st1232.c

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/*
 * ST1232 Touchscreen Controller Driver
 *
 * Copyright (C) 2010 Renesas Solutions Corp.
 *  Tony SIM <[email protected]>
 *
 * Using code from:
 *  - android.git.kernel.org: projects/kernel/common.git: synaptics_i2c_rmi.c
 *  Copyright (C) 2007 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/pm_qos.h>
#include <linux/slab.h>
#include <linux/types.h>

#define ST1232_TS_NAME  "st1232-ts"

#define MIN_X       0x00
#define MIN_Y       0x00
#define MAX_X       0x31f   /* (800 - 1) */
#define MAX_Y       0x1df   /* (480 - 1) */
#define MAX_AREA    0xff
#define MAX_FINGERS 2

struct st1232_ts_finger {
    u16 x;
    u16 y;
    u8 t;
    bool is_valid;
};

struct st1232_ts_data {
    struct i2c_client *client;
    struct input_dev *input_dev;
    struct st1232_ts_finger finger[MAX_FINGERS];
    struct dev_pm_qos_request low_latency_req;
};

static int st1232_ts_read_data(struct st1232_ts_data *ts)
{
    struct st1232_ts_finger *finger = ts->finger;
    struct i2c_client *client = ts->client;
    struct i2c_msg msg[2];
    int error;
    u8 start_reg;
    u8 buf[10];

    /* read touchscreen data from ST1232 */
    msg[0].addr = client->addr;
    msg[0].flags = 0;
    msg[0].len = 1;
    msg[0].buf = &start_reg;
    start_reg = 0x10;

    msg[1].addr = ts->client->addr;
    msg[1].flags = I2C_M_RD;
    msg[1].len = sizeof(buf);
    msg[1].buf = buf;

    error = i2c_transfer(client->adapter, msg, 2);
    if (error < 0)
        return error;

    /* get "valid" bits */
    finger[0].is_valid = buf[2] >> 7;
    finger[1].is_valid = buf[5] >> 7;

    /* get xy coordinate */
    if (finger[0].is_valid) {
        finger[0].x = ((buf[2] & 0x0070) << 4) | buf[3];
        finger[0].y = ((buf[2] & 0x0007) << 8) | buf[4];
        finger[0].t = buf[8];
    }

    if (finger[1].is_valid) {
        finger[1].x = ((buf[5] & 0x0070) << 4) | buf[6];
        finger[1].y = ((buf[5] & 0x0007) << 8) | buf[7];
        finger[1].t = buf[9];
    }

    return 0;
}

static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
{
    struct st1232_ts_data *ts = dev_id;
    struct st1232_ts_finger *finger = ts->finger;
    struct input_dev *input_dev = ts->input_dev;
    int count = 0;
    int i, ret;

    ret = st1232_ts_read_data(ts);
    if (ret < 0)
        goto end;

    /* multi touch protocol */
    for (i = 0; i < MAX_FINGERS; i++) {
        if (!finger[i].is_valid)
            continue;

        input_report_abs(input_dev, ABS_MT_TOUCH_MAJOR, finger[i].t);
        input_report_abs(input_dev, ABS_MT_POSITION_X, finger[i].x);
        input_report_abs(input_dev, ABS_MT_POSITION_Y, finger[i].y);
        input_mt_sync(input_dev);
        count++;
    }

    /* SYN_MT_REPORT only if no contact */
    if (!count) {
        input_mt_sync(input_dev);
        if (ts->low_latency_req.dev) {
            dev_pm_qos_remove_request(&ts->low_latency_req);
            ts->low_latency_req.dev = NULL;
        }
    } else if (!ts->low_latency_req.dev) {
        /* First contact, request 100 us latency. */
        dev_pm_qos_add_ancestor_request(&ts->client->dev,
                        &ts->low_latency_req, 100);
    }

    /* SYN_REPORT */
    input_sync(input_dev);

end:
    return IRQ_HANDLED;
}

static int __devinit st1232_ts_probe(struct i2c_client *client,
                    const struct i2c_device_id *id)
{
    struct st1232_ts_data *ts;
    struct input_dev *input_dev;
    int error;

    if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
        dev_err(&client->dev, "need I2C_FUNC_I2C\n");
        return -EIO;
    }

    if (!client->irq) {
        dev_err(&client->dev, "no IRQ?\n");
        return -EINVAL;
    }


    ts = kzalloc(sizeof(struct st1232_ts_data), GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!ts || !input_dev) {
        error = -ENOMEM;
        goto err_free_mem;
    }

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

    input_dev->name = "st1232-touchscreen";
    input_dev->id.bustype = BUS_I2C;
    input_dev->dev.parent = &client->dev;

    __set_bit(EV_SYN, input_dev->evbit);
    __set_bit(EV_KEY, input_dev->evbit);
    __set_bit(EV_ABS, input_dev->evbit);

    input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, MAX_AREA, 0, 0);
    input_set_abs_params(input_dev, ABS_MT_POSITION_X, MIN_X, MAX_X, 0, 0);
    input_set_abs_params(input_dev, ABS_MT_POSITION_Y, MIN_Y, MAX_Y, 0, 0);

    error = request_threaded_irq(client->irq, NULL, st1232_ts_irq_handler,
                     IRQF_ONESHOT, client->name, ts);
    if (error) {
        dev_err(&client->dev, "Failed to register interrupt\n");
        goto err_free_mem;
    }

    error = input_register_device(ts->input_dev);
    if (error) {
        dev_err(&client->dev, "Unable to register %s input device\n",
            input_dev->name);
        goto err_free_irq;
    }

    i2c_set_clientdata(client, ts);
    device_init_wakeup(&client->dev, 1);

    return 0;

err_free_irq:
    free_irq(client->irq, ts);
err_free_mem:
    input_free_device(input_dev);
    kfree(ts);
    return error;
}

static int __devexit st1232_ts_remove(struct i2c_client *client)
{
    struct st1232_ts_data *ts = i2c_get_clientdata(client);

    device_init_wakeup(&client->dev, 0);
    free_irq(client->irq, ts);
    input_unregister_device(ts->input_dev);
    kfree(ts);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int st1232_ts_suspend(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);

    if (device_may_wakeup(&client->dev))
        enable_irq_wake(client->irq);
    else
        disable_irq(client->irq);

    return 0;
}

static int st1232_ts_resume(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);

    if (device_may_wakeup(&client->dev))
        disable_irq_wake(client->irq);
    else
        enable_irq(client->irq);

    return 0;
}

#endif

static SIMPLE_DEV_PM_OPS(st1232_ts_pm_ops,
             st1232_ts_suspend, st1232_ts_resume);

static const struct i2c_device_id st1232_ts_id[] = {
    { ST1232_TS_NAME, 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, st1232_ts_id);

#ifdef CONFIG_OF
static const struct of_device_id st1232_ts_dt_ids[] __devinitconst = {
    { .compatible = "sitronix,st1232", },
    { }
};
MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
#endif

static struct i2c_driver st1232_ts_driver = {
    .probe      = st1232_ts_probe,
    .remove     = __devexit_p(st1232_ts_remove),
    .id_table   = st1232_ts_id,
    .driver = {
        .name   = ST1232_TS_NAME,
        .owner  = THIS_MODULE,
        .of_match_table = of_match_ptr(st1232_ts_dt_ids),
        .pm = &st1232_ts_pm_ops,
    },
};

module_i2c_driver(st1232_ts_driver);

MODULE_AUTHOR("Tony SIM <[email protected]>");
MODULE_DESCRIPTION("SITRONIX ST1232 Touchscreen Controller Driver");
MODULE_LICENSE("GPL");