---

yaml
---
r: 289149
b: refs/heads/master
c: 5f420b4
h: refs/heads/master
i:
  289147: 95328a4
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 519ff1d2878e34de5bf68337ac29f2f1f50da159
+refs/heads/master: 5f420b42079c115daf3b45bbd15bcb6b7b05ad21

trunk/drivers/staging/iio/iio.h

@@ -88,6 +88,25 @@ enum iio_endian {
 	IIO_LE,
 };
 
+struct iio_chan_spec;
+struct iio_dev;
+
+/**
+ * struct iio_chan_spec_ext_info - Extended channel info attribute
+ * @name:	Info attribute name
+ * @shared:	Whether this attribute is shared between all channels.
+ * @read:	Read callback for this info attribute, may be NULL.
+ * @write:	Write callback for this info attribute, may be NULL.
+ */
+struct iio_chan_spec_ext_info {
+	const char *name;
+	bool shared;
+	ssize_t (*read)(struct iio_dev *, struct iio_chan_spec const *,
+			char *buf);
+	ssize_t (*write)(struct iio_dev *, struct iio_chan_spec const *,
+			const char *buf, size_t len);
+};
+
 /**
  * struct iio_chan_spec - specification of a single channel
  * @type:		What type of measurement is the channel making.
@@ -107,6 +126,9 @@ enum iio_endian {
  * @info_mask:		What information is to be exported about this channel.
  *			This includes calibbias, scale etc.
  * @event_mask:	What events can this channel produce.
+ * @ext_info:		Array of extended info attributes for this channel.
+ *			The array is NULL terminated, the last element should
+ *			have it's name field set to NULL.
  * @extend_name:	Allows labeling of channel attributes with an
  *			informative name. Note this has no effect codes etc,
  *			unlike modifiers.
@@ -141,6 +163,7 @@ struct iio_chan_spec {
 	} scan_type;
 	long			info_mask;
 	long			event_mask;
+	const struct iio_chan_spec_ext_info *ext_info;
 	char			*extend_name;
 	const char		*datasheet_name;
 	unsigned		processed_val:1;

trunk/drivers/staging/iio/industrialio-core.c

@@ -144,6 +144,33 @@ static void __exit iio_exit(void)
 	bus_unregister(&iio_bus_type);
 }
 
+static ssize_t iio_read_channel_ext_info(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	const struct iio_chan_spec_ext_info *ext_info;
+
+	ext_info = &this_attr->c->ext_info[this_attr->address];
+
+	return ext_info->read(indio_dev, this_attr->c, buf);
+}
+
+static ssize_t iio_write_channel_ext_info(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf,
+					 size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	const struct iio_chan_spec_ext_info *ext_info;
+
+	ext_info = &this_attr->c->ext_info[this_attr->address];
+
+	return ext_info->write(indio_dev, this_attr->c, buf, len);
+}
+
 static ssize_t iio_read_channel_info(struct device *dev,
 				     struct device_attribute *attr,
 				     char *buf)
@@ -423,6 +450,7 @@ static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
 					struct iio_chan_spec const *chan)
 {
 	int ret, i, attrcount = 0;
+	const struct iio_chan_spec_ext_info *ext_info;
 
 	if (chan->channel < 0)
 		return 0;
@@ -457,6 +485,31 @@ static int iio_device_add_channel_sysfs(struct iio_dev *indio_dev,
 			goto error_ret;
 		attrcount++;
 	}
+
+	if (chan->ext_info) {
+		unsigned int i = 0;
+		for (ext_info = chan->ext_info; ext_info->name; ext_info++) {
+			ret = __iio_add_chan_devattr(ext_info->name,
+					chan,
+					ext_info->read ?
+					    &iio_read_channel_ext_info : NULL,
+					ext_info->write ?
+					    &iio_write_channel_ext_info : NULL,
+					i,
+					ext_info->shared,
+					&indio_dev->dev,
+					&indio_dev->channel_attr_list);
+			i++;
+			if (ret == -EBUSY && ext_info->shared)
+				continue;
+
+			if (ret)
+				goto error_ret;
+
+			attrcount++;
+		}
+	}
+
 	ret = attrcount;
 error_ret:
 	return ret;