--- /dev/null
+/*
+ * sysfs support for HD-audio core device
+ */
+
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/device.h>
+#include <sound/core.h>
+#include <sound/hdaudio.h>
+#include "local.h"
+
+struct hdac_widget_tree {
+       struct kobject *root;
+       struct kobject *afg;
+       struct kobject **nodes;
+};
+
+#define CODEC_ATTR(type)                                       \
+static ssize_t type##_show(struct device *dev,                 \
+                          struct device_attribute *attr,       \
+                          char *buf)                           \
+{                                                              \
+       struct hdac_device *codec = dev_to_hdac_dev(dev);       \
+       return sprintf(buf, "0x%x\n", codec->type);             \
+} \
+static DEVICE_ATTR_RO(type)
+
+#define CODEC_ATTR_STR(type)                                   \
+static ssize_t type##_show(struct device *dev,                 \
+                            struct device_attribute *attr,     \
+                                       char *buf)              \
+{                                                              \
+       struct hdac_device *codec = dev_to_hdac_dev(dev);       \
+       return sprintf(buf, "%s\n",                             \
+                      codec->type ? codec->type : "");         \
+} \
+static DEVICE_ATTR_RO(type)
+
+CODEC_ATTR(vendor_id);
+CODEC_ATTR(subsystem_id);
+CODEC_ATTR(revision_id);
+CODEC_ATTR(afg);
+CODEC_ATTR(mfg);
+CODEC_ATTR_STR(vendor_name);
+CODEC_ATTR_STR(chip_name);
+
+static struct attribute *hdac_dev_attrs[] = {
+       &dev_attr_vendor_id.attr,
+       &dev_attr_subsystem_id.attr,
+       &dev_attr_revision_id.attr,
+       &dev_attr_afg.attr,
+       &dev_attr_mfg.attr,
+       &dev_attr_vendor_name.attr,
+       &dev_attr_chip_name.attr,
+       NULL
+};
+
+static struct attribute_group hdac_dev_attr_group = {
+       .attrs  = hdac_dev_attrs,
+};
+
+const struct attribute_group *hdac_dev_attr_groups[] = {
+       &hdac_dev_attr_group,
+       NULL
+};
+
+/*
+ * Widget tree sysfs
+ *
+ * This is a tree showing the attributes of each widget.  It appears like
+ * /sys/bus/hdaudioC0D0/widgets/04/caps
+ */
+
+struct widget_attribute;
+
+struct widget_attribute {
+       struct attribute        attr;
+       ssize_t (*show)(struct hdac_device *codec, hda_nid_t nid,
+                       struct widget_attribute *attr, char *buf);
+       ssize_t (*store)(struct hdac_device *codec, hda_nid_t nid,
+                        struct widget_attribute *attr,
+                        const char *buf, size_t count);
+};
+
+static int get_codec_nid(struct kobject *kobj, struct hdac_device **codecp)
+{
+       struct device *dev = kobj_to_dev(kobj->parent->parent);
+       int nid;
+       ssize_t ret;
+
+       ret = kstrtoint(kobj->name, 16, &nid);
+       if (ret < 0)
+               return ret;
+       *codecp = dev_to_hdac_dev(dev);
+       return nid;
+}
+
+static ssize_t widget_attr_show(struct kobject *kobj, struct attribute *attr,
+                               char *buf)
+{
+       struct widget_attribute *wid_attr =
+               container_of(attr, struct widget_attribute, attr);
+       struct hdac_device *codec;
+       int nid;
+
+       if (!wid_attr->show)
+               return -EIO;
+       nid = get_codec_nid(kobj, &codec);
+       if (nid < 0)
+               return nid;
+       return wid_attr->show(codec, nid, wid_attr, buf);
+}
+
+static ssize_t widget_attr_store(struct kobject *kobj, struct attribute *attr,
+                                const char *buf, size_t count)
+{
+       struct widget_attribute *wid_attr =
+               container_of(attr, struct widget_attribute, attr);
+       struct hdac_device *codec;
+       int nid;
+
+       if (!wid_attr->store)
+               return -EIO;
+       nid = get_codec_nid(kobj, &codec);
+       if (nid < 0)
+               return nid;
+       return wid_attr->store(codec, nid, wid_attr, buf, count);
+}
+
+static const struct sysfs_ops widget_sysfs_ops = {
+       .show   = widget_attr_show,
+       .store  = widget_attr_store,
+};
+
+static void widget_release(struct kobject *kobj)
+{
+       kfree(kobj);
