Loading...
1/*
2 * pps-gpio.c -- PPS client driver using GPIO
3 *
4 *
5 * Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
6 * Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23#define PPS_GPIO_NAME "pps-gpio"
24#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
25
26#include <linux/init.h>
27#include <linux/kernel.h>
28#include <linux/interrupt.h>
29#include <linux/module.h>
30#include <linux/platform_device.h>
31#include <linux/slab.h>
32#include <linux/pps_kernel.h>
33#include <linux/pps-gpio.h>
34#include <linux/gpio.h>
35#include <linux/list.h>
36#include <linux/of_device.h>
37#include <linux/of_gpio.h>
38
39/* Info for each registered platform device */
40struct pps_gpio_device_data {
41 int irq; /* IRQ used as PPS source */
42 struct pps_device *pps; /* PPS source device */
43 struct pps_source_info info; /* PPS source information */
44 bool assert_falling_edge;
45 bool capture_clear;
46 unsigned int gpio_pin;
47};
48
49/*
50 * Report the PPS event
51 */
52
53static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
54{
55 const struct pps_gpio_device_data *info;
56 struct pps_event_time ts;
57 int rising_edge;
58
59 /* Get the time stamp first */
60 pps_get_ts(&ts);
61
62 info = data;
63
64 rising_edge = gpio_get_value(info->gpio_pin);
65 if ((rising_edge && !info->assert_falling_edge) ||
66 (!rising_edge && info->assert_falling_edge))
67 pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
68 else if (info->capture_clear &&
69 ((rising_edge && info->assert_falling_edge) ||
70 (!rising_edge && !info->assert_falling_edge)))
71 pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
72
73 return IRQ_HANDLED;
74}
75
76static unsigned long
77get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
78{
79 unsigned long flags = data->assert_falling_edge ?
80 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
81
82 if (data->capture_clear) {
83 flags |= ((flags & IRQF_TRIGGER_RISING) ?
84 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
85 }
86
87 return flags;
88}
89
90static int pps_gpio_probe(struct platform_device *pdev)
91{
92 struct pps_gpio_device_data *data;
93 const char *gpio_label;
94 int ret;
95 int pps_default_params;
96 const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
97 struct device_node *np = pdev->dev.of_node;
98
99 /* allocate space for device info */
100 data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),
101 GFP_KERNEL);
102 if (!data)
103 return -ENOMEM;
104
105 if (pdata) {
106 data->gpio_pin = pdata->gpio_pin;
107 gpio_label = pdata->gpio_label;
108
109 data->assert_falling_edge = pdata->assert_falling_edge;
110 data->capture_clear = pdata->capture_clear;
111 } else {
112 ret = of_get_gpio(np, 0);
113 if (ret < 0) {
114 dev_err(&pdev->dev, "failed to get GPIO from device tree\n");
115 return ret;
116 }
117 data->gpio_pin = ret;
118 gpio_label = PPS_GPIO_NAME;
119
120 if (of_get_property(np, "assert-falling-edge", NULL))
121 data->assert_falling_edge = true;
122 }
123
124 /* GPIO setup */
125 ret = devm_gpio_request(&pdev->dev, data->gpio_pin, gpio_label);
126 if (ret) {
127 dev_err(&pdev->dev, "failed to request GPIO %u\n",
128 data->gpio_pin);
129 return ret;
130 }
131
132 ret = gpio_direction_input(data->gpio_pin);
133 if (ret) {
134 dev_err(&pdev->dev, "failed to set pin direction\n");
135 return -EINVAL;
136 }
137
138 /* IRQ setup */
139 ret = gpio_to_irq(data->gpio_pin);
140 if (ret < 0) {
141 dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
142 return -EINVAL;
143 }
144 data->irq = ret;
145
146 /* initialize PPS specific parts of the bookkeeping data structure. */
147 data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
148 PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
149 if (data->capture_clear)
150 data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
151 PPS_ECHOCLEAR;
152 data->info.owner = THIS_MODULE;
