This source file includes following definitions.
- pps_gpio_irq_handler
- pps_gpio_echo
- pps_gpio_echo_timer_callback
- pps_gpio_setup
- get_irqf_trigger_flags
- pps_gpio_probe
- pps_gpio_remove
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8
9 #define PPS_GPIO_NAME "pps-gpio"
10 #define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
11
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/interrupt.h>
15 #include <linux/module.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 #include <linux/pps_kernel.h>
19 #include <linux/pps-gpio.h>
20 #include <linux/gpio/consumer.h>
21 #include <linux/list.h>
22 #include <linux/of_device.h>
23 #include <linux/of_gpio.h>
24 #include <linux/timer.h>
25 #include <linux/jiffies.h>
26
27
28 struct pps_gpio_device_data {
29 int irq;
30 struct pps_device *pps;
31 struct pps_source_info info;
32 struct gpio_desc *gpio_pin;
33 struct gpio_desc *echo_pin;
34 struct timer_list echo_timer;
35 bool assert_falling_edge;
36 bool capture_clear;
37 unsigned int echo_active_ms;
38 unsigned long echo_timeout;
39 };
40
41
42
43
44
45 static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
46 {
47 const struct pps_gpio_device_data *info;
48 struct pps_event_time ts;
49 int rising_edge;
50
51
52 pps_get_ts(&ts);
53
54 info = data;
55
56 rising_edge = gpiod_get_value(info->gpio_pin);
57 if ((rising_edge && !info->assert_falling_edge) ||
58 (!rising_edge && info->assert_falling_edge))
59 pps_event(info->pps, &ts, PPS_CAPTUREASSERT, data);
60 else if (info->capture_clear &&
61 ((rising_edge && info->assert_falling_edge) ||
62 (!rising_edge && !info->assert_falling_edge)))
63 pps_event(info->pps, &ts, PPS_CAPTURECLEAR, data);
64
65 return IRQ_HANDLED;
66 }
67
68
69 static void pps_gpio_echo(struct pps_device *pps, int event, void *data)
70 {
71
72 struct pps_gpio_device_data *info = data;
73
74 switch (event) {
75 case PPS_CAPTUREASSERT:
76 if (pps->params.mode & PPS_ECHOASSERT)
77 gpiod_set_value(info->echo_pin, 1);
78 break;
79
80 case PPS_CAPTURECLEAR:
81 if (pps->params.mode & PPS_ECHOCLEAR)
82 gpiod_set_value(info->echo_pin, 1);
83 break;
84 }
85
86
87 if (info->pps->params.mode & (PPS_ECHOASSERT | PPS_ECHOCLEAR)) {
88 info->echo_timer.expires = jiffies + info->echo_timeout;
89 add_timer(&info->echo_timer);
90 }
91 }
92
93
94 static void pps_gpio_echo_timer_callback(struct timer_list *t)
95 {
96 const struct pps_gpio_device_data *info;
97
98 info = from_timer(info, t, echo_timer);
99
100 gpiod_set_value(info->echo_pin, 0);
101 }
102
103 static int pps_gpio_setup(struct platform_device *pdev)
104 {
105 struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
106 struct device_node *np = pdev->dev.of_node;
107 int ret;
108 u32 value;
109
110 data->gpio_pin = devm_gpiod_get(&pdev->dev,
111 NULL,
112 GPIOD_IN);
113 if (IS_ERR(data->gpio_pin)) {
114 dev_err(&pdev->dev,
115 "failed to request PPS GPIO\n");
116 return PTR_ERR(data->gpio_pin);
117 }
118
119 data->echo_pin = devm_gpiod_get_optional(&pdev->dev,
120 "echo",
121 GPIOD_OUT_LOW);
122 if (data->echo_pin) {
123 if (IS_ERR(data->echo_pin)) {
124 dev_err(&pdev->dev, "failed to request ECHO GPIO\n");
125 return PTR_ERR(data->echo_pin);
126 }
127
128 ret = of_property_read_u32(np,
129 "echo-active-ms",
130 &value);
131 if (ret) {
132 dev_err(&pdev->dev,
133 "failed to get echo-active-ms from OF\n");
134 return ret;
135 }
136 data->echo_active_ms = value;
137
138 if (!data->echo_active_ms || data->echo_active_ms > 999) {
139 dev_err(&pdev->dev,
140 "echo-active-ms: %u - bad value from OF\n",
141 data->echo_active_ms);
142 return -EINVAL;
143 }
144 }
145
146 if (of_property_read_bool(np, "assert-falling-edge"))
147 data->assert_falling_edge = true;
148 return 0;
149 }
150
151 static unsigned long
152 get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
153 {
154 unsigned long flags = data->assert_falling_edge ?
