ALSA: hdac: Add snd_hdac_ext_bus_link_power_down_all()

New HDA controllers like Skylake sport multiple HDA links, so we need a
helper to turn off all the links in one go while suspending the device so
add snd_hdac_ext_bus_link_power_down_all() API
Signed-off-by: Jeeja KP <jeeja.kp@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/hdaudio_ext.h

@@ -116,6 +116,7 @@ struct hdac_ext_link {
 
 int snd_hdac_ext_bus_link_power_up(struct hdac_ext_link *link);
 int snd_hdac_ext_bus_link_power_down(struct hdac_ext_link *link);
+int snd_hdac_ext_bus_link_power_down_all(struct hdac_ext_bus *ebus);
 void snd_hdac_ext_link_set_stream_id(struct hdac_ext_link *link,
 				 int stream);
 void snd_hdac_ext_link_clear_stream_id(struct hdac_ext_link *link,

sound/hda/ext/hdac_ext_controller.c

@@ -280,3 +280,23 @@ int snd_hdac_ext_bus_link_power_down(struct hdac_ext_link *link)
 	return check_hdac_link_power_active(link, false);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down);
+
+/**
+ * snd_hdac_ext_bus_link_power_down_all -power down all hda link
+ * @ebus: HD-audio extended bus
+ */
+int snd_hdac_ext_bus_link_power_down_all(struct hdac_ext_bus *ebus)
+{
+	struct hdac_ext_link *hlink = NULL;
+	int ret;
+
+	list_for_each_entry(hlink, &ebus->hlink_list, list) {
+		snd_hdac_updatel(hlink->ml_addr, AZX_REG_ML_LCTL, AZX_MLCTL_SPA, 0);
+		ret = check_hdac_link_power_active(hlink, false);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down_all);