Revert "iio: add support for multiple scan types per channel"

Revert commit f1aa31e ("iio: add support for multiple scan types
per channel").

Somehow, this was not the same as the upstream commit. The actual
upstream commit will be added in a following commit.

Signed-off-by: David Lechner <[email protected]>

Author: dlech

drivers/iio/industrialio-buffer.c

@@ -399,16 +399,9 @@ static ssize_t iio_show_fixed_type(struct device *dev,
 				   struct device_attribute *attr,
 				   char *buf)
 {
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
-	const struct iio_scan_type *scan_type;
-	u8 type;
-
-	scan_type = iio_get_current_scan_type(indio_dev, this_attr->c);
-	if (IS_ERR(scan_type))
-		return PTR_ERR(scan_type);
-
-	type = scan_type->endianness;
+	const struct iio_scan_type *scan_type = &this_attr->c->scan_type;
+	u8 type = scan_type->endianness;
 
 	if (type == IIO_CPU) {
 #ifdef __LITTLE_ENDIAN
@@ -739,20 +732,24 @@ static ssize_t enable_show(struct device *dev, struct device_attribute *attr,
 	return sysfs_emit(buf, "%d\n", iio_buffer_is_active(buffer));
 }
 
-static int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
-				    unsigned int scan_index)
+static unsigned int iio_storage_bytes_for_si(struct iio_dev *indio_dev,
+					     unsigned int scan_index)
 {
 	const struct iio_chan_spec *ch;
+	const struct iio_scan_type *scan_type;
 	unsigned int bytes;
 
 	ch = iio_find_channel_from_si(indio_dev, scan_index);
-	bytes = ch->scan_type.storagebits / 8;
-	if (ch->scan_type.repeat > 1)
-		bytes *= ch->scan_type.repeat;
+	scan_type = &ch->scan_type;
+	bytes = scan_type->storagebits / 8;
+
+	if (scan_type->repeat > 1)
+		bytes *= scan_type->repeat;
+
 	return bytes;
 }
 
-static int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
+static unsigned int iio_storage_bytes_for_timestamp(struct iio_dev *indio_dev)
 {
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 
@@ -770,19 +767,13 @@ static int iio_compute_scan_bytes(struct iio_dev *indio_dev,
 	for_each_set_bit(i, mask,
 			 indio_dev->masklength) {
 		length = iio_storage_bytes_for_si(indio_dev, i);
-		if (length < 0)
-			return length;
-
 		bytes = ALIGN(bytes, length);
 		bytes += length;
 		largest = max(largest, length);
 	}
 
 	if (timestamp) {
 		length = iio_storage_bytes_for_timestamp(indio_dev);
-		if (length < 0)
-			return length;
-
 		bytes = ALIGN(bytes, length);
 		bytes += length;
 		largest = max(largest, length);
@@ -1061,22 +1052,14 @@ static int iio_buffer_update_demux(struct iio_dev *indio_dev,
 				       indio_dev->masklength,
 				       in_ind + 1);
 		while (in_ind != out_ind) {
-			ret = iio_storage_bytes_for_si(indio_dev, in_ind);
-			if (ret < 0)
-				goto error_clear_mux_table;
-
-			length = ret;
+			length = iio_storage_bytes_for_si(indio_dev, in_ind);
 			/* Make sure we are aligned */
 			in_loc = roundup(in_loc, length) + length;
 			in_ind = find_next_bit(indio_dev->active_scan_mask,
 					       indio_dev->masklength,
 					       in_ind + 1);
 		}
-		ret = iio_storage_bytes_for_si(indio_dev, in_ind);
-		if (ret < 0)
-			goto error_clear_mux_table;
-
-		length = ret;
+		length = iio_storage_bytes_for_si(indio_dev, in_ind);
 		out_loc = roundup(out_loc, length);
 		in_loc = roundup(in_loc, length);
 		ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
@@ -1087,11 +1070,7 @@ static int iio_buffer_update_demux(struct iio_dev *indio_dev,
 	}
 	/* Relies on scan_timestamp being last */
 	if (buffer->scan_timestamp) {
-		ret = iio_storage_bytes_for_timestamp(indio_dev);
-		if (ret < 0)
-			goto error_clear_mux_table;
-
-		length = ret;
+		length = iio_storage_bytes_for_timestamp(indio_dev);
 		out_loc = roundup(out_loc, length);
 		in_loc = roundup(in_loc, length);
 		ret = iio_buffer_add_demux(buffer, &p, in_loc, out_loc, length);
@@ -1920,14 +1899,16 @@ static int __iio_buffer_alloc_sysfs_and_mask(struct iio_buffer *buffer,
 			if (channels[i].scan_index < 0)
 				continue;
 
