[RFC PATCH v2 1/5] hw/misc: Add a LED device

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

A LED device can be connected to a GPIO output.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
 include/hw/misc/led.h | 30 ++++++++++++++++
 hw/misc/led.c         | 84 +++++++++++++++++++++++++++++++++++++++++++
 MAINTAINERS           |  6 ++++
 hw/misc/Kconfig       |  3 ++
 hw/misc/Makefile.objs |  1 +
 hw/misc/trace-events  |  3 ++
 6 files changed, 127 insertions(+)
 create mode 100644 include/hw/misc/led.h
 create mode 100644 hw/misc/led.c

diff --git a/include/hw/misc/led.h b/include/hw/misc/led.h
new file mode 100644
index 0000000000..427ca1418e
--- /dev/null
+++ b/include/hw/misc/led.h
@@ -0,0 +1,30 @@
+/*
+ * QEMU single LED device
+ *
+ * Copyright (C) 2020 Philippe Mathieu-Daudé <f4bug@amsat.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef HW_MISC_LED_H
+#define HW_MISC_LED_H
+
+#include "hw/qdev-core.h"
+#include "hw/sysbus.h" /* FIXME remove */
+
+#define TYPE_LED "led"
+#define LED(obj) OBJECT_CHECK(LEDState, (obj), TYPE_LED)
+
+typedef struct LEDState {
+    /* Private */
+    SysBusDevice parent_obj; /* FIXME DeviceState */
+    /* Public */
+
+    qemu_irq irq;
+    uint8_t current_state;
+
+    /* Properties */
+    char *name;
+    uint8_t reset_state; /* TODO [GPIO_ACTIVE_LOW, GPIO_ACTIVE_HIGH] */
+} LEDState;
+
+#endif /* HW_MISC_LED_H */
diff --git a/hw/misc/led.c b/hw/misc/led.c
new file mode 100644
index 0000000000..1bae1a34c0
--- /dev/null
+++ b/hw/misc/led.c
@@ -0,0 +1,84 @@
+/*
+ * QEMU single LED device
+ *
+ * Copyright (C) 2020 Philippe Mathieu-Daudé <f4bug@amsat.org>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "migration/vmstate.h"
+#include "hw/qdev-properties.h"
+#include "hw/misc/led.h"
+#include "hw/irq.h"
+#include "trace.h"
+
+static void led_set(void *opaque, int line, int new_state)
+{
+    LEDState *s = LED(opaque);
+
+    trace_led_set(s->name, s->current_state, new_state);
+
+    s->current_state = new_state;
+}
+
+static void led_reset(DeviceState *dev)
+{
+    LEDState *s = LED(dev);
+
+    led_set(dev, 0, s->reset_state);
+}
+
+static const VMStateDescription vmstate_led = {
+    .name = TYPE_LED,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8(reset_state, LEDState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void led_realize(DeviceState *dev, Error **errp)
+{
+    LEDState *s = LED(dev);
+
+    if (s->name == NULL) {
+        error_setg(errp, "property 'name' not specified");
+        return;
+    }
+
+    qdev_init_gpio_in(DEVICE(s), led_set, 1);
+}
+
+static Property led_properties[] = {
+    DEFINE_PROP_STRING("name", LEDState, name),
+    DEFINE_PROP_UINT8("reset_state", LEDState, reset_state, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void led_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->desc = "LED";
+    dc->vmsd = &vmstate_led;
+    dc->reset = led_reset;
+    dc->realize = led_realize;
+    set_bit(DEVICE_CATEGORY_DISPLAY, dc->categories);
+    device_class_set_props(dc, led_properties);
+}
+
+static const TypeInfo led_info = {
+    .name = TYPE_LED,
+    .parent = TYPE_SYS_BUS_DEVICE, /* FIXME TYPE_DEVICE */
+    .instance_size = sizeof(LEDState),
+    .class_init = led_class_init
+};
+
+static void led_register_types(void)
+{
+    type_register_static(&led_info);
+}
+
+type_init(led_register_types)
diff --git a/MAINTAINERS b/MAINTAINERS
index 3abe3faa4e..10593863dc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1857,6 +1857,12 @@ F: docs/specs/vmgenid.txt
 F: tests/qtest/vmgenid-test.c
 F: stubs/vmgenid.c
 
+LED
+M: Philippe Mathieu-Daudé <f4bug@amsat.org>
+S: Maintained
+F: include/hw/misc/led.h
+F: hw/misc/led.c
+
 Unimplemented device
 M: Peter Maydell <peter.maydell@linaro.org>
 R: Philippe Mathieu-Daudé <f4bug@amsat.org>
diff --git a/hw/misc/Kconfig b/hw/misc/Kconfig
index bdd77d8020..f60dce694d 100644
--- a/hw/misc/Kconfig
+++ b/hw/misc/Kconfig
@@ -126,6 +126,9 @@ config AUX
 config UNIMP
     bool
 
+config LED
+    bool
+
 config MAC_VIA
     bool
     select MOS6522
diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index 5aaca8a039..9efa3c941c 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -91,3 +91,4 @@ common-obj-$(CONFIG_NRF51_SOC) += nrf51_rng.o
 obj-$(CONFIG_MAC_VIA) += mac_via.o
 
 common-obj-$(CONFIG_GRLIB) += grlib_ahb_apb_pnp.o
+common-obj-$(CONFIG_LED) += led.o
diff --git a/hw/misc/trace-events b/hw/misc/trace-events
index 5561746866..e15b7f7c81 100644
--- a/hw/misc/trace-events
+++ b/hw/misc/trace-events
@@ -206,3 +206,6 @@ via1_rtc_cmd_pram_sect_write(int sector, int offset, int addr, int value) "secto
 # grlib_ahb_apb_pnp.c
 grlib_ahb_pnp_read(uint64_t addr, uint32_t value) "AHB PnP read addr:0x%03"PRIx64" data:0x%08x"
 grlib_apb_pnp_read(uint64_t addr, uint32_t value) "APB PnP read addr:0x%03"PRIx64" data:0x%08x"
+
+# led.c
+led_set(const char *name, uint8_t old_state, uint8_t new_state) "led name:'%s' state %d -> %d"
-- 
2.21.3