sound/hda/hdac_device.c - kernel/msm-4.9 - Gitiles

 /*
  * HD-audio codec core device
  */

 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/export.h>
 #include <linux/pm_runtime.h>
 #include <sound/hdaudio.h>
 #include "local.h"

 static void setup_fg_nodes(struct hdac_device *codec);
 static int get_codec_vendor_name(struct hdac_device *codec);

 static void default_release(struct device *dev)
 {
 	snd_hdac_device_exit(container_of(dev, struct hdac_device, dev));
 }

 /**
  * snd_hdac_device_init - initialize the HD-audio codec base device
  * @codec: device to initialize
  * @bus: but to attach
  * @name: device name string
  * @addr: codec address
  *
  * Returns zero for success or a negative error code.
  *
  * This function increments the runtime PM counter and marks it active.
  * The caller needs to turn it off appropriately later.
  *
  * The caller needs to set the device's release op properly by itself.
  */
 int snd_hdac_device_init(struct hdac_device *codec, struct hdac_bus *bus,
 			 const char *name, unsigned int addr)
 {
 	struct device *dev;
 	hda_nid_t fg;
 	int err;

 	dev = &codec->dev;
 	device_initialize(dev);
 	dev->parent = bus->dev;
 	dev->bus = &snd_hda_bus_type;
 	dev->release = default_release;
 	dev->groups = hdac_dev_attr_groups;
 	dev_set_name(dev, "%s", name);
 	device_enable_async_suspend(dev);

 	codec->bus = bus;
 	codec->addr = addr;
 	codec->type = HDA_DEV_CORE;
 	pm_runtime_set_active(&codec->dev);
 	pm_runtime_get_noresume(&codec->dev);
 	atomic_set(&codec->in_pm, 0);

 	err = snd_hdac_bus_add_device(bus, codec);
 	if (err < 0)
 		goto error;

 	/* fill parameters */
 	codec->vendor_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
 					      AC_PAR_VENDOR_ID);
 	if (codec->vendor_id == -1) {
 		/* read again, hopefully the access method was corrected
 		 * in the last read...
 		 */
 		codec->vendor_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
 						      AC_PAR_VENDOR_ID);
 	}

 	codec->subsystem_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
 						 AC_PAR_SUBSYSTEM_ID);
 	codec->revision_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
 						AC_PAR_REV_ID);

 	setup_fg_nodes(codec);
 	if (!codec->afg && !codec->mfg) {
 		dev_err(dev, "no AFG or MFG node found\n");
 		err = -ENODEV;
 		goto error;
 	}

 	fg = codec->afg ? codec->afg : codec->mfg;

 	err = snd_hdac_refresh_widgets(codec);
 	if (err < 0)
 		goto error;

 	codec->power_caps = snd_hdac_read_parm(codec, fg, AC_PAR_POWER_STATE);
 	/* reread ssid if not set by parameter */
 	if (codec->subsystem_id == -1)
 		snd_hdac_read(codec, fg, AC_VERB_GET_SUBSYSTEM_ID, 0,
 			      &codec->subsystem_id);

 	err = get_codec_vendor_name(codec);
 	if (err < 0)
 		goto error;

 	codec->chip_name = kasprintf(GFP_KERNEL, "ID %x",
 				     codec->vendor_id & 0xffff);
 	if (!codec->chip_name) {
 		err = -ENOMEM;
 		goto error;
 	}

 	return 0;

  error:
 	pm_runtime_put_noidle(&codec->dev);
 	put_device(&codec->dev);
 	return err;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_device_init);

 /**
  * snd_hdac_device_exit - clean up the HD-audio codec base device
  * @codec: device to clean up
  */
 void snd_hdac_device_exit(struct hdac_device *codec)
 {
 	/* pm_runtime_put_noidle(&codec->dev); */
 	snd_hdac_bus_remove_device(codec->bus, codec);
 	kfree(codec->vendor_name);
 	kfree(codec->chip_name);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_device_exit);

