tca8418_keypad.c

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/*
 * Driver for TCA8418 I2C keyboard
 *
 * Copyright (C) 2011 Fuel7, Inc.  All rights reserved.
 *
 * Author: Kyle Manna <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License v2 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 021110-1307, USA.
 *
 * If you can't comply with GPLv2, alternative licensing terms may be
 * arranged. Please contact Fuel7, Inc. (http://fuel7.com/) for proprietary
 * alternative licensing inquiries.
 */

#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/input/tca8418_keypad.h>

/* TCA8418 hardware limits */
#define TCA8418_MAX_ROWS    8
#define TCA8418_MAX_COLS    10

/* TCA8418 register offsets */
#define REG_CFG         0x01
#define REG_INT_STAT        0x02
#define REG_KEY_LCK_EC      0x03
#define REG_KEY_EVENT_A     0x04
#define REG_KEY_EVENT_B     0x05
#define REG_KEY_EVENT_C     0x06
#define REG_KEY_EVENT_D     0x07
#define REG_KEY_EVENT_E     0x08
#define REG_KEY_EVENT_F     0x09
#define REG_KEY_EVENT_G     0x0A
#define REG_KEY_EVENT_H     0x0B
#define REG_KEY_EVENT_I     0x0C
#define REG_KEY_EVENT_J     0x0D
#define REG_KP_LCK_TIMER    0x0E
#define REG_UNLOCK1     0x0F
#define REG_UNLOCK2     0x10
#define REG_GPIO_INT_STAT1  0x11
#define REG_GPIO_INT_STAT2  0x12
#define REG_GPIO_INT_STAT3  0x13
#define REG_GPIO_DAT_STAT1  0x14
#define REG_GPIO_DAT_STAT2  0x15
#define REG_GPIO_DAT_STAT3  0x16
#define REG_GPIO_DAT_OUT1   0x17
#define REG_GPIO_DAT_OUT2   0x18
#define REG_GPIO_DAT_OUT3   0x19
#define REG_GPIO_INT_EN1    0x1A
#define REG_GPIO_INT_EN2    0x1B
#define REG_GPIO_INT_EN3    0x1C
#define REG_KP_GPIO1        0x1D
#define REG_KP_GPIO2        0x1E
#define REG_KP_GPIO3        0x1F
#define REG_GPI_EM1     0x20
#define REG_GPI_EM2     0x21
#define REG_GPI_EM3     0x22
#define REG_GPIO_DIR1       0x23
#define REG_GPIO_DIR2       0x24
#define REG_GPIO_DIR3       0x25
#define REG_GPIO_INT_LVL1   0x26
#define REG_GPIO_INT_LVL2   0x27
#define REG_GPIO_INT_LVL3   0x28
#define REG_DEBOUNCE_DIS1   0x29
#define REG_DEBOUNCE_DIS2   0x2A
#define REG_DEBOUNCE_DIS3   0x2B
#define REG_GPIO_PULL1      0x2C
#define REG_GPIO_PULL2      0x2D
#define REG_GPIO_PULL3      0x2E

/* TCA8418 bit definitions */
#define CFG_AI          BIT(7)
#define CFG_GPI_E_CFG       BIT(6)
#define CFG_OVR_FLOW_M      BIT(5)
#define CFG_INT_CFG     BIT(4)
#define CFG_OVR_FLOW_IEN    BIT(3)
#define CFG_K_LCK_IEN       BIT(2)
#define CFG_GPI_IEN     BIT(1)
#define CFG_KE_IEN      BIT(0)

#define INT_STAT_CAD_INT    BIT(4)
#define INT_STAT_OVR_FLOW_INT   BIT(3)
#define INT_STAT_K_LCK_INT  BIT(2)
#define INT_STAT_GPI_INT    BIT(1)
#define INT_STAT_K_INT      BIT(0)

/* TCA8418 register masks */
#define KEY_LCK_EC_KEC      0x7
#define KEY_EVENT_CODE      0x7f
#define KEY_EVENT_VALUE     0x80


static const struct i2c_device_id tca8418_id[] = {
    { TCA8418_NAME, 8418, },
    { }
};
MODULE_DEVICE_TABLE(i2c, tca8418_id);

struct tca8418_keypad {
    unsigned int rows;
    unsigned int cols;
    unsigned int keypad_mask; /* Mask for keypad col/rol regs */
    unsigned int irq;
    unsigned int row_shift;

    struct i2c_client *client;
    struct input_dev *input;

