tca6416-keypad.c

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/*
 * Driver for keys on TCA6416 I2C IO expander
 *
 * Copyright (C) 2010 Texas Instruments
 *
 * Author : Sriramakrishnan.A.G. <[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.
 */

#include <linux/types.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/gpio.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/tca6416_keypad.h>

#define TCA6416_INPUT          0
#define TCA6416_OUTPUT         1
#define TCA6416_INVERT         2
#define TCA6416_DIRECTION      3

static const struct i2c_device_id tca6416_id[] = {
    { "tca6416-keys", 16, },
    { "tca6408-keys", 8, },
    { }
};
MODULE_DEVICE_TABLE(i2c, tca6416_id);

struct tca6416_drv_data {
    struct input_dev *input;
    struct tca6416_button data[0];
};

struct tca6416_keypad_chip {
    uint16_t reg_output;
    uint16_t reg_direction;
    uint16_t reg_input;

    struct i2c_client *client;
    struct input_dev *input;
    struct delayed_work dwork;
    int io_size;
    int irqnum;
    u16 pinmask;
    bool use_polling;
    struct tca6416_button buttons[0];
};

static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)
{
    int error;

    error = chip->io_size > 8 ?
        i2c_smbus_write_word_data(chip->client, reg << 1, val) :
        i2c_smbus_write_byte_data(chip->client, reg, val);
    if (error < 0) {
        dev_err(&chip->client->dev,
            "%s failed, reg: %d, val: %d, error: %d\n",
            __func__, reg, val, error);
        return error;
    }

    return 0;
}

static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val)
{
    int retval;

    retval = chip->io_size > 8 ?
         i2c_smbus_read_word_data(chip->client, reg << 1) :
         i2c_smbus_read_byte_data(chip->client, reg);
    if (retval < 0) {
        dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n",
            __func__, reg, retval);
        return retval;
    }

    *val = (u16)retval;
    return 0;
}

static void tca6416_keys_scan(struct tca6416_keypad_chip *chip)
{
    struct input_dev *input = chip->input;
    u16 reg_val, val;
    int error, i, pin_index;

    error = tca6416_read_reg(chip, TCA6416_INPUT, &reg_val);
    if (error)
        return;

    reg_val &= chip->pinmask;

    /* Figure out which lines have changed */
    val = reg_val ^ chip->reg_input;
    chip->reg_input = reg_val;

    for (i = 0, pin_index = 0; i < 16; i++) {
        if (val & (1 << i)) {
            struct tca6416_button *button = &chip->buttons[pin_index];
            unsigned int type = button->type ?: EV_KEY;
            int state = ((reg_val & (1 << i)) ? 1 : 0)
                        ^ button->active_low;

            input_event(input, type, button->code, !!state);
            input_sync(input);
        }

        if (chip->pinmask & (1 << i))
            pin_index++;
    }
}

/*
 * This is threaded IRQ handler and this can (and will) sleep.
 */
static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
{
    struct tca6416_keypad_chip *chip = dev_id;

    tca6416_keys_scan(chip);

    return IRQ_HANDLED;
}

static void tca6416_keys_work_func(struct work_struct *work)
{
    struct tca6416_keypad_chip *chip =
        container_of(work, struct tca6416_keypad_chip, dwork.work);

    tca6416_keys_scan(chip);
    schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100));
}

static int tca6416_keys_open(struct input_dev *dev)
{
    struct tca6416_keypad_chip *chip = input_get_drvdata(dev);

    /* Get initial device state in case it has switches */
    tca6416_keys_scan(chip);

    if (chip->use_polling)
        schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100));
    else
        enable_irq(chip->irqnum);

    return 0;
}

static void tca6416_keys_close(struct input_dev *dev)
{
    struct tca6416_keypad_chip *chip = input_get_drvdata(dev);

    if (chip->use_polling)
        cancel_delayed_work_sync(&chip->dwork);
    else
        disable_irq(chip->irqnum);
}

static int __devinit tca6416_setup_registers(struct tca6416_keypad_chip *chip)
{
    int error;

    error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
    if (error)
        return error;

    error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
    if (error)
        return error;

    /* ensure that keypad pins are set to input */
    error = tca6416_write_reg(chip, TCA6416_DIRECTION,
                  chip->reg_direction | chip->pinmask);
    if (error)
        return error;

    error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
    if (error)
        return error;

    error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
    if (error)
        return error;

    chip->reg_input &= chip->pinmask;

    return 0;
}

static int __devinit tca6416_keypad_probe(struct i2c_client *client,
                   const struct i2c_device_id *id)
{
    struct tca6416_keys_platform_data *pdata;
    struct tca6416_keypad_chip *chip;
    struct input_dev *input;
    int error;
    int i;

