qemu/hw/misc/led.c
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   1/*
   2 * QEMU single LED device
   3 *
   4 * Copyright (C) 2020 Philippe Mathieu-Daudé <f4bug@amsat.org>
   5 *
   6 * SPDX-License-Identifier: GPL-2.0-or-later
   7 */
   8#include "qemu/osdep.h"
   9#include "qapi/error.h"
  10#include "migration/vmstate.h"
  11#include "hw/qdev-properties.h"
  12#include "hw/misc/led.h"
  13#include "trace.h"
  14
  15#define LED_INTENSITY_PERCENT_MAX   100
  16
  17static const char * const led_color_name[] = {
  18    [LED_COLOR_VIOLET]  = "violet",
  19    [LED_COLOR_BLUE]    = "blue",
  20    [LED_COLOR_CYAN]    = "cyan",
  21    [LED_COLOR_GREEN]   = "green",
  22    [LED_COLOR_YELLOW]  = "yellow",
  23    [LED_COLOR_AMBER]   = "amber",
  24    [LED_COLOR_ORANGE]  = "orange",
  25    [LED_COLOR_RED]     = "red",
  26};
  27
  28static bool led_color_name_is_valid(const char *color_name)
  29{
  30    for (size_t i = 0; i < ARRAY_SIZE(led_color_name); i++) {
  31        if (strcmp(color_name, led_color_name[i]) == 0) {
  32            return true;
  33        }
  34    }
  35    return false;
  36}
  37
  38void led_set_intensity(LEDState *s, unsigned intensity_percent)
  39{
  40    if (intensity_percent > LED_INTENSITY_PERCENT_MAX) {
  41        intensity_percent = LED_INTENSITY_PERCENT_MAX;
  42    }
  43    trace_led_set_intensity(s->description, s->color, intensity_percent);
  44    if (intensity_percent != s->intensity_percent) {
  45        trace_led_change_intensity(s->description, s->color,
  46                                   s->intensity_percent, intensity_percent);
  47    }
  48    s->intensity_percent = intensity_percent;
  49}
  50
  51unsigned led_get_intensity(LEDState *s)
  52{
  53    return s->intensity_percent;
  54}
  55
  56void led_set_state(LEDState *s, bool is_emitting)
  57{
  58    led_set_intensity(s, is_emitting ? LED_INTENSITY_PERCENT_MAX : 0);
  59}
  60
  61static void led_set_state_gpio_handler(void *opaque, int line, int new_state)
  62{
  63    LEDState *s = LED(opaque);
  64
  65    assert(line == 0);
  66    led_set_state(s, !!new_state != s->gpio_active_high);
  67}
  68
  69static void led_reset(DeviceState *dev)
  70{
  71    LEDState *s = LED(dev);
  72
  73    led_set_state(s, s->gpio_active_high);
  74}
  75
  76static const VMStateDescription vmstate_led = {
  77    .name = TYPE_LED,
  78    .version_id = 1,
  79    .minimum_version_id = 1,
  80    .fields = (VMStateField[]) {
  81        VMSTATE_UINT8(intensity_percent, LEDState),
  82        VMSTATE_END_OF_LIST()
  83    }
  84};
  85
  86static void led_realize(DeviceState *dev, Error **errp)
  87{
  88    LEDState *s = LED(dev);
  89
  90    if (s->color == NULL) {
  91        error_setg(errp, "property 'color' not specified");
  92        return;
  93    } else if (!led_color_name_is_valid(s->color)) {
  94        error_setg(errp, "property 'color' invalid or not supported");
  95        return;
  96    }
  97    if (s->description == NULL) {
  98        s->description = g_strdup("n/a");
  99    }
 100
 101    qdev_init_gpio_in(DEVICE(s), led_set_state_gpio_handler, 1);
 102}
 103
 104static Property led_properties[] = {
 105    DEFINE_PROP_STRING("color", LEDState, color),
 106    DEFINE_PROP_STRING("description", LEDState, description),
 107    DEFINE_PROP_BOOL("gpio-active-high", LEDState, gpio_active_high, true),
 108    DEFINE_PROP_END_OF_LIST(),
 109};
 110
 111static void led_class_init(ObjectClass *klass, void *data)
 112{
 113    DeviceClass *dc = DEVICE_CLASS(klass);
 114
 115    dc->desc = "LED";
 116    dc->vmsd = &vmstate_led;
 117    dc->reset = led_reset;
 118    dc->realize = led_realize;
 119    set_bit(DEVICE_CATEGORY_DISPLAY, dc->categories);
 120    device_class_set_props(dc, led_properties);
 121}
 122
 123static const TypeInfo led_info = {
 124    .name = TYPE_LED,
 125    .parent = TYPE_DEVICE,
 126    .instance_size = sizeof(LEDState),
 127    .class_init = led_class_init
 128};
 129
 130static void led_register_types(void)
 131{
 132    type_register_static(&led_info);
 133}
 134
 135type_init(led_register_types)
 136
 137LEDState *led_create_simple(Object *parentobj,
 138                            GpioPolarity gpio_polarity,
 139                            LEDColor color,
 140                            const char *description)
 141{
 142    g_autofree char *name = NULL;
 143    DeviceState *dev;
 144
 145    dev = qdev_new(TYPE_LED);
 146    qdev_prop_set_bit(dev, "gpio-active-high",
 147                      gpio_polarity == GPIO_POLARITY_ACTIVE_HIGH);
 148    qdev_prop_set_string(dev, "color", led_color_name[color]);
 149    if (!description) {
 150        static unsigned undescribed_led_id;
 151        name = g_strdup_printf("undescribed-led-#%u", undescribed_led_id++);
 152    } else {
 153        qdev_prop_set_string(dev, "description", description);
 154        name = g_ascii_strdown(description, -1);
 155        name = g_strdelimit(name, " #", '-');
 156    }
 157    object_property_add_child(parentobj, name, OBJECT(dev));
 158    qdev_realize_and_unref(dev, NULL, &error_fatal);
 159
 160    return LED(dev);
 161}
 162