matrix_keypad.c

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/*
 *  GPIO driven matrix keyboard driver
 *
 *  Copyright (c) 2008 Marek Vasut <[email protected]>
 *
 *  Based on corgikbd.c
 *
 *  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/delay.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/input/matrix_keypad.h>
#include <linux/slab.h>

struct matrix_keypad {
    const struct matrix_keypad_platform_data *pdata;
    struct input_dev *input_dev;
    unsigned int row_shift;

    DECLARE_BITMAP(disabled_gpios, MATRIX_MAX_ROWS);

    uint32_t last_key_state[MATRIX_MAX_COLS];
    struct delayed_work work;
    spinlock_t lock;
    bool scan_pending;
    bool stopped;
    bool gpio_all_disabled;

    unsigned short keycodes[];
};

/*
 * NOTE: normally the GPIO has to be put into HiZ when de-activated to cause
 * minmal side effect when scanning other columns, here it is configured to
 * be input, and it should work on most platforms.
 */
static void __activate_col(const struct matrix_keypad_platform_data *pdata,
               int col, bool on)
{
    bool level_on = !pdata->active_low;

    if (on) {
        gpio_direction_output(pdata->col_gpios[col], level_on);
    } else {
        gpio_set_value_cansleep(pdata->col_gpios[col], !level_on);
        gpio_direction_input(pdata->col_gpios[col]);
    }
}

static void activate_col(const struct matrix_keypad_platform_data *pdata,
             int col, bool on)
{
    __activate_col(pdata, col, on);

    if (on && pdata->col_scan_delay_us)
        udelay(pdata->col_scan_delay_us);
}

static void activate_all_cols(const struct matrix_keypad_platform_data *pdata,
                  bool on)
{
    int col;

    for (col = 0; col < pdata->num_col_gpios; col++)
        __activate_col(pdata, col, on);
}

static bool row_asserted(const struct matrix_keypad_platform_data *pdata,
             int row)
{
    return gpio_get_value_cansleep(pdata->row_gpios[row]) ?
            !pdata->active_low : pdata->active_low;
}

static void enable_row_irqs(struct matrix_keypad *keypad)
{
    const struct matrix_keypad_platform_data *pdata = keypad->pdata;
    int i;

    if (pdata->clustered_irq > 0)
        enable_irq(pdata->clustered_irq);
    else {
        for (i = 0; i < pdata->num_row_gpios; i++)
            enable_irq(gpio_to_irq(pdata->row_gpios[i]));
    }
}

static void disable_row_irqs(struct matrix_keypad *keypad)
{
    const struct matrix_keypad_platform_data *pdata = keypad->pdata;
    int i;

    if (pdata->clustered_irq > 0)
        disable_irq_nosync(pdata->clustered_irq);
    else {
        for (i = 0; i < pdata->num_row_gpios; i++)
            disable_irq_nosync(gpio_to_irq(pdata->row_gpios[i]));
    }
}

/*
 * This gets the keys from keyboard and reports it to input subsystem
 */
static void matrix_keypad_scan(struct work_struct *work)
{
    struct matrix_keypad *keypad =
        container_of(work, struct matrix_keypad, work.work);
    struct input_dev *input_dev = keypad->input_dev;
    const struct matrix_keypad_platform_data *pdata = keypad->pdata;
    uint32_t new_state[MATRIX_MAX_COLS];
    int row, col, code;

    /* de-activate all columns for scanning */
    activate_all_cols(pdata, false);

    memset(new_state, 0, sizeof(new_state));

    /* assert each column and read the row status out */
    for (col = 0; col < pdata->num_col_gpios; col++) {

        activate_col(pdata, col, true);

        for (row = 0; row < pdata->num_row_gpios; row++)
            new_state[col] |=
                row_asserted(pdata, row) ? (1 << row) : 0;

        activate_col(pdata, col, false);
    }

    for (col = 0; col < pdata->num_col_gpios; col++) {
        uint32_t bits_changed;

        bits_changed = keypad->last_key_state[col] ^ new_state[col];
        if (bits_changed == 0)
            continue;

        for (row = 0; row < pdata->num_row_gpios; row++) {
            if ((bits_changed & (1 << row)) == 0)
                continue;

            code = MATRIX_SCAN_CODE(row, col, keypad->row_shift);
            input_event(input_dev, EV_MSC, MSC_SCAN, code);
            input_report_key(input_dev,
                     keypad->keycodes[code],
                     new_state[col] & (1 << row));
        }
    }
    input_sync(input_dev);

    memcpy(keypad->last_key_state, new_state, sizeof(new_state));

    activate_all_cols(pdata, true);

    /* Enable IRQs again */
    spin_lock_irq(&keypad->lock);
    keypad->scan_pending = false;
    enable_row_irqs(keypad);
    spin_unlock_irq(&keypad->lock);
}

static irqreturn_t matrix_keypad_interrupt(int irq, void *id)
{
    struct matrix_keypad *keypad = id;
    unsigned long flags;

    spin_lock_irqsave(&keypad->lock, flags);

