wacom_i2c.c

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/*
 * Wacom Penabled Driver for I2C
 *
 * Copyright (c) 2011 Tatsunosuke Tobita, Wacom.
 * <[email protected]>
 *
 * 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 of 2 of the License,
 * or (at your option) any later version.
 */

#include <linux/module.h>
#include <linux/input.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <asm/unaligned.h>

#define WACOM_CMD_QUERY0    0x04
#define WACOM_CMD_QUERY1    0x00
#define WACOM_CMD_QUERY2    0x33
#define WACOM_CMD_QUERY3    0x02
#define WACOM_CMD_THROW0    0x05
#define WACOM_CMD_THROW1    0x00
#define WACOM_QUERY_SIZE    19
#define WACOM_RETRY_CNT     100

struct wacom_features {
    int x_max;
    int y_max;
    int pressure_max;
    char fw_version;
};

struct wacom_i2c {
    struct i2c_client *client;
    struct input_dev *input;
    u8 data[WACOM_QUERY_SIZE];
};

static int wacom_query_device(struct i2c_client *client,
                  struct wacom_features *features)
{
    int ret;
    u8 cmd1[] = { WACOM_CMD_QUERY0, WACOM_CMD_QUERY1,
            WACOM_CMD_QUERY2, WACOM_CMD_QUERY3 };
    u8 cmd2[] = { WACOM_CMD_THROW0, WACOM_CMD_THROW1 };
    u8 data[WACOM_QUERY_SIZE];
    struct i2c_msg msgs[] = {
        {
            .addr = client->addr,
            .flags = 0,
            .len = sizeof(cmd1),
            .buf = cmd1,
        },
        {
            .addr = client->addr,
            .flags = 0,
            .len = sizeof(cmd2),
            .buf = cmd2,
        },
        {
            .addr = client->addr,
            .flags = I2C_M_RD,
            .len = sizeof(data),
            .buf = data,
        },
    };

    ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
    if (ret < 0)
        return ret;
    if (ret != ARRAY_SIZE(msgs))
        return -EIO;

    features->x_max = get_unaligned_le16(&data[3]);
    features->y_max = get_unaligned_le16(&data[5]);
    features->pressure_max = get_unaligned_le16(&data[11]);
    features->fw_version = get_unaligned_le16(&data[13]);

    dev_dbg(&client->dev,
        "x_max:%d, y_max:%d, pressure:%d, fw:%d\n",
        features->x_max, features->y_max,
        features->pressure_max, features->fw_version);

    return 0;
}

static irqreturn_t wacom_i2c_irq(int irq, void *dev_id)
{
    struct wacom_i2c *wac_i2c = dev_id;
    struct input_dev *input = wac_i2c->input;
    u8 *data = wac_i2c->data;
    unsigned int x, y, pressure;
    unsigned char tsw, f1, f2, ers;
    int error;

    error = i2c_master_recv(wac_i2c->client,
                wac_i2c->data, sizeof(wac_i2c->data));
    if (error < 0)
        goto out;

    tsw = data[3] & 0x01;
    ers = data[3] & 0x04;
    f1 = data[3] & 0x02;
    f2 = data[3] & 0x10;
    x = le16_to_cpup((__le16 *)&data[4]);
    y = le16_to_cpup((__le16 *)&data[6]);
    pressure = le16_to_cpup((__le16 *)&data[8]);

    input_report_key(input, BTN_TOUCH, tsw || ers);
    input_report_key(input, BTN_TOOL_PEN, tsw);
    input_report_key(input, BTN_TOOL_RUBBER, ers);
    input_report_key(input, BTN_STYLUS, f1);
    input_report_key(input, BTN_STYLUS2, f2);
    input_report_abs(input, ABS_X, x);
    input_report_abs(input, ABS_Y, y);
    input_report_abs(input, ABS_PRESSURE, pressure);
    input_sync(input);

out:
    return IRQ_HANDLED;
}

static int wacom_i2c_open(struct input_dev *dev)
{
    struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
    struct i2c_client *client = wac_i2c->client;

    enable_irq(client->irq);

    return 0;
}

static void wacom_i2c_close(struct input_dev *dev)
{
    struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
    struct i2c_client *client = wac_i2c->client;

    disable_irq(client->irq);
}

static int __devinit wacom_i2c_probe(struct i2c_client *client,
                     const struct i2c_device_id *id)
{
    struct wacom_i2c *wac_i2c;
    struct input_dev *input;
    struct wacom_features features = { 0 };
    int error;

