hw/misc/led.c

   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
  17 static 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
  28 static 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
  38 void 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
  51 unsigned led_get_intensity(LEDState *s)
  52 {
  53     return s->intensity_percent;
  54 }
  55
  56 void led_set_state(LEDState *s, bool is_emitting)
  57 {
  58     led_set_intensity(s, is_emitting ? LED_INTENSITY_PERCENT_MAX : 0);
  59 }
  60
  61 static 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
  69 static void led_reset(DeviceState *dev)
  70 {
  71     LEDState *s = LED(dev);
  72
  73     led_set_state(s, s->gpio_active_high);
  74 }
  75
  76 static 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
  86 static 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
 104 static 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
 111 static 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
 123 static 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
 130 static void led_register_types(void)
 131 {
 132     type_register_static(&led_info);
 133 }
 134
 135 type_init(led_register_types)
 136
 137 LEDState *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 }