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 <[email protected]>
Reviewed-by: Takashi Iwai <[email protected]>
Signed-off-by: Mark Brown <[email protected]>

include/sound/ac97/codec.h

@@ -0,0 +1,118 @@
+/*
+ *  Copyright (C) 2016 Robert Jarzmik <[email protected]>
+ *
+ * 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.
+ */
+#ifndef __SOUND_AC97_CODEC2_H
+#define __SOUND_AC97_CODEC2_H
+
+#include <linux/device.h>
+
+#define AC97_ID(vendor_id1, vendor_id2) \
+	((((vendor_id1) & 0xffff) << 16) | ((vendor_id2) & 0xffff))
+#define AC97_DRIVER_ID(vendor_id1, vendor_id2, mask_id1, mask_id2, _data) \
+	{ .id = (((vendor_id1) & 0xffff) << 16) | ((vendor_id2) & 0xffff), \
+	  .mask = (((mask_id1) & 0xffff) << 16) | ((mask_id2) & 0xffff), \
+	  .data = (_data) }
+
+struct ac97_controller;
+struct clk;
+
+/**
+ * struct ac97_id - matches a codec device and driver on an ac97 bus
+ * @id: The significant bits if the codec vendor ID1 and ID2
+ * @mask: Bitmask specifying which bits of the id field are significant when
+ *	  matching. A driver binds to a device when :
+ *        ((vendorID1 << 8 | vendorID2) & (mask_id1 << 8 | mask_id2)) == id.
+ * @data: Private data used by the driver.
+ */
+struct ac97_id {
+	unsigned int		id;
+	unsigned int		mask;
+	void			*data;
+};
+
+/**
+ * ac97_codec_device - a ac97 codec
+ * @dev: the core device
+ * @vendor_id: the vendor_id of the codec, as sensed on the AC-link
+ * @num: the codec number, 0 is primary, 1 is first slave, etc ...
+ * @clk: the clock BIT_CLK provided by the codec
+ * @ac97_ctrl: ac97 digital controller on the same AC-link
+ *
+ * This is the device instantiated for each codec living on a AC-link. There are
+ * normally 0 to 4 codec devices per AC-link, and all of them are controlled by
+ * an AC97 digital controller.
+ */
+struct ac97_codec_device {
+	struct device		dev;
+	unsigned int		vendor_id;
+	unsigned int		num;
+	struct clk		*clk;
+	struct ac97_controller	*ac97_ctrl;
+};
+
+/**
+ * ac97_codec_driver - a ac97 codec driver
+ * @driver: the device driver structure
+ * @probe: the function called when a ac97_codec_device is matched
+ * @remove: the function called when the device is unbound/removed
+ * @shutdown: shutdown function (might be NULL)
+ * @id_table: ac97 vendor_id match table, { } member terminated
+ */
+struct ac97_codec_driver {
+	struct device_driver	driver;
+	int			(*probe)(struct ac97_codec_device *);
+	int			(*remove)(struct ac97_codec_device *);
+	void			(*shutdown)(struct ac97_codec_device *);
+	const struct ac97_id	*id_table;
+};
+
+static inline struct ac97_codec_device *to_ac97_device(struct device *d)
+{
+	return container_of(d, struct ac97_codec_device, dev);
+}
+
+static inline struct ac97_codec_driver *to_ac97_driver(struct device_driver *d)
+{
+	return container_of(d, struct ac97_codec_driver, driver);
+}
+
+#if IS_ENABLED(CONFIG_AC97_BUS_NEW)
+int snd_ac97_codec_driver_register(struct ac97_codec_driver *drv);
+void snd_ac97_codec_driver_unregister(struct ac97_codec_driver *drv);
+#else
+static inline int
+snd_ac97_codec_driver_register(struct ac97_codec_driver *drv)
+{
+	return 0;
+}
+static inline void
+snd_ac97_codec_driver_unregister(struct ac97_codec_driver *drv)
+{
+}
+#endif
+
+
+static inline struct device *
+ac97_codec_dev2dev(struct ac97_codec_device *adev)
+{
+	return &adev->dev;
+}
+
+static inline void *ac97_get_drvdata(struct ac97_codec_device *adev)
+{
+	return dev_get_drvdata(ac97_codec_dev2dev(adev));
+}
+
+static inline void ac97_set_drvdata(struct ac97_codec_device *adev,
+				    void *data)
+{
+	dev_set_drvdata(ac97_codec_dev2dev(adev), data);
+}
+
+void *snd_ac97_codec_get_platdata(const struct ac97_codec_device *adev);
+
+#endif

include/sound/ac97/compat.h

@@ -0,0 +1,20 @@
+/*
+ *  Copyright (C) 2016 Robert Jarzmik <[email protected]>
+ *
+ * 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.
+ *
+ * This file is for backward compatibility with snd_ac97 structure and its
+ * multiple usages, such as the snd_ac97_bus and snd_ac97_build_ops.
+ *
+ */
+#ifndef AC97_COMPAT_H
+#define AC97_COMPAT_H
+
+#include <sound/ac97_codec.h>
+
+struct snd_ac97 *snd_ac97_compat_alloc(struct ac97_codec_device *adev);
+void snd_ac97_compat_release(struct snd_ac97 *ac97);
+
+#endif

