ALSA: ac97: add an ac97 bus

AC97 is a bus for sound usage. It enables for a AC97 AC-Link to link one
controller to 0 to 4 AC97 codecs.

The goal of this new implementation is to implement a device/driver
model for AC97, with an automatic scan of the bus and automatic
discovery of AC97 codec devices.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/ac97/snd_ac97_compat.c b/sound/ac97/snd_ac97_compat.c
new file mode 100644
index 0000000..61544e0
--- /dev/null
+++ b/sound/ac97/snd_ac97_compat.c
@@ -0,0 +1,108 @@
+/*
+ *  Copyright (C) 2016 Robert Jarzmik <robert.jarzmik@free.fr>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <sound/ac97/codec.h>
+#include <sound/ac97/compat.h>
+#include <sound/ac97/controller.h>
+#include <sound/soc.h>
+
+#include "ac97_core.h"
+
+static void compat_ac97_reset(struct snd_ac97 *ac97)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+
+	if (actrl->ops->reset)
+		actrl->ops->reset(actrl);
+}
+
+static void compat_ac97_warm_reset(struct snd_ac97 *ac97)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+
+	if (actrl->ops->warm_reset)
+		actrl->ops->warm_reset(actrl);
+}
+
+static void compat_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
+			      unsigned short val)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+
+	actrl->ops->write(actrl, ac97->num, reg, val);
+}
+
+static unsigned short compat_ac97_read(struct snd_ac97 *ac97,
+				       unsigned short reg)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+
+	return actrl->ops->read(actrl, ac97->num, reg);
+}
+
+static struct snd_ac97_bus_ops compat_snd_ac97_bus_ops = {
+	.reset = compat_ac97_reset,
+	.warm_reset = compat_ac97_warm_reset,
+	.write = compat_ac97_write,
+	.read = compat_ac97_read,
+};
+
+static struct snd_ac97_bus compat_soc_ac97_bus = {
+	.ops = &compat_snd_ac97_bus_ops,
+};
+
+struct snd_ac97 *snd_ac97_compat_alloc(struct ac97_codec_device *adev)
+{
+	struct snd_ac97 *ac97;
+
+	ac97 = kzalloc(sizeof(struct snd_ac97), GFP_KERNEL);
+	if (ac97 == NULL)
+		return ERR_PTR(-ENOMEM);
+
+	ac97->dev = adev->dev;
+	ac97->private_data = adev;
+	ac97->bus = &compat_soc_ac97_bus;
+	return ac97;
+}
+EXPORT_SYMBOL_GPL(snd_ac97_compat_alloc);
+
+void snd_ac97_compat_release(struct snd_ac97 *ac97)
+{
+	kfree(ac97);
+}
+EXPORT_SYMBOL_GPL(snd_ac97_compat_release);
+
+int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
+	unsigned int id_mask)
+{
+	struct ac97_codec_device *adev = to_ac97_device(ac97->private_data);
+	struct ac97_controller *actrl = adev->ac97_ctrl;
+	unsigned int scanned;
+
+	if (try_warm) {
+		compat_ac97_warm_reset(ac97);
+		scanned = snd_ac97_bus_scan_one(actrl, adev->num);
+		if (ac97_ids_match(scanned, adev->vendor_id, id_mask))
+			return 1;
+	}
+
+	compat_ac97_reset(ac97);
+	compat_ac97_warm_reset(ac97);
+	scanned = snd_ac97_bus_scan_one(actrl, adev->num);
+	if (ac97_ids_match(scanned, adev->vendor_id, id_mask))
+		return 0;
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(snd_ac97_reset);