1 /* drivers/misc/timed_gpio.c
3 * Copyright (C) 2008 Google, Inc.
4 * Author: Mike Lockwood <lockwood@android.com>
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.
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.
17 #include <linux/module.h>
18 #include <linux/platform_device.h>
19 #include <linux/slab.h>
20 #include <linux/hrtimer.h>
21 #include <linux/err.h>
22 #include <linux/gpio.h>
23 #include <linux/ktime.h>
25 #include "timed_output.h"
26 #include "timed_gpio.h"
28 struct timed_gpio_data
{
29 struct timed_output_dev dev
;
37 static enum hrtimer_restart
gpio_timer_func(struct hrtimer
*timer
)
39 struct timed_gpio_data
*data
=
40 container_of(timer
, struct timed_gpio_data
, timer
);
42 gpio_direction_output(data
->gpio
, data
->active_low
? 1 : 0);
43 return HRTIMER_NORESTART
;
46 static int gpio_get_time(struct timed_output_dev
*dev
)
48 struct timed_gpio_data
*data
;
51 data
= container_of(dev
, struct timed_gpio_data
, dev
);
53 if (!hrtimer_active(&data
->timer
))
56 t
= hrtimer_get_remaining(&data
->timer
);
58 return ktime_to_ms(t
);
61 static void gpio_enable(struct timed_output_dev
*dev
, int value
)
63 struct timed_gpio_data
*data
=
64 container_of(dev
, struct timed_gpio_data
, dev
);
67 spin_lock_irqsave(&data
->lock
, flags
);
69 /* cancel previous timer and set GPIO according to value */
70 hrtimer_cancel(&data
->timer
);
71 gpio_direction_output(data
->gpio
, data
->active_low
? !value
: !!value
);
74 if (value
> data
->max_timeout
)
75 value
= data
->max_timeout
;
77 hrtimer_start(&data
->timer
,
78 ktime_set(value
/ 1000, (value
% 1000) * 1000000),
82 spin_unlock_irqrestore(&data
->lock
, flags
);
85 static int timed_gpio_probe(struct platform_device
*pdev
)
87 struct timed_gpio_platform_data
*pdata
= pdev
->dev
.platform_data
;
88 struct timed_gpio
*cur_gpio
;
89 struct timed_gpio_data
*gpio_data
, *gpio_dat
;
95 gpio_data
= devm_kcalloc(&pdev
->dev
, pdata
->num_gpios
,
96 sizeof(*gpio_data
), GFP_KERNEL
);
100 for (i
= 0; i
< pdata
->num_gpios
; i
++) {
101 cur_gpio
= &pdata
->gpios
[i
];
102 gpio_dat
= &gpio_data
[i
];
104 hrtimer_init(&gpio_dat
->timer
, CLOCK_MONOTONIC
,
106 gpio_dat
->timer
.function
= gpio_timer_func
;
107 spin_lock_init(&gpio_dat
->lock
);
109 gpio_dat
->dev
.name
= cur_gpio
->name
;
110 gpio_dat
->dev
.get_time
= gpio_get_time
;
111 gpio_dat
->dev
.enable
= gpio_enable
;
112 ret
= gpio_request(cur_gpio
->gpio
, cur_gpio
->name
);
115 ret
= timed_output_dev_register(&gpio_dat
->dev
);
117 gpio_free(cur_gpio
->gpio
);
121 gpio_dat
->gpio
= cur_gpio
->gpio
;
122 gpio_dat
->max_timeout
= cur_gpio
->max_timeout
;
123 gpio_dat
->active_low
= cur_gpio
->active_low
;
124 gpio_direction_output(gpio_dat
->gpio
, gpio_dat
->active_low
);
127 platform_set_drvdata(pdev
, gpio_data
);
133 timed_output_dev_unregister(&gpio_data
[i
].dev
);
134 gpio_free(gpio_data
[i
].gpio
);
140 static int timed_gpio_remove(struct platform_device
*pdev
)
142 struct timed_gpio_platform_data
*pdata
= pdev
->dev
.platform_data
;
143 struct timed_gpio_data
*gpio_data
= platform_get_drvdata(pdev
);
146 for (i
= 0; i
< pdata
->num_gpios
; i
++) {
147 timed_output_dev_unregister(&gpio_data
[i
].dev
);
148 gpio_free(gpio_data
[i
].gpio
);
154 static struct platform_driver timed_gpio_driver
= {
155 .probe
= timed_gpio_probe
,
156 .remove
= timed_gpio_remove
,
158 .name
= TIMED_GPIO_NAME
,
162 module_platform_driver(timed_gpio_driver
);
164 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>");
165 MODULE_DESCRIPTION("timed gpio driver");
166 MODULE_LICENSE("GPL");