Commit | Line | Data |
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16152045 JN |
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 | ||
37 | /* Info for each registered platform device */ | |
38 | struct pps_gpio_device_data { | |
39 | int irq; /* IRQ used as PPS source */ | |
40 | struct pps_device *pps; /* PPS source device */ | |
41 | struct pps_source_info info; /* PPS source information */ | |
42 | const struct pps_gpio_platform_data *pdata; | |
43 | }; | |
44 | ||
45 | /* | |
46 | * Report the PPS event | |
47 | */ | |
48 | ||
49 | static irqreturn_t pps_gpio_irq_handler(int irq, void *data) | |
50 | { | |
51 | const struct pps_gpio_device_data *info; | |
52 | struct pps_event_time ts; | |
53 | int rising_edge; | |
54 | ||
55 | /* Get the time stamp first */ | |
56 | pps_get_ts(&ts); | |
57 | ||
58 | info = data; | |
59 | ||
60 | rising_edge = gpio_get_value(info->pdata->gpio_pin); | |
61 | if ((rising_edge && !info->pdata->assert_falling_edge) || | |
62 | (!rising_edge && info->pdata->assert_falling_edge)) | |
63 | pps_event(info->pps, &ts, PPS_CAPTUREASSERT, NULL); | |
64 | else if (info->pdata->capture_clear && | |
65 | ((rising_edge && info->pdata->assert_falling_edge) || | |
66 | (!rising_edge && !info->pdata->assert_falling_edge))) | |
67 | pps_event(info->pps, &ts, PPS_CAPTURECLEAR, NULL); | |
68 | ||
69 | return IRQ_HANDLED; | |
70 | } | |
71 | ||
72 | static int pps_gpio_setup(struct platform_device *pdev) | |
73 | { | |
74 | int ret; | |
75 | const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data; | |
76 | ||
77 | ret = gpio_request(pdata->gpio_pin, pdata->gpio_label); | |
78 | if (ret) { | |
79 | pr_warning("failed to request GPIO %u\n", pdata->gpio_pin); | |
80 | return -EINVAL; | |
81 | } | |
82 | ||
83 | ret = gpio_direction_input(pdata->gpio_pin); | |
84 | if (ret) { | |
85 | pr_warning("failed to set pin direction\n"); | |
86 | gpio_free(pdata->gpio_pin); | |
87 | return -EINVAL; | |
88 | } | |
89 | ||
90 | return 0; | |
91 | } | |
92 | ||
93 | static unsigned long | |
94 | get_irqf_trigger_flags(const struct pps_gpio_platform_data *pdata) | |
95 | { | |
96 | unsigned long flags = pdata->assert_falling_edge ? | |
97 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING; | |
98 | ||
99 | if (pdata->capture_clear) { | |
100 | flags |= ((flags & IRQF_TRIGGER_RISING) ? | |
101 | IRQF_TRIGGER_FALLING : IRQF_TRIGGER_RISING); | |
102 | } | |
103 | ||
104 | return flags; | |
105 | } | |
106 | ||
107 | static int pps_gpio_probe(struct platform_device *pdev) | |
108 | { | |
109 | struct pps_gpio_device_data *data; | |
110 | int irq; | |
111 | int ret; | |
112 | int err; | |
113 | int pps_default_params; | |
114 | const struct pps_gpio_platform_data *pdata = pdev->dev.platform_data; | |
115 | ||
116 | ||
117 | /* GPIO setup */ | |
118 | ret = pps_gpio_setup(pdev); | |
119 | if (ret) | |
120 | return -EINVAL; | |
121 | ||
122 | /* IRQ setup */ | |
123 | irq = gpio_to_irq(pdata->gpio_pin); | |
124 | if (irq < 0) { | |
125 | pr_err("failed to map GPIO to IRQ: %d\n", irq); | |
126 | err = -EINVAL; | |
127 | goto return_error; | |
128 | } | |
129 | ||
130 | /* allocate space for device info */ | |
131 | data = kzalloc(sizeof(struct pps_gpio_device_data), GFP_KERNEL); | |
132 | if (data == NULL) { | |
133 | err = -ENOMEM; | |