    /*
     * See if another IRQ beaten us to it and scheduled the
     * scan already. In that case we should not try to
     * disable IRQs again.
     */
    if (unlikely(keypad->scan_pending || keypad->stopped))
        goto out;

    disable_row_irqs(keypad);
    keypad->scan_pending = true;
    schedule_delayed_work(&keypad->work,
        msecs_to_jiffies(keypad->pdata->debounce_ms));

out:
    spin_unlock_irqrestore(&keypad->lock, flags);
    return IRQ_HANDLED;
}

static int matrix_keypad_start(struct input_dev *dev)
{
    struct matrix_keypad *keypad = input_get_drvdata(dev);

    keypad->stopped = false;
    mb();

    /*
     * Schedule an immediate key scan to capture current key state;
     * columns will be activated and IRQs be enabled after the scan.
     */
    schedule_delayed_work(&keypad->work, 0);

    return 0;
}

static void matrix_keypad_stop(struct input_dev *dev)
{
    struct matrix_keypad *keypad = input_get_drvdata(dev);

    keypad->stopped = true;
    mb();
    flush_work(&keypad->work.work);
    /*
     * matrix_keypad_scan() will leave IRQs enabled;
     * we should disable them now.
     */
    disable_row_irqs(keypad);
}

#ifdef CONFIG_PM_SLEEP
static void matrix_keypad_enable_wakeup(struct matrix_keypad *keypad)
{
    const struct matrix_keypad_platform_data *pdata = keypad->pdata;
    unsigned int gpio;
    int i;

    if (pdata->clustered_irq > 0) {
        if (enable_irq_wake(pdata->clustered_irq) == 0)
            keypad->gpio_all_disabled = true;
    } else {

        for (i = 0; i < pdata->num_row_gpios; i++) {
            if (!test_bit(i, keypad->disabled_gpios)) {
                gpio = pdata->row_gpios[i];

                if (enable_irq_wake(gpio_to_irq(gpio)) == 0)
                    __set_bit(i, keypad->disabled_gpios);
            }
        }
    }
}

static void matrix_keypad_disable_wakeup(struct matrix_keypad *keypad)
{
    const struct matrix_keypad_platform_data *pdata = keypad->pdata;
    unsigned int gpio;
    int i;

    if (pdata->clustered_irq > 0) {
        if (keypad->gpio_all_disabled) {
            disable_irq_wake(pdata->clustered_irq);
            keypad->gpio_all_disabled = false;
        }
    } else {
        for (i = 0; i < pdata->num_row_gpios; i++) {
            if (test_and_clear_bit(i, keypad->disabled_gpios)) {
                gpio = pdata->row_gpios[i];
                disable_irq_wake(gpio_to_irq(gpio));
            }
        }
    }
}

static int matrix_keypad_suspend(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct matrix_keypad *keypad = platform_get_drvdata(pdev);

    matrix_keypad_stop(keypad->input_dev);

    if (device_may_wakeup(&pdev->dev))
        matrix_keypad_enable_wakeup(keypad);

    return 0;
}

static int matrix_keypad_resume(struct device *dev)
{
    struct platform_device *pdev = to_platform_device(dev);
    struct matrix_keypad *keypad = platform_get_drvdata(pdev);

    if (device_may_wakeup(&pdev->dev))
        matrix_keypad_disable_wakeup(keypad);

    matrix_keypad_start(keypad->input_dev);

    return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(matrix_keypad_pm_ops,
             matrix_keypad_suspend, matrix_keypad_resume);

static int __devinit matrix_keypad_init_gpio(struct platform_device *pdev,
                         struct matrix_keypad *keypad)
{
    const struct matrix_keypad_platform_data *pdata = keypad->pdata;
    int i, err;

    /* initialized strobe lines as outputs, activated */
    for (i = 0; i < pdata->num_col_gpios; i++) {
        err = gpio_request(pdata->col_gpios[i], "matrix_kbd_col");
        if (err) {
            dev_err(&pdev->dev,
                "failed to request GPIO%d for COL%d\n",
                pdata->col_gpios[i], i);
            goto err_free_cols;
        }

        gpio_direction_output(pdata->col_gpios[i], !pdata->active_low);
    }

    for (i = 0; i < pdata->num_row_gpios; i++) {
        err = gpio_request(pdata->row_gpios[i], "matrix_kbd_row");
        if (err) {
            dev_err(&pdev->dev,
                "failed to request GPIO%d for ROW%d\n",
                pdata->row_gpios[i], i);
            goto err_free_rows;
        }

        gpio_direction_input(pdata->row_gpios[i]);
    }

    if (pdata->clustered_irq > 0) {
        err = request_irq(pdata->clustered_irq,
                matrix_keypad_interrupt,
                pdata->clustered_irq_flags,
                "matrix-keypad", keypad);
        if (err) {
            dev_err(&pdev->dev,
                "Unable to acquire clustered interrupt\n");
            goto err_free_rows;
        }
    } else {
        for (i = 0; i < pdata->num_row_gpios; i++) {
            err = request_irq(gpio_to_irq(pdata->row_gpios[i]),
                    matrix_keypad_interrupt,
                    IRQF_TRIGGER_RISING |
                    IRQF_TRIGGER_FALLING,
                    "matrix-keypad", keypad);
            if (err) {
                dev_err(&pdev->dev,
                    "Unable to acquire interrupt for GPIO line %i\n",
                    pdata->row_gpios[i]);
                goto err_free_irqs;
            }
        }
    }

