synaptics_i2c.c

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/*
 * Synaptics touchpad with I2C interface
 *
 * Copyright (C) 2009 Compulab, Ltd.
 * Mike Rapoport <[email protected]>
 * Igor Grinberg <[email protected]>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive for
 * more details.
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/pm.h>

#define DRIVER_NAME     "synaptics_i2c"
/* maximum product id is 15 characters */
#define PRODUCT_ID_LENGTH   15
#define REGISTER_LENGTH     8

/*
 * after soft reset, we should wait for 1 ms
 * before the device becomes operational
 */
#define SOFT_RESET_DELAY_MS 3
/* and after hard reset, we should wait for max 500ms */
#define HARD_RESET_DELAY_MS 500

/* Registers by SMBus address */
#define PAGE_SEL_REG        0xff
#define DEVICE_STATUS_REG   0x09

/* Registers by RMI address */
#define DEV_CONTROL_REG     0x0000
#define INTERRUPT_EN_REG    0x0001
#define ERR_STAT_REG        0x0002
#define INT_REQ_STAT_REG    0x0003
#define DEV_COMMAND_REG     0x0004

#define RMI_PROT_VER_REG    0x0200
#define MANUFACT_ID_REG     0x0201
#define PHYS_INT_VER_REG    0x0202
#define PROD_PROPERTY_REG   0x0203
#define INFO_QUERY_REG0     0x0204
#define INFO_QUERY_REG1     (INFO_QUERY_REG0 + 1)
#define INFO_QUERY_REG2     (INFO_QUERY_REG0 + 2)
#define INFO_QUERY_REG3     (INFO_QUERY_REG0 + 3)

#define PRODUCT_ID_REG0     0x0210
#define PRODUCT_ID_REG1     (PRODUCT_ID_REG0 + 1)
#define PRODUCT_ID_REG2     (PRODUCT_ID_REG0 + 2)
#define PRODUCT_ID_REG3     (PRODUCT_ID_REG0 + 3)
#define PRODUCT_ID_REG4     (PRODUCT_ID_REG0 + 4)
#define PRODUCT_ID_REG5     (PRODUCT_ID_REG0 + 5)
#define PRODUCT_ID_REG6     (PRODUCT_ID_REG0 + 6)
#define PRODUCT_ID_REG7     (PRODUCT_ID_REG0 + 7)
#define PRODUCT_ID_REG8     (PRODUCT_ID_REG0 + 8)
#define PRODUCT_ID_REG9     (PRODUCT_ID_REG0 + 9)
#define PRODUCT_ID_REG10    (PRODUCT_ID_REG0 + 10)
#define PRODUCT_ID_REG11    (PRODUCT_ID_REG0 + 11)
#define PRODUCT_ID_REG12    (PRODUCT_ID_REG0 + 12)
#define PRODUCT_ID_REG13    (PRODUCT_ID_REG0 + 13)
#define PRODUCT_ID_REG14    (PRODUCT_ID_REG0 + 14)
#define PRODUCT_ID_REG15    (PRODUCT_ID_REG0 + 15)

#define DATA_REG0       0x0400
#define ABS_PRESSURE_REG    0x0401
#define ABS_MSB_X_REG       0x0402
#define ABS_LSB_X_REG       (ABS_MSB_X_REG + 1)
#define ABS_MSB_Y_REG       0x0404
#define ABS_LSB_Y_REG       (ABS_MSB_Y_REG + 1)
#define REL_X_REG       0x0406
#define REL_Y_REG       0x0407

#define DEV_QUERY_REG0      0x1000
#define DEV_QUERY_REG1      (DEV_QUERY_REG0 + 1)
#define DEV_QUERY_REG2      (DEV_QUERY_REG0 + 2)
#define DEV_QUERY_REG3      (DEV_QUERY_REG0 + 3)
#define DEV_QUERY_REG4      (DEV_QUERY_REG0 + 4)
#define DEV_QUERY_REG5      (DEV_QUERY_REG0 + 5)
#define DEV_QUERY_REG6      (DEV_QUERY_REG0 + 6)
#define DEV_QUERY_REG7      (DEV_QUERY_REG0 + 7)
#define DEV_QUERY_REG8      (DEV_QUERY_REG0 + 8)

