/*
 * Helpers for matrix keyboard bindings
 *
 * Copyright (C) 2012 Google, Inc
 *
 * Author:
 *	Olof Johansson <olof@lixom.net>
 *
 * 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/gfp.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

/**
 * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
 * @keymap_data: keymap supplied by the platform code
 * @keymap_name: name of device tree property containing keymap (if device
 *	tree support is enabled).
 * @rows: number of rows in target keymap array
 * @cols: number of cols in target keymap array
 * @keymap: expanded version of keymap that is suitable for use by
 * matrix keyboard driver
 * @input_dev: input devices for which we are setting up the keymap
 *
 * This function converts platform keymap (encoded with KEY() macro) into
 * an array of keycodes that is suitable for using in a standard matrix
 * keyboard driver that uses row and col as indices.
 *
 * If @keymap_data is not supplied and device tree support is enabled
 * it will attempt load the keymap from property specified by @keymap_name
 * argument (or "linux,keymap" if @keymap_name is %NULL).
 *
 * If @keymap is %NULL the function will automatically allocate managed
 * block of memory to store the keymap. This memory will be associated with
 * the parent device and automatically freed when device unbinds from the
 * driver.
 *
 * Callers are expected to set up input_dev->dev.parent before calling this
 * function.
 */
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);
	size_t max_keys = rows << row_shift;
	int i;
	int error;

	if (WARN_ON(!input_dev->dev.parent))
		return -EINVAL;

	if (!keymap) {
		keymap = devm_kzalloc(input_dev->dev.parent,
				      max_keys * sizeof(*keymap),
				      GFP_KERNEL);
		if (!keymap) {
			dev_err(input_dev->dev.parent,
				"Unable to allocate memory for keymap");
			return -ENOMEM;
		}
	}

	input_dev->keycode = keymap;
	input_dev->keycodesize = sizeof(*keymap);
	input_dev->keycodemax = max_keys;

	__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");