ALSA: fireface: add proc node to help debugging

Drivers can retrieve the state and configuration of clock by read
transactions.

This commit allows protocol abstraction layer to to dump the
information for debugging, via proc interface.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/fireface/Makefile

-snd-fireface-objs := ff.o ff-transaction.o ff-midi.o
+snd-fireface-objs := ff.o ff-transaction.o ff-midi.o ff-proc.o
 obj-$(CONFIG_SND_FIREFACE) += snd-fireface.o

sound/firewire/fireface/ff-proc.c

+/*
+ * ff-proc.c - a part of driver for RME Fireface series
+ *
+ * Copyright (c) 2015-2017 Takashi Sakamoto
+ *
+ * Licensed under the terms of the GNU General Public License, version 2.
+ */
+
+#include "./ff.h"
+
+static void proc_dump_clock_config(struct snd_info_entry *entry,
+				   struct snd_info_buffer *buffer)
+{
+	struct snd_ff *ff = entry->private_data;
+
+	ff->spec->protocol->dump_clock_config(ff, buffer);
+}
+
+static void proc_dump_sync_status(struct snd_info_entry *entry,
+				  struct snd_info_buffer *buffer)
+{
+	struct snd_ff *ff = entry->private_data;
+
+	ff->spec->protocol->dump_sync_status(ff, buffer);
+}
+
+static void add_node(struct snd_ff *ff, struct snd_info_entry *root,
+		     const char *name,
+		     void (*op)(struct snd_info_entry *e,
+				struct snd_info_buffer *b))
+{
+	struct snd_info_entry *entry;
+
+	entry = snd_info_create_card_entry(ff->card, name, root);
+	if (entry == NULL)
+		return;
+
+	snd_info_set_text_ops(entry, ff, op);
+	if (snd_info_register(entry) < 0)
+		snd_info_free_entry(entry);
+}
+
+void snd_ff_proc_init(struct snd_ff *ff)
+{
+	struct snd_info_entry *root;
+
+	/*
+	 * All nodes are automatically removed at snd_card_disconnect(),
+	 * by following to link list.
+	 */
+	root = snd_info_create_card_entry(ff->card, "firewire",
+					  ff->card->proc_root);
+	if (root == NULL)
+		return;
+	root->mode = S_IFDIR | S_IRUGO | S_IXUGO;
+	if (snd_info_register(root) < 0) {
+		snd_info_free_entry(root);
+		return;
+	}
+
+	add_node(ff, root, "clock-config", proc_dump_clock_config);
+	add_node(ff, root, "sync-status", proc_dump_sync_status);
+}

sound/firewire/fireface/ff.c

@@ -61,6 +61,8 @@ static void do_registration(struct work_struct *work)
 
 	name_card(ff);
 
+	snd_ff_proc_init(ff);
+
 	err = snd_ff_create_midi_devices(ff);
 	if (err < 0)
 		goto error;

sound/firewire/fireface/ff.h

@@ -99,6 +99,8 @@ int snd_ff_transaction_register(struct snd_ff *ff);
 int snd_ff_transaction_reregister(struct snd_ff *ff);
 void snd_ff_transaction_unregister(struct snd_ff *ff);
 
+void snd_ff_proc_init(struct snd_ff *ff);
+
 int snd_ff_create_midi_devices(struct snd_ff *ff);
 
 #endif