#define GENERAL_2D_CONTROL_REG  0x1041
#define SENSOR_SENSITIVITY_REG  0x1044
#define SENS_MAX_POS_MSB_REG    0x1046
#define SENS_MAX_POS_LSB_REG    (SENS_MAX_POS_UPPER_REG + 1)

/* Register bits */
/* Device Control Register Bits */
#define REPORT_RATE_1ST_BIT 6

/* Interrupt Enable Register Bits (INTERRUPT_EN_REG) */
#define F10_ABS_INT_ENA     0
#define F10_REL_INT_ENA     1
#define F20_INT_ENA     2

/* Interrupt Request Register Bits (INT_REQ_STAT_REG | DEVICE_STATUS_REG) */
#define F10_ABS_INT_REQ     0
#define F10_REL_INT_REQ     1
#define F20_INT_REQ     2
/* Device Status Register Bits (DEVICE_STATUS_REG) */
#define STAT_CONFIGURED     6
#define STAT_ERROR      7

/* Device Command Register Bits (DEV_COMMAND_REG) */
#define RESET_COMMAND       0x01
#define REZERO_COMMAND      0x02

/* Data Register 0 Bits (DATA_REG0) */
#define GESTURE         3

/* Device Query Registers Bits */
/* DEV_QUERY_REG3 */
#define HAS_PALM_DETECT     1
#define HAS_MULTI_FING      2
#define HAS_SCROLLER        4
#define HAS_2D_SCROLL       5

/* General 2D Control Register Bits (GENERAL_2D_CONTROL_REG) */
#define NO_DECELERATION     1
#define REDUCE_REPORTING    3
#define NO_FILTER       5

/* Function Masks */
/* Device Control Register Masks (DEV_CONTROL_REG) */
#define REPORT_RATE_MSK     0xc0
#define SLEEP_MODE_MSK      0x07

/* Device Sleep Modes */
#define FULL_AWAKE      0x0
#define NORMAL_OP       0x1
#define LOW_PWR_OP      0x2
#define VERY_LOW_PWR_OP     0x3
#define SENS_SLEEP      0x4
#define SLEEP_MOD       0x5
#define DEEP_SLEEP      0x6
#define HIBERNATE       0x7

/* Interrupt Register Mask */
/* (INT_REQ_STAT_REG | DEVICE_STATUS_REG | INTERRUPT_EN_REG) */
#define INT_ENA_REQ_MSK     0x07
#define INT_ENA_ABS_MSK     0x01
#define INT_ENA_REL_MSK     0x02
#define INT_ENA_F20_MSK     0x04

/* Device Status Register Masks (DEVICE_STATUS_REG) */
#define CONFIGURED_MSK      0x40
#define ERROR_MSK       0x80

/* Data Register 0 Masks */
#define FINGER_WIDTH_MSK    0xf0
#define GESTURE_MSK     0x08
#define SENSOR_STATUS_MSK   0x07

/*
 * MSB Position Register Masks
 * ABS_MSB_X_REG | ABS_MSB_Y_REG | SENS_MAX_POS_MSB_REG |
 * DEV_QUERY_REG3 | DEV_QUERY_REG5
 */
#define MSB_POSITION_MSK    0x1f

/* Device Query Registers Masks */

/* DEV_QUERY_REG2 */
#define NUM_EXTRA_POS_MSK   0x07

/* When in IRQ mode read the device every THREAD_IRQ_SLEEP_SECS */
#define THREAD_IRQ_SLEEP_SECS   2
#define THREAD_IRQ_SLEEP_MSECS  (THREAD_IRQ_SLEEP_SECS * MSEC_PER_SEC)

