xref: /openbmc/qemu/hw/gpio/gpio_key.c (revision 64552b6b)
1 /*
2  * GPIO key
3  *
4  * Copyright (c) 2016 Linaro Limited
5  *
6  * Author: Shannon Zhao <shannon.zhao@linaro.org>
7  *
8  * Emulate a (human) keypress -- when the key is triggered by
9  * setting the incoming gpio line, the outbound irq line is
10  * raised for 100ms before being dropped again.
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License; either version 2
14  * of the License, or (at your option) any later version.
15  *
16  * This program is distributed in the hope that it will be useful,
17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19  * GNU General Public License for more details.
20  *
21  * You should have received a copy of the GNU General Public License along
22  * with this program; if not, see <http://www.gnu.org/licenses/>.
23  */
24 
25 #include "qemu/osdep.h"
26 #include "hw/irq.h"
27 #include "hw/sysbus.h"
28 #include "qemu/module.h"
29 #include "qemu/timer.h"
30 
31 #define TYPE_GPIOKEY "gpio-key"
32 #define GPIOKEY(obj) OBJECT_CHECK(GPIOKEYState, (obj), TYPE_GPIOKEY)
33 #define GPIO_KEY_LATENCY 100 /* 100ms */
34 
35 typedef struct GPIOKEYState {
36     SysBusDevice parent_obj;
37 
38     QEMUTimer *timer;
39     qemu_irq irq;
40 } GPIOKEYState;
41 
42 static const VMStateDescription vmstate_gpio_key = {
43     .name = "gpio-key",
44     .version_id = 1,
45     .minimum_version_id = 1,
46     .fields = (VMStateField[]) {
47         VMSTATE_TIMER_PTR(timer, GPIOKEYState),
48         VMSTATE_END_OF_LIST()
49     }
50 };
51 
52 static void gpio_key_reset(DeviceState *dev)
53 {
54     GPIOKEYState *s = GPIOKEY(dev);
55 
56     timer_del(s->timer);
57 }
58 
59 static void gpio_key_timer_expired(void *opaque)
60 {
61     GPIOKEYState *s = (GPIOKEYState *)opaque;
62 
63     qemu_set_irq(s->irq, 0);
64     timer_del(s->timer);
65 }
66 
67 static void gpio_key_set_irq(void *opaque, int irq, int level)
68 {
69     GPIOKEYState *s = (GPIOKEYState *)opaque;
70 
71     qemu_set_irq(s->irq, 1);
72     timer_mod(s->timer,
73               qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + GPIO_KEY_LATENCY);
74 }
75 
76 static void gpio_key_realize(DeviceState *dev, Error **errp)
77 {
78     GPIOKEYState *s = GPIOKEY(dev);
79     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
80 
81     sysbus_init_irq(sbd, &s->irq);
82     qdev_init_gpio_in(dev, gpio_key_set_irq, 1);
83     s->timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, gpio_key_timer_expired, s);
84 }
85 
86 static void gpio_key_class_init(ObjectClass *klass, void *data)
87 {
88     DeviceClass *dc = DEVICE_CLASS(klass);
89 
90     dc->realize = gpio_key_realize;
91     dc->vmsd = &vmstate_gpio_key;
92     dc->reset = &gpio_key_reset;
93 }
94 
95 static const TypeInfo gpio_key_info = {
96     .name          = TYPE_GPIOKEY,
97     .parent        = TYPE_SYS_BUS_DEVICE,
98     .instance_size = sizeof(GPIOKEYState),
99     .class_init    = gpio_key_class_init,
100 };
101 
102 static void gpio_key_register_types(void)
103 {
104     type_register_static(&gpio_key_info);
105 }
106 
107 type_init(gpio_key_register_types)
108