+}
+
+static struct kobj_type widget_ktype = {
+       .release        = widget_release,
+       .sysfs_ops      = &widget_sysfs_ops,
+};
+
+#define WIDGET_ATTR_RO(_name) \
+       struct widget_attribute wid_attr_##_name = __ATTR_RO(_name)
+#define WIDGET_ATTR_RW(_name) \
+       struct widget_attribute wid_attr_##_name = __ATTR_RW(_name)
+
+static ssize_t caps_show(struct hdac_device *codec, hda_nid_t nid,
+                       struct widget_attribute *attr, char *buf)
+{
+       return sprintf(buf, "0x%08x\n", get_wcaps(codec, nid));
+}
+
+static ssize_t pin_caps_show(struct hdac_device *codec, hda_nid_t nid,
+                            struct widget_attribute *attr, char *buf)
+{
+       if (get_wcaps_type(get_wcaps(codec, nid)) != AC_WID_PIN)
+               return 0;
+       return sprintf(buf, "0x%08x\n",
+                      snd_hdac_read_parm(codec, nid, AC_PAR_PIN_CAP));
+}
+
+static ssize_t pin_cfg_show(struct hdac_device *codec, hda_nid_t nid,
+                           struct widget_attribute *attr, char *buf)
+{
+       unsigned int val;
+
+       if (get_wcaps_type(get_wcaps(codec, nid)) != AC_WID_PIN)
+               return 0;
+       if (snd_hdac_read(codec, nid, AC_VERB_GET_CONFIG_DEFAULT, 0, &val))
+               return 0;
+       return sprintf(buf, "0x%08x\n", val);
+}
+
+static bool has_pcm_cap(struct hdac_device *codec, hda_nid_t nid)
+{
+       if (nid == codec->afg || nid == codec->mfg)
+               return true;
+       switch (get_wcaps_type(get_wcaps(codec, nid))) {
+       case AC_WID_AUD_OUT:
+       case AC_WID_AUD_IN:
+               return true;
+       default:
+               return false;
+       }
+}
+
+static ssize_t pcm_caps_show(struct hdac_device *codec, hda_nid_t nid,
+                            struct widget_attribute *attr, char *buf)
+{
+       if (!has_pcm_cap(codec, nid))
+               return 0;
+       return sprintf(buf, "0x%08x\n",
+                      snd_hdac_read_parm(codec, nid, AC_PAR_PCM));
+}
+
+static ssize_t pcm_formats_show(struct hdac_device *codec, hda_nid_t nid,
+                               struct widget_attribute *attr, char *buf)
+{
+       if (!has_pcm_cap(codec, nid))
+               return 0;
+       return sprintf(buf, "0x%08x\n",
+                      snd_hdac_read_parm(codec, nid, AC_PAR_STREAM));
+}
+
+static ssize_t amp_in_caps_show(struct hdac_device *codec, hda_nid_t nid,
+                               struct widget_attribute *attr, char *buf)
+{
+       if (nid != codec->afg && !(get_wcaps(codec, nid) & AC_WCAP_IN_AMP))
+               return 0;
+       return sprintf(buf, "0x%08x\n",
+                      snd_hdac_read_parm(codec, nid, AC_PAR_AMP_IN_CAP));
+}
+
+static ssize_t amp_out_caps_show(struct hdac_device *codec, hda_nid_t nid,
+                                struct widget_attribute *attr, char *buf)
+{
+       if (nid != codec->afg && !(get_wcaps(codec, nid) & AC_WCAP_OUT_AMP))
+               return 0;
+       return sprintf(buf, "0x%08x\n",
+                      snd_hdac_read_parm(codec, nid, AC_PAR_AMP_OUT_CAP));
+}
+
+static ssize_t power_caps_show(struct hdac_device *codec, hda_nid_t nid,
+                              struct widget_attribute *attr, char *buf)
+{
+       if (nid != codec->afg && !(get_wcaps(codec, nid) & AC_WCAP_POWER))
+               return 0;
+       return sprintf(buf, "0x%08x\n",
+                      snd_hdac_read_parm(codec, nid, AC_PAR_POWER_STATE));
+}
+
+static ssize_t gpio_caps_show(struct hdac_device *codec, hda_nid_t nid,
+                             struct widget_attribute *attr, char *buf)
+{
+       return sprintf(buf, "0x%08x\n",
+                      snd_hdac_read_parm(codec, nid, AC_PAR_GPIO_CAP));
+}
+
+static ssize_t connections_show(struct hdac_device *codec, hda_nid_t nid,
+                               struct widget_attribute *attr, char *buf)
+{
+       hda_nid_t list[32];
+       int i, nconns;
+       ssize_t ret = 0;
+
+       nconns = snd_hdac_get_connections(codec, nid, list, ARRAY_SIZE(list));
+       if (nconns <= 0)
+               return nconns;
+       for (i = 0; i < nconns; i++)
+               ret += sprintf(buf + ret, "%s0x%02x", i ? " " : "", list[i]);