/*
 * When in Polling mode and no data received for NO_DATA_THRES msecs
 * reduce the polling rate to NO_DATA_SLEEP_MSECS
 */
#define NO_DATA_THRES       (MSEC_PER_SEC)
#define NO_DATA_SLEEP_MSECS (MSEC_PER_SEC / 4)

/* Control touchpad's No Deceleration option */
static bool no_decel = 1;
module_param(no_decel, bool, 0644);
MODULE_PARM_DESC(no_decel, "No Deceleration. Default = 1 (on)");

/* Control touchpad's Reduced Reporting option */
static bool reduce_report;
module_param(reduce_report, bool, 0644);
MODULE_PARM_DESC(reduce_report, "Reduced Reporting. Default = 0 (off)");

/* Control touchpad's No Filter option */
static bool no_filter;
module_param(no_filter, bool, 0644);
MODULE_PARM_DESC(no_filter, "No Filter. Default = 0 (off)");

/*
 * touchpad Attention line is Active Low and Open Drain,
 * therefore should be connected to pulled up line
 * and the irq configuration should be set to Falling Edge Trigger
 */
/* Control IRQ / Polling option */
static bool polling_req;
module_param(polling_req, bool, 0444);
MODULE_PARM_DESC(polling_req, "Request Polling. Default = 0 (use irq)");

/* Control Polling Rate */
static int scan_rate = 80;
module_param(scan_rate, int, 0644);
MODULE_PARM_DESC(scan_rate, "Polling rate in times/sec. Default = 80");

/* The main device structure */
struct synaptics_i2c {
    struct i2c_client   *client;
    struct input_dev    *input;
    struct delayed_work dwork;
    spinlock_t      lock;
    int         no_data_count;
    int         no_decel_param;
    int         reduce_report_param;
    int         no_filter_param;
    int         scan_rate_param;
    int         scan_ms;
};

static inline void set_scan_rate(struct synaptics_i2c *touch, int scan_rate)
{
    touch->scan_ms = MSEC_PER_SEC / scan_rate;
    touch->scan_rate_param = scan_rate;
}

/*
 * Driver's initial design makes no race condition possible on i2c bus,
 * so there is no need in any locking.
 * Keep it in mind, while playing with the code.
 */
static s32 synaptics_i2c_reg_get(struct i2c_client *client, u16 reg)
{
    int ret;

    ret = i2c_smbus_write_byte_data(client, PAGE_SEL_REG, reg >> 8);
    if (ret == 0)
        ret = i2c_smbus_read_byte_data(client, reg & 0xff);

    return ret;
}

static s32 synaptics_i2c_reg_set(struct i2c_client *client, u16 reg, u8 val)
{
    int ret;

    ret = i2c_smbus_write_byte_data(client, PAGE_SEL_REG, reg >> 8);
    if (ret == 0)
        ret = i2c_smbus_write_byte_data(client, reg & 0xff, val);

    return ret;
}

static s32 synaptics_i2c_word_get(struct i2c_client *client, u16 reg)
{
    int ret;

    ret = i2c_smbus_write_byte_data(client, PAGE_SEL_REG, reg >> 8);
    if (ret == 0)
        ret = i2c_smbus_read_word_data(client, reg & 0xff);

    return ret;
}

static int synaptics_i2c_config(struct i2c_client *client)
{
    int ret, control;
    u8 int_en;

    /* set Report Rate to Device Highest (>=80) and Sleep to normal */
    ret = synaptics_i2c_reg_set(client, DEV_CONTROL_REG, 0xc1);
    if (ret)
        return ret;

