led: Add flash LED type

Camera flashes are also exported via the LED subsystem. We use a
separate LED type so they're not picked by default.

We don't use them as fallbacks either.

src/fbd-dev-led-flash.c

@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2024 The Phosh Developers
+ *
+ * SPDX-License-Identifier: GPL-3.0+
+ * Author: Guido Günther <agx@sigxcpu.org>
+ *
+ * See Documentation/ABI/testing/sysfs-class-led-trigger-pattern
+ */
+
+#define G_LOG_DOMAIN "fbd-dev-led-flash"
+
+#include "fbd-dev-led-priv.h"
+#include "fbd-dev-led-flash.h"
+#include "fbd-enums.h"
+#include "fbd-udev.h"
+
+#include <gio/gio.h>
+
+/**
+ * fbd-dev-led-flash:
+ *
+ * The LED of a camera flash
+ */
+typedef struct _FbdDevLedFlash {
+  FbdDevLed parent;
+} FbdDevLedFlash;
+
+
+G_DEFINE_TYPE (FbdDevLedFlash, fbd_dev_led_flash, FBD_TYPE_DEV_LED)
+
+
+static gboolean
+fbd_dev_led_flash_probe (FbdDevLed *led, GError **error)
+{
+  GUdevDevice *dev = fbd_dev_led_get_device (led);
+  const gchar *name, *path;
+  guint max_brightness;
+
+  name = g_udev_device_get_name (dev);
+  if (!g_udev_device_get_sysfs_attr (dev, "flash_strobe") ||
+      !g_udev_device_get_sysfs_attr (dev, "flash_brightness")) {
+    g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_FAILED, "%s is no flash LED", name);
+    return FALSE;
+  }
+
+  max_brightness = g_udev_device_get_sysfs_attr_as_int (dev, LED_MAX_BRIGHTNESS_ATTR);
+  if (!max_brightness) {
+    g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_FAILED, "%s has no max_brightness", name);
+    return FALSE;
+  }
+
+  fbd_dev_led_set_max_brightness (led, max_brightness);
+  fbd_dev_led_set_supported_color (led, FBD_FEEDBACK_LED_COLOR_FLASH);
+
+  path = g_udev_device_get_sysfs_path (dev);
+  g_debug ("LED at '%s' usable as flash", path);
+
+  return TRUE;
+}
+
+
+static void
+fbd_dev_led_flash_class_init (FbdDevLedFlashClass *klass)
+{
+  FbdDevLedClass *fbd_dev_led_class = FBD_DEV_LED_CLASS (klass);
+
+  fbd_dev_led_class->probe = fbd_dev_led_flash_probe;
+}
+
+
+static void
+fbd_dev_led_flash_init (FbdDevLedFlash *self)
+{
+}
+
+
+FbdDevLed *
+fbd_dev_led_flash_new (GUdevDevice *dev, GError **err)
+{
+  return g_initable_new (FBD_TYPE_DEV_LED_FLASH, NULL, err, "dev", dev, NULL);
+}

src/fbd-dev-led-flash.h

@@ -0,0 +1,18 @@
+/*
+ * Copyright (C) 2024 The Phosh Developers
+ *
+ * SPDX-License-Identifier: GPL-3.0+
+ */
+#pragma once
+
+#include "fbd-dev-led.h"
+
+G_BEGIN_DECLS
+
+#define FBD_TYPE_DEV_LED_FLASH fbd_dev_led_flash_get_type()
+
+G_DECLARE_FINAL_TYPE (FbdDevLedFlash, fbd_dev_led_flash, FBD, DEV_LED_FLASH, FbdDevLed)
+
+FbdDevLed          *fbd_dev_led_flash_new  (GUdevDevice *dev, GError **err);
+
+G_END_DECLS

src/fbd-dev-leds.c

@@ -53,8 +53,15 @@ find_led_by_color (FbdDevLeds *self, FbdFeedbackLedColor color)
       return led;
   }
 
-  /* If we did not match a color pick the first */
-  return self->leds->data;
+  /* If we did not match a color pick the first non flash LED */
+  for (GSList *l = self->leds; l != NULL; l = l->next) {
+    FbdDevLed *led = FBD_DEV_LED (l->data);
+
+    if (!fbd_dev_led_supports_color (led, FBD_FEEDBACK_LED_COLOR_FLASH))
+      return led;
+  }
+
+  return NULL;
 }
 
 

src/fbd-feedback-led.h

@@ -16,6 +16,7 @@ G_BEGIN_DECLS
  * @FBD_FEEDBACK_LED_COLOR_GREEN: A green LED
  * @FBD_FEEDBACK_LED_COLOR_BLUE: A blue LED
  * @FBD_FEEDBACK_LED_COLOR_RGB: A multicolor LED that can display arbitrary RGB values
+ * @FBD_FEEDBACK_LED_COLOR_FLASH: A flash (usually white)
  *
  * The color of a hardware LED.
  */
@@ -25,6 +26,8 @@ typedef enum _FbdFeedbackLedColor {
   FBD_FEEDBACK_LED_COLOR_GREEN = 2,
   FBD_FEEDBACK_LED_COLOR_BLUE = 3,
   FBD_FEEDBACK_LED_COLOR_RGB = 4,
+  /* Keep this last in the list */
+  FBD_FEEDBACK_LED_COLOR_FLASH = 5,
 } FbdFeedbackLedColor;
 
 typedef struct {

src/meson.build

@@ -16,6 +16,7 @@ sources = [
   'fbd-dev-vibra.c',
   'fbd-dev-sound.c',
   'fbd-dev-led.c',
+  'fbd-dev-led-flash.c',
   'fbd-dev-led-multicolor.c',
   'fbd-dev-led-qcom.c',
   'fbd-dev-led-qcom-multicolor.c',