1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
/*
* Driver for a keypad w/16 buttons connected to a PCF8574 I2C I/O expander
*
* Copyright 2005-2008 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/slab.h>
#include <linux/workqueue.h>
#define DRV_NAME "pcf8574_keypad"
static const unsigned char pcf8574_kp_btncode[] = {
[0] = KEY_RESERVED,
[1] = KEY_ENTER,
[2] = KEY_BACKSLASH,
[3] = KEY_0,
[4] = KEY_RIGHTBRACE,
[5] = KEY_C,
[6] = KEY_9,
[7] = KEY_8,
[8] = KEY_7,
[9] = KEY_B,
[10] = KEY_6,
[11] = KEY_5,
[12] = KEY_4,
[13] = KEY_A,
[14] = KEY_3,
[15] = KEY_2,
[16] = KEY_1
};
struct kp_data {
unsigned short btncode[ARRAY_SIZE(pcf8574_kp_btncode)];
struct input_dev *idev;
struct i2c_client *client;
char name[64];
char phys[32];
unsigned char laststate;
};
static short read_state(struct kp_data *lp)
{
unsigned char x, y, a, b;
i2c_smbus_write_byte(lp->client, 240);
x = 0xF & (~(i2c_smbus_read_byte(lp->client) >> 4));
i2c_smbus_write_byte(lp->client, 15);
y = 0xF & (~i2c_smbus_read_byte(lp->client));
for (a = 0; x > 0; a++)
x = x >> 1;
for (b = 0; y > 0; b++)
y = y >> 1;
return ((a - 1) * 4) + b;
}
static irqreturn_t pcf8574_kp_irq_handler(int irq, void *dev_id)
{
struct kp_data *lp = dev_id;
unsigned char nextstate = read_state(lp);
if (lp->laststate != nextstate) {
int key_down = nextstate < ARRAY_SIZE(lp->btncode);
unsigned short keycode = key_down ?
lp->btncode[nextstate] : lp->btncode[lp->laststate];
input_report_key(lp->idev, keycode, key_down);
input_sync(lp->idev);
lp->laststate = nextstate;
}
return IRQ_HANDLED;
}
static int pcf8574_kp_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
int i, ret;
struct input_dev *idev;
struct kp_data *lp;
if (i2c_smbus_write_byte(client, 240) < 0) {
dev_err(&client->dev, "probe: write fail\n");
return -ENODEV;
}
lp = kzalloc(sizeof(*lp), GFP_KERNEL);
if (!lp)
return -ENOMEM;
idev = input_allocate_device();
if (!idev) {
dev_err(&client->dev, "Can't allocate input device\n");
ret = -ENOMEM;
goto fail_allocate;
}
lp->idev = idev;
lp->client = client;
idev->evbit[0] = BIT_MASK(EV_KEY);
idev->keycode = lp->btncode;
idev->keycodesize = sizeof(lp->btncode[0]);
idev->keycodemax = ARRAY_SIZE(lp->btncode);
for (i = 0; i < ARRAY_SIZE(pcf8574_kp_btncode); i++) {
if (lp->btncode[i] <= KEY_MAX) {
lp->btncode[i] = pcf8574_kp_btncode[i];
__set_bit(lp->btncode[i], idev->keybit);
}
}
__clear_bit(KEY_RESERVED, idev->keybit);
sprintf(lp->name, DRV_NAME);
sprintf(lp->phys, "kp_data/input0");
idev->name = lp->name;
idev->phys = lp->phys;
idev->id.bustype = BUS_I2C;
idev->id.vendor = 0x0001;
idev->id.product = 0x0001;
idev->id.version = 0x0100;
lp->laststate = read_state(lp);
ret = request_threaded_irq(client->irq, NULL, pcf8574_kp_irq_handler,
IRQF_TRIGGER_LOW | IRQF_ONESHOT,
DRV_NAME, lp);
if (ret) {
dev_err(&client->dev, "IRQ %d is not free\n", client->irq);
goto fail_free_device;
}
ret = input_register_device(idev);
if (ret) {
dev_err(&client->dev, "input_register_device() failed\n");
goto fail_free_irq;
}
i2c_set_clientdata(client, lp);
return 0;
fail_free_irq:
free_irq(client->irq, lp);
fail_free_device:
input_free_device(idev);
fail_allocate:
kfree(lp);
return ret;
}
static int pcf8574_kp_remove(struct i2c_client *client)
{
struct kp_data *lp = i2c_get_clientdata(client);
free_irq(client->irq, lp);
input_unregister_device(lp->idev);
kfree(lp);
return 0;
}
#ifdef CONFIG_PM
static int pcf8574_kp_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
enable_irq(client->irq);
return 0;
}
static int pcf8574_kp_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
disable_irq(client->irq);
return 0;
}
static const struct dev_pm_ops pcf8574_kp_pm_ops = {
.suspend = pcf8574_kp_suspend,
.resume = pcf8574_kp_resume,
};
#else
# define pcf8574_kp_resume NULL
# define pcf8574_kp_suspend NULL
#endif
static const struct i2c_device_id pcf8574_kp_id[] = {
{ DRV_NAME, 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, pcf8574_kp_id);
static struct i2c_driver pcf8574_kp_driver = {
.driver = {
.name = DRV_NAME,
.owner = THIS_MODULE,
#ifdef CONFIG_PM
.pm = &pcf8574_kp_pm_ops,
#endif
},
.probe = pcf8574_kp_probe,
.remove = pcf8574_kp_remove,
.id_table = pcf8574_kp_id,
};
module_i2c_driver(pcf8574_kp_driver);
MODULE_AUTHOR("Michael Hennerich");
MODULE_DESCRIPTION("Keypad input driver for 16 keys connected to PCF8574");
MODULE_LICENSE("GPL");
|