    /* set Interrupt Disable to Func20 / Enable to Func10) */
    int_en = (polling_req) ? 0 : INT_ENA_ABS_MSK | INT_ENA_REL_MSK;
    ret = synaptics_i2c_reg_set(client, INTERRUPT_EN_REG, int_en);
    if (ret)
        return ret;

    control = synaptics_i2c_reg_get(client, GENERAL_2D_CONTROL_REG);
    /* No Deceleration */
    control |= no_decel ? 1 << NO_DECELERATION : 0;
    /* Reduced Reporting */
    control |= reduce_report ? 1 << REDUCE_REPORTING : 0;
    /* No Filter */
    control |= no_filter ? 1 << NO_FILTER : 0;
    ret = synaptics_i2c_reg_set(client, GENERAL_2D_CONTROL_REG, control);
    if (ret)
        return ret;

    return 0;
}

static int synaptics_i2c_reset_config(struct i2c_client *client)
{
    int ret;

    /* Reset the Touchpad */
    ret = synaptics_i2c_reg_set(client, DEV_COMMAND_REG, RESET_COMMAND);
    if (ret) {
        dev_err(&client->dev, "Unable to reset device\n");
    } else {
        msleep(SOFT_RESET_DELAY_MS);
        ret = synaptics_i2c_config(client);
        if (ret)
            dev_err(&client->dev, "Unable to config device\n");
    }

    return ret;
}

static int synaptics_i2c_check_error(struct i2c_client *client)
{
    int status, ret = 0;

    status = i2c_smbus_read_byte_data(client, DEVICE_STATUS_REG) &
        (CONFIGURED_MSK | ERROR_MSK);

    if (status != CONFIGURED_MSK)
        ret = synaptics_i2c_reset_config(client);

    return ret;
}

static bool synaptics_i2c_get_input(struct synaptics_i2c *touch)
{
    struct input_dev *input = touch->input;
    int xy_delta, gesture;
    s32 data;
    s8 x_delta, y_delta;

    /* Deal with spontanious resets and errors */
    if (synaptics_i2c_check_error(touch->client))
        return 0;

    /* Get Gesture Bit */
    data = synaptics_i2c_reg_get(touch->client, DATA_REG0);
    gesture = (data >> GESTURE) & 0x1;

    /*
     * Get Relative axes. we have to get them in one shot,
     * so we get 2 bytes starting from REL_X_REG.
     */
    xy_delta = synaptics_i2c_word_get(touch->client, REL_X_REG) & 0xffff;

    /* Separate X from Y */
    x_delta = xy_delta & 0xff;
    y_delta = (xy_delta >> REGISTER_LENGTH) & 0xff;

    /* Report the button event */
    input_report_key(input, BTN_LEFT, gesture);

    /* Report the deltas */
    input_report_rel(input, REL_X, x_delta);
    input_report_rel(input, REL_Y, -y_delta);
    input_sync(input);

    return xy_delta || gesture;
}

static void synaptics_i2c_reschedule_work(struct synaptics_i2c *touch,
                      unsigned long delay)
{
    unsigned long flags;

    spin_lock_irqsave(&touch->lock, flags);

    mod_delayed_work(system_wq, &touch->dwork, delay);

    spin_unlock_irqrestore(&touch->lock, flags);
}

static irqreturn_t synaptics_i2c_irq(int irq, void *dev_id)
{
    struct synaptics_i2c *touch = dev_id;

    synaptics_i2c_reschedule_work(touch, 0);

    return IRQ_HANDLED;
}

static void synaptics_i2c_check_params(struct synaptics_i2c *touch)
{
    bool reset = false;

    if (scan_rate != touch->scan_rate_param)
        set_scan_rate(touch, scan_rate);

    if (no_decel != touch->no_decel_param) {
        touch->no_decel_param = no_decel;
        reset = true;
    }

    if (no_filter != touch->no_filter_param) {
        touch->no_filter_param = no_filter;
        reset = true;
    }

    if (reduce_report != touch->reduce_report_param) {
        touch->reduce_report_param = reduce_report;
        reset = true;
    }

