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
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*/
#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/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/pps_kernel.h>
#include <linux/gpio/consumer.h>
#include <linux/list.h>
#include <linux/property.h>
#include <linux/timer.h>
#include <linux/jiffies.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 */
struct gpio_desc *gpio_pin; /* GPIO port descriptors */
struct gpio_desc *echo_pin;
struct timer_list echo_timer; /* timer to reset echo active state */
bool assert_falling_edge;
bool capture_clear;
unsigned int echo_active_ms; /* PPS echo active duration */
unsigned long echo_timeout; /* timer timeout value in jiffies */
};
/*
* 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 = gpiod_get_value(info->gpio_pin);
if ((rising_edge && !info->assert_falling_edge) ||
(!rising_edge && info->assert_falling_edge))
pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data);
else if (info->capture_clear &&
((rising_edge && info->assert_falling_edge) ||
(!rising_edge && !info->assert_falling_edge)))
pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data);
return IRQ_HANDLED;
}
/* This function will only be called when an ECHO GPIO is defined */
static void pps_gpio_echo(struct pps_device *pps, int event, void *data)
{
/* add_timer() needs to write into info->echo_timer */
struct pps_gpio_device_data *info = data;
switch (event) {
case PPS_CAPTUREASSERT:
if (pps->params.mode & PPS_ECHOASSERT)
gpiod_set_value(info->echo_pin, 1);
break;
case PPS_CAPTURECLEAR:
if (pps->params.mode & PPS_ECHOCLEAR)
gpiod_set_value(info->echo_pin, 1);
break;
}
/* fire the timer */
if (info->pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) {
info->echo_timer.expires = jiffies + info->echo_timeout;
add_timer(&info->echo_timer);
}
}
/* Timer callback to reset the echo pin to the inactive state */
static void pps_gpio_echo_timer_callback(struct timer_list *t)
{
const struct pps_gpio_device_data *info;
info = from_timer(info, t, echo_timer);
gpiod_set_value(info->echo_pin, 0);
}
static int pps_gpio_setup(struct device *dev)
{
struct pps_gpio_device_data *data = dev_get_drvdata(dev);
int ret;
u32 value;
data->gpio_pin = devm_gpiod_get(dev, NULL, GPIOD_IN);
if (IS_ERR(data->gpio_pin))
return dev_err_probe(dev, PTR_ERR(data->gpio_pin),
"failed to request PPS GPIO\n");
data->assert_falling_edge =
device_property_read_bool(dev, "assert-falling-edge");
data->echo_pin = devm_gpiod_get_optional(dev, "echo", GPIOD_OUT_LOW);
if (IS_ERR(data->echo_pin))
return dev_err_probe(dev, PTR_ERR(data->echo_pin),
"failed to request ECHO GPIO\n");
if (!data->echo_pin)
return 0;
ret = device_property_read_u32(dev, "echo-active-ms", &value);
if (ret) {
dev_err(dev, "failed to get echo-active-ms from FW\n");
return ret;
}
/* sanity check on echo_active_ms */
if (!value || value > 999) {
dev_err(dev, "echo-active-ms: %u - bad value from FW\n", value);
return -EINVAL;
}
data->echo_active_ms = value;
return 0;
}
static unsigned long
get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
{
unsigned long flags = data->assert_falling_edge ?
IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
if (data->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;
struct device *dev = &pdev->dev;
int ret;
int pps_default_params;
/* allocate space for device info */
data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
dev_set_drvdata(dev, data);
/* GPIO setup */
ret = pps_gpio_setup(dev);
if (ret)
return -EINVAL;
/* IRQ setup */
ret = gpiod_to_irq(data->gpio_pin);
if (ret < 0) {
dev_err(dev, "failed to map GPIO to IRQ: %d\n", ret);
return -EINVAL;
}
data->irq = ret;
/* initialize PPS specific parts of the bookkeeping data structure. */
data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
if (data->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);
if (data->echo_pin) {
data->info.echo = pps_gpio_echo;
data->echo_timeout = msecs_to_jiffies(data->echo_active_ms);
timer_setup(&data->echo_timer, pps_gpio_echo_timer_callback, 0);
}
/* register PPS source */
pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
if (data->capture_clear)
pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
data->pps = pps_register_source(&data->info, pps_default_params);
if (IS_ERR(data->pps)) {
dev_err(dev, "failed to register IRQ %d as PPS source\n",
data->irq);
return PTR_ERR(data->pps);
}
/* register IRQ interrupt handler */
ret = devm_request_irq(dev, data->irq, pps_gpio_irq_handler,
get_irqf_trigger_flags(data), data->info.name, data);
if (ret) {
pps_unregister_source(data->pps);
dev_err(dev, "failed to acquire IRQ %d\n", data->irq);
return -EINVAL;
}
dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
data->irq);
return 0;
}
static int pps_gpio_remove(struct platform_device *pdev)
{
struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
pps_unregister_source(data->pps);
del_timer_sync(&data->echo_timer);
/* reset echo pin in any case */
gpiod_set_value(data->echo_pin, 0);
dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
return 0;
}
static const struct of_device_id pps_gpio_dt_ids[] = {
{ .compatible = "pps-gpio", },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
static struct platform_driver pps_gpio_driver = {
.probe = pps_gpio_probe,
.remove = pps_gpio_remove,
.driver = {
.name = PPS_GPIO_NAME,
.of_match_table = pps_gpio_dt_ids,
},
};
module_platform_driver(pps_gpio_driver);
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("1.2.0");
|