    /* initialized as disabled - enabled by input->open */
    disable_row_irqs(keypad);
    return 0;

err_free_irqs:
    while (--i >= 0)
        free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
    i = pdata->num_row_gpios;
err_free_rows:
    while (--i >= 0)
        gpio_free(pdata->row_gpios[i]);
    i = pdata->num_col_gpios;
err_free_cols:
    while (--i >= 0)
        gpio_free(pdata->col_gpios[i]);

    return err;
}

static void matrix_keypad_free_gpio(struct matrix_keypad *keypad)
{
    const struct matrix_keypad_platform_data *pdata = keypad->pdata;
    int i;

    if (pdata->clustered_irq > 0) {
        free_irq(pdata->clustered_irq, keypad);
    } else {
        for (i = 0; i < pdata->num_row_gpios; i++)
            free_irq(gpio_to_irq(pdata->row_gpios[i]), keypad);
    }

    for (i = 0; i < pdata->num_row_gpios; i++)
        gpio_free(pdata->row_gpios[i]);

    for (i = 0; i < pdata->num_col_gpios; i++)
        gpio_free(pdata->col_gpios[i]);
}

static int __devinit matrix_keypad_probe(struct platform_device *pdev)
{
    const struct matrix_keypad_platform_data *pdata;
    const struct matrix_keymap_data *keymap_data;
    struct matrix_keypad *keypad;
    struct input_dev *input_dev;
    unsigned int row_shift;
    size_t keymap_size;
    int err;

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

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

    row_shift = get_count_order(pdata->num_col_gpios);
    keymap_size = (pdata->num_row_gpios << row_shift) *
            sizeof(keypad->keycodes[0]);
    keypad = kzalloc(sizeof(struct matrix_keypad) + keymap_size,
             GFP_KERNEL);
    input_dev = input_allocate_device();
    if (!keypad || !input_dev) {
        err = -ENOMEM;
        goto err_free_mem;
    }

    keypad->input_dev = input_dev;
    keypad->pdata = pdata;
    keypad->row_shift = row_shift;
    keypad->stopped = true;
    INIT_DELAYED_WORK(&keypad->work, matrix_keypad_scan);
    spin_lock_init(&keypad->lock);

    input_dev->name     = pdev->name;
    input_dev->id.bustype   = BUS_HOST;
    input_dev->dev.parent   = &pdev->dev;
    input_dev->open     = matrix_keypad_start;
    input_dev->close    = matrix_keypad_stop;

    err = matrix_keypad_build_keymap(keymap_data, NULL,
                     pdata->num_row_gpios,
                     pdata->num_col_gpios,
                     keypad->keycodes, input_dev);
    if (err)
        goto err_free_mem;

    if (!pdata->no_autorepeat)
        __set_bit(EV_REP, input_dev->evbit);
    input_set_capability(input_dev, EV_MSC, MSC_SCAN);
    input_set_drvdata(input_dev, keypad);

    err = matrix_keypad_init_gpio(pdev, keypad);
    if (err)
        goto err_free_mem;

    err = input_register_device(keypad->input_dev);
    if (err)
        goto err_free_gpio;

    device_init_wakeup(&pdev->dev, pdata->wakeup);
    platform_set_drvdata(pdev, keypad);

    return 0;

err_free_gpio:
    matrix_keypad_free_gpio(keypad);
err_free_mem:
    input_free_device(input_dev);
    kfree(keypad);
    return err;
}

static int __devexit matrix_keypad_remove(struct platform_device *pdev)
{
    struct matrix_keypad *keypad = platform_get_drvdata(pdev);

    device_init_wakeup(&pdev->dev, 0);

    matrix_keypad_free_gpio(keypad);
    input_unregister_device(keypad->input_dev);
    kfree(keypad);

    platform_set_drvdata(pdev, NULL);

    return 0;
}

static struct platform_driver matrix_keypad_driver = {
    .probe      = matrix_keypad_probe,
    .remove     = __devexit_p(matrix_keypad_remove),
    .driver     = {
        .name   = "matrix-keypad",
        .owner  = THIS_MODULE,
        .pm = &matrix_keypad_pm_ops,
    },
};
module_platform_driver(matrix_keypad_driver);

MODULE_AUTHOR("Marek Vasut <[email protected]>");
MODULE_DESCRIPTION("GPIO Driven Matrix Keypad Driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:matrix-keypad");