    if (reset)
        synaptics_i2c_reset_config(touch->client);
}

/* Control the Device polling rate / Work Handler sleep time */
static unsigned long synaptics_i2c_adjust_delay(struct synaptics_i2c *touch,
                        bool have_data)
{
    unsigned long delay, nodata_count_thres;

    if (polling_req) {
        delay = touch->scan_ms;
        if (have_data) {
            touch->no_data_count = 0;
        } else {
            nodata_count_thres = NO_DATA_THRES / touch->scan_ms;
            if (touch->no_data_count < nodata_count_thres)
                touch->no_data_count++;
            else
                delay = NO_DATA_SLEEP_MSECS;
        }
        return msecs_to_jiffies(delay);
    } else {
        delay = msecs_to_jiffies(THREAD_IRQ_SLEEP_MSECS);
        return round_jiffies_relative(delay);
    }
}

/* Work Handler */
static void synaptics_i2c_work_handler(struct work_struct *work)
{
    bool have_data;
    struct synaptics_i2c *touch =
            container_of(work, struct synaptics_i2c, dwork.work);
    unsigned long delay;

    synaptics_i2c_check_params(touch);

    have_data = synaptics_i2c_get_input(touch);
    delay = synaptics_i2c_adjust_delay(touch, have_data);

    /*
     * While interrupt driven, there is no real need to poll the device.
     * But touchpads are very sensitive, so there could be errors
     * related to physical environment and the attention line isn't
     * necessarily asserted. In such case we can lose the touchpad.
     * We poll the device once in THREAD_IRQ_SLEEP_SECS and
     * if error is detected, we try to reset and reconfigure the touchpad.
     */
    synaptics_i2c_reschedule_work(touch, delay);
}

static int synaptics_i2c_open(struct input_dev *input)
{
    struct synaptics_i2c *touch = input_get_drvdata(input);
    int ret;

    ret = synaptics_i2c_reset_config(touch->client);
    if (ret)
        return ret;

    if (polling_req)
        synaptics_i2c_reschedule_work(touch,
                msecs_to_jiffies(NO_DATA_SLEEP_MSECS));

    return 0;
}

static void synaptics_i2c_close(struct input_dev *input)
{
    struct synaptics_i2c *touch = input_get_drvdata(input);

    if (!polling_req)
        synaptics_i2c_reg_set(touch->client, INTERRUPT_EN_REG, 0);

    cancel_delayed_work_sync(&touch->dwork);

    /* Save some power */
    synaptics_i2c_reg_set(touch->client, DEV_CONTROL_REG, DEEP_SLEEP);
}

static void synaptics_i2c_set_input_params(struct synaptics_i2c *touch)
{
    struct input_dev *input = touch->input;

    input->name = touch->client->name;
    input->phys = touch->client->adapter->name;
    input->id.bustype = BUS_I2C;
    input->id.version = synaptics_i2c_word_get(touch->client,
                           INFO_QUERY_REG0);
    input->dev.parent = &touch->client->dev;
    input->open = synaptics_i2c_open;
    input->close = synaptics_i2c_close;
    input_set_drvdata(input, touch);

    /* Register the device as mouse */
    __set_bit(EV_REL, input->evbit);
    __set_bit(REL_X, input->relbit);
    __set_bit(REL_Y, input->relbit);

