1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Helpers for matrix keyboard bindings
  4 *
  5 * Copyright (C) 2012 Google, Inc
  6 *
  7 * Author:
  8 *	Olof Johansson <olof@lixom.net>
  9 */
 10
 11#include <linux/device.h>
 12#include <linux/export.h>
 13#include <linux/gfp.h>
 14#include <linux/input.h>
 15#include <linux/input/matrix_keypad.h>
 16#include <linux/kernel.h>
 17#include <linux/module.h>
 18#include <linux/property.h>
 19#include <linux/slab.h>
 20#include <linux/types.h>
 21
 22static bool matrix_keypad_map_key(struct input_dev *input_dev,
 23				  unsigned int rows, unsigned int cols,
 24				  unsigned int row_shift, unsigned int key)
 25{
 26	unsigned short *keymap = input_dev->keycode;
 27	unsigned int row = KEY_ROW(key);
 28	unsigned int col = KEY_COL(key);
 29	unsigned short code = KEY_VAL(key);
 30
 31	if (row >= rows || col >= cols) {
 32		dev_err(input_dev->dev.parent,
 33			"%s: invalid keymap entry 0x%x (row: %d, col: %d, rows: %d, cols: %d)\n",
 34			__func__, key, row, col, rows, cols);
 35		return false;
 36	}
 37
 38	keymap[MATRIX_SCAN_CODE(row, col, row_shift)] = code;
 39	__set_bit(code, input_dev->keybit);
 40
 41	return true;
 42}
 43
 44/**
 45 * matrix_keypad_parse_properties() - Read properties of matrix keypad
 46 *
 47 * @dev: Device containing properties
 48 * @rows: Returns number of matrix rows
 49 * @cols: Returns number of matrix columns
 50 * @return 0 if OK, <0 on error
 51 */
 52int matrix_keypad_parse_properties(struct device *dev,
 53				   unsigned int *rows, unsigned int *cols)
 54{
 55	*rows = *cols = 0;
 56
 57	device_property_read_u32(dev, "keypad,num-rows", rows);
 58	device_property_read_u32(dev, "keypad,num-columns", cols);
 59
 60	if (!*rows || !*cols) {
 61		dev_err(dev, "number of keypad rows/columns not specified\n");
 62		return -EINVAL;
 63	}
 64
 65	return 0;
 66}
 67EXPORT_SYMBOL_GPL(matrix_keypad_parse_properties);
 68
 69static int matrix_keypad_parse_keymap(const char *propname,
 70				      unsigned int rows, unsigned int cols,
 71				      struct input_dev *input_dev)
 72{
 73	struct device *dev = input_dev->dev.parent;
 74	unsigned int row_shift = get_count_order(cols);
 75	unsigned int max_keys = rows << row_shift;
 76	int i;
 77	int size;
 78	int error;
 79
 80	if (!propname)
 81		propname = "linux,keymap";
 82
 83	size = device_property_count_u32(dev, propname);
 84	if (size <= 0) {
 85		dev_err(dev, "missing or malformed property %s: %d\n",
 86			propname, size);
 87		return size < 0 ? size : -EINVAL;
 88	}
 89
 90	if (size > max_keys) {
 91		dev_err(dev, "%s size overflow (%d vs max %u)\n",
 92			propname, size, max_keys);
 93		return -EINVAL;
 94	}
 95
 96	u32 *keys __free(kfree) = kmalloc_array(size, sizeof(*keys), GFP_KERNEL);
 97	if (!keys)
 98		return -ENOMEM;
 99
100	error = device_property_read_u32_array(dev, propname, keys, size);
101	if (error) {
102		dev_err(dev, "failed to read %s property: %d\n",
103			propname, error);
104		return error;
105	}
106
107	for (i = 0; i < size; i++) {
108		if (!matrix_keypad_map_key(input_dev, rows, cols,
109					   row_shift, keys[i]))
110			return -EINVAL;
111	}
112
113	return 0;
114}
115
116/**
117 * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
118 * @keymap_data: keymap supplied by the platform code
119 * @keymap_name: name of device tree property containing keymap (if device
120 *	tree support is enabled).
121 * @rows: number of rows in target keymap array
122 * @cols: number of cols in target keymap array
123 * @keymap: expanded version of keymap that is suitable for use by
124 * matrix keyboard driver
125 * @input_dev: input devices for which we are setting up the keymap
126 *
127 * This function converts platform keymap (encoded with KEY() macro) into
128 * an array of keycodes that is suitable for using in a standard matrix
129 * keyboard driver that uses row and col as indices.
130 *
131 * If @keymap_data is not supplied and device tree support is enabled
132 * it will attempt load the keymap from property specified by @keymap_name
133 * argument (or "linux,keymap" if @keymap_name is %NULL).
134 *
135 * If @keymap is %NULL the function will automatically allocate managed
136 * block of memory to store the keymap. This memory will be associated with
137 * the parent device and automatically freed when device unbinds from the
138 * driver.
139 *
140 * Callers are expected to set up input_dev->dev.parent before calling this
141 * function.
142 */
143int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
144			       const char *keymap_name,
145			       unsigned int rows, unsigned int cols,
146			       unsigned short *keymap,
147			       struct input_dev *input_dev)
148{
149	unsigned int row_shift = get_count_order(cols);
150	size_t max_keys = rows << row_shift;
151	int i;
152	int error;
153
154	if (WARN_ON(!input_dev->dev.parent))
155		return -EINVAL;
156
157	if (!keymap) {
158		keymap = devm_kcalloc(input_dev->dev.parent,
159				      max_keys, sizeof(*keymap),
160				      GFP_KERNEL);
161		if (!keymap) {
162			dev_err(input_dev->dev.parent,
163				"Unable to allocate memory for keymap");
164			return -ENOMEM;
165		}
166	}
167
168	input_dev->keycode = keymap;
169	input_dev->keycodesize = sizeof(*keymap);
170	input_dev->keycodemax = max_keys;
171
172	__set_bit(EV_KEY, input_dev->evbit);
173
174	if (keymap_data) {
175		for (i = 0; i < keymap_data->keymap_size; i++) {
176			unsigned int key = keymap_data->keymap[i];
177
178			if (!matrix_keypad_map_key(input_dev, rows, cols,
179						   row_shift, key))
180				return -EINVAL;
181		}
182	} else {
183		error = matrix_keypad_parse_keymap(keymap_name, rows, cols,
184						   input_dev);
185		if (error)
186			return error;
187	}
188
189	__clear_bit(KEY_RESERVED, input_dev->keybit);
190
191	return 0;
192}
193EXPORT_SYMBOL(matrix_keypad_build_keymap);
194
195MODULE_DESCRIPTION("Helpers for matrix keyboard bindings");
196MODULE_LICENSE("GPL");