    /* Flexible array member, must be at end of struct */
    unsigned short keymap[];
};

/*
 * Write a byte to the TCA8418
 */
static int tca8418_write_byte(struct tca8418_keypad *keypad_data,
                  int reg, u8 val)
{
    int error;

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

    return 0;
}

/*
 * Read a byte from the TCA8418
 */
static int tca8418_read_byte(struct tca8418_keypad *keypad_data,
                 int reg, u8 *val)
{
    int error;

    error = i2c_smbus_read_byte_data(keypad_data->client, reg);
    if (error < 0) {
        dev_err(&keypad_data->client->dev,
                "%s failed, reg: %d, error: %d\n",
                __func__, reg, error);
        return error;
    }

    *val = (u8)error;

    return 0;
}

static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)
{
    int error, col, row;
    u8 reg, state, code;

    /* Initial read of the key event FIFO */
    error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);

    /* Assume that key code 0 signifies empty FIFO */
    while (error >= 0 && reg > 0) {
        state = reg & KEY_EVENT_VALUE;
        code  = reg & KEY_EVENT_CODE;

        row = code / TCA8418_MAX_COLS;
        col = code % TCA8418_MAX_COLS;

        row = (col) ? row : row - 1;
        col = (col) ? col - 1 : TCA8418_MAX_COLS - 1;

        code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);
        input_event(keypad_data->input, EV_MSC, MSC_SCAN, code);
        input_report_key(keypad_data->input,
                keypad_data->keymap[code], state);

        /* Read for next loop */
        error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
    }

    if (error < 0)
        dev_err(&keypad_data->client->dev,
            "unable to read REG_KEY_EVENT_A\n");

    input_sync(keypad_data->input);
}

/*
 * Threaded IRQ handler and this can (and will) sleep.
 */
static irqreturn_t tca8418_irq_handler(int irq, void *dev_id)
{
    struct tca8418_keypad *keypad_data = dev_id;
    u8 reg;
    int error;

    error = tca8418_read_byte(keypad_data, REG_INT_STAT, &reg);
    if (error) {
        dev_err(&keypad_data->client->dev,
            "unable to read REG_INT_STAT\n");
        goto exit;
    }

    if (reg & INT_STAT_OVR_FLOW_INT)
        dev_warn(&keypad_data->client->dev, "overflow occurred\n");

    if (reg & INT_STAT_K_INT)
        tca8418_read_keypad(keypad_data);

exit:
    /* Clear all interrupts, even IRQs we didn't check (GPI, CAD, LCK) */
    reg = 0xff;
    error = tca8418_write_byte(keypad_data, REG_INT_STAT, reg);
    if (error)
        dev_err(&keypad_data->client->dev,
            "unable to clear REG_INT_STAT\n");

    return IRQ_HANDLED;
}

/*
 * Configure the TCA8418 for keypad operation
 */
static int __devinit tca8418_configure(struct tca8418_keypad *keypad_data)
{
    int reg, error;

    /* Write config register, if this fails assume device not present */
    error = tca8418_write_byte(keypad_data, REG_CFG,
                CFG_INT_CFG | CFG_OVR_FLOW_IEN | CFG_KE_IEN);
    if (error < 0)
        return -ENODEV;


    /* Assemble a mask for row and column registers */
    reg  =  ~(~0 << keypad_data->rows);
    reg += (~(~0 << keypad_data->cols)) << 8;
    keypad_data->keypad_mask = reg;

    /* Set registers to keypad mode */
    error |= tca8418_write_byte(keypad_data, REG_KP_GPIO1, reg);
    error |= tca8418_write_byte(keypad_data, REG_KP_GPIO2, reg >> 8);
    error |= tca8418_write_byte(keypad_data, REG_KP_GPIO3, reg >> 16);

    /* Enable column debouncing */
    error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, reg);
    error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, reg >> 8);
    error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, reg >> 16);

    return error;
}

static int __devinit tca8418_keypad_probe(struct i2c_client *client,
                      const struct i2c_device_id *id)
{
    const struct tca8418_keypad_platform_data *pdata =
                        client->dev.platform_data;
    struct tca8418_keypad *keypad_data;
    struct input_dev *input;
    int error, row_shift, max_keys;

