/*
   * 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)
  ",
  			__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
  int matrix_keypad_parse_of_params(struct device *dev,
  				  unsigned int *rows, unsigned int *cols)
  {
  	struct device_node *np = dev->of_node;
  
  	if (!np) {
  		dev_err(dev, "missing DT data");
  		return -EINVAL;
  	}
  	of_property_read_u32(np, "keypad,num-rows", rows);
  	of_property_read_u32(np, "keypad,num-columns", cols);
  	if (!*rows || !*cols) {
  		dev_err(dev, "number of keypad rows/columns not specified
  ");
  		return -EINVAL;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(matrix_keypad_parse_of_params);
  
  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
  ",
  			propname, np->full_name);
  		return -ENOENT;
  	}
  
  	if (proplen % sizeof(u32)) {
  		dev_err(dev, "OF: Malformed keycode property %s in %s
  ",
  			propname, np->full_name);
  		return -EINVAL;
  	}
  
  	size = proplen / sizeof(u32);
  	if (size > max_keys) {
  		dev_err(dev, "OF: %s size overflow
  ", 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");