kxtj9.c

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/*
 * Copyright (C) 2011 Kionix, Inc.
 * Written by Chris Hudson <[email protected]>
 *
 * 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.
 *
 * 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
 */

#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input/kxtj9.h>
#include <linux/input-polldev.h>

#define NAME            "kxtj9"
#define G_MAX           8000
/* OUTPUT REGISTERS */
#define XOUT_L          0x06
#define WHO_AM_I        0x0F
/* CONTROL REGISTERS */
#define INT_REL         0x1A
#define CTRL_REG1       0x1B
#define INT_CTRL1       0x1E
#define DATA_CTRL       0x21
/* CONTROL REGISTER 1 BITS */
#define PC1_OFF         0x7F
#define PC1_ON          (1 << 7)
/* Data ready funtion enable bit: set during probe if using irq mode */
#define DRDYE           (1 << 5)
/* DATA CONTROL REGISTER BITS */
#define ODR12_5F        0
#define ODR25F          1
#define ODR50F          2
#define ODR100F     3
#define ODR200F     4
#define ODR400F     5
#define ODR800F     6
/* INTERRUPT CONTROL REGISTER 1 BITS */
/* Set these during probe if using irq mode */
#define KXTJ9_IEL       (1 << 3)
#define KXTJ9_IEA       (1 << 4)
#define KXTJ9_IEN       (1 << 5)
/* INPUT_ABS CONSTANTS */
#define FUZZ            3
#define FLAT            3
/* RESUME STATE INDICES */
#define RES_DATA_CTRL       0
#define RES_CTRL_REG1       1
#define RES_INT_CTRL1       2
#define RESUME_ENTRIES      3

/*
 * The following table lists the maximum appropriate poll interval for each
 * available output data rate.
 */
static const struct {
    unsigned int cutoff;
    u8 mask;
} kxtj9_odr_table[] = {
    { 3,    ODR800F },
    { 5,    ODR400F },
    { 10,   ODR200F },
    { 20,   ODR100F },
    { 40,   ODR50F  },
    { 80,   ODR25F  },
    { 0,    ODR12_5F},
};

struct kxtj9_data {
    struct i2c_client *client;
    struct kxtj9_platform_data pdata;
    struct input_dev *input_dev;
#ifdef CONFIG_INPUT_KXTJ9_POLLED_MODE
    struct input_polled_dev *poll_dev;
#endif
    unsigned int last_poll_interval;
    u8 shift;
    u8 ctrl_reg1;
    u8 data_ctrl;
    u8 int_ctrl;
};

static int kxtj9_i2c_read(struct kxtj9_data *tj9, u8 addr, u8 *data, int len)
{
    struct i2c_msg msgs[] = {
        {
            .addr = tj9->client->addr,
            .flags = tj9->client->flags,
            .len = 1,
            .buf = &addr,
        },
        {
            .addr = tj9->client->addr,
            .flags = tj9->client->flags | I2C_M_RD,
            .len = len,
            .buf = data,
        },
    };

    return i2c_transfer(tj9->client->adapter, msgs, 2);
}

static void kxtj9_report_acceleration_data(struct kxtj9_data *tj9)
{
    s16 acc_data[3]; /* Data bytes from hardware xL, xH, yL, yH, zL, zH */
    s16 x, y, z;
    int err;

    err = kxtj9_i2c_read(tj9, XOUT_L, (u8 *)acc_data, 6);
    if (err < 0)
        dev_err(&tj9->client->dev, "accelerometer data read failed\n");

    x = le16_to_cpu(acc_data[tj9->pdata.axis_map_x]);
    y = le16_to_cpu(acc_data[tj9->pdata.axis_map_y]);
    z = le16_to_cpu(acc_data[tj9->pdata.axis_map_z]);

    x >>= tj9->shift;
    y >>= tj9->shift;
    z >>= tj9->shift;

    input_report_abs(tj9->input_dev, ABS_X, tj9->pdata.negate_x ? -x : x);
    input_report_abs(tj9->input_dev, ABS_Y, tj9->pdata.negate_y ? -y : y);
    input_report_abs(tj9->input_dev, ABS_Z, tj9->pdata.negate_z ? -z : z);
    input_sync(tj9->input_dev);
}

static irqreturn_t kxtj9_isr(int irq, void *dev)
{
    struct kxtj9_data *tj9 = dev;
    int err;