 /**
  * snd_hdac_device_register - register the hd-audio codec base device
  * codec: the device to register
  */
 int snd_hdac_device_register(struct hdac_device *codec)
 {
 	int err;

 	err = device_add(&codec->dev);
 	if (err < 0)
 		return err;
 	err = hda_widget_sysfs_init(codec);
 	if (err < 0) {
 		device_del(&codec->dev);
 		return err;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_device_register);

 /**
  * snd_hdac_device_unregister - unregister the hd-audio codec base device
  * codec: the device to unregister
  */
 void snd_hdac_device_unregister(struct hdac_device *codec)
 {
 	if (device_is_registered(&codec->dev)) {
 		hda_widget_sysfs_exit(codec);
 		device_del(&codec->dev);
 	}
 }
 EXPORT_SYMBOL_GPL(snd_hdac_device_unregister);

 /**
  * snd_hdac_make_cmd - compose a 32bit command word to be sent to the
  *	HD-audio controller
  * @codec: the codec object
  * @nid: NID to encode
  * @verb: verb to encode
  * @parm: parameter to encode
  *
  * Return an encoded command verb or -1 for error.
  */
 unsigned int snd_hdac_make_cmd(struct hdac_device *codec, hda_nid_t nid,
 			       unsigned int verb, unsigned int parm)
 {
 	u32 val, addr;

 	addr = codec->addr;
 	if ((addr & ~0xf) || (nid & ~0x7f) ||
 	    (verb & ~0xfff) || (parm & ~0xffff)) {
 		dev_err(&codec->dev, "out of range cmd %x:%x:%x:%x\n",
 			addr, nid, verb, parm);
 		return -1;
 	}

 	val = addr << 28;
 	val |= (u32)nid << 20;
 	val |= verb << 8;
 	val |= parm;
 	return val;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_make_cmd);

 /**
  * snd_hdac_exec_verb - execute an encoded verb
  * @codec: the codec object
  * @cmd: encoded verb to execute
  * @flags: optional flags, pass zero for default
  * @res: the pointer to store the result, NULL if running async
  *
  * Returns zero if successful, or a negative error code.
  *
  * This calls the exec_verb op when set in hdac_codec.  If not,
  * call the default snd_hdac_bus_exec_verb().
  */
 int snd_hdac_exec_verb(struct hdac_device *codec, unsigned int cmd,
 		       unsigned int flags, unsigned int *res)
 {
 	if (codec->exec_verb)
 		return codec->exec_verb(codec, cmd, flags, res);
 	return snd_hdac_bus_exec_verb(codec->bus, codec->addr, cmd, res);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_exec_verb);


 /**
  * snd_hdac_read - execute a verb
  * @codec: the codec object
  * @nid: NID to execute a verb
  * @verb: verb to execute
  * @parm: parameter for a verb
  * @res: the pointer to store the result, NULL if running async
  *
  * Returns zero if successful, or a negative error code.
  */
 int snd_hdac_read(struct hdac_device *codec, hda_nid_t nid,
 		  unsigned int verb, unsigned int parm, unsigned int *res)
 {
 	unsigned int cmd = snd_hdac_make_cmd(codec, nid, verb, parm);

 	return snd_hdac_exec_verb(codec, cmd, 0, res);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_read);

 /**
  * snd_hdac_read_parm - read a codec parameter
  * @codec: the codec object
  * @nid: NID to read a parameter
  * @parm: parameter to read
  *
  * Returns -1 for error.  If you need to distinguish the error more
  * strictly, use snd_hdac_read() directly.
  */
 int snd_hdac_read_parm(struct hdac_device *codec, hda_nid_t nid, int parm)
 {
 	int val;

 	if (snd_hdac_read(codec, nid, AC_VERB_PARAMETERS, parm, &val))
 		return -1;
 	return val;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_read_parm);

 /**
  * snd_hdac_get_sub_nodes - get start NID and number of subtree nodes
  * @codec: the codec object
  * @nid: NID to inspect
  * @start_id: the pointer to store the starting NID
  *
  * Returns the number of subtree nodes or zero if not found.
  */
 int snd_hdac_get_sub_nodes(struct hdac_device *codec, hda_nid_t nid,
 			   hda_nid_t *start_id)
 {
 	unsigned int parm;

 	parm = snd_hdac_read_parm(codec, nid, AC_PAR_NODE_COUNT);
 	if (parm == -1) {
 		*start_id = 0;
 		return 0;
 	}
 	*start_id = (parm >> 16) & 0x7fff;
 	return (int)(parm & 0x7fff);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_get_sub_nodes);