+			scan_type = &channels[i].scan_type;
+
 			/* Verify that sample bits fit into storage */
 			if (scan_type->storagebits <
 			    scan_type->realbits + scan_type->shift) {
 				dev_err(&indio_dev->dev,
 					"Channel %d storagebits (%d) < shifted realbits (%d + %d)\n",
-					i, channels[i].scan_type.storagebits,
-					channels[i].scan_type.realbits,
-					channels[i].scan_type.shift);
+					i, scan_type->storagebits,
+					scan_type->realbits,
+					scan_type->shift);
 				ret = -EINVAL;
 				goto error_cleanup_dynamic;
 			}

include/linux/iio/iio.h

@@ -204,13 +204,7 @@ struct iio_scan_type {
  * @address:		Driver specific identifier.
  * @scan_index:		Monotonic index to give ordering in scans when read
  *			from a buffer.
- * @scan_type:		struct describing the scan type - mutually exclusive
- *			with ext_scan_type.
- * @ext_scan_type:	Used in rare cases where there is more than one scan
- *			format for a channel. When this is used, the flag
- *			has_ext_scan_type must be set and the driver must
- *			implement get_current_scan_type in struct iio_info.
- * @num_ext_scan_type:	Number of elements in ext_scan_type.
+ * @scan_type:		struct describing the scan type
  * @info_mask_separate: What information is to be exported that is specific to
  *			this channel.
  * @info_mask_separate_available: What availability information is to be
@@ -251,21 +245,14 @@ struct iio_scan_type {
  *			attributes but not for event codes.
  * @output:		Channel is output.
  * @differential:	Channel is differential.
- * @has_ext_scan_type:	True if ext_scan_type is used instead of scan_type.
  */
 struct iio_chan_spec {
 	enum iio_chan_type	type;
 	int			channel;
 	int			channel2;
 	unsigned long		address;
 	int			scan_index;
-	union {
-		struct iio_scan_type scan_type;
-		struct {
-			const struct iio_scan_type *ext_scan_type;
-			unsigned int num_ext_scan_type;
-		};
-	};
+	struct iio_scan_type scan_type;
 	long			info_mask_separate;
 	long			info_mask_separate_available;
 	long			info_mask_shared_by_type;
@@ -283,7 +270,6 @@ struct iio_chan_spec {
 	unsigned		indexed:1;
 	unsigned		output:1;
 	unsigned		differential:1;
-	unsigned		has_ext_scan_type:1;
 };
 
 
@@ -441,9 +427,6 @@ struct iio_trigger; /* forward declaration */
  *			for better event identification.
  * @validate_trigger:	function to validate the trigger when the
  *			current trigger gets changed.
- * @get_current_scan_type: must be implemented by drivers that use ext_scan_type
- *			in the channel spec to return the index of the currently
- *			active ext_scan type for a channel.
  * @update_scan_mode:	function to configure device and scan buffer when
  *			channels have changed
  * @debugfs_reg_access:	function to read or write register value of device
@@ -534,8 +517,6 @@ struct iio_info {
 
 	int (*validate_trigger)(struct iio_dev *indio_dev,
 				struct iio_trigger *trig);
-	int (*get_current_scan_type)(const struct iio_dev *indio_dev,
-				     const struct iio_chan_spec *chan);
 	int (*update_scan_mode)(struct iio_dev *indio_dev,
 				const unsigned long *scan_mask);
 	int (*debugfs_reg_access)(struct iio_dev *indio_dev,
@@ -806,38 +787,6 @@ static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
 }
 #endif
 
-/**
- * iio_get_current_scan_type - Get the current scan type for a channel
- * @indio_dev:	the IIO device to get the scan type for
- * @chan:	the channel to get the scan type for
- *
- * Most devices only have one scan type per channel and can just access it
- * directly without calling this function. Core IIO code and drivers that
- * implement ext_scan_type in the channel spec should use this function to
- * get the current scan type for a channel.
- *
- * Returns: the current scan type for the channel or error.
- */
-static inline const struct iio_scan_type
-*iio_get_current_scan_type(const struct iio_dev *indio_dev,
-			   const struct iio_chan_spec *chan)
-{
-	int ret;
-
-	if (chan->has_ext_scan_type) {
-		ret = indio_dev->info->get_current_scan_type(indio_dev, chan);
-		if (ret < 0)
-			return ERR_PTR(ret);
-
-		if (ret >= chan->num_ext_scan_type)
-			return ERR_PTR(-EINVAL);
-
-		return &chan->ext_scan_type[ret];
-	}
-
-	return &chan->scan_type;
-}
-
 /**
  * iio_get_masklength - Get length of the channels mask
  * @indio_dev: the IIO device to get the masklength for