egalax_ts.c

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/*
 * Driver for EETI eGalax Multiple Touch Controller
 *
 * Copyright (C) 2011 Freescale Semiconductor, Inc.
 *
 * based on max11801_ts.c
 *
 * 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.
 */

/* EETI eGalax serial touch screen controller is a I2C based multiple
 * touch screen controller, it supports 5 point multiple touch. */

/* TODO:
  - auto idle mode support
*/

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/input/mt.h>
#include <linux/of_gpio.h>

/*
 * Mouse Mode: some panel may configure the controller to mouse mode,
 * which can only report one point at a given time.
 * This driver will ignore events in this mode.
 */
#define REPORT_MODE_MOUSE       0x1
/*
 * Vendor Mode: this mode is used to transfer some vendor specific
 * messages.
 * This driver will ignore events in this mode.
 */
#define REPORT_MODE_VENDOR      0x3
/* Multiple Touch Mode */
#define REPORT_MODE_MTTOUCH     0x4

#define MAX_SUPPORT_POINTS      5

#define EVENT_VALID_OFFSET  7
#define EVENT_VALID_MASK    (0x1 << EVENT_VALID_OFFSET)
#define EVENT_ID_OFFSET     2
#define EVENT_ID_MASK       (0xf << EVENT_ID_OFFSET)
#define EVENT_IN_RANGE      (0x1 << 1)
#define EVENT_DOWN_UP       (0X1 << 0)

#define MAX_I2C_DATA_LEN    10

#define EGALAX_MAX_X    32760
#define EGALAX_MAX_Y    32760
#define EGALAX_MAX_TRIES 100

struct egalax_ts {
    struct i2c_client       *client;
    struct input_dev        *input_dev;
};

static irqreturn_t egalax_ts_interrupt(int irq, void *dev_id)
{
    struct egalax_ts *ts = dev_id;
    struct input_dev *input_dev = ts->input_dev;
    struct i2c_client *client = ts->client;
    u8 buf[MAX_I2C_DATA_LEN];
    int id, ret, x, y, z;
    int tries = 0;
    bool down, valid;
    u8 state;

    do {
        ret = i2c_master_recv(client, buf, MAX_I2C_DATA_LEN);
    } while (ret == -EAGAIN && tries++ < EGALAX_MAX_TRIES);

    if (ret < 0)
        return IRQ_HANDLED;

    if (buf[0] != REPORT_MODE_MTTOUCH) {
        /* ignore mouse events and vendor events */
        return IRQ_HANDLED;
    }

    state = buf[1];
    x = (buf[3] << 8) | buf[2];
    y = (buf[5] << 8) | buf[4];
    z = (buf[7] << 8) | buf[6];

    valid = state & EVENT_VALID_MASK;
    id = (state & EVENT_ID_MASK) >> EVENT_ID_OFFSET;
    down = state & EVENT_DOWN_UP;

    if (!valid || id > MAX_SUPPORT_POINTS) {
        dev_dbg(&client->dev, "point invalid\n");
        return IRQ_HANDLED;
    }

    input_mt_slot(input_dev, id);
    input_mt_report_slot_state(input_dev, MT_TOOL_FINGER, down);

    dev_dbg(&client->dev, "%s id:%d x:%d y:%d z:%d",
        down ? "down" : "up", id, x, y, z);

    if (down) {
        input_report_abs(input_dev, ABS_MT_POSITION_X, x);
        input_report_abs(input_dev, ABS_MT_POSITION_Y, y);
        input_report_abs(input_dev, ABS_MT_PRESSURE, z);
    }

    input_mt_report_pointer_emulation(input_dev, true);
    input_sync(input_dev);

    return IRQ_HANDLED;
}

/* wake up controller by an falling edge of interrupt gpio.  */
static int egalax_wake_up_device(struct i2c_client *client)
{
    struct device_node *np = client->dev.of_node;
    int gpio;
    int ret;

    if (!np)
        return -ENODEV;

    gpio = of_get_named_gpio(np, "wakeup-gpios", 0);
    if (!gpio_is_valid(gpio))
        return -ENODEV;

    ret = gpio_request(gpio, "egalax_irq");
    if (ret < 0) {
        dev_err(&client->dev,
            "request gpio failed, cannot wake up controller: %d\n",
            ret);
        return ret;
    }

    /* wake up controller via an falling edge on IRQ gpio. */
    gpio_direction_output(gpio, 0);
    gpio_set_value(gpio, 1);