 /*
  * look for an AFG and MFG nodes
  */
 static void setup_fg_nodes(struct hdac_device *codec)
 {
 	int i, total_nodes, function_id;
 	hda_nid_t nid;

 	total_nodes = snd_hdac_get_sub_nodes(codec, AC_NODE_ROOT, &nid);
 	for (i = 0; i < total_nodes; i++, nid++) {
 		function_id = snd_hdac_read_parm(codec, nid,
 						 AC_PAR_FUNCTION_TYPE);
 		switch (function_id & 0xff) {
 		case AC_GRP_AUDIO_FUNCTION:
 			codec->afg = nid;
 			codec->afg_function_id = function_id & 0xff;
 			codec->afg_unsol = (function_id >> 8) & 1;
 			break;
 		case AC_GRP_MODEM_FUNCTION:
 			codec->mfg = nid;
 			codec->mfg_function_id = function_id & 0xff;
 			codec->mfg_unsol = (function_id >> 8) & 1;
 			break;
 		default:
 			break;
 		}
 	}
 }

 /**
  * snd_hdac_refresh_widgets - Reset the widget start/end nodes
  * @codec: the codec object
  */
 int snd_hdac_refresh_widgets(struct hdac_device *codec)
 {
 	hda_nid_t start_nid;
 	int nums;

 	nums = snd_hdac_get_sub_nodes(codec, codec->afg, &start_nid);
 	if (!start_nid || nums <= 0 || nums >= 0xff) {
 		dev_err(&codec->dev, "cannot read sub nodes for FG 0x%02x\n",
 			codec->afg);
 		return -EINVAL;
 	}

 	codec->num_nodes = nums;
 	codec->start_nid = start_nid;
 	codec->end_nid = start_nid + nums;
 	return 0;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_refresh_widgets);

 /* return CONNLIST_LEN parameter of the given widget */
 static unsigned int get_num_conns(struct hdac_device *codec, hda_nid_t nid)
 {
 	unsigned int wcaps = get_wcaps(codec, nid);
 	unsigned int parm;

 	if (!(wcaps & AC_WCAP_CONN_LIST) &&
 	    get_wcaps_type(wcaps) != AC_WID_VOL_KNB)
 		return 0;

 	parm = snd_hdac_read_parm(codec, nid, AC_PAR_CONNLIST_LEN);
 	if (parm == -1)
 		parm = 0;
 	return parm;
 }

 /**
  * snd_hdac_get_connections - get a widget connection list
  * @codec: the codec object
  * @nid: NID
  * @conn_list: the array to store the results, can be NULL
  * @max_conns: the max size of the given array
  *
  * Returns the number of connected widgets, zero for no connection, or a
  * negative error code.  When the number of elements don't fit with the
  * given array size, it returns -ENOSPC.
  *
  * When @conn_list is NULL, it just checks the number of connections.
  */
 int snd_hdac_get_connections(struct hdac_device *codec, hda_nid_t nid,
 			     hda_nid_t *conn_list, int max_conns)
 {
 	unsigned int parm;
 	int i, conn_len, conns, err;
 	unsigned int shift, num_elems, mask;
 	hda_nid_t prev_nid;
 	int null_count = 0;

 	parm = get_num_conns(codec, nid);
 	if (!parm)
 		return 0;

 	if (parm & AC_CLIST_LONG) {
 		/* long form */
 		shift = 16;
 		num_elems = 2;
 	} else {
 		/* short form */
 		shift = 8;
 		num_elems = 4;
 	}
 	conn_len = parm & AC_CLIST_LENGTH;
 	mask = (1 << (shift-1)) - 1;

 	if (!conn_len)
 		return 0; /* no connection */

 	if (conn_len == 1) {
 		/* single connection */
 		err = snd_hdac_read(codec, nid, AC_VERB_GET_CONNECT_LIST, 0,
 				    &parm);
 		if (err < 0)
 			return err;
 		if (conn_list)
 			conn_list[0] = parm & mask;
 		return 1;
 	}