    /* data ready is the only possible interrupt type */
    kxtj9_report_acceleration_data(tj9);

    err = i2c_smbus_read_byte_data(tj9->client, INT_REL);
    if (err < 0)
        dev_err(&tj9->client->dev,
            "error clearing interrupt status: %d\n", err);

    return IRQ_HANDLED;
}

static int kxtj9_update_g_range(struct kxtj9_data *tj9, u8 new_g_range)
{
    switch (new_g_range) {
    case KXTJ9_G_2G:
        tj9->shift = 4;
        break;
    case KXTJ9_G_4G:
        tj9->shift = 3;
        break;
    case KXTJ9_G_8G:
        tj9->shift = 2;
        break;
    default:
        return -EINVAL;
    }

    tj9->ctrl_reg1 &= 0xe7;
    tj9->ctrl_reg1 |= new_g_range;

    return 0;
}

static int kxtj9_update_odr(struct kxtj9_data *tj9, unsigned int poll_interval)
{
    int err;
    int i;

    /* Use the lowest ODR that can support the requested poll interval */
    for (i = 0; i < ARRAY_SIZE(kxtj9_odr_table); i++) {
        tj9->data_ctrl = kxtj9_odr_table[i].mask;
        if (poll_interval < kxtj9_odr_table[i].cutoff)
            break;
    }

    err = i2c_smbus_write_byte_data(tj9->client, CTRL_REG1, 0);
    if (err < 0)
        return err;

    err = i2c_smbus_write_byte_data(tj9->client, DATA_CTRL, tj9->data_ctrl);
    if (err < 0)
        return err;

    err = i2c_smbus_write_byte_data(tj9->client, CTRL_REG1, tj9->ctrl_reg1);
    if (err < 0)
        return err;

    return 0;
}

static int kxtj9_device_power_on(struct kxtj9_data *tj9)
{
    if (tj9->pdata.power_on)
        return tj9->pdata.power_on();

    return 0;
}

static void kxtj9_device_power_off(struct kxtj9_data *tj9)
{
    int err;

    tj9->ctrl_reg1 &= PC1_OFF;
    err = i2c_smbus_write_byte_data(tj9->client, CTRL_REG1, tj9->ctrl_reg1);
    if (err < 0)
        dev_err(&tj9->client->dev, "soft power off failed\n");

    if (tj9->pdata.power_off)
        tj9->pdata.power_off();
}

static int kxtj9_enable(struct kxtj9_data *tj9)
{
    int err;

    err = kxtj9_device_power_on(tj9);
    if (err < 0)
        return err;

    /* ensure that PC1 is cleared before updating control registers */
    err = i2c_smbus_write_byte_data(tj9->client, CTRL_REG1, 0);
    if (err < 0)
        return err;

    /* only write INT_CTRL_REG1 if in irq mode */
    if (tj9->client->irq) {
        err = i2c_smbus_write_byte_data(tj9->client,
                        INT_CTRL1, tj9->int_ctrl);
        if (err < 0)
            return err;
    }

    err = kxtj9_update_g_range(tj9, tj9->pdata.g_range);
    if (err < 0)
        return err;

    /* turn on outputs */
    tj9->ctrl_reg1 |= PC1_ON;
    err = i2c_smbus_write_byte_data(tj9->client, CTRL_REG1, tj9->ctrl_reg1);
    if (err < 0)
        return err;

    err = kxtj9_update_odr(tj9, tj9->last_poll_interval);
    if (err < 0)
        return err;

