hw/gpio/gpio_key.c

   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/sysbus.h"
  27 #include "qemu/timer.h"
  28
  29 #define TYPE_GPIOKEY "gpio-key"
  30 #define GPIOKEY(obj) OBJECT_CHECK(GPIOKEYState, (obj), TYPE_GPIOKEY)
  31 #define GPIO_KEY_LATENCY 100 /* 100ms */
  32
  33 typedef struct GPIOKEYState {
  34     SysBusDevice parent_obj;
  35
  36     QEMUTimer *timer;
  37     qemu_irq irq;
  38 } GPIOKEYState;
  39
  40 static const VMStateDescription vmstate_gpio_key = {
  41     .name = "gpio-key",
  42     .version_id = 1,
  43     .minimum_version_id = 1,
  44     .fields = (VMStateField[]) {
  45         VMSTATE_TIMER_PTR(timer, GPIOKEYState),
  46         VMSTATE_END_OF_LIST()
  47     }
  48 };
  49
  50 static void gpio_key_reset(DeviceState *dev)
  51 {
  52     GPIOKEYState *s = GPIOKEY(dev);
  53
  54     timer_del(s->timer);
  55 }
  56
  57 static void gpio_key_timer_expired(void *opaque)
  58 {
  59     GPIOKEYState *s = (GPIOKEYState *)opaque;
  60
  61     qemu_set_irq(s->irq, 0);
  62     timer_del(s->timer);
  63 }
  64
  65 static void gpio_key_set_irq(void *opaque, int irq, int level)
  66 {
  67     GPIOKEYState *s = (GPIOKEYState *)opaque;
  68
  69     qemu_set_irq(s->irq, 1);
  70     timer_mod(s->timer,
  71               qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + GPIO_KEY_LATENCY);
  72 }
  73
  74 static void gpio_key_realize(DeviceState *dev, Error **errp)
  75 {
  76     GPIOKEYState *s = GPIOKEY(dev);
  77     SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
  78
  79     sysbus_init_irq(sbd, &s->irq);
  80     qdev_init_gpio_in(dev, gpio_key_set_irq, 1);
  81     s->timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, gpio_key_timer_expired, s);
  82 }
  83
  84 static void gpio_key_class_init(ObjectClass *klass, void *data)
  85 {
  86     DeviceClass *dc = DEVICE_CLASS(klass);
  87
  88     dc->realize = gpio_key_realize;
  89     dc->vmsd = &vmstate_gpio_key;
  90     dc->reset = &gpio_key_reset;
  91 }
  92
  93 static const TypeInfo gpio_key_info = {
  94     .name          = TYPE_GPIOKEY,
  95     .parent        = TYPE_SYS_BUS_DEVICE,
  96     .instance_size = sizeof(GPIOKEYState),
  97     .class_init    = gpio_key_class_init,
  98 };
  99
 100 static void gpio_key_register_types(void)
 101 {
 102     type_register_static(&gpio_key_info);
 103 }
 104
 105 type_init(gpio_key_register_types)