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 "migration/vmstate.h"
29 #include "qemu/module.h"
30 #include "qemu/timer.h"
31 #include "qom/object.h"
32
33 #define TYPE_GPIOKEY "gpio-key"
34 OBJECT_DECLARE_SIMPLE_TYPE(GPIOKEYState, GPIOKEY)
35 #define GPIO_KEY_LATENCY 100 /* 100ms */
36
37 struct GPIOKEYState {
38 SysBusDevice parent_obj;
39
40 QEMUTimer *timer;
41 qemu_irq irq;
42 };
43
44 static const VMStateDescription vmstate_gpio_key = {
45 .name = "gpio-key",
46 .version_id = 1,
47 .minimum_version_id = 1,
48 .fields = (const VMStateField[]) {
49 VMSTATE_TIMER_PTR(timer, GPIOKEYState),
50 VMSTATE_END_OF_LIST()
51 }
52 };
53
gpio_key_reset(DeviceState * dev)54 static void gpio_key_reset(DeviceState *dev)
55 {
56 GPIOKEYState *s = GPIOKEY(dev);
57
58 timer_del(s->timer);
59 }
60
gpio_key_timer_expired(void * opaque)61 static void gpio_key_timer_expired(void *opaque)
62 {
63 GPIOKEYState *s = (GPIOKEYState *)opaque;
64
65 qemu_set_irq(s->irq, 0);
66 timer_del(s->timer);
67 }
68
gpio_key_set_irq(void * opaque,int irq,int level)69 static void gpio_key_set_irq(void *opaque, int irq, int level)
70 {
71 GPIOKEYState *s = (GPIOKEYState *)opaque;
72
73 qemu_set_irq(s->irq, 1);
74 timer_mod(s->timer,
75 qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + GPIO_KEY_LATENCY);
76 }
77
gpio_key_realize(DeviceState * dev,Error ** errp)78 static void gpio_key_realize(DeviceState *dev, Error **errp)
79 {
80 GPIOKEYState *s = GPIOKEY(dev);
81 SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
82
83 sysbus_init_irq(sbd, &s->irq);
84 qdev_init_gpio_in(dev, gpio_key_set_irq, 1);
85 s->timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, gpio_key_timer_expired, s);
86 }
87
gpio_key_class_init(ObjectClass * klass,void * data)88 static void gpio_key_class_init(ObjectClass *klass, void *data)
89 {
90 DeviceClass *dc = DEVICE_CLASS(klass);
91
92 dc->realize = gpio_key_realize;
93 dc->vmsd = &vmstate_gpio_key;
94 dc->reset = &gpio_key_reset;
95 }
96
97 static const TypeInfo gpio_key_info = {
98 .name = TYPE_GPIOKEY,
99 .parent = TYPE_SYS_BUS_DEVICE,
100 .instance_size = sizeof(GPIOKEYState),
101 .class_init = gpio_key_class_init,
102 };
103
gpio_key_register_types(void)104 static void gpio_key_register_types(void)
105 {
106 type_register_static(&gpio_key_info);
107 }
108
109 type_init(gpio_key_register_types)
110