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355b0502 GKH |
1 | /* drivers/misc/timed_gpio.c |
2 | * | |
3 | * Copyright (C) 2008 Google, Inc. | |
4 | * Author: Mike Lockwood <lockwood@android.com> | |
5 | * | |
6 | * This software is licensed under the terms of the GNU General Public | |
7 | * License version 2, as published by the Free Software Foundation, and | |
8 | * may be copied, distributed, and modified under those terms. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | * | |
15 | */ | |
16 | ||
17 | #include <linux/module.h> | |
18 | #include <linux/platform_device.h> | |
c1b197ae | 19 | #include <linux/slab.h> |
355b0502 GKH |
20 | #include <linux/hrtimer.h> |
21 | #include <linux/err.h> | |
22 | #include <linux/gpio.h> | |
23 | ||
24 | #include "timed_output.h" | |
25 | #include "timed_gpio.h" | |
26 | ||
27 | ||
28 | struct timed_gpio_data { | |
29 | struct timed_output_dev dev; | |
30 | struct hrtimer timer; | |
31 | spinlock_t lock; | |
e3251e0d TD |
32 | unsigned gpio; |
33 | int max_timeout; | |
34 | u8 active_low; | |
355b0502 GKH |
35 | }; |
36 | ||
37 | static enum hrtimer_restart gpio_timer_func(struct hrtimer *timer) | |
38 | { | |
39 | struct timed_gpio_data *data = | |
40 | container_of(timer, struct timed_gpio_data, timer); | |
41 | ||
42 | gpio_direction_output(data->gpio, data->active_low ? 1 : 0); | |
43 | return HRTIMER_NORESTART; | |
44 | } | |
45 | ||
46 | static int gpio_get_time(struct timed_output_dev *dev) | |
47 | { | |
48 | struct timed_gpio_data *data = | |
49 | container_of(dev, struct timed_gpio_data, dev); | |
50 | ||
51 | if (hrtimer_active(&data->timer)) { | |
52 | ktime_t r = hrtimer_get_remaining(&data->timer); | |
53 | struct timeval t = ktime_to_timeval(r); | |
54 | return t.tv_sec * 1000 + t.tv_usec / 1000; | |
55 | } else | |
56 | return 0; | |
57 | } | |
58 | ||
59 | static void gpio_enable(struct timed_output_dev *dev, int value) | |
60 | { | |
61 | struct timed_gpio_data *data = | |
62 | container_of(dev, struct timed_gpio_data, dev); | |
63 | unsigned long flags; | |
64 | ||
65 | spin_lock_irqsave(&data->lock, flags); | |
66 | ||
67 | /* cancel previous timer and set GPIO according to value */ | |
68 | hrtimer_cancel(&data->timer); | |
69 | gpio_direction_output(data->gpio, data->active_low ? !value : !!value); | |
70 | ||
71 | if (value > 0) { | |
72 | if (value > data->max_timeout) | |
73 | value = data->max_timeout; | |
74 | ||
75 | hrtimer_start(&data->timer, | |
76 | ktime_set(value / 1000, (value % 1000) * 1000000), | |
77 | HRTIMER_MODE_REL); | |
78 | } | |
79 | ||
80 | spin_unlock_irqrestore(&data->lock, flags); | |
81 | } | |
82 | ||
83 | static int timed_gpio_probe(struct platform_device *pdev) | |
84 | { | |
85 | struct timed_gpio_platform_data *pdata = pdev->dev.platform_data; | |
86 | struct timed_gpio *cur_gpio; | |
87 | struct timed_gpio_data *gpio_data, *gpio_dat; | |
5d92f71e | 88 | int i, ret; |
355b0502 GKH |
89 | |
90 | if (!pdata) | |
91 | return -EBUSY; | |
92 | ||
93 | gpio_data = kzalloc(sizeof(struct timed_gpio_data) * pdata->num_gpios, | |
94 | GFP_KERNEL); | |
95 | if (!gpio_data) | |
96 | return -ENOMEM; | |
97 | ||
98 | for (i = 0; i < pdata->num_gpios; i++) { | |
99 | cur_gpio = &pdata->gpios[i]; | |
100 | gpio_dat = &gpio_data[i]; | |
101 | ||
102 | hrtimer_init(&gpio_dat->timer, CLOCK_MONOTONIC, | |
103 | HRTIMER_MODE_REL); | |
104 | gpio_dat->timer.function = gpio_timer_func; | |
105 | spin_lock_init(&gpio_dat->lock); | |
106 | ||
107 | gpio_dat->dev.name = cur_gpio->name; | |
108 | gpio_dat->dev.get_time = gpio_get_time; | |
109 | gpio_dat->dev.enable = gpio_enable; | |
0445f154 | 110 | ret = gpio_request(cur_gpio->gpio, cur_gpio->name); |
5d92f71e AL |
111 | if (ret < 0) |
112 | goto err_out; | |
113 | ret = timed_output_dev_register(&gpio_dat->dev); | |
355b0502 | 114 | if (ret < 0) { |
5d92f71e AL |
115 | gpio_free(cur_gpio->gpio); |
116 | goto err_out; | |
355b0502 GKH |
117 | } |
118 | ||
119 | gpio_dat->gpio = cur_gpio->gpio; | |
120 | gpio_dat->max_timeout = cur_gpio->max_timeout; | |
121 | gpio_dat->active_low = cur_gpio->active_low; | |
122 | gpio_direction_output(gpio_dat->gpio, gpio_dat->active_low); | |
123 | } | |
124 | ||
125 | platform_set_drvdata(pdev, gpio_data); | |
126 | ||
127 | return 0; | |
5d92f71e AL |
128 | |
129 | err_out: | |
130 | while (--i >= 0) { | |
131 | timed_output_dev_unregister(&gpio_data[i].dev); | |
132 | gpio_free(gpio_data[i].gpio); | |
133 | } | |
134 | kfree(gpio_data); | |
135 | ||
136 | return ret; | |
355b0502 GKH |
137 | } |
138 | ||
139 | static int timed_gpio_remove(struct platform_device *pdev) | |
140 | { | |
141 | struct timed_gpio_platform_data *pdata = pdev->dev.platform_data; | |
142 | struct timed_gpio_data *gpio_data = platform_get_drvdata(pdev); | |
143 | int i; | |
144 | ||
0445f154 | 145 | for (i = 0; i < pdata->num_gpios; i++) { |
355b0502 | 146 | timed_output_dev_unregister(&gpio_data[i].dev); |
0445f154 AH |
147 | gpio_free(gpio_data[i].gpio); |
148 | } | |
355b0502 GKH |
149 | |
150 | kfree(gpio_data); | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | static struct platform_driver timed_gpio_driver = { | |
156 | .probe = timed_gpio_probe, | |
157 | .remove = timed_gpio_remove, | |
158 | .driver = { | |
159 | .name = TIMED_GPIO_NAME, | |
160 | .owner = THIS_MODULE, | |
161 | }, | |
162 | }; | |
163 | ||
c21be47c | 164 | module_platform_driver(timed_gpio_driver); |
355b0502 GKH |
165 | |
166 | MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); | |
167 | MODULE_DESCRIPTION("timed gpio driver"); | |
168 | MODULE_LICENSE("GPL"); |