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/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 = (VMStateField[]) {
  49         VMSTATE_TIMER_PTR(timer, GPIOKEYState),
  50         VMSTATE_END_OF_LIST()
  51     }
  52 };
  53
  54 static void gpio_key_reset(DeviceState *dev)
  55 {
  56     GPIOKEYState *s = GPIOKEY(dev);
  57
  58     timer_del(s->timer);
  59 }
  60
  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
  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
  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
  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
 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)