include/sound/ac97/controller.h

@@ -0,0 +1,85 @@
+/*
+ *  Copyright (C) 2016 Robert Jarzmik <[email protected]>
+ *
+ * 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.
+ */
+#ifndef AC97_CONTROLLER_H
+#define AC97_CONTROLLER_H
+
+#include <linux/device.h>
+#include <linux/list.h>
+
+#define AC97_BUS_MAX_CODECS 4
+#define AC97_SLOTS_AVAILABLE_ALL 0xf
+
+struct ac97_controller_ops;
+
+/**
+ * struct ac97_controller - The AC97 controller of the AC-Link
+ * @ops:		the AC97 operations.
+ * @controllers:	linked list of all existing controllers.
+ * @adap:		the shell device ac97-%d, ie. ac97 adapter
+ * @nr:			the number of the shell device
+ * @slots_available:	the mask of accessible/scanable codecs.
+ * @parent:		the device providing the AC97 controller.
+ * @codecs:		the 4 possible AC97 codecs (NULL if none found).
+ * @codecs_pdata:	platform_data for each codec (NULL if no pdata).
+ *
+ * This structure is internal to AC97 bus, and should not be used by the
+ * controllers themselves, excepting for using @dev.
+ */
+struct ac97_controller {
+	const struct ac97_controller_ops *ops;
+	struct list_head controllers;
+	struct device adap;
+	int nr;
+	unsigned short slots_available;
+	struct device *parent;
+	struct ac97_codec_device *codecs[AC97_BUS_MAX_CODECS];
+	void *codecs_pdata[AC97_BUS_MAX_CODECS];
+};
+
+/**
+ * struct ac97_controller_ops - The AC97 operations
+ * @reset:	Cold reset of the AC97 AC-Link.
+ * @warm_reset:	Warm reset of the AC97 AC-Link.
+ * @read:	Read of a single AC97 register.
+ *		Returns the register value or a negative error code.
+ * @write:	Write of a single AC97 register.
+ *
+ * These are the basic operation an AC97 controller must provide for an AC97
+ * access functions. Amongst these, all but the last 2 are mandatory.
+ * The slot number is also known as the AC97 codec number, between 0 and 3.
+ */
+struct ac97_controller_ops {
+	void (*reset)(struct ac97_controller *adrv);
+	void (*warm_reset)(struct ac97_controller *adrv);
+	int (*write)(struct ac97_controller *adrv, int slot,
+		     unsigned short reg, unsigned short val);
+	int (*read)(struct ac97_controller *adrv, int slot, unsigned short reg);
+};
+
+#if IS_ENABLED(CONFIG_AC97_BUS_NEW)
+struct ac97_controller *snd_ac97_controller_register(
+	const struct ac97_controller_ops *ops, struct device *dev,
+	unsigned short slots_available, void **codecs_pdata);
+void snd_ac97_controller_unregister(struct ac97_controller *ac97_ctrl);
+#else
+static inline struct ac97_controller *
+snd_ac97_controller_register(const struct ac97_controller_ops *ops,
+			     struct device *dev,
+			     unsigned short slots_available,
+			     void **codecs_pdata)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline void
+snd_ac97_controller_unregister(struct ac97_controller *ac97_ctrl)
+{
+}
+#endif
+
+#endif

sound/ac97/Kconfig

@@ -0,0 +1,19 @@
+#
+# AC97 configuration
+#
+
+
+config AC97_BUS_NEW
+	tristate
+	select AC97
+	help
+	  This is the new AC97 bus type, successor of AC97_BUS. The ported
+	  drivers which benefit from the AC97 automatic probing should "select"
+	  this instead of the AC97_BUS.
+	  Say Y here if you want to have AC97 devices, which are sound oriented
+	  devices around an AC-Link.
+
+config AC97_BUS_COMPAT
+	bool
+	depends on AC97_BUS_NEW
+	depends on !AC97_BUS

sound/ac97/Makefile

@@ -0,0 +1,8 @@
+#
+# make for AC97 bus drivers
+#
+
+obj-$(CONFIG_AC97_BUS_NEW)	+= ac97.o
+
+ac97-y				+= bus.o codec.o
+ac97-$(CONFIG_AC97_BUS_COMPAT)	+= snd_ac97_compat.o

sound/ac97/ac97_core.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright (C) 2016 Robert Jarzmik <[email protected]>
+ *
+ * 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.
+ */
+
+unsigned int snd_ac97_bus_scan_one(struct ac97_controller *ac97,
+				   unsigned int codec_num);
+
+static inline bool ac97_ids_match(unsigned int id1, unsigned int id2,
+				  unsigned int mask)
+{
+	return (id1 & mask) == (id2 & mask);
+}