as5011.c

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/*
 * Copyright (c) 2010, 2011 Fabien Marteau <[email protected]>
 * Sponsored by ARMadeus Systems
 *
 * 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.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Driver for Austria Microsystems joysticks AS5011
 *
 * TODO:
 *  - Power on the chip when open() and power down when close()
 *  - Manage power mode
 */

#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/gpio.h>
#include <linux/delay.h>
#include <linux/input/as5011.h>
#include <linux/slab.h>
#include <linux/module.h>

#define DRIVER_DESC "Driver for Austria Microsystems AS5011 joystick"
#define MODULE_DEVICE_ALIAS "as5011"

MODULE_AUTHOR("Fabien Marteau <[email protected]>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/* registers */
#define AS5011_CTRL1        0x76
#define AS5011_CTRL2        0x75
#define AS5011_XP       0x43
#define AS5011_XN       0x44
#define AS5011_YP       0x53
#define AS5011_YN       0x54
#define AS5011_X_REG        0x41
#define AS5011_Y_REG        0x42
#define AS5011_X_RES_INT    0x51
#define AS5011_Y_RES_INT    0x52

/* CTRL1 bits */
#define AS5011_CTRL1_LP_PULSED      0x80
#define AS5011_CTRL1_LP_ACTIVE      0x40
#define AS5011_CTRL1_LP_CONTINUE    0x20
#define AS5011_CTRL1_INT_WUP_EN     0x10
#define AS5011_CTRL1_INT_ACT_EN     0x08
#define AS5011_CTRL1_EXT_CLK_EN     0x04
#define AS5011_CTRL1_SOFT_RST       0x02
#define AS5011_CTRL1_DATA_VALID     0x01

/* CTRL2 bits */
#define AS5011_CTRL2_EXT_SAMPLE_EN  0x08
#define AS5011_CTRL2_RC_BIAS_ON     0x04
#define AS5011_CTRL2_INV_SPINNING   0x02

#define AS5011_MAX_AXIS 80
#define AS5011_MIN_AXIS (-80)
#define AS5011_FUZZ 8
#define AS5011_FLAT 40

struct as5011_device {
    struct input_dev *input_dev;
    struct i2c_client *i2c_client;
    unsigned int button_gpio;
    unsigned int button_irq;
    unsigned int axis_irq;
};

static int as5011_i2c_write(struct i2c_client *client,
                uint8_t aregaddr,
                uint8_t avalue)
{
    uint8_t data[2] = { aregaddr, avalue };
    struct i2c_msg msg = {
        client->addr, I2C_M_IGNORE_NAK, 2, (uint8_t *)data
    };
    int error;

    error = i2c_transfer(client->adapter, &msg, 1);
    return error < 0 ? error : 0;
}

static int as5011_i2c_read(struct i2c_client *client,
               uint8_t aregaddr, signed char *value)
{
    uint8_t data[2] = { aregaddr };
    struct i2c_msg msg_set[2] = {
        { client->addr, I2C_M_REV_DIR_ADDR, 1, (uint8_t *)data },
        { client->addr, I2C_M_RD | I2C_M_NOSTART, 1, (uint8_t *)data }
    };
    int error;

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

    *value = data[0] & 0x80 ? -1 * (1 + ~data[0]) : data[0];
    return 0;
}

static irqreturn_t as5011_button_interrupt(int irq, void *dev_id)
{
    struct as5011_device *as5011 = dev_id;
    int val = gpio_get_value_cansleep(as5011->button_gpio);

    input_report_key(as5011->input_dev, BTN_JOYSTICK, !val);
    input_sync(as5011->input_dev);

    return IRQ_HANDLED;
}

static irqreturn_t as5011_axis_interrupt(int irq, void *dev_id)
{
    struct as5011_device *as5011 = dev_id;
    int error;
    signed char x, y;

    error = as5011_i2c_read(as5011->i2c_client, AS5011_X_RES_INT, &x);
    if (error < 0)
        goto out;

    error = as5011_i2c_read(as5011->i2c_client, AS5011_Y_RES_INT, &y);
    if (error < 0)
        goto out;

    input_report_abs(as5011->input_dev, ABS_X, x);
    input_report_abs(as5011->input_dev, ABS_Y, y);
    input_sync(as5011->input_dev);

out:
    return IRQ_HANDLED;
}

static int __devinit as5011_configure_chip(struct as5011_device *as5011,
                const struct as5011_platform_data *plat_dat)
{
    struct i2c_client *client = as5011->i2c_client;
    int error;
    signed char value;

    /* chip soft reset */
    error = as5011_i2c_write(client, AS5011_CTRL1,
                 AS5011_CTRL1_SOFT_RST);
    if (error < 0) {
        dev_err(&client->dev, "Soft reset failed\n");
        return error;
    }

    mdelay(10);

    error = as5011_i2c_write(client, AS5011_CTRL1,
                 AS5011_CTRL1_LP_PULSED |
                 AS5011_CTRL1_LP_ACTIVE |
                 AS5011_CTRL1_INT_ACT_EN);
    if (error < 0) {
        dev_err(&client->dev, "Power config failed\n");
        return error;
    }

    error = as5011_i2c_write(client, AS5011_CTRL2,
                 AS5011_CTRL2_INV_SPINNING);
    if (error < 0) {
        dev_err(&client->dev, "Can't invert spinning\n");
        return error;
    }

