LXR qemu/hw/gpio/gpio

   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
  33typedef struct GPIOKEYState {
  34    SysBusDevice parent_obj;
  35
  36    QEMUTimer *timer;
  37    qemu_irq irq;
  38} GPIOKEYState;
  39
  40static 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
  50static void gpio_key_reset(DeviceState *dev)
  51{
  52    GPIOKEYState *s = GPIOKEY(dev);
  53
  54    timer_del(s->timer);
  55}
  56
  57static 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
  65static 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
  74static 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
  84static 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
  93static 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
 100static void gpio_key_register_types(void)
 101{
 102    type_register_static(&gpio_key_info);
 103}
 104
 105type_init(gpio_key_register_types)
 106