[ALSA] virtuoso: monitor external power on D2X

On the Xonar D2X, monitor the GPIO pin that indicates whether external
power is present.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/pci/oxygen/oxygen.h b/sound/pci/oxygen/oxygen.h
index e71c534..ad50fb8 100644
--- a/sound/pci/oxygen/oxygen.h
+++ b/sound/pci/oxygen/oxygen.h
@@ -66,6 +66,7 @@
 	struct snd_pcm_substream *streams[PCM_COUNT];
 	struct snd_kcontrol *controls[CONTROL_COUNT];
 	struct work_struct spdif_input_bits_work;
+	struct work_struct gpio_work;
 	wait_queue_head_t ac97_waitqueue;
 };
 
@@ -88,6 +89,7 @@
 	void (*update_dac_mute)(struct oxygen *chip);
 	void (*ac97_switch_hook)(struct oxygen *chip, unsigned int codec,
 				 unsigned int reg, int mute);
+	void (*gpio_changed)(struct oxygen *chip);
 	size_t model_data_size;
 	u8 dac_channels;
 	u8 used_channels;