    /* Register device's buttons and keys */
    __set_bit(EV_KEY, input->evbit);
    __set_bit(BTN_LEFT, input->keybit);
}

static struct synaptics_i2c *synaptics_i2c_touch_create(struct i2c_client *client)
{
    struct synaptics_i2c *touch;

    touch = kzalloc(sizeof(struct synaptics_i2c), GFP_KERNEL);
    if (!touch)
        return NULL;

    touch->client = client;
    touch->no_decel_param = no_decel;
    touch->scan_rate_param = scan_rate;
    set_scan_rate(touch, scan_rate);
    INIT_DELAYED_WORK(&touch->dwork, synaptics_i2c_work_handler);
    spin_lock_init(&touch->lock);

    return touch;
}

static int __devinit synaptics_i2c_probe(struct i2c_client *client,
                   const struct i2c_device_id *dev_id)
{
    int ret;
    struct synaptics_i2c *touch;

    touch = synaptics_i2c_touch_create(client);
    if (!touch)
        return -ENOMEM;

    ret = synaptics_i2c_reset_config(client);
    if (ret)
        goto err_mem_free;

    if (client->irq < 1)
        polling_req = true;

    touch->input = input_allocate_device();
    if (!touch->input) {
        ret = -ENOMEM;
        goto err_mem_free;
    }

    synaptics_i2c_set_input_params(touch);

    if (!polling_req) {
        dev_dbg(&touch->client->dev,
             "Requesting IRQ: %d\n", touch->client->irq);

        ret = request_irq(touch->client->irq, synaptics_i2c_irq,
                  IRQ_TYPE_EDGE_FALLING,
                  DRIVER_NAME, touch);
        if (ret) {
            dev_warn(&touch->client->dev,
                  "IRQ request failed: %d, "
                  "falling back to polling\n", ret);
            polling_req = true;
            synaptics_i2c_reg_set(touch->client,
                          INTERRUPT_EN_REG, 0);
        }
    }

    if (polling_req)
        dev_dbg(&touch->client->dev,
             "Using polling at rate: %d times/sec\n", scan_rate);

    /* Register the device in input subsystem */
    ret = input_register_device(touch->input);
    if (ret) {
        dev_err(&client->dev,
             "Input device register failed: %d\n", ret);
        goto err_input_free;
    }

    i2c_set_clientdata(client, touch);

    return 0;

err_input_free:
    input_free_device(touch->input);
err_mem_free:
    kfree(touch);

    return ret;
}

static int __devexit synaptics_i2c_remove(struct i2c_client *client)
{
    struct synaptics_i2c *touch = i2c_get_clientdata(client);

    if (!polling_req)
        free_irq(client->irq, touch);

    input_unregister_device(touch->input);
    kfree(touch);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int synaptics_i2c_suspend(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct synaptics_i2c *touch = i2c_get_clientdata(client);

    cancel_delayed_work_sync(&touch->dwork);

    /* Save some power */
    synaptics_i2c_reg_set(touch->client, DEV_CONTROL_REG, DEEP_SLEEP);

    return 0;
}

static int synaptics_i2c_resume(struct device *dev)
{
    int ret;
    struct i2c_client *client = to_i2c_client(dev);
    struct synaptics_i2c *touch = i2c_get_clientdata(client);

    ret = synaptics_i2c_reset_config(client);
    if (ret)
        return ret;

    synaptics_i2c_reschedule_work(touch,
                msecs_to_jiffies(NO_DATA_SLEEP_MSECS));

    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(synaptics_i2c_pm, synaptics_i2c_suspend,
             synaptics_i2c_resume);

static const struct i2c_device_id synaptics_i2c_id_table[] = {
    { "synaptics_i2c", 0 },
    { },
};
MODULE_DEVICE_TABLE(i2c, synaptics_i2c_id_table);

static struct i2c_driver synaptics_i2c_driver = {
    .driver = {
        .name   = DRIVER_NAME,
        .owner  = THIS_MODULE,
        .pm = &synaptics_i2c_pm,
    },

    .probe      = synaptics_i2c_probe,
    .remove     = __devexit_p(synaptics_i2c_remove),

    .id_table   = synaptics_i2c_id_table,
};

module_i2c_driver(synaptics_i2c_driver);

MODULE_DESCRIPTION("Synaptics I2C touchpad driver");
MODULE_AUTHOR("Mike Rapoport, Igor Grinberg, Compulab");
MODULE_LICENSE("GPL");