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
227
|
/*
* pps-gpio.c -- PPS client driver using GPIO
*
*
* Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
* Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#define PPS_GPIO_NAME "pps-gpio"
#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/pps_kernel.h>
#include <linux/pps-gpio.h>
#include <linux/gpio.h>
#include <linux/list.h>
/* Info for each registered platform device */
struct pps_gpio_device_data {
int irq; /* IRQ used as PPS source */
struct pps_device *pps; /* PPS source device */
struct pps_source_info info; /* PPS source information */
const struct pps_gpio_platform_data *pdata;
};
/*
* Report the PPS event
*/
static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
{
const struct pps_gpio_device_data *info;
struct pps_event_time ts;
int rising_edge;
/* Get the time stamp first */
pps_get_ts(&ts);
info = data;
rising_edge = gpio_get_value(info->pdata->gpio_pin);
if ((rising_edge && !info->pdata->assert_falling_edge) ||
(!rising_edge && info->pdata->assert_falling_edge))
pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
else if (info->pdata->capture_clear &&
((rising_edge && info->pdata->assert_falling_edge) ||
(!rising_edge && !info->pdata->assert_falling_edge)))
pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
return IRQ_HANDLED;
}
static int pps_gpio_setup(struct platform_device *pdev)
{
int ret;
const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
ret = gpio_request(pdata->gpio_pin, pdata->gpio_label);
if (ret) {
pr_warning("failed to request GPIO %u\n", pdata->gpio_pin);
return -EINVAL;
}
ret = gpio_direction_input(pdata->gpio_pin);
if (ret) {
pr_warning("failed to set pin direction\n");
gpio_free(pdata->gpio_pin);
return -EINVAL;
}
return 0;
}
static unsigned long
get_irqf_trigger_flags(const struct pps_gpio_platform_data *pdata)
{
unsigned long flags = pdata->assert_falling_edge ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
if (pdata->capture_clear) {
flags |= ((flags & IRQF_TRIGGER_RISING) ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
}
return flags;
}
static int pps_gpio_probe(struct platform_device *pdev)
{
struct pps_gpio_device_data *data;
int irq;
int ret;
int err;
int pps_default_params;
const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
/* GPIO setup */
ret = pps_gpio_setup(pdev);
if (ret)
return -EINVAL;
/* IRQ setup */
irq = gpio_to_irq(pdata->gpio_pin);
if (irq < 0) {
pr_err("failed to map GPIO to IRQ: %d\n", irq);
err = -EINVAL;
goto return_error;
}
/* allocate space for device info */
data = kzalloc(sizeof(struct pps_gpio_device_data), GFP_KERNEL);
if (data == NULL) {
err = -ENOMEM;
goto return_error;
}
/* initialize PPS specific parts of the bookkeeping data structure. */
data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
if (pdata->capture_clear)
data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
PPS_ECHOCLEAR;
data->info.owner = THIS_MODULE;
snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
pdev->name, pdev->id);
/* register PPS source */
pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
if (pdata->capture_clear)
pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
data->pps = pps_register_source(&data->info, pps_default_params);
if (data->pps == NULL) {
kfree(data);
pr_err("failed to register IRQ %d as PPS source\n", irq);
err = -EINVAL;
goto return_error;
}
data->irq = irq;
data->pdata = pdata;
/* register IRQ interrupt handler */
ret = request_irq(irq, pps_gpio_irq_handler,
get_irqf_trigger_flags(pdata), data->info.name, data);
if (ret) {
pps_unregister_source(data->pps);
kfree(data);
pr_err("failed to acquire IRQ %d\n", irq);
err = -EINVAL;
goto return_error;
}
platform_set_drvdata(pdev, data);
dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n", irq);
return 0;
return_error:
gpio_free(pdata->gpio_pin);
return err;
}
static int pps_gpio_remove(struct platform_device *pdev)
{
struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
const struct pps_gpio_platform_data *pdata = data->pdata;
platform_set_drvdata(pdev, NULL);
free_irq(data->irq, data);
gpio_free(pdata->gpio_pin);
pps_unregister_source(data->pps);
pr_info("removed IRQ %d as PPS source\n", data->irq);
kfree(data);
return 0;
}
static struct platform_driver pps_gpio_driver = {
.probe = pps_gpio_probe,
.remove = __devexit_p(pps_gpio_remove),
.driver = {
.name = PPS_GPIO_NAME,
.owner = THIS_MODULE
},
};
static int __init pps_gpio_init(void)
{
int ret = platform_driver_register(&pps_gpio_driver);
if (ret < 0)
pr_err("failed to register platform driver\n");
return ret;
}
static void __exit pps_gpio_exit(void)
{
platform_driver_unregister(&pps_gpio_driver);
pr_debug("unregistered platform driver\n");
}
module_init(pps_gpio_init);
module_exit(pps_gpio_exit);
MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
MODULE_DESCRIPTION("Use GPIO pin as PPS source");
MODULE_LICENSE("GPL");
MODULE_VERSION("1.0.0");
|