    /* write threshold */
    error = as5011_i2c_write(client, AS5011_XP, plat_dat->xp);
    if (error < 0) {
        dev_err(&client->dev, "Can't write threshold\n");
        return error;
    }

    error = as5011_i2c_write(client, AS5011_XN, plat_dat->xn);
    if (error < 0) {
        dev_err(&client->dev, "Can't write threshold\n");
        return error;
    }

    error = as5011_i2c_write(client, AS5011_YP, plat_dat->yp);
    if (error < 0) {
        dev_err(&client->dev, "Can't write threshold\n");
        return error;
    }

    error = as5011_i2c_write(client, AS5011_YN, plat_dat->yn);
    if (error < 0) {
        dev_err(&client->dev, "Can't write threshold\n");
        return error;
    }

    /* to free irq gpio in chip */
    error = as5011_i2c_read(client, AS5011_X_RES_INT, &value);
    if (error < 0) {
        dev_err(&client->dev, "Can't read i2c X resolution value\n");
        return error;
    }

    return 0;
}

static int __devinit as5011_probe(struct i2c_client *client,
                const struct i2c_device_id *id)
{
    const struct as5011_platform_data *plat_data;
    struct as5011_device *as5011;
    struct input_dev *input_dev;
    int irq;
    int error;

    plat_data = client->dev.platform_data;
    if (!plat_data)
        return -EINVAL;

    if (!plat_data->axis_irq) {
        dev_err(&client->dev, "No axis IRQ?\n");
        return -EINVAL;
    }

    if (!i2c_check_functionality(client->adapter,
                     I2C_FUNC_NOSTART |
                     I2C_FUNC_PROTOCOL_MANGLING)) {
        dev_err(&client->dev,
            "need i2c bus that supports protocol mangling\n");
        return -ENODEV;
    }

    as5011 = kmalloc(sizeof(struct as5011_device), GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!as5011 || !input_dev) {
        dev_err(&client->dev,
            "Can't allocate memory for device structure\n");
        error = -ENOMEM;
        goto err_free_mem;
    }

    as5011->i2c_client = client;
    as5011->input_dev = input_dev;
    as5011->button_gpio = plat_data->button_gpio;
    as5011->axis_irq = plat_data->axis_irq;

    input_dev->name = "Austria Microsystem as5011 joystick";
    input_dev->id.bustype = BUS_I2C;
    input_dev->dev.parent = &client->dev;

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

    input_set_abs_params(input_dev, ABS_X,
        AS5011_MIN_AXIS, AS5011_MAX_AXIS, AS5011_FUZZ, AS5011_FLAT);
    input_set_abs_params(as5011->input_dev, ABS_Y,
        AS5011_MIN_AXIS, AS5011_MAX_AXIS, AS5011_FUZZ, AS5011_FLAT);

    error = gpio_request(as5011->button_gpio, "AS5011 button");
    if (error < 0) {
        dev_err(&client->dev, "Failed to request button gpio\n");
        goto err_free_mem;
    }

    irq = gpio_to_irq(as5011->button_gpio);
    if (irq < 0) {
        dev_err(&client->dev,
            "Failed to get irq number for button gpio\n");
        goto err_free_button_gpio;
    }

    as5011->button_irq = irq;

    error = request_threaded_irq(as5011->button_irq,
                     NULL, as5011_button_interrupt,
                     IRQF_TRIGGER_RISING |
                    IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                     "as5011_button", as5011);
    if (error < 0) {
        dev_err(&client->dev,
            "Can't allocate button irq %d\n", as5011->button_irq);
        goto err_free_button_gpio;
    }

    error = as5011_configure_chip(as5011, plat_data);
    if (error)
        goto err_free_button_irq;

    error = request_threaded_irq(as5011->axis_irq, NULL,
                     as5011_axis_interrupt,
                     plat_data->axis_irqflags | IRQF_ONESHOT,
                     "as5011_joystick", as5011);
    if (error) {
        dev_err(&client->dev,
            "Can't allocate axis irq %d\n", plat_data->axis_irq);
        goto err_free_button_irq;
    }

    error = input_register_device(as5011->input_dev);
    if (error) {
        dev_err(&client->dev, "Failed to register input device\n");
        goto err_free_axis_irq;
    }

    i2c_set_clientdata(client, as5011);

    return 0;

err_free_axis_irq:
    free_irq(as5011->axis_irq, as5011);
err_free_button_irq:
    free_irq(as5011->button_irq, as5011);
err_free_button_gpio:
    gpio_free(as5011->button_gpio);
err_free_mem:
    input_free_device(input_dev);
    kfree(as5011);

    return error;
}

static int __devexit as5011_remove(struct i2c_client *client)
{
    struct as5011_device *as5011 = i2c_get_clientdata(client);

    free_irq(as5011->axis_irq, as5011);
    free_irq(as5011->button_irq, as5011);
    gpio_free(as5011->button_gpio);

    input_unregister_device(as5011->input_dev);
    kfree(as5011);

    return 0;
}

static const struct i2c_device_id as5011_id[] = {
    { MODULE_DEVICE_ALIAS, 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, as5011_id);

static struct i2c_driver as5011_driver = {
    .driver = {
        .name = "as5011",
    },
    .probe      = as5011_probe,
    .remove     = __devexit_p(as5011_remove),
    .id_table   = as5011_id,
};

module_i2c_driver(as5011_driver);