    /* Copy the platform data */
    if (!pdata) {
        dev_dbg(&client->dev, "no platform data\n");
        return -EINVAL;
    }

    if (!pdata->keymap_data) {
        dev_err(&client->dev, "no keymap data defined\n");
        return -EINVAL;
    }

    if (!pdata->rows || pdata->rows > TCA8418_MAX_ROWS) {
        dev_err(&client->dev, "invalid rows\n");
        return -EINVAL;
    }

    if (!pdata->cols || pdata->cols > TCA8418_MAX_COLS) {
        dev_err(&client->dev, "invalid columns\n");
        return -EINVAL;
    }

    /* Check i2c driver capabilities */
    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;
    }

    row_shift = get_count_order(pdata->cols);
    max_keys = pdata->rows << row_shift;

    /* Allocate memory for keypad_data, keymap and input device */
    keypad_data = kzalloc(sizeof(*keypad_data) +
            max_keys * sizeof(keypad_data->keymap[0]), GFP_KERNEL);
    if (!keypad_data)
        return -ENOMEM;

    keypad_data->rows = pdata->rows;
    keypad_data->cols = pdata->cols;
    keypad_data->client = client;
    keypad_data->row_shift = row_shift;

    /* Initialize the chip or fail if chip isn't present */
    error = tca8418_configure(keypad_data);
    if (error < 0)
        goto fail1;

    /* Configure input device */
    input = input_allocate_device();
    if (!input) {
        error = -ENOMEM;
        goto fail1;
    }
    keypad_data->input = input;

    input->name = client->name;
    input->dev.parent = &client->dev;

    input->id.bustype = BUS_I2C;
    input->id.vendor  = 0x0001;
    input->id.product = 0x001;
    input->id.version = 0x0001;

    error = matrix_keypad_build_keymap(pdata->keymap_data, NULL,
                       pdata->rows, pdata->cols,
                       keypad_data->keymap, input);
    if (error) {
        dev_dbg(&client->dev, "Failed to build keymap\n");
        goto fail2;
    }

    if (pdata->rep)
        __set_bit(EV_REP, input->evbit);
    input_set_capability(input, EV_MSC, MSC_SCAN);

    input_set_drvdata(input, keypad_data);

    if (pdata->irq_is_gpio)
        client->irq = gpio_to_irq(client->irq);

    error = request_threaded_irq(client->irq, NULL, tca8418_irq_handler,
                     IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
                     client->name, keypad_data);
    if (error) {
        dev_dbg(&client->dev,
            "Unable to claim irq %d; error %d\n",
            client->irq, error);
        goto fail2;
    }

    error = input_register_device(input);
    if (error) {
        dev_dbg(&client->dev,
            "Unable to register input device, error: %d\n", error);
        goto fail3;
    }

    i2c_set_clientdata(client, keypad_data);
    return 0;

fail3:
    free_irq(client->irq, keypad_data);
fail2:
    input_free_device(input);
fail1:
    kfree(keypad_data);
    return error;
}

static int __devexit tca8418_keypad_remove(struct i2c_client *client)
{
    struct tca8418_keypad *keypad_data = i2c_get_clientdata(client);

    free_irq(keypad_data->client->irq, keypad_data);

    input_unregister_device(keypad_data->input);

    kfree(keypad_data);

    return 0;
}


static struct i2c_driver tca8418_keypad_driver = {
    .driver = {
        .name   = TCA8418_NAME,
        .owner  = THIS_MODULE,
    },
    .probe      = tca8418_keypad_probe,
    .remove     = __devexit_p(tca8418_keypad_remove),
    .id_table   = tca8418_id,
};

static int __init tca8418_keypad_init(void)
{
    return i2c_add_driver(&tca8418_keypad_driver);
}
subsys_initcall(tca8418_keypad_init);

static void __exit tca8418_keypad_exit(void)
{
    i2c_del_driver(&tca8418_keypad_driver);
}
module_exit(tca8418_keypad_exit);

MODULE_AUTHOR("Kyle Manna <[email protected]>");
MODULE_DESCRIPTION("Keypad driver for TCA8418");
MODULE_LICENSE("GPL");