 	/* multi connection */
 	conns = 0;
 	prev_nid = 0;
 	for (i = 0; i < conn_len; i++) {
 		int range_val;
 		hda_nid_t val, n;

 		if (i % num_elems == 0) {
 			err = snd_hdac_read(codec, nid,
 					    AC_VERB_GET_CONNECT_LIST, i,
 					    &parm);
 			if (err < 0)
 				return -EIO;
 		}
 		range_val = !!(parm & (1 << (shift-1))); /* ranges */
 		val = parm & mask;
 		if (val == 0 && null_count++) {  /* no second chance */
 			dev_dbg(&codec->dev,
 				"invalid CONNECT_LIST verb %x[%i]:%x\n",
 				nid, i, parm);
 			return 0;
 		}
 		parm >>= shift;
 		if (range_val) {
 			/* ranges between the previous and this one */
 			if (!prev_nid || prev_nid >= val) {
 				dev_warn(&codec->dev,
 					 "invalid dep_range_val %x:%x\n",
 					 prev_nid, val);
 				continue;
 			}
 			for (n = prev_nid + 1; n <= val; n++) {
 				if (conn_list) {
 					if (conns >= max_conns)
 						return -ENOSPC;
 					conn_list[conns] = n;
 				}
 				conns++;
 			}
 		} else {
 			if (conn_list) {
 				if (conns >= max_conns)
 					return -ENOSPC;
 				conn_list[conns] = val;
 			}
 			conns++;
 		}
 		prev_nid = val;
 	}
 	return conns;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_get_connections);

 #ifdef CONFIG_PM
 /**
  * snd_hdac_power_up - increment the runtime pm counter
  * @codec: the codec object
  */
 void snd_hdac_power_up(struct hdac_device *codec)
 {
 	struct device *dev = &codec->dev;

 	if (atomic_read(&codec->in_pm))
 		return;
 	pm_runtime_get_sync(dev);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_power_up);

 /**
  * snd_hdac_power_up - decrement the runtime pm counter
  * @codec: the codec object
  */
 void snd_hdac_power_down(struct hdac_device *codec)
 {
 	struct device *dev = &codec->dev;

 	if (atomic_read(&codec->in_pm))
 		return;
 	pm_runtime_mark_last_busy(dev);
 	pm_runtime_put_autosuspend(dev);
 }
 EXPORT_SYMBOL_GPL(snd_hdac_power_down);
 #endif

 /* codec vendor labels */
 struct hda_vendor_id {
 	unsigned int id;
 	const char *name;
 };

 static struct hda_vendor_id hda_vendor_ids[] = {
 	{ 0x1002, "ATI" },
 	{ 0x1013, "Cirrus Logic" },
 	{ 0x1057, "Motorola" },
 	{ 0x1095, "Silicon Image" },
 	{ 0x10de, "Nvidia" },
 	{ 0x10ec, "Realtek" },
 	{ 0x1102, "Creative" },
 	{ 0x1106, "VIA" },
 	{ 0x111d, "IDT" },
 	{ 0x11c1, "LSI" },
 	{ 0x11d4, "Analog Devices" },
 	{ 0x13f6, "C-Media" },
 	{ 0x14f1, "Conexant" },
 	{ 0x17e8, "Chrontel" },
 	{ 0x1854, "LG" },
 	{ 0x1aec, "Wolfson Microelectronics" },
 	{ 0x1af4, "QEMU" },
 	{ 0x434d, "C-Media" },
 	{ 0x8086, "Intel" },
 	{ 0x8384, "SigmaTel" },
 	{} /* terminator */
 };

 /* store the codec vendor name */
 static int get_codec_vendor_name(struct hdac_device *codec)
 {
 	const struct hda_vendor_id *c;
 	u16 vendor_id = codec->vendor_id >> 16;

 	for (c = hda_vendor_ids; c->id; c++) {
 		if (c->id == vendor_id) {
 			codec->vendor_name = kstrdup(c->name, GFP_KERNEL);
 			return codec->vendor_name ? 0 : -ENOMEM;
 		}
 	}

 	codec->vendor_name = kasprintf(GFP_KERNEL, "Generic %04x", vendor_id);
 	return codec->vendor_name ? 0 : -ENOMEM;
 }
	/*
	* HD-audio codec core device
	*/

