Root/drivers/input/matrix-keymap.c

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
20#include <linux/device.h>
21#include <linux/gfp.h>
22#include <linux/kernel.h>
23#include <linux/types.h>
24#include <linux/input.h>
25#include <linux/of.h>
26#include <linux/export.h>
27#include <linux/module.h>
28#include <linux/input/matrix_keypad.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#ifdef CONFIG_OF
53static int matrix_keypad_parse_of_keymap(const char *propname,
54                     unsigned int rows, unsigned int cols,
55                     struct input_dev *input_dev)
56{
57    struct device *dev = input_dev->dev.parent;
58    struct device_node *np = dev->of_node;
59    unsigned int row_shift = get_count_order(cols);
60    unsigned int max_keys = rows << row_shift;
61    unsigned int proplen, i, size;
62    const __be32 *prop;
63
64    if (!np)
65        return -ENOENT;
66
67    if (!propname)
68        propname = "linux,keymap";
69
70    prop = of_get_property(np, propname, &proplen);
71    if (!prop) {
72        dev_err(dev, "OF: %s property not defined in %s\n",
73            propname, np->full_name);
74        return -ENOENT;
75    }
76
77    if (proplen % sizeof(u32)) {
78        dev_err(dev, "OF: Malformed keycode property %s in %s\n",
79            propname, np->full_name);
80        return -EINVAL;
81    }
82
83    size = proplen / sizeof(u32);
84    if (size > max_keys) {
85        dev_err(dev, "OF: %s size overflow\n", propname);
86        return -EINVAL;
87    }
88
89    for (i = 0; i < size; i++) {
90        unsigned int key = be32_to_cpup(prop + i);
91
92        if (!matrix_keypad_map_key(input_dev, rows, cols,
93                       row_shift, key))
94            return -EINVAL;
95    }
96
97    return 0;
98}
99#else
100static int matrix_keypad_parse_of_keymap(const char *propname,
101                     unsigned int rows, unsigned int cols,
102                     struct input_dev *input_dev)
103{
104    return -ENOSYS;
105}
106#endif
107
108/**
109 * matrix_keypad_build_keymap - convert platform keymap into matrix keymap
110 * @keymap_data: keymap supplied by the platform code
111 * @keymap_name: name of device tree property containing keymap (if device
112 * tree support is enabled).
113 * @rows: number of rows in target keymap array
114 * @cols: number of cols in target keymap array
115 * @keymap: expanded version of keymap that is suitable for use by
116 * matrix keyboard driver
117 * @input_dev: input devices for which we are setting up the keymap
118 *
119 * This function converts platform keymap (encoded with KEY() macro) into
120 * an array of keycodes that is suitable for using in a standard matrix
121 * keyboard driver that uses row and col as indices.
122 *
123 * If @keymap_data is not supplied and device tree support is enabled
124 * it will attempt load the keymap from property specified by @keymap_name
125 * argument (or "linux,keymap" if @keymap_name is %NULL).
126 *
127 * If @keymap is %NULL the function will automatically allocate managed
128 * block of memory to store the keymap. This memory will be associated with
129 * the parent device and automatically freed when device unbinds from the
130 * driver.
131 *
132 * Callers are expected to set up input_dev->dev.parent before calling this
133 * function.
134 */
135int matrix_keypad_build_keymap(const struct matrix_keymap_data *keymap_data,
136                   const char *keymap_name,
137                   unsigned int rows, unsigned int cols,
138                   unsigned short *keymap,
139                   struct input_dev *input_dev)
140{
141    unsigned int row_shift = get_count_order(cols);
142    size_t max_keys = rows << row_shift;
143    int i;
144    int error;
145
146    if (WARN_ON(!input_dev->dev.parent))
147        return -EINVAL;
148
149    if (!keymap) {
150        keymap = devm_kzalloc(input_dev->dev.parent,
151                      max_keys * sizeof(*keymap),
152                      GFP_KERNEL);
153        if (!keymap) {
154            dev_err(input_dev->dev.parent,
155                "Unable to allocate memory for keymap");
156            return -ENOMEM;
157        }
158    }
159
160    input_dev->keycode = keymap;
161    input_dev->keycodesize = sizeof(*keymap);
162    input_dev->keycodemax = max_keys;
163
164    __set_bit(EV_KEY, input_dev->evbit);
165
166    if (keymap_data) {
167        for (i = 0; i < keymap_data->keymap_size; i++) {
168            unsigned int key = keymap_data->keymap[i];
169
170            if (!matrix_keypad_map_key(input_dev, rows, cols,
171                           row_shift, key))
172                return -EINVAL;
173        }
174    } else {
175        error = matrix_keypad_parse_of_keymap(keymap_name, rows, cols,
176                              input_dev);
177        if (error)
178            return error;
179    }
180
181    __clear_bit(KEY_RESERVED, input_dev->keybit);
182
183    return 0;
184}
185EXPORT_SYMBOL(matrix_keypad_build_keymap);
186
187MODULE_LICENSE("GPL");
188

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