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