	#include <linux/init.h>
	#include <linux/device.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/export.h>
	#include <linux/pm_runtime.h>
	#include <sound/hdaudio.h>
	#include "local.h"

	static void setup_fg_nodes(struct hdac_device *codec);
	static int get_codec_vendor_name(struct hdac_device *codec);

	static void default_release(struct device *dev)
	{
	snd_hdac_device_exit(container_of(dev, struct hdac_device, dev));
	}

	/**
	* snd_hdac_device_init - initialize the HD-audio codec base device
	* @codec: device to initialize
	* @bus: but to attach
	* @name: device name string
	* @addr: codec address
	*
	* Returns zero for success or a negative error code.
	*
	* This function increments the runtime PM counter and marks it active.
	* The caller needs to turn it off appropriately later.
	*
	* The caller needs to set the device's release op properly by itself.
	*/
	int snd_hdac_device_init(struct hdac_device codec, struct hdac_bus bus,
	const char *name, unsigned int addr)
	{
	struct device *dev;
	hda_nid_t fg;
	int err;

	dev = &codec->dev;
	device_initialize(dev);
	dev->parent = bus->dev;
	dev->bus = &snd_hda_bus_type;
	dev->release = default_release;
	dev->groups = hdac_dev_attr_groups;
	dev_set_name(dev, "%s", name);
	device_enable_async_suspend(dev);

	codec->bus = bus;
	codec->addr = addr;
	codec->type = HDA_DEV_CORE;
	pm_runtime_set_active(&codec->dev);
	pm_runtime_get_noresume(&codec->dev);
	atomic_set(&codec->in_pm, 0);

	err = snd_hdac_bus_add_device(bus, codec);
	if (err < 0)
	goto error;

	/* fill parameters */
	codec->vendor_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
	AC_PAR_VENDOR_ID);
	if (codec->vendor_id == -1) {
	/* read again, hopefully the access method was corrected
	* in the last read...
	*/
	codec->vendor_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
	AC_PAR_VENDOR_ID);
	}

	codec->subsystem_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
	AC_PAR_SUBSYSTEM_ID);
	codec->revision_id = snd_hdac_read_parm(codec, AC_NODE_ROOT,
	AC_PAR_REV_ID);

	setup_fg_nodes(codec);
	if (!codec->afg && !codec->mfg) {
	dev_err(dev, "no AFG or MFG node found\n");
	err = -ENODEV;
	goto error;
	}

	fg = codec->afg ? codec->afg : codec->mfg;

	err = snd_hdac_refresh_widgets(codec);
	if (err < 0)
	goto error;

	codec->power_caps = snd_hdac_read_parm(codec, fg, AC_PAR_POWER_STATE);
	/* reread ssid if not set by parameter */
	if (codec->subsystem_id == -1)
	snd_hdac_read(codec, fg, AC_VERB_GET_SUBSYSTEM_ID, 0,
	&codec->subsystem_id);

	err = get_codec_vendor_name(codec);
	if (err < 0)
	goto error;

	codec->chip_name = kasprintf(GFP_KERNEL, "ID %x",
	codec->vendor_id & 0xffff);
	if (!codec->chip_name) {
	err = -ENOMEM;
	goto error;
	}

	return 0;

	error:
	pm_runtime_put_noidle(&codec->dev);
	put_device(&codec->dev);
	return err;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_device_init);

	/**
	* snd_hdac_device_exit - clean up the HD-audio codec base device
	* @codec: device to clean up
	*/
	void snd_hdac_device_exit(struct hdac_device *codec)
	{
	/* pm_runtime_put_noidle(&codec->dev); */
	snd_hdac_bus_remove_device(codec->bus, codec);
	kfree(codec->vendor_name);
	kfree(codec->chip_name);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_device_exit);

