1/*
  2 * Helpers for matrix keyboard bindings
  3 *
  4 * Copyright (C) 2012 Google, Inc
  5 *
  6 * Author:
  7 *	Olof Johansson <olof@lixom.net>
  8 *
  9 * This software is licensed under the terms of the GNU General Public
 10 * License version 2, as published by the Free Software Foundation, and
 11 * may be copied, distributed, and modified under those terms.
 12 *
 13 * This program is distributed in the hope that it will be useful,
 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 16 * GNU General Public License for more details.
 17 */
 18
 19#include <linux/device.h>
 20#include <linux/export.h>
 21#include <linux/gfp.h>
 22#include <linux/input.h>
 23#include <linux/input/matrix_keypad.h>
 24#include <linux/kernel.h>
 25#include <linux/module.h>
 26#include <linux/property.h>
 27#include <linux/slab.h>
 28#include <linux/types.h>
 29
 30static bool matrix_keypad_map_key(struct input_dev *input_dev,
 31				  unsigned int rows, unsigned int cols,
 32				  unsigned int row_shift, unsigned int key)
 33{
 34	unsigned short *keymap = input_dev->keycode;
 35	unsigned int row = KEY_ROW(key);
 36	unsigned int col = KEY_COL(key);
 37	unsigned short code = KEY_VAL(key);
 38
 39	if (row >= rows || col >= cols) {
 40		dev_err(input_dev->dev.parent,
 41			"%s: invalid keymap entry 0x%x (row: %d, col: %d, rows: %d, cols: %d)\n",
 42			__func__, key, row, col, rows, cols);
 43		return false;
 44	}
 45
 46	keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
 47	__set_bit(code, input_dev->keybit);
 48
 49	return true;
 50}
 51
 52/**
 53 * matrix_keypad_parse_properties() - Read properties of matrix keypad
 54 *
 55 * @dev: Device containing properties
 56 * @rows: Returns number of matrix rows
 57 * @cols: Returns number of matrix columns
 58 * @return 0 if OK, <0 on error
 59 */
 60int matrix_keypad_parse_properties(struct device *dev,
 61				   unsigned int *rows, unsigned int *cols)
 62{
 63	*rows = *cols = 0;
 64
 65	device_property_read_u32(dev, "keypad,num-rows", rows);
 66	device_property_read_u32(dev, "keypad,num-columns", cols);
 67
 68	if (!*rows || !*cols) {
 69		dev_err(dev, "number of keypad rows/columns not specified\n");
 70		return -EINVAL;
 71	}
 72
 73	return 0;
 74}
 75EXPORT_SYMBOL_GPL(matrix_keypad_parse_properties);
 76
 77static int matrix_keypad_parse_keymap(const char *propname,
 78				      unsigned int rows, unsigned int cols,
 79				      struct input_dev *input_dev)
 80{
 81	struct device *dev = input_dev->dev.parent;
 82	unsigned int row_shift = get_count_order(cols);
 83	unsigned int max_keys = rows << row_shift;
 84	u32 *keys;
 85	int i;
 86	int size;
 87	int retval;
 88
 89	if (!propname)
 90		propname = "linux,keymap";
 91
 92	size = device_property_read_u32_array(dev, propname, NULL, 0);
 93	if (size <= 0) {
 94		dev_err(dev, "missing or malformed property %s: %d\n",
 95			propname, size);
 96		return size < 0 ? size : -EINVAL;
 97	}
 98
 99	if (size > max_keys) {
100		dev_err(dev, "%s size overflow (%d vs max %u)\n",
101			propname, size, max_keys);
102		return -EINVAL;
103	}
104
105	keys = kmalloc_array(size, sizeof(u32), GFP_KERNEL);
106	if (!keys)
107		return -ENOMEM;
108
109	retval = device_property_read_u32_array(dev, propname, keys, size);
110	if (retval) {
111		dev_err(dev, "failed to read %s property: %d\n",
112			propname, retval);
113		goto out;
114	}
115
116	for (i = 0; i < size; i++) {
117		if (!matrix_keypad_map_key(input_dev, rows, cols,
118					   row_shift, keys[i])) {
119			retval = -EINVAL;
120			goto out;
121		}
122	}
123
124	retval = 0;
125
126out:
127	kfree(keys);
128	return retval;
129}
130
131/**
132 * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
133 * @keymap_data: keymap supplied by the platform code
134 * @keymap_name: name of device tree property containing keymap (if device
135 *	tree support is enabled).
136 * @rows: number of rows in target keymap array
137 * @cols: number of cols in target keymap array
138 * @keymap: expanded version of keymap that is suitable for use by
139 * matrix keyboard driver
140 * @input_dev: input devices for which we are setting up the keymap
141 *
142 * This function converts platform keymap (encoded with KEY() macro) into
143 * an array of keycodes that is suitable for using in a standard matrix
144 * keyboard driver that uses row and col as indices.
145 *
146 * If @keymap_data is not supplied and device tree support is enabled
147 * it will attempt load the keymap from property specified by @keymap_name
148 * argument (or "linux,keymap" if @keymap_name is %NULL).
149 *
150 * If @keymap is %NULL the function will automatically allocate managed
151 * block of memory to store the keymap. This memory will be associated with
152 * the parent device and automatically freed when device unbinds from the
153 * driver.
154 *
155 * Callers are expected to set up input_dev->dev.parent before calling this
156 * function.
157 */
158int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
159			       const char *keymap_name,
160			       unsigned int rows, unsigned int cols,
161			       unsigned short *keymap,
162			       struct input_dev *input_dev)
163{
164	unsigned int row_shift = get_count_order(cols);
165	size_t max_keys = rows << row_shift;
166	int i;
167	int error;
168
169	if (WARN_ON(!input_dev->dev.parent))
170		return -EINVAL;
171
172	if (!keymap) {
173		keymap = devm_kzalloc(input_dev->dev.parent,
174				      max_keys * sizeof(*keymap),
175				      GFP_KERNEL);
176		if (!keymap) {
177			dev_err(input_dev->dev.parent,
178				"Unable to allocate memory for keymap");
179			return -ENOMEM;
180		}
181	}
182
183	input_dev->keycode = keymap;
184	input_dev->keycodesize = sizeof(*keymap);
185	input_dev->keycodemax = max_keys;
186
187	__set_bit(EV_KEY, input_dev->evbit);
188
189	if (keymap_data) {
190		for (i = 0; i < keymap_data->keymap_size; i++) {
191			unsigned int key = keymap_data->keymap[i];
192
193			if (!matrix_keypad_map_key(input_dev, rows, cols,
194						   row_shift, key))
195				return -EINVAL;
196		}
197	} else {
198		error = matrix_keypad_parse_keymap(keymap_name, rows, cols,
199						   input_dev);
200		if (error)
201			return error;
202	}
203
204	__clear_bit(KEY_RESERVED, input_dev->keybit);
205
206	return 0;
207}
208EXPORT_SYMBOL(matrix_keypad_build_keymap);
209
210MODULE_LICENSE("GPL");