ALSA: fireface: add skeleton for RME Fireface series

This commit adds a new driver for RME Fireface series. This commit just
creates/removes card instance according to IEEE 1394 bus event. More
functions will be added in following commits.

Three types of firmware have released by RME GmbH; for Fireface 400, for
Fireface 800 and for UCX/802/UFX. It's reasonable that these models use
different protocol for communication. Currently, I've investigated
Fireface 400 and nothing others.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/firewire/Kconfig

@@ -152,4 +152,10 @@ config SND_FIREWIRE_MOTU
 	 To compile this driver as a module, choose M here: the module
 	 will be called snd-firewire-motu.
 
+config SND_FIREFACE
+	tristate "RME Fireface series support"
+	select SND_FIREWIRE_LIB
+	help
+	 Say Y here to include support for RME fireface series.
+
 endif # SND_FIREWIRE

sound/firewire/Makefile

@@ -14,3 +14,4 @@ obj-$(CONFIG_SND_BEBOB) += bebob/
 obj-$(CONFIG_SND_FIREWIRE_DIGI00X) += digi00x/
 obj-$(CONFIG_SND_FIREWIRE_TASCAM) += tascam/
 obj-$(CONFIG_SND_FIREWIRE_MOTU) += motu/
+obj-$(CONFIG_SND_FIREFACE) += fireface/

sound/firewire/fireface/Makefile

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

sound/firewire/fireface/ff.c

+/*
+ * ff.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"
+
+#define OUI_RME	0x000a35
+
+MODULE_DESCRIPTION("RME Fireface series Driver");
+MODULE_AUTHOR("Takashi Sakamoto <o-takashi@sakamocchi.jp>");
+MODULE_LICENSE("GPL v2");
+
+static void name_card(struct snd_ff *ff)
+{
+	struct fw_device *fw_dev = fw_parent_device(ff->unit);
+	const char *const model = "Fireface Skeleton";
+
+	strcpy(ff->card->driver, "Fireface");
+	strcpy(ff->card->shortname, model);
+	strcpy(ff->card->mixername, model);
+	snprintf(ff->card->longname, sizeof(ff->card->longname),
+		 "RME %s, GUID %08x%08x at %s, S%d", model,
+		 fw_dev->config_rom[3], fw_dev->config_rom[4],
+		 dev_name(&ff->unit->device), 100 << fw_dev->max_speed);
+}
+
+static void ff_card_free(struct snd_card *card)
+{
+	struct snd_ff *ff = card->private_data;
+
+	fw_unit_put(ff->unit);
+
+	mutex_destroy(&ff->mutex);
+}
+
+static int snd_ff_probe(struct fw_unit *unit,
+			   const struct ieee1394_device_id *entry)
+{
+	struct snd_card *card;
+	struct snd_ff *ff;
+	int err;
+
+	err = snd_card_new(&unit->device, -1, NULL, THIS_MODULE,
+			   sizeof(struct snd_ff), &card);
+	if (err < 0)
+		return err;
+	card->private_free = ff_card_free;
+
+	/* initialize myself */
+	ff = card->private_data;
+	ff->card = card;
+	ff->unit = fw_unit_get(unit);
+	dev_set_drvdata(&unit->device, ff);
+
+	mutex_init(&ff->mutex);
+
+	name_card(ff);
+
+	err = snd_card_register(card);
+	if (err < 0) {
+		snd_card_free(card);
+		return err;
+	}
+
+	return 0;
+}
+
+static void snd_ff_update(struct fw_unit *unit)
+{
+	return;
+}
+
+static void snd_ff_remove(struct fw_unit *unit)
+{
+	struct snd_ff *ff = dev_get_drvdata(&unit->device);
+
+	/* No need to wait for releasing card object in this context. */
+	snd_card_free_when_closed(ff->card);
+}
+
+static const struct ieee1394_device_id snd_ff_id_table[] = {
+	{}
+};
+MODULE_DEVICE_TABLE(ieee1394, snd_ff_id_table);
+
+static struct fw_driver ff_driver = {
+	.driver = {
+		.owner	= THIS_MODULE,
+		.name	= "snd-fireface",
+		.bus	= &fw_bus_type,
+	},
+	.probe    = snd_ff_probe,
+	.update   = snd_ff_update,
+	.remove   = snd_ff_remove,
+	.id_table = snd_ff_id_table,
+};
+
+static int __init snd_ff_init(void)
+{
+	return driver_register(&ff_driver.driver);
+}
+
+static void __exit snd_ff_exit(void)
+{
+	driver_unregister(&ff_driver.driver);
+}
+
+module_init(snd_ff_init);
+module_exit(snd_ff_exit);

sound/firewire/fireface/ff.h

+/*
+ * ff.h - 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.
+ */
+
+#ifndef SOUND_FIREFACE_H_INCLUDED
+#define SOUND_FIREFACE_H_INCLUDED
+
+#include <linux/device.h>
+#include <linux/firewire.h>
+#include <linux/firewire-constants.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/compat.h>
+
+#include <sound/core.h>
+
+struct snd_ff {
+	struct snd_card *card;
+	struct fw_unit *unit;
+	struct mutex mutex;
+};
+#endif