	/**
	* snd_hdac_device_register - register the hd-audio codec base device
	* codec: the device to register
	*/
	int snd_hdac_device_register(struct hdac_device *codec)
	{
	int err;

	err = device_add(&codec->dev);
	if (err < 0)
	return err;
	err = hda_widget_sysfs_init(codec);
	if (err < 0) {
	device_del(&codec->dev);
	return err;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_device_register);

	/**
	* snd_hdac_device_unregister - unregister the hd-audio codec base device
	* codec: the device to unregister
	*/
	void snd_hdac_device_unregister(struct hdac_device *codec)
	{
	if (device_is_registered(&codec->dev)) {
	hda_widget_sysfs_exit(codec);
	device_del(&codec->dev);
	}
	}
	EXPORT_SYMBOL_GPL(snd_hdac_device_unregister);

	/**
	* snd_hdac_make_cmd - compose a 32bit command word to be sent to the
	* HD-audio controller
	* @codec: the codec object
	* @nid: NID to encode
	* @verb: verb to encode
	* @parm: parameter to encode
	*
	* Return an encoded command verb or -1 for error.
	*/
	unsigned int snd_hdac_make_cmd(struct hdac_device *codec, hda_nid_t nid,
	unsigned int verb, unsigned int parm)
	{
	u32 val, addr;

	addr = codec->addr;
	if ((addr & ~0xf) \|\| (nid & ~0x7f) \|\|
	(verb & ~0xfff) \|\| (parm & ~0xffff)) {
	dev_err(&codec->dev, "out of range cmd %x:%x:%x:%x\n",
	addr, nid, verb, parm);
	return -1;
	}

	val = addr << 28;
	val \|= (u32)nid << 20;
	val \|= verb << 8;
	val \|= parm;
	return val;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_make_cmd);

	/**
	* snd_hdac_exec_verb - execute an encoded verb
	* @codec: the codec object
	* @cmd: encoded verb to execute
	* @flags: optional flags, pass zero for default
	* @res: the pointer to store the result, NULL if running async
	*
	* Returns zero if successful, or a negative error code.
	*
	* This calls the exec_verb op when set in hdac_codec. If not,
	* call the default snd_hdac_bus_exec_verb().
	*/
	int snd_hdac_exec_verb(struct hdac_device *codec, unsigned int cmd,
	unsigned int flags, unsigned int *res)
	{
	if (codec->exec_verb)
	return codec->exec_verb(codec, cmd, flags, res);
	return snd_hdac_bus_exec_verb(codec->bus, codec->addr, cmd, res);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_exec_verb);


	/**
	* snd_hdac_read - execute a verb
	* @codec: the codec object
	* @nid: NID to execute a verb
	* @verb: verb to execute
	* @parm: parameter for a verb
	* @res: the pointer to store the result, NULL if running async
	*
	* Returns zero if successful, or a negative error code.
	*/
	int snd_hdac_read(struct hdac_device *codec, hda_nid_t nid,
	unsigned int verb, unsigned int parm, unsigned int *res)
	{
	unsigned int cmd = snd_hdac_make_cmd(codec, nid, verb, parm);

	return snd_hdac_exec_verb(codec, cmd, 0, res);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_read);

	/**
	* snd_hdac_read_parm - read a codec parameter
	* @codec: the codec object
	* @nid: NID to read a parameter
	* @parm: parameter to read
	*
	* Returns -1 for error. If you need to distinguish the error more
	* strictly, use snd_hdac_read() directly.
	*/
	int snd_hdac_read_parm(struct hdac_device *codec, hda_nid_t nid, int parm)
	{
	int val;

	if (snd_hdac_read(codec, nid, AC_VERB_PARAMETERS, parm, &val))
	return -1;
	return val;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_read_parm);

	/**
	* snd_hdac_get_sub_nodes - get start NID and number of subtree nodes
	* @codec: the codec object
	* @nid: NID to inspect
	* @start_id: the pointer to store the starting NID
	*
	* Returns the number of subtree nodes or zero if not found.
	*/
	int snd_hdac_get_sub_nodes(struct hdac_device *codec, hda_nid_t nid,
	hda_nid_t *start_id)
	{
	unsigned int parm;

	parm = snd_hdac_read_parm(codec, nid, AC_PAR_NODE_COUNT);
	if (parm == -1) {
	*start_id = 0;
	return 0;
	}
	*start_id = (parm >> 16) & 0x7fff;
	return (int)(parm & 0x7fff);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_get_sub_nodes);