155 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
156
157 if (data->capture_clear) {
158 flags |= ((flags & IRQF_TRIGGER_RISING) ?
159 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
160 }
161
162 return flags;
163 }
164
165 static int pps_gpio_probe(struct platform_device *pdev)
166 {
167 struct pps_gpio_device_data *data;
168 int ret;
169 int pps_default_params;
170 const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
171
172
173 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
174 if (!data)
175 return -ENOMEM;
176 platform_set_drvdata(pdev, data);
177
178
179 if (pdata) {
180 data->gpio_pin = pdata->gpio_pin;
181 data->echo_pin = pdata->echo_pin;
182
183 data->assert_falling_edge = pdata->assert_falling_edge;
184 data->capture_clear = pdata->capture_clear;
185 data->echo_active_ms = pdata->echo_active_ms;
186 } else {
187 ret = pps_gpio_setup(pdev);
188 if (ret)
189 return -EINVAL;
190 }
191
192
193 ret = gpiod_to_irq(data->gpio_pin);
194 if (ret < 0) {
195 dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
196 return -EINVAL;
197 }
198 data->irq = ret;
199
200
201 data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
202 PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
203 if (data->capture_clear)
204 data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
205 PPS_ECHOCLEAR;
206 data->info.owner = THIS_MODULE;
207 snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
208 pdev->name, pdev->id);
209 if (data->echo_pin) {
210 data->info.echo = pps_gpio_echo;
211 data->echo_timeout = msecs_to_jiffies(data->echo_active_ms);
212 timer_setup(&data->echo_timer, pps_gpio_echo_timer_callback, 0);
213 }
214
215
216 pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
217 if (data->capture_clear)
218 pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
219 data->pps = pps_register_source(&data->info, pps_default_params);
220 if (IS_ERR(data->pps)) {
221 dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
222 data->irq);
223 return PTR_ERR(data->pps);
224 }
225
226
227 ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
228 get_irqf_trigger_flags(data), data->info.name, data);
229 if (ret) {
230 pps_unregister_source(data->pps);
231 dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
232 return -EINVAL;
233 }
234
235 dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
236 data->irq);
237
238 return 0;
239 }
240
241 static int pps_gpio_remove(struct platform_device *pdev)
242 {
243 struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
244
245 pps_unregister_source(data->pps);
246 if (data->echo_pin) {
247 del_timer_sync(&data->echo_timer);
248
249 gpiod_set_value(data->echo_pin, 0);
250 }
251 dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
252 return 0;
253 }
254
255 static const struct of_device_id pps_gpio_dt_ids[] = {
256 { .compatible = "pps-gpio", },
257 { }
258 };
259 MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
260
261 static struct platform_driver pps_gpio_driver = {
262 .probe = pps_gpio_probe,
263 .remove = pps_gpio_remove,
264 .driver = {
265 .name = PPS_GPIO_NAME,
266 .of_match_table = pps_gpio_dt_ids,
267 },
268 };
269
270 module_platform_driver(pps_gpio_driver);
271 MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
272 MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
273 MODULE_DESCRIPTION("Use GPIO pin as PPS source");
274 MODULE_LICENSE("GPL");
275 MODULE_VERSION("1.2.0");