hw/gpio: Add the emulation of gpio_key

This will be used by ARM virt machine as a power button.

Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
Message-id: 1458221140-15232-2-git-send-email-zhaoshenglong@huawei.com
[PMM: Use hyphen rather than underscore in type names;
 add a comment briefly describing what the device does]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

default-configs/arm-softmmu.mak

@@ -111,3 +111,4 @@ CONFIG_I82801B11=y
 CONFIG_ACPI=y
 CONFIG_SMBIOS=y
 CONFIG_ASPEED_SOC=y
+CONFIG_GPIO_KEY=y

hw/gpio/Makefile.objs

@@ -3,6 +3,7 @@ common-obj-$(CONFIG_PL061) += pl061.o
 common-obj-$(CONFIG_PUV3) += puv3_gpio.o
 common-obj-$(CONFIG_ZAURUS) += zaurus.o
 common-obj-$(CONFIG_E500) += mpc8xxx.o
+common-obj-$(CONFIG_GPIO_KEY) += gpio_key.o
 
 obj-$(CONFIG_OMAP) += omap_gpio.o
 obj-$(CONFIG_IMX) += imx_gpio.o

hw/gpio/gpio_key.c

@@ -0,0 +1,104 @@
+/*
+ * GPIO key
+ *
+ * Copyright (c) 2016 Linaro Limited
+ *
+ * Author: Shannon Zhao <shannon.zhao@linaro.org>
+ *
+ * Emulate a (human) keypress -- when the key is triggered by
+ * setting the incoming gpio line, the outbound irq line is
+ * raised for 100ms before being dropped again.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/sysbus.h"
+
+#define TYPE_GPIOKEY "gpio-key"
+#define GPIOKEY(obj) OBJECT_CHECK(GPIOKEYState, (obj), TYPE_GPIOKEY)
+#define GPIO_KEY_LATENCY 100 /* 100ms */
+
+typedef struct GPIOKEYState {
+    SysBusDevice parent_obj;
+
+    QEMUTimer *timer;
+    qemu_irq irq;
+} GPIOKEYState;
+
+static const VMStateDescription vmstate_gpio_key = {
+    .name = "gpio-key",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_TIMER_PTR(timer, GPIOKEYState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void gpio_key_reset(DeviceState *dev)
+{
+    GPIOKEYState *s = GPIOKEY(dev);
+
+    timer_del(s->timer);
+}
+
+static void gpio_key_timer_expired(void *opaque)
+{
+    GPIOKEYState *s = (GPIOKEYState *)opaque;
+
+    qemu_set_irq(s->irq, 0);
+    timer_del(s->timer);
+}
+
+static void gpio_key_set_irq(void *opaque, int irq, int level)
+{
+    GPIOKEYState *s = (GPIOKEYState *)opaque;
+
+    qemu_set_irq(s->irq, 1);
+    timer_mod(s->timer,
+              qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + GPIO_KEY_LATENCY);
+}
+
+static void gpio_key_realize(DeviceState *dev, Error **errp)
+{
+    GPIOKEYState *s = GPIOKEY(dev);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+
+    sysbus_init_irq(sbd, &s->irq);
+    qdev_init_gpio_in(dev, gpio_key_set_irq, 1);
+    s->timer = timer_new_ms(QEMU_CLOCK_VIRTUAL, gpio_key_timer_expired, s);
+}
+
+static void gpio_key_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = gpio_key_realize;
+    dc->vmsd = &vmstate_gpio_key;
+    dc->reset = &gpio_key_reset;
+}
+
+static const TypeInfo gpio_key_info = {
+    .name          = TYPE_GPIOKEY,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(GPIOKEYState),
+    .class_init    = gpio_key_class_init,
+};
+
+static void gpio_key_register_types(void)
+{
+    type_register_static(&gpio_key_info);
+}
+
+type_init(gpio_key_register_types)