	/*
	* look for an AFG and MFG nodes
	*/
	static void setup_fg_nodes(struct hdac_device *codec)
	{
	int i, total_nodes, function_id;
	hda_nid_t nid;

	total_nodes = snd_hdac_get_sub_nodes(codec, AC_NODE_ROOT, &nid);
	for (i = 0; i < total_nodes; i++, nid++) {
	function_id = snd_hdac_read_parm(codec, nid,
	AC_PAR_FUNCTION_TYPE);
	switch (function_id & 0xff) {
	case AC_GRP_AUDIO_FUNCTION:
	codec->afg = nid;
	codec->afg_function_id = function_id & 0xff;
	codec->afg_unsol = (function_id >> 8) & 1;
	break;
	case AC_GRP_MODEM_FUNCTION:
	codec->mfg = nid;
	codec->mfg_function_id = function_id & 0xff;
	codec->mfg_unsol = (function_id >> 8) & 1;
	break;
	default:
	break;
	}
	}
	}

	/**
	* snd_hdac_refresh_widgets - Reset the widget start/end nodes
	* @codec: the codec object
	*/
	int snd_hdac_refresh_widgets(struct hdac_device *codec)
	{
	hda_nid_t start_nid;
	int nums;

	nums = snd_hdac_get_sub_nodes(codec, codec->afg, &start_nid);
	if (!start_nid \|\| nums <= 0 \|\| nums >= 0xff) {
	dev_err(&codec->dev, "cannot read sub nodes for FG 0x%02x\n",
	codec->afg);
	return -EINVAL;
	}

	codec->num_nodes = nums;
	codec->start_nid = start_nid;
	codec->end_nid = start_nid + nums;
	return 0;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_refresh_widgets);

	/* return CONNLIST_LEN parameter of the given widget */
	static unsigned int get_num_conns(struct hdac_device *codec, hda_nid_t nid)
	{
	unsigned int wcaps = get_wcaps(codec, nid);
	unsigned int parm;

	if (!(wcaps & AC_WCAP_CONN_LIST) &&
	get_wcaps_type(wcaps) != AC_WID_VOL_KNB)
	return 0;

	parm = snd_hdac_read_parm(codec, nid, AC_PAR_CONNLIST_LEN);
	if (parm == -1)
	parm = 0;
	return parm;
	}

	/**
	* snd_hdac_get_connections - get a widget connection list
	* @codec: the codec object
	* @nid: NID
	* @conn_list: the array to store the results, can be NULL
	* @max_conns: the max size of the given array
	*
	* Returns the number of connected widgets, zero for no connection, or a
	* negative error code. When the number of elements don't fit with the
	* given array size, it returns -ENOSPC.
	*
	* When @conn_list is NULL, it just checks the number of connections.
	*/
	int snd_hdac_get_connections(struct hdac_device *codec, hda_nid_t nid,
	hda_nid_t *conn_list, int max_conns)
	{
	unsigned int parm;
	int i, conn_len, conns, err;
	unsigned int shift, num_elems, mask;
	hda_nid_t prev_nid;
	int null_count = 0;

	parm = get_num_conns(codec, nid);
	if (!parm)
	return 0;

	if (parm & AC_CLIST_LONG) {
	/* long form */
	shift = 16;
	num_elems = 2;
	} else {
	/* short form */
	shift = 8;
	num_elems = 4;
	}
	conn_len = parm & AC_CLIST_LENGTH;
	mask = (1 << (shift-1)) - 1;

	if (!conn_len)
	return 0; /* no connection */

	if (conn_len == 1) {
	/* single connection */
	err = snd_hdac_read(codec, nid, AC_VERB_GET_CONNECT_LIST, 0,
	&parm);
	if (err < 0)
	return err;
	if (conn_list)
	conn_list[0] = parm & mask;
	return 1;
	}

