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
|
/*
* drivers/switch/switch_gpio.c
*
* Copyright (C) 2008 Google, Inc.
* Author: Mike Lockwood <lockwood@android.com>
*
* 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/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/switch.h>
#include <linux/workqueue.h>
#include <linux/gpio.h>
struct gpio_switch_data {
struct switch_dev sdev;
unsigned gpio;
const char *name_on;
const char *name_off;
const char *state_on;
const char *state_off;
int irq;
struct work_struct work;
};
static void gpio_switch_work(struct work_struct *work)
{
int state;
struct gpio_switch_data *data =
container_of(work, struct gpio_switch_data, work);
state = gpio_get_value(data->gpio);
switch_set_state(&data->sdev, state);
}
static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
{
struct gpio_switch_data *switch_data =
(struct gpio_switch_data *)dev_id;
schedule_work(&switch_data->work);
return IRQ_HANDLED;
}
static ssize_t switch_gpio_print_state(struct switch_dev *sdev, char *buf)
{
struct gpio_switch_data *switch_data =
container_of(sdev, struct gpio_switch_data, sdev);
const char *state;
if (switch_get_state(sdev))
state = switch_data->state_on;
else
state = switch_data->state_off;
if (state)
return sprintf(buf, "%s\n", state);
return -1;
}
static int gpio_switch_probe(struct platform_device *pdev)
{
struct gpio_switch_platform_data *pdata = pdev->dev.platform_data;
struct gpio_switch_data *switch_data;
int ret = 0;
if (!pdata)
return -EBUSY;
switch_data = kzalloc(sizeof(struct gpio_switch_data), GFP_KERNEL);
if (!switch_data)
return -ENOMEM;
switch_data->sdev.name = pdata->name;
switch_data->gpio = pdata->gpio;
switch_data->name_on = pdata->name_on;
switch_data->name_off = pdata->name_off;
switch_data->state_on = pdata->state_on;
switch_data->state_off = pdata->state_off;
switch_data->sdev.print_state = switch_gpio_print_state;
ret = switch_dev_register(&switch_data->sdev);
if (ret < 0)
goto err_switch_dev_register;
ret = gpio_request(switch_data->gpio, pdev->name);
if (ret < 0)
goto err_request_gpio;
ret = gpio_direction_input(switch_data->gpio);
if (ret < 0)
goto err_set_gpio_input;
INIT_WORK(&switch_data->work, gpio_switch_work);
switch_data->irq = gpio_to_irq(switch_data->gpio);
if (switch_data->irq < 0) {
ret = switch_data->irq;
goto err_detect_irq_num_failed;
}
ret = request_irq(switch_data->irq, gpio_irq_handler,
IRQF_TRIGGER_LOW, pdev->name, switch_data);
if (ret < 0)
goto err_request_irq;
/* Perform initial detection */
gpio_switch_work(&switch_data->work);
return 0;
err_request_irq:
err_detect_irq_num_failed:
err_set_gpio_input:
gpio_free(switch_data->gpio);
err_request_gpio:
switch_dev_unregister(&switch_data->sdev);
err_switch_dev_register:
kfree(switch_data);
return ret;
}
static int __devexit gpio_switch_remove(struct platform_device *pdev)
{
struct gpio_switch_data *switch_data = platform_get_drvdata(pdev);
cancel_work_sync(&switch_data->work);
gpio_free(switch_data->gpio);
switch_dev_unregister(&switch_data->sdev);
kfree(switch_data);
return 0;
}
static struct platform_driver gpio_switch_driver = {
.probe = gpio_switch_probe,
.remove = __devexit_p(gpio_switch_remove),
.driver = {
.name = "switch-gpio",
.owner = THIS_MODULE,
},
};
static int __init gpio_switch_init(void)
{
return platform_driver_register(&gpio_switch_driver);
}
static void __exit gpio_switch_exit(void)
{
platform_driver_unregister(&gpio_switch_driver);
}
module_init(gpio_switch_init);
module_exit(gpio_switch_exit);
MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
MODULE_DESCRIPTION("GPIO Switch driver");
MODULE_LICENSE("GPL");
|