    /* clear initial interrupt if in irq mode */
    if (tj9->client->irq) {
        err = i2c_smbus_read_byte_data(tj9->client, INT_REL);
        if (err < 0) {
            dev_err(&tj9->client->dev,
                "error clearing interrupt: %d\n", err);
            goto fail;
        }
    }

    return 0;

fail:
    kxtj9_device_power_off(tj9);
    return err;
}

static void kxtj9_disable(struct kxtj9_data *tj9)
{
    kxtj9_device_power_off(tj9);
}

static int kxtj9_input_open(struct input_dev *input)
{
    struct kxtj9_data *tj9 = input_get_drvdata(input);

    return kxtj9_enable(tj9);
}

static void kxtj9_input_close(struct input_dev *dev)
{
    struct kxtj9_data *tj9 = input_get_drvdata(dev);

    kxtj9_disable(tj9);
}

static void __devinit kxtj9_init_input_device(struct kxtj9_data *tj9,
                          struct input_dev *input_dev)
{
    __set_bit(EV_ABS, input_dev->evbit);
    input_set_abs_params(input_dev, ABS_X, -G_MAX, G_MAX, FUZZ, FLAT);
    input_set_abs_params(input_dev, ABS_Y, -G_MAX, G_MAX, FUZZ, FLAT);
    input_set_abs_params(input_dev, ABS_Z, -G_MAX, G_MAX, FUZZ, FLAT);

    input_dev->name = "kxtj9_accel";
    input_dev->id.bustype = BUS_I2C;
    input_dev->dev.parent = &tj9->client->dev;
}

static int __devinit kxtj9_setup_input_device(struct kxtj9_data *tj9)
{
    struct input_dev *input_dev;
    int err;

    input_dev = input_allocate_device();
    if (!input_dev) {
        dev_err(&tj9->client->dev, "input device allocate failed\n");
        return -ENOMEM;
    }

    tj9->input_dev = input_dev;

    input_dev->open = kxtj9_input_open;
    input_dev->close = kxtj9_input_close;
    input_set_drvdata(input_dev, tj9);

    kxtj9_init_input_device(tj9, input_dev);

    err = input_register_device(tj9->input_dev);
    if (err) {
        dev_err(&tj9->client->dev,
            "unable to register input polled device %s: %d\n",
            tj9->input_dev->name, err);
        input_free_device(tj9->input_dev);
        return err;
    }

    return 0;
}

/*
 * When IRQ mode is selected, we need to provide an interface to allow the user
 * to change the output data rate of the part.  For consistency, we are using
 * the set_poll method, which accepts a poll interval in milliseconds, and then
 * calls update_odr() while passing this value as an argument.  In IRQ mode, the
 * data outputs will not be read AT the requested poll interval, rather, the
 * lowest ODR that can support the requested interval.  The client application
 * will be responsible for retrieving data from the input node at the desired
 * interval.
 */

/* Returns currently selected poll interval (in ms) */
static ssize_t kxtj9_get_poll(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct kxtj9_data *tj9 = i2c_get_clientdata(client);

    return sprintf(buf, "%d\n", tj9->last_poll_interval);
}

/* Allow users to select a new poll interval (in ms) */
static ssize_t kxtj9_set_poll(struct device *dev, struct device_attribute *attr,
                        const char *buf, size_t count)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct kxtj9_data *tj9 = i2c_get_clientdata(client);
    struct input_dev *input_dev = tj9->input_dev;
    unsigned int interval;
    int error;

    error = kstrtouint(buf, 10, &interval);
    if (error < 0)
        return error;

    /* Lock the device to prevent races with open/close (and itself) */
    mutex_lock(&input_dev->mutex);

    disable_irq(client->irq);

    /*
     * Set current interval to the greater of the minimum interval or
     * the requested interval
     */
    tj9->last_poll_interval = max(interval, tj9->pdata.min_interval);

    kxtj9_update_odr(tj9, tj9->last_poll_interval);

    enable_irq(client->irq);
    mutex_unlock(&input_dev->mutex);

    return count;
}

static DEVICE_ATTR(poll, S_IRUGO|S_IWUSR, kxtj9_get_poll, kxtj9_set_poll);

static struct attribute *kxtj9_attributes[] = {
    &dev_attr_poll.attr,
    NULL
};

static struct attribute_group kxtj9_attribute_group = {
    .attrs = kxtj9_attributes
};