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

    error = wacom_query_device(client, &features);
    if (error)
        return error;

    wac_i2c = kzalloc(sizeof(*wac_i2c), GFP_KERNEL);
    input = input_allocate_device();
    if (!wac_i2c || !input) {
        error = -ENOMEM;
        goto err_free_mem;
    }

    wac_i2c->client = client;
    wac_i2c->input = input;

    input->name = "Wacom I2C Digitizer";
    input->id.bustype = BUS_I2C;
    input->id.vendor = 0x56a;
    input->id.version = features.fw_version;
    input->dev.parent = &client->dev;
    input->open = wacom_i2c_open;
    input->close = wacom_i2c_close;

    input->evbit[0] |= BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);

    __set_bit(BTN_TOOL_PEN, input->keybit);
    __set_bit(BTN_TOOL_RUBBER, input->keybit);
    __set_bit(BTN_STYLUS, input->keybit);
    __set_bit(BTN_STYLUS2, input->keybit);
    __set_bit(BTN_TOUCH, input->keybit);

    input_set_abs_params(input, ABS_X, 0, features.x_max, 0, 0);
    input_set_abs_params(input, ABS_Y, 0, features.y_max, 0, 0);
    input_set_abs_params(input, ABS_PRESSURE,
                 0, features.pressure_max, 0, 0);

    input_set_drvdata(input, wac_i2c);

    error = request_threaded_irq(client->irq, NULL, wacom_i2c_irq,
                     IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                     "wacom_i2c", wac_i2c);
    if (error) {
        dev_err(&client->dev,
            "Failed to enable IRQ, error: %d\n", error);
        goto err_free_mem;
    }

    /* Disable the IRQ, we'll enable it in wac_i2c_open() */
    disable_irq(client->irq);

    error = input_register_device(wac_i2c->input);
    if (error) {
        dev_err(&client->dev,
            "Failed to register input device, error: %d\n", error);
        goto err_free_irq;
    }

    i2c_set_clientdata(client, wac_i2c);
    return 0;

err_free_irq:
    free_irq(client->irq, wac_i2c);
err_free_mem:
    input_free_device(input);
    kfree(wac_i2c);

    return error;
}

static int __devexit wacom_i2c_remove(struct i2c_client *client)
{
    struct wacom_i2c *wac_i2c = i2c_get_clientdata(client);

    free_irq(client->irq, wac_i2c);
    input_unregister_device(wac_i2c->input);
    kfree(wac_i2c);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int wacom_i2c_suspend(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);

    disable_irq(client->irq);

    return 0;
}

static int wacom_i2c_resume(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);

    enable_irq(client->irq);

    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(wacom_i2c_pm, wacom_i2c_suspend, wacom_i2c_resume);

static const struct i2c_device_id wacom_i2c_id[] = {
    { "WAC_I2C_EMR", 0 },
    { },
};
MODULE_DEVICE_TABLE(i2c, wacom_i2c_id);

static struct i2c_driver wacom_i2c_driver = {
    .driver = {
        .name   = "wacom_i2c",
        .owner  = THIS_MODULE,
        .pm = &wacom_i2c_pm,
    },

    .probe      = wacom_i2c_probe,
    .remove     = __devexit_p(wacom_i2c_remove),
    .id_table   = wacom_i2c_id,
};
module_i2c_driver(wacom_i2c_driver);

MODULE_AUTHOR("Tatsunosuke Tobita <[email protected]>");
MODULE_DESCRIPTION("WACOM EMR I2C Driver");
MODULE_LICENSE("GPL");