153 snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
154 pdev->name, pdev->id);
155
156 /* register PPS source */
157 pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
158 if (data->capture_clear)
159 pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
160 data->pps = pps_register_source(&data->info, pps_default_params);
161 if (data->pps == NULL) {
162 dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
163 data->irq);
164 return -EINVAL;
165 }
166
167 /* register IRQ interrupt handler */
168 ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
169 get_irqf_trigger_flags(data), data->info.name, data);
170 if (ret) {
171 pps_unregister_source(data->pps);
172 dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
173 return -EINVAL;
174 }
175
176 platform_set_drvdata(pdev, data);
177 dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
178 data->irq);
179
180 return 0;
181}
182
183static int pps_gpio_remove(struct platform_device *pdev)
184{
185 struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
186
187 pps_unregister_source(data->pps);
188 dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
189 return 0;
190}
191
192static const struct of_device_id pps_gpio_dt_ids[] = {
193 { .compatible = "pps-gpio", },
194 { /* sentinel */ }
195};
196MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
197
198static struct platform_driver pps_gpio_driver = {
199 .probe = pps_gpio_probe,
200 .remove = pps_gpio_remove,
201 .driver = {
202 .name = PPS_GPIO_NAME,
203 .owner = THIS_MODULE,
204 .of_match_table = pps_gpio_dt_ids,
205 },
206};
207
208module_platform_driver(pps_gpio_driver);
209MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
210MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
211MODULE_DESCRIPTION("Use GPIO pin as PPS source");
212MODULE_LICENSE("GPL");
213MODULE_VERSION("1.0.0");
1/*
2 * pps-gpio.c -- PPS client driver using GPIO
3 *
4 *
5 * Copyright (C) 2010 Ricardo Martins <rasm@fe.up.pt>
6 * Copyright (C) 2011 James Nuss <jamesnuss@nanometrics.ca>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23#define PPS_GPIO_NAME "pps-gpio"
24#define pr_fmt(fmt) PPS_GPIO_NAME ": " fmt
25
26#include <linux/init.h>
27#include <linux/kernel.h>
28#include <linux/interrupt.h>
29#include <linux/module.h>
30#include <linux/platform_device.h>
31#include <linux/slab.h>
32#include <linux/pps_kernel.h>
33#include <linux/pps-gpio.h>
34#include <linux/gpio.h>
35#include <linux/list.h>
36#include <linux/of_device.h>
37#include <linux/of_gpio.h>
38
39/* Info for each registered platform device */
40struct pps_gpio_device_data {
41 int irq; /* IRQ used as PPS source */
42 struct pps_device *pps; /* PPS source device */
43 struct pps_source_info info; /* PPS source information */
44 bool assert_falling_edge;
45 bool capture_clear;
46 unsigned int gpio_pin;
47};
48
49/*
50 * Report the PPS event
51 */
52
53static irqreturn_t pps_gpio_irq_handler(int irq, void *data)
54{
55 const struct pps_gpio_device_data *info;
56 struct pps_event_time ts;
57 int rising_edge;
58
59 /* Get the time stamp first */
60 pps_get_ts(&ts);
61
62 info = data;
63
64 rising_edge = gpio_get_value(info->gpio_pin);
65 if ((rising_edge && !info->assert_falling_edge) ||
66 (!rising_edge && info->assert_falling_edge))
67 pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL);
68 else if (info->capture_clear &&
69 ((rising_edge && info->assert_falling_edge) ||
70 (!rising_edge && !info->assert_falling_edge)))
71 pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL);
72
73 return IRQ_HANDLED;
74}
75
76static unsigned long
77get_irqf_trigger_flags(const struct pps_gpio_device_data *data)
78{
79 unsigned long flags = data->assert_falling_edge ?
80 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING;
81
82 if (data->capture_clear) {
83 flags |= ((flags & IRQF_TRIGGER_RISING) ?