#ifdef CONFIG_INPUT_KXTJ9_POLLED_MODE
static void kxtj9_poll(struct input_polled_dev *dev)
{
    struct kxtj9_data *tj9 = dev->private;
    unsigned int poll_interval = dev->poll_interval;

    kxtj9_report_acceleration_data(tj9);

    if (poll_interval != tj9->last_poll_interval) {
        kxtj9_update_odr(tj9, poll_interval);
        tj9->last_poll_interval = poll_interval;
    }
}

static void kxtj9_polled_input_open(struct input_polled_dev *dev)
{
    struct kxtj9_data *tj9 = dev->private;

    kxtj9_enable(tj9);
}

static void kxtj9_polled_input_close(struct input_polled_dev *dev)
{
    struct kxtj9_data *tj9 = dev->private;

    kxtj9_disable(tj9);
}

static int __devinit kxtj9_setup_polled_device(struct kxtj9_data *tj9)
{
    int err;
    struct input_polled_dev *poll_dev;
    poll_dev = input_allocate_polled_device();

    if (!poll_dev) {
        dev_err(&tj9->client->dev,
            "Failed to allocate polled device\n");
        return -ENOMEM;
    }

    tj9->poll_dev = poll_dev;
    tj9->input_dev = poll_dev->input;

    poll_dev->private = tj9;
    poll_dev->poll = kxtj9_poll;
    poll_dev->open = kxtj9_polled_input_open;
    poll_dev->close = kxtj9_polled_input_close;

    kxtj9_init_input_device(tj9, poll_dev->input);

    err = input_register_polled_device(poll_dev);
    if (err) {
        dev_err(&tj9->client->dev,
            "Unable to register polled device, err=%d\n", err);
        input_free_polled_device(poll_dev);
        return err;
    }

    return 0;
}

static void __devexit kxtj9_teardown_polled_device(struct kxtj9_data *tj9)
{
    input_unregister_polled_device(tj9->poll_dev);
    input_free_polled_device(tj9->poll_dev);
}

#else

static inline int kxtj9_setup_polled_device(struct kxtj9_data *tj9)
{
    return -ENOSYS;
}

static inline void kxtj9_teardown_polled_device(struct kxtj9_data *tj9)
{
}

#endif

static int __devinit kxtj9_verify(struct kxtj9_data *tj9)
{
    int retval;

    retval = kxtj9_device_power_on(tj9);
    if (retval < 0)
        return retval;

    retval = i2c_smbus_read_byte_data(tj9->client, WHO_AM_I);
    if (retval < 0) {
        dev_err(&tj9->client->dev, "read err int source\n");
        goto out;
    }

    retval = (retval != 0x07 && retval != 0x08) ? -EIO : 0;

out:
    kxtj9_device_power_off(tj9);
    return retval;
}

static int __devinit kxtj9_probe(struct i2c_client *client,
                 const struct i2c_device_id *id)
{
    const struct kxtj9_platform_data *pdata = client->dev.platform_data;
    struct kxtj9_data *tj9;
    int err;

    if (!i2c_check_functionality(client->adapter,
                I2C_FUNC_I2C | I2C_FUNC_SMBUS_BYTE_DATA)) {
        dev_err(&client->dev, "client is not i2c capable\n");
        return -ENXIO;
    }

    if (!pdata) {
        dev_err(&client->dev, "platform data is NULL; exiting\n");
        return -EINVAL;
    }

    tj9 = kzalloc(sizeof(*tj9), GFP_KERNEL);
    if (!tj9) {
        dev_err(&client->dev,
            "failed to allocate memory for module data\n");
        return -ENOMEM;
    }

    tj9->client = client;
    tj9->pdata = *pdata;