+       ret += sprintf(buf + ret, "\n");
+       return ret;
+}
+
+static WIDGET_ATTR_RO(caps);
+static WIDGET_ATTR_RO(pin_caps);
+static WIDGET_ATTR_RO(pin_cfg);
+static WIDGET_ATTR_RO(pcm_caps);
+static WIDGET_ATTR_RO(pcm_formats);
+static WIDGET_ATTR_RO(amp_in_caps);
+static WIDGET_ATTR_RO(amp_out_caps);
+static WIDGET_ATTR_RO(power_caps);
+static WIDGET_ATTR_RO(gpio_caps);
+static WIDGET_ATTR_RO(connections);
+
+static struct attribute *widget_node_attrs[] = {
+       &wid_attr_caps.attr,
+       &wid_attr_pin_caps.attr,
+       &wid_attr_pin_cfg.attr,
+       &wid_attr_pcm_caps.attr,
+       &wid_attr_pcm_formats.attr,
+       &wid_attr_amp_in_caps.attr,
+       &wid_attr_amp_out_caps.attr,
+       &wid_attr_power_caps.attr,
+       &wid_attr_connections.attr,
+       NULL,
+};
+
+static struct attribute *widget_afg_attrs[] = {
+       &wid_attr_pcm_caps.attr,
+       &wid_attr_pcm_formats.attr,
+       &wid_attr_amp_in_caps.attr,
+       &wid_attr_amp_out_caps.attr,
+       &wid_attr_power_caps.attr,
+       &wid_attr_gpio_caps.attr,
+       NULL,
+};
+
+static const struct attribute_group widget_node_group = {
+       .attrs = widget_node_attrs,
+};
+
+static const struct attribute_group widget_afg_group = {
+       .attrs = widget_afg_attrs,
+};
+
+static void free_widget_node(struct kobject *kobj,
+                            const struct attribute_group *group)
+{
+       if (kobj) {
+               sysfs_remove_group(kobj, group);
+               kobject_put(kobj);
+       }
+}
+
+static void widget_tree_free(struct hdac_device *codec)
+{
+       struct hdac_widget_tree *tree = codec->widgets;
+       struct kobject **p;
+
+       if (!tree)
+               return;
+       if (tree->nodes) {
+               for (p = tree->nodes; *p; p++)
+                       free_widget_node(*p, &widget_node_group);
+               kfree(tree->nodes);
+       }
+       free_widget_node(tree->afg, &widget_afg_group);
+       if (tree->root)
+               kobject_put(tree->root);
+       kfree(tree);
+       codec->widgets = NULL;
+}
+
+static int add_widget_node(struct kobject *parent, hda_nid_t nid,
+                          const struct attribute_group *group,
+                          struct kobject **res)
+{
+       struct kobject *kobj = kzalloc(sizeof(*kobj), GFP_KERNEL);
+       int err;
+
+       if (!kobj)
+               return -ENOMEM;
+       kobject_init(kobj, &widget_ktype);
+       err = kobject_add(kobj, parent, "%02x", nid);
+       if (err < 0)
+               return err;
+       err = sysfs_create_group(kobj, group);
+       if (err < 0) {
+               kobject_put(kobj);
+               return err;
+       }
+
+       *res = kobj;
+       return 0;
+}
+
+static int widget_tree_create(struct hdac_device *codec)
+{
+       struct hdac_widget_tree *tree;
+       int i, err;
+       hda_nid_t nid;
+
+       tree = codec->widgets = kzalloc(sizeof(*tree), GFP_KERNEL);
+       if (!tree)
+               return -ENOMEM;
+
+       tree->root = kobject_create_and_add("widgets", &codec->dev.kobj);
+       if (!tree->root)
+               return -ENOMEM;
+
+       if (codec->afg) {
+               err = add_widget_node(tree->root, codec->afg,
+                                     &widget_afg_group, &tree->afg);
+               if (err < 0)
+                       return err;
+       }
+
+       tree->nodes = kcalloc(codec->num_nodes + 1, sizeof(*tree->nodes),
+                             GFP_KERNEL);
+       if (!tree->nodes)
+               return -ENOMEM;
+
+       for (i = 0, nid = codec->start_nid; i < codec->num_nodes; i++, nid++) {
+               err = add_widget_node(tree->root, nid, &widget_node_group,
+                                     &tree->nodes[i]);
+               if (err < 0)
+                       return err;
+       }
+
+       kobject_uevent(tree->root, KOBJ_CHANGE);
+       return 0;
+}
+
+int hda_widget_sysfs_init(struct hdac_device *codec)
+{
+       int err;
+
+       err = widget_tree_create(codec);
+       if (err < 0) {
+               widget_tree_free(codec);
+               return err;
+       }
+
+       return 0;
+}
+
+void hda_widget_sysfs_exit(struct hdac_device *codec)
+{
+       widget_tree_free(codec);
+}