	/* multi connection */
	conns = 0;
	prev_nid = 0;
	for (i = 0; i < conn_len; i++) {
	int range_val;
	hda_nid_t val, n;

	if (i % num_elems == 0) {
	err = snd_hdac_read(codec, nid,
	AC_VERB_GET_CONNECT_LIST, i,
	&parm);
	if (err < 0)
	return -EIO;
	}
	range_val = !!(parm & (1 << (shift-1))); /* ranges */
	val = parm & mask;
	if (val == 0 && null_count++) { /* no second chance */
	dev_dbg(&codec->dev,
	"invalid CONNECT_LIST verb %x[%i]:%x\n",
	nid, i, parm);
	return 0;
	}
	parm >>= shift;
	if (range_val) {
	/* ranges between the previous and this one */
	if (!prev_nid \|\| prev_nid >= val) {
	dev_warn(&codec->dev,
	"invalid dep_range_val %x:%x\n",
	prev_nid, val);
	continue;
	}
	for (n = prev_nid + 1; n <= val; n++) {
	if (conn_list) {
	if (conns >= max_conns)
	return -ENOSPC;
	conn_list[conns] = n;
	}
	conns++;
	}
	} else {
	if (conn_list) {
	if (conns >= max_conns)
	return -ENOSPC;
	conn_list[conns] = val;
	}
	conns++;
	}
	prev_nid = val;
	}
	return conns;
	}
	EXPORT_SYMBOL_GPL(snd_hdac_get_connections);

	#ifdef CONFIG_PM
	/**
	* snd_hdac_power_up - increment the runtime pm counter
	* @codec: the codec object
	*/
	void snd_hdac_power_up(struct hdac_device *codec)
	{
	struct device *dev = &codec->dev;

	if (atomic_read(&codec->in_pm))
	return;
	pm_runtime_get_sync(dev);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_power_up);

	/**
	* snd_hdac_power_up - decrement the runtime pm counter
	* @codec: the codec object
	*/
	void snd_hdac_power_down(struct hdac_device *codec)
	{
	struct device *dev = &codec->dev;

	if (atomic_read(&codec->in_pm))
	return;
	pm_runtime_mark_last_busy(dev);
	pm_runtime_put_autosuspend(dev);
	}
	EXPORT_SYMBOL_GPL(snd_hdac_power_down);
	#endif

	/* codec vendor labels */
	struct hda_vendor_id {
	unsigned int id;
	const char *name;
	};

	static struct hda_vendor_id hda_vendor_ids[] = {
	{ 0x1002, "ATI" },
	{ 0x1013, "Cirrus Logic" },
	{ 0x1057, "Motorola" },
	{ 0x1095, "Silicon Image" },
	{ 0x10de, "Nvidia" },
	{ 0x10ec, "Realtek" },
	{ 0x1102, "Creative" },
	{ 0x1106, "VIA" },
	{ 0x111d, "IDT" },
	{ 0x11c1, "LSI" },
	{ 0x11d4, "Analog Devices" },
	{ 0x13f6, "C-Media" },
	{ 0x14f1, "Conexant" },
	{ 0x17e8, "Chrontel" },
	{ 0x1854, "LG" },
	{ 0x1aec, "Wolfson Microelectronics" },
	{ 0x1af4, "QEMU" },
	{ 0x434d, "C-Media" },
	{ 0x8086, "Intel" },
	{ 0x8384, "SigmaTel" },
	{} /* terminator */
	};

	/* store the codec vendor name */
	static int get_codec_vendor_name(struct hdac_device *codec)
	{
	const struct hda_vendor_id *c;
	u16 vendor_id = codec->vendor_id >> 16;

	for (c = hda_vendor_ids; c->id; c++) {
	if (c->id == vendor_id) {
	codec->vendor_name = kstrdup(c->name, GFP_KERNEL);
	return codec->vendor_name ? 0 : -ENOMEM;
	}
	}

	codec->vendor_name = kasprintf(GFP_KERNEL, "Generic %04x", vendor_id);
	return codec->vendor_name ? 0 : -ENOMEM;
	}