    if (pdata->init) {
        err = pdata->init();
        if (err < 0)
            goto err_free_mem;
    }

    err = kxtj9_verify(tj9);
    if (err < 0) {
        dev_err(&client->dev, "device not recognized\n");
        goto err_pdata_exit;
    }

    i2c_set_clientdata(client, tj9);

    tj9->ctrl_reg1 = tj9->pdata.res_12bit | tj9->pdata.g_range;
    tj9->last_poll_interval = tj9->pdata.init_interval;

    if (client->irq) {
        /* If in irq mode, populate INT_CTRL_REG1 and enable DRDY. */
        tj9->int_ctrl |= KXTJ9_IEN | KXTJ9_IEA | KXTJ9_IEL;
        tj9->ctrl_reg1 |= DRDYE;

        err = kxtj9_setup_input_device(tj9);
        if (err)
            goto err_pdata_exit;

        err = request_threaded_irq(client->irq, NULL, kxtj9_isr,
                       IRQF_TRIGGER_RISING | IRQF_ONESHOT,
                       "kxtj9-irq", tj9);
        if (err) {
            dev_err(&client->dev, "request irq failed: %d\n", err);
            goto err_destroy_input;
        }

        err = sysfs_create_group(&client->dev.kobj, &kxtj9_attribute_group);
        if (err) {
            dev_err(&client->dev, "sysfs create failed: %d\n", err);
            goto err_free_irq;
        }

    } else {
        err = kxtj9_setup_polled_device(tj9);
        if (err)
            goto err_pdata_exit;
    }

    return 0;

err_free_irq:
    free_irq(client->irq, tj9);
err_destroy_input:
    input_unregister_device(tj9->input_dev);
err_pdata_exit:
    if (tj9->pdata.exit)
        tj9->pdata.exit();
err_free_mem:
    kfree(tj9);
    return err;
}

static int __devexit kxtj9_remove(struct i2c_client *client)
{
    struct kxtj9_data *tj9 = i2c_get_clientdata(client);

    if (client->irq) {
        sysfs_remove_group(&client->dev.kobj, &kxtj9_attribute_group);
        free_irq(client->irq, tj9);
        input_unregister_device(tj9->input_dev);
    } else {
        kxtj9_teardown_polled_device(tj9);
    }

    if (tj9->pdata.exit)
        tj9->pdata.exit();

    kfree(tj9);

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int kxtj9_suspend(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct kxtj9_data *tj9 = i2c_get_clientdata(client);
    struct input_dev *input_dev = tj9->input_dev;

    mutex_lock(&input_dev->mutex);

    if (input_dev->users)
        kxtj9_disable(tj9);

    mutex_unlock(&input_dev->mutex);
    return 0;
}

static int kxtj9_resume(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct kxtj9_data *tj9 = i2c_get_clientdata(client);
    struct input_dev *input_dev = tj9->input_dev;
    int retval = 0;

    mutex_lock(&input_dev->mutex);

    if (input_dev->users)
        kxtj9_enable(tj9);

    mutex_unlock(&input_dev->mutex);
    return retval;
}
#endif

static SIMPLE_DEV_PM_OPS(kxtj9_pm_ops, kxtj9_suspend, kxtj9_resume);

static const struct i2c_device_id kxtj9_id[] = {
    { NAME, 0 },
    { },
};

MODULE_DEVICE_TABLE(i2c, kxtj9_id);

static struct i2c_driver kxtj9_driver = {
    .driver = {
        .name   = NAME,
        .owner  = THIS_MODULE,
        .pm = &kxtj9_pm_ops,
    },
    .probe      = kxtj9_probe,
    .remove     = __devexit_p(kxtj9_remove),
    .id_table   = kxtj9_id,
};

module_i2c_driver(kxtj9_driver);

MODULE_DESCRIPTION("KXTJ9 accelerometer driver");
MODULE_AUTHOR("Chris Hudson <[email protected]>");
MODULE_LICENSE("GPL");