84 IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING);
85 }
86
87 return flags;
88}
89
90static int pps_gpio_probe(struct platform_device *pdev)
91{
92 struct pps_gpio_device_data *data;
93 const char *gpio_label;
94 int ret;
95 int pps_default_params;
96 const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data;
97 struct device_node *np = pdev->dev.of_node;
98
99 /* allocate space for device info */
100 data = devm_kzalloc(&pdev->dev, sizeof(struct pps_gpio_device_data),
101 GFP_KERNEL);
102 if (!data)
103 return -ENOMEM;
104
105 if (pdata) {
106 data->gpio_pin = pdata->gpio_pin;
107 gpio_label = pdata->gpio_label;
108
109 data->assert_falling_edge = pdata->assert_falling_edge;
110 data->capture_clear = pdata->capture_clear;
111 } else {
112 ret = of_get_gpio(np, 0);
113 if (ret < 0) {
114 dev_err(&pdev->dev, "failed to get GPIO from device tree\n");
115 return ret;
116 }
117 data->gpio_pin = ret;
118 gpio_label = PPS_GPIO_NAME;
119
120 if (of_get_property(np, "assert-falling-edge", NULL))
121 data->assert_falling_edge = true;
122 }
123
124 /* GPIO setup */
125 ret = devm_gpio_request(&pdev->dev, data->gpio_pin, gpio_label);
126 if (ret) {
127 dev_err(&pdev->dev, "failed to request GPIO %u\n",
128 data->gpio_pin);
129 return ret;
130 }
131
132 ret = gpio_direction_input(data->gpio_pin);
133 if (ret) {
134 dev_err(&pdev->dev, "failed to set pin direction\n");
135 return -EINVAL;
136 }
137
138 /* IRQ setup */
139 ret = gpio_to_irq(data->gpio_pin);
140 if (ret < 0) {
141 dev_err(&pdev->dev, "failed to map GPIO to IRQ: %d\n", ret);
142 return -EINVAL;
143 }
144 data->irq = ret;
145
146 /* initialize PPS specific parts of the bookkeeping data structure. */
147 data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT |
148 PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC;
149 if (data->capture_clear)
150 data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR |
151 PPS_ECHOCLEAR;
152 data->info.owner = THIS_MODULE;
153 snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d",
154 pdev->name, pdev->id);
155
156 /* register PPS source */
157 pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT;
158 if (data->capture_clear)
159 pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR;
160 data->pps = pps_register_source(&data->info, pps_default_params);
161 if (data->pps == NULL) {
162 dev_err(&pdev->dev, "failed to register IRQ %d as PPS source\n",
163 data->irq);
164 return -EINVAL;
165 }
166
167 /* register IRQ interrupt handler */
168 ret = devm_request_irq(&pdev->dev, data->irq, pps_gpio_irq_handler,
169 get_irqf_trigger_flags(data), data->info.name, data);
170 if (ret) {
171 pps_unregister_source(data->pps);
172 dev_err(&pdev->dev, "failed to acquire IRQ %d\n", data->irq);
173 return -EINVAL;
174 }
175
176 platform_set_drvdata(pdev, data);
177 dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n",
178 data->irq);
179
180 return 0;
181}
182
183static int pps_gpio_remove(struct platform_device *pdev)
184{
185 struct pps_gpio_device_data *data = platform_get_drvdata(pdev);
186
187 pps_unregister_source(data->pps);
188 dev_info(&pdev->dev, "removed IRQ %d as PPS source\n", data->irq);
189 return 0;
190}
191
192static const struct of_device_id pps_gpio_dt_ids[] = {
193 { .compatible = "pps-gpio", },
194 { /* sentinel */ }
195};
196MODULE_DEVICE_TABLE(of, pps_gpio_dt_ids);
197
198static struct platform_driver pps_gpio_driver = {
199 .probe = pps_gpio_probe,
200 .remove = pps_gpio_remove,
201 .driver = {
202 .name = PPS_GPIO_NAME,
203 .of_match_table = pps_gpio_dt_ids,
204 },
205};
206
207module_platform_driver(pps_gpio_driver);
208MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>");
209MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>");
210MODULE_DESCRIPTION("Use GPIO pin as PPS source");
211MODULE_LICENSE("GPL");
212MODULE_VERSION("1.0.0");