    /* controller should be waken up, return irq.  */
    gpio_direction_input(gpio);
    gpio_free(gpio);

    return 0;
}

static int __devinit egalax_firmware_version(struct i2c_client *client)
{
    static const u8 cmd[MAX_I2C_DATA_LEN] = { 0x03, 0x03, 0xa, 0x01, 0x41 };
    int ret;

    ret = i2c_master_send(client, cmd, MAX_I2C_DATA_LEN);
    if (ret < 0)
        return ret;

    return 0;
}

static int __devinit egalax_ts_probe(struct i2c_client *client,
                       const struct i2c_device_id *id)
{
    struct egalax_ts *ts;
    struct input_dev *input_dev;
    int ret;
    int error;

    ts = kzalloc(sizeof(struct egalax_ts), GFP_KERNEL);
    if (!ts) {
        dev_err(&client->dev, "Failed to allocate memory\n");
        return -ENOMEM;
    }

    input_dev = input_allocate_device();
    if (!input_dev) {
        dev_err(&client->dev, "Failed to allocate memory\n");
        error = -ENOMEM;
        goto err_free_ts;
    }

    ts->client = client;
    ts->input_dev = input_dev;

    /* controller may be in sleep, wake it up. */
    error = egalax_wake_up_device(client);
    if (error) {
        dev_err(&client->dev, "Failed to wake up the controller\n");
        goto err_free_dev;
    }

    ret = egalax_firmware_version(client);
    if (ret < 0) {
        dev_err(&client->dev, "Failed to read firmware version\n");
        error = -EIO;
        goto err_free_dev;
    }

    input_dev->name = "EETI eGalax Touch Screen";
    input_dev->id.bustype = BUS_I2C;
    input_dev->dev.parent = &client->dev;

    __set_bit(EV_ABS, input_dev->evbit);
    __set_bit(EV_KEY, input_dev->evbit);
    __set_bit(BTN_TOUCH, input_dev->keybit);

    input_set_abs_params(input_dev, ABS_X, 0, EGALAX_MAX_X, 0, 0);
    input_set_abs_params(input_dev, ABS_Y, 0, EGALAX_MAX_Y, 0, 0);
    input_set_abs_params(input_dev,
                 ABS_MT_POSITION_X, 0, EGALAX_MAX_X, 0, 0);
    input_set_abs_params(input_dev,
                 ABS_MT_POSITION_X, 0, EGALAX_MAX_Y, 0, 0);
    input_mt_init_slots(input_dev, MAX_SUPPORT_POINTS, 0);

    input_set_drvdata(input_dev, ts);

    error = request_threaded_irq(client->irq, NULL, egalax_ts_interrupt,
                     IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                     "egalax_ts", ts);
    if (error < 0) {
        dev_err(&client->dev, "Failed to register interrupt\n");
        goto err_free_dev;
    }

    error = input_register_device(ts->input_dev);
    if (error)
        goto err_free_irq;

    i2c_set_clientdata(client, ts);
    return 0;

err_free_irq:
    free_irq(client->irq, ts);
err_free_dev:
    input_free_device(input_dev);
err_free_ts:
    kfree(ts);

    return error;
}

static __devexit int egalax_ts_remove(struct i2c_client *client)
{
    struct egalax_ts *ts = i2c_get_clientdata(client);

    free_irq(client->irq, ts);

    input_unregister_device(ts->input_dev);
    kfree(ts);

    return 0;
}

static const struct i2c_device_id egalax_ts_id[] = {
    { "egalax_ts", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, egalax_ts_id);

#ifdef CONFIG_PM_SLEEP
static int egalax_ts_suspend(struct device *dev)
{
    static const u8 suspend_cmd[MAX_I2C_DATA_LEN] = {
        0x3, 0x6, 0xa, 0x3, 0x36, 0x3f, 0x2, 0, 0, 0
    };
    struct i2c_client *client = to_i2c_client(dev);
    int ret;

    ret = i2c_master_send(client, suspend_cmd, MAX_I2C_DATA_LEN);
    return ret > 0 ? 0 : ret;
}

static int egalax_ts_resume(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);

    return egalax_wake_up_device(client);
}
#endif

static SIMPLE_DEV_PM_OPS(egalax_ts_pm_ops, egalax_ts_suspend, egalax_ts_resume);

static struct of_device_id egalax_ts_dt_ids[] = {
    { .compatible = "eeti,egalax_ts" },
    { /* sentinel */ }
};

static struct i2c_driver egalax_ts_driver = {
    .driver = {
        .name   = "egalax_ts",
        .owner  = THIS_MODULE,
        .pm = &egalax_ts_pm_ops,
        .of_match_table = of_match_ptr(egalax_ts_dt_ids),
    },
    .id_table   = egalax_ts_id,
    .probe      = egalax_ts_probe,
    .remove     = __devexit_p(egalax_ts_remove),
};

module_i2c_driver(egalax_ts_driver);

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("Touchscreen driver for EETI eGalax touch controller");
MODULE_LICENSE("GPL");