xref: /openbmc/qemu/hw/misc/led.c (revision e4ea952f)
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 
led_color_name_is_valid(const char * color_name)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 
led_set_intensity(LEDState * s,unsigned intensity_percent)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 
led_get_intensity(LEDState * s)51 unsigned led_get_intensity(LEDState *s)
52 {
53     return s->intensity_percent;
54 }
55 
led_set_state(LEDState * s,bool is_emitting)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 
led_set_state_gpio_handler(void * opaque,int line,int new_state)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 
led_reset(DeviceState * dev)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 = (const VMStateField[]) {
81         VMSTATE_UINT8(intensity_percent, LEDState),
82         VMSTATE_END_OF_LIST()
83     }
84 };
85 
led_realize(DeviceState * dev,Error ** errp)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 
led_class_init(ObjectClass * klass,void * data)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 
led_register_types(void)130 static void led_register_types(void)
131 {
132     type_register_static(&led_info);
133 }
134 
type_init(led_register_types)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 }
162