    /* Check functionality */
    if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
        dev_err(&client->dev, "%s adapter not supported\n",
            dev_driver_string(&client->adapter->dev));
        return -ENODEV;
    }

    pdata = client->dev.platform_data;
    if (!pdata) {
        dev_dbg(&client->dev, "no platform data\n");
        return -EINVAL;
    }

    chip = kzalloc(sizeof(struct tca6416_keypad_chip) +
               pdata->nbuttons * sizeof(struct tca6416_button),
               GFP_KERNEL);
    input = input_allocate_device();
    if (!chip || !input) {
        error = -ENOMEM;
        goto fail1;
    }

    chip->client = client;
    chip->input = input;
    chip->io_size = id->driver_data;
    chip->pinmask = pdata->pinmask;
    chip->use_polling = pdata->use_polling;

    INIT_DELAYED_WORK(&chip->dwork, tca6416_keys_work_func);

    input->phys = "tca6416-keys/input0";
    input->name = client->name;
    input->dev.parent = &client->dev;

    input->open = tca6416_keys_open;
    input->close = tca6416_keys_close;

    input->id.bustype = BUS_HOST;
    input->id.vendor = 0x0001;
    input->id.product = 0x0001;
    input->id.version = 0x0100;

    /* Enable auto repeat feature of Linux input subsystem */
    if (pdata->rep)
        __set_bit(EV_REP, input->evbit);

    for (i = 0; i < pdata->nbuttons; i++) {
        unsigned int type;

        chip->buttons[i] = pdata->buttons[i];
        type = (pdata->buttons[i].type) ?: EV_KEY;
        input_set_capability(input, type, pdata->buttons[i].code);
    }

    input_set_drvdata(input, chip);

    /*
     * Initialize cached registers from their original values.
     * we can't share this chip with another i2c master.
     */
    error = tca6416_setup_registers(chip);
    if (error)
        goto fail1;

    if (!chip->use_polling) {
        if (pdata->irq_is_gpio)
            chip->irqnum = gpio_to_irq(client->irq);
        else
            chip->irqnum = client->irq;

        error = request_threaded_irq(chip->irqnum, NULL,
                         tca6416_keys_isr,
                         IRQF_TRIGGER_FALLING |
                        IRQF_ONESHOT,
                         "tca6416-keypad", chip);
        if (error) {
            dev_dbg(&client->dev,
                "Unable to claim irq %d; error %d\n",
                chip->irqnum, error);
            goto fail1;
        }
        disable_irq(chip->irqnum);
    }

    error = input_register_device(input);
    if (error) {
        dev_dbg(&client->dev,
            "Unable to register input device, error: %d\n", error);
        goto fail2;
    }

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

    return 0;

fail2:
    if (!chip->use_polling) {
        free_irq(chip->irqnum, chip);
        enable_irq(chip->irqnum);
    }
fail1:
    input_free_device(input);
    kfree(chip);
    return error;
}

static int __devexit tca6416_keypad_remove(struct i2c_client *client)
{
    struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);

    if (!chip->use_polling) {
        free_irq(chip->irqnum, chip);
        enable_irq(chip->irqnum);
    }

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

    return 0;
}

#ifdef CONFIG_PM_SLEEP
static int tca6416_keypad_suspend(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);

    if (device_may_wakeup(dev))
        enable_irq_wake(chip->irqnum);

    return 0;
}

static int tca6416_keypad_resume(struct device *dev)
{
    struct i2c_client *client = to_i2c_client(dev);
    struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);

    if (device_may_wakeup(dev))
        disable_irq_wake(chip->irqnum);

    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(tca6416_keypad_dev_pm_ops,
             tca6416_keypad_suspend, tca6416_keypad_resume);

static struct i2c_driver tca6416_keypad_driver = {
    .driver = {
        .name   = "tca6416-keypad",
        .pm = &tca6416_keypad_dev_pm_ops,
    },
    .probe      = tca6416_keypad_probe,
    .remove     = __devexit_p(tca6416_keypad_remove),
    .id_table   = tca6416_id,
};

static int __init tca6416_keypad_init(void)
{
    return i2c_add_driver(&tca6416_keypad_driver);
}

subsys_initcall(tca6416_keypad_init);

static void __exit tca6416_keypad_exit(void)
{
    i2c_del_driver(&tca6416_keypad_driver);
}
module_exit(tca6416_keypad_exit);

MODULE_AUTHOR("Sriramakrishnan <[email protected]>");
MODULE_DESCRIPTION("Keypad driver over tca6146 IO expander");
MODULE_LICENSE("GPL");