hw/misc/led: Add a LED device

Add a LED device which can be connected to a GPIO output.
They can also be dimmed with PWM devices. For now we do
not implement the dimmed mode, but in preparation of a
future implementation, we start using the LED intensity.

LEDs are limited to a fixed set of colors.

Reviewed-by: Luc Michel <luc.michel@greensocs.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20200912134041.946260-2-f4bug@amsat.org>

1 files changed, 87 insertions, 0 deletions

diff --git a/include/hw/misc/led.h b/include/hw/misc/led.h
new file mode 100644
index 0000000000..286d37c75c
--- /dev/null
+++ b/include/hw/misc/led.h
@@ -0,0 +1,87 @@
+/*
+ * 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 "qom/object.h"
+
+#define TYPE_LED "led"
+
+/**
+ * LEDColor: Color of a LED
+ *
+ * This set is restricted to physically available LED colors.
+ *
+ * LED colors from 'Table 1. Product performance of LUXEON Rebel Color
+ * Line' of the 'DS68 LUXEON Rebel Color Line' datasheet available at:
+ * https://www.lumileds.com/products/color-leds/luxeon-rebel-color/
+ */
+typedef enum {          /* Coarse wavelength range */
+    LED_COLOR_VIOLET,   /* 425 nm */
+    LED_COLOR_BLUE,     /* 475 nm */
+    LED_COLOR_CYAN,     /* 500 nm */
+    LED_COLOR_GREEN,    /* 535 nm */
+    LED_COLOR_AMBER,    /* 590 nm */
+    LED_COLOR_ORANGE,   /* 615 nm */
+    LED_COLOR_RED,      /* 630 nm */
+} LEDColor;
+
+struct LEDState {
+    /* Private */
+    DeviceState parent_obj;
+    /* Public */
+
+    uint8_t intensity_percent;
+
+    /* Properties */
+    char *description;
+    char *color;
+};
+typedef struct LEDState LEDState;
+DECLARE_INSTANCE_CHECKER(LEDState, LED, TYPE_LED)
+
+/**
+ * led_set_intensity: Set the intensity of a LED device
+ * @s: the LED object
+ * @intensity_percent: intensity as percentage in range 0 to 100.
+ */
+void led_set_intensity(LEDState *s, unsigned intensity_percent);
+
+/**
+ * led_get_intensity:
+ * @s: the LED object
+ *
+ * Returns: The LED intensity as percentage in range 0 to 100.
+ */
+unsigned led_get_intensity(LEDState *s);
+
+/**
+ * led_set_state: Set the state of a LED device
+ * @s: the LED object
+ * @is_emitting: boolean indicating whether the LED is emitting
+ *
+ * This utility is meant for LED connected to GPIO.
+ */
+void led_set_state(LEDState *s, bool is_emitting);
+
+/**
+ * led_create_simple: Create and realize a LED device
+ * @parentobj: the parent object
+ * @color: color of the LED
+ * @description: description of the LED (optional)
+ *
+ * Create the device state structure, initialize it, and
+ * drop the reference to it (the device is realized).
+ *
+ * Returns: The newly allocated and instantiated LED object.
+ */
+LEDState *led_create_simple(Object *parentobj,
+                            LEDColor color,
+                            const char *description);
+
+#endif /* HW_MISC_LED_H */