matrix-keymap.c

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/*
 * Helpers for matrix keyboard bindings
 *
 * Copyright (C) 2012 Google, Inc
 *
 * Author:
 *  Olof Johansson <[email protected]>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/input.h>
#include <linux/of.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/input/matrix_keypad.h>

static bool matrix_keypad_map_key(struct input_dev *input_dev,
                  unsigned int rows, unsigned int cols,
                  unsigned int row_shift, unsigned int key)
{
    unsigned short *keymap = input_dev->keycode;
    unsigned int row = KEY_ROW(key);
    unsigned int col = KEY_COL(key);
    unsigned short code = KEY_VAL(key);

    if (row >= rows || col >= cols) {
        dev_err(input_dev->dev.parent,
            "%s: invalid keymap entry 0x%x (row: %d, col: %d, rows: %d, cols: %d)\n",
            __func__, key, row, col, rows, cols);
        return false;
    }

    keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
    __set_bit(code, input_dev->keybit);

    return true;
}

#ifdef CONFIG_OF
static int matrix_keypad_parse_of_keymap(const char *propname,
                     unsigned int rows, unsigned int cols,
                     struct input_dev *input_dev)
{
    struct device *dev = input_dev->dev.parent;
    struct device_node *np = dev->of_node;
    unsigned int row_shift = get_count_order(cols);
    unsigned int max_keys = rows << row_shift;
    unsigned int proplen, i, size;
    const __be32 *prop;

    if (!np)
        return -ENOENT;

    if (!propname)
        propname = "linux,keymap";

    prop = of_get_property(np, propname, &proplen);
    if (!prop) {
        dev_err(dev, "OF: %s property not defined in %s\n",
            propname, np->full_name);
        return -ENOENT;
    }

    if (proplen % sizeof(u32)) {
        dev_err(dev, "OF: Malformed keycode property %s in %s\n",
            propname, np->full_name);
        return -EINVAL;
    }

    size = proplen / sizeof(u32);
    if (size > max_keys) {
        dev_err(dev, "OF: %s size overflow\n", propname);
        return -EINVAL;
    }

    for (i = 0; i < size; i++) {
        unsigned int key = be32_to_cpup(prop + i);

        if (!matrix_keypad_map_key(input_dev, rows, cols,
                       row_shift, key))
            return -EINVAL;
    }

    return 0;
}
#else
static int matrix_keypad_parse_of_keymap(const char *propname,
                     unsigned int rows, unsigned int cols,
                     struct input_dev *input_dev)
{
    return -ENOSYS;
}
#endif

int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
                   const char *keymap_name,
                   unsigned int rows, unsigned int cols,
                   unsigned short *keymap,
                   struct input_dev *input_dev)
{
    unsigned int row_shift = get_count_order(cols);
    int i;
    int error;

    input_dev->keycode = keymap;
    input_dev->keycodesize = sizeof(*keymap);
    input_dev->keycodemax = rows << row_shift;

    __set_bit(EV_KEY, input_dev->evbit);

    if (keymap_data) {
        for (i = 0; i < keymap_data->keymap_size; i++) {
            unsigned int key = keymap_data->keymap[i];

            if (!matrix_keypad_map_key(input_dev, rows, cols,
                           row_shift, key))
                return -EINVAL;
        }
    } else {
        error = matrix_keypad_parse_of_keymap(keymap_name, rows, cols,
                              input_dev);
        if (error)
            return error;
    }

    __clear_bit(KEY_RESERVED, input_dev->keybit);

    return 0;
}
EXPORT_SYMBOL(matrix_keypad_build_keymap);

MODULE_LICENSE("GPL");