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