts->ref_sel = ts_pdata->ref_sel;
        ts->adc_freq = ts_pdata->adc_freq;
        ts->ave_ctrl = ts_pdata->ave_ctrl;
        ts->touch_det_delay = ts_pdata->touch_det_delay;
        ts->settling = ts_pdata->settling;
        ts->fraction_z = ts_pdata->fraction_z;
        ts->i_drive = ts_pdata->i_drive;
    }

    INIT_DELAYED_WORK(&ts->work, stmpe_work);

    ret = request_threaded_irq(ts_irq, NULL, stmpe_ts_handler,
            IRQF_ONESHOT, STMPE_TS_NAME, ts);
    if (ret) {
        dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
        goto err_free_input;
    }

    ret = stmpe_init_hw(ts);
    if (ret)
        goto err_free_irq;

    idev->name = STMPE_TS_NAME;
    idev->id.bustype = BUS_I2C;
    idev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
    idev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);

    idev->open = stmpe_ts_open;
    idev->close = stmpe_ts_close;

    input_set_drvdata(idev, ts);

    input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
    input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
    input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);

    ret = input_register_device(idev);
    if (ret) {
        dev_err(&pdev->dev, "Could not register input device\n");
        goto err_free_irq;
    }

    return ret;

err_free_irq:
    free_irq(ts_irq, ts);
err_free_input:
    input_free_device(idev);
    platform_set_drvdata(pdev, NULL);
err_free_ts:
    kfree(ts);
err_out:
    return ret;
}

static int __devexit stmpe_ts_remove(struct platform_device *pdev)
{
    struct stmpe_touch *ts = platform_get_drvdata(pdev);
    unsigned int ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");

    stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);

    free_irq(ts_irq, ts);

    platform_set_drvdata(pdev, NULL);

    input_unregister_device(ts->idev);

    kfree(ts);

    return 0;
}

static struct platform_driver stmpe_ts_driver = {
    .driver = {
           .name = STMPE_TS_NAME,
           .owner = THIS_MODULE,
           },
    .probe = stmpe_input_probe,
    .remove = __devexit_p(stmpe_ts_remove),
};
module_platform_driver(stmpe_ts_driver);

MODULE_AUTHOR("Luotao Fu <[email protected]>");
MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" STMPE_TS_NAME);