134 | goto return_error; | |
135 | } | |
136 | ||
137 | /* initialize PPS specific parts of the bookkeeping data structure. */ | |
138 | data->info.mode = PPS_CAPTUREASSERT | PPS_OFFSETASSERT | | |
139 | PPS_ECHOASSERT | PPS_CANWAIT | PPS_TSFMT_TSPEC; | |
140 | if (pdata->capture_clear) | |
141 | data->info.mode |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR | | |
142 | PPS_ECHOCLEAR; | |
143 | data->info.owner = THIS_MODULE; | |
144 | snprintf(data->info.name, PPS_MAX_NAME_LEN - 1, "%s.%d", | |
145 | pdev->name, pdev->id); | |
146 | ||
147 | /* register PPS source */ | |
148 | pps_default_params = PPS_CAPTUREASSERT | PPS_OFFSETASSERT; | |
149 | if (pdata->capture_clear) | |
150 | pps_default_params |= PPS_CAPTURECLEAR | PPS_OFFSETCLEAR; | |
151 | data->pps = pps_register_source(&data->info, pps_default_params); | |
152 | if (data->pps == NULL) { | |
153 | kfree(data); | |
154 | pr_err("failed to register IRQ %d as PPS source\n", irq); | |
155 | err = -EINVAL; | |
156 | goto return_error; | |
157 | } | |
158 | ||
159 | data->irq = irq; | |
160 | data->pdata = pdata; | |
161 | ||
162 | /* register IRQ interrupt handler */ | |
163 | ret = request_irq(irq, pps_gpio_irq_handler, | |
164 | get_irqf_trigger_flags(pdata), data->info.name, data); | |
165 | if (ret) { | |
166 | pps_unregister_source(data->pps); | |
167 | kfree(data); | |
168 | pr_err("failed to acquire IRQ %d\n", irq); | |
169 | err = -EINVAL; | |
170 | goto return_error; | |
171 | } | |
172 | ||
173 | platform_set_drvdata(pdev, data); | |
174 | dev_info(data->pps->dev, "Registered IRQ %d as PPS source\n", irq); | |
175 | ||
176 | return 0; | |
177 | ||
178 | return_error: | |
179 | gpio_free(pdata->gpio_pin); | |
180 | return err; | |
181 | } | |
182 | ||
183 | static int pps_gpio_remove(struct platform_device *pdev) | |
184 | { | |
185 | struct pps_gpio_device_data *data = platform_get_drvdata(pdev); | |
186 | const struct pps_gpio_platform_data *pdata = data->pdata; | |
187 | ||
188 | platform_set_drvdata(pdev, NULL); | |
189 | free_irq(data->irq, data); | |
190 | gpio_free(pdata->gpio_pin); | |
191 | pps_unregister_source(data->pps); | |
192 | pr_info("removed IRQ %d as PPS source\n", data->irq); | |
193 | kfree(data); | |
194 | return 0; | |
195 | } | |
196 | ||
197 | static struct platform_driver pps_gpio_driver = { | |
198 | .probe = pps_gpio_probe, | |
0fe763c5 | 199 | .remove = pps_gpio_remove, |
16152045 JN |
200 | .driver = { |
201 | .name = PPS_GPIO_NAME, | |
202 | .owner = THIS_MODULE | |
203 | }, | |
204 | }; | |
205 | ||
206 | static int __init pps_gpio_init(void) | |
207 | { | |
208 | int ret = platform_driver_register(&pps_gpio_driver); | |
209 | if (ret < 0) | |
210 | pr_err("failed to register platform driver\n"); | |
211 | return ret; | |
212 | } | |
213 | ||
214 | static void __exit pps_gpio_exit(void) | |
215 | { | |
216 | platform_driver_unregister(&pps_gpio_driver); | |
217 | pr_debug("unregistered platform driver\n"); | |
218 | } | |
219 | ||
220 | module_init(pps_gpio_init); | |
221 | module_exit(pps_gpio_exit); | |
222 | ||
223 | MODULE_AUTHOR("Ricardo Martins <rasm@fe.up.pt>"); | |
224 | MODULE_AUTHOR("James Nuss <jamesnuss@nanometrics.ca>"); | |
225 | MODULE_DESCRIPTION("Use GPIO pin as PPS source"); | |
226 | MODULE_LICENSE("GPL"); | |
227 | MODULE_VERSION("1.0.0"); |