3 files changed, 46 insertions, 8 deletions

diff --git a/include/linux/iio/backend.h b/include/linux/iio/backend.h
index 4d15c2a9802c..3f95ed1fdf9e 100644
--- a/include/linux/iio/backend.h
+++ b/include/linux/iio/backend.h
@@ -261,6 +261,7 @@ int iio_backend_extend_chan_spec(struct iio_backend *back,
 bool iio_backend_has_caps(struct iio_backend *back, u32 caps);
 void *iio_backend_get_priv(const struct iio_backend *conv);
 struct iio_backend *devm_iio_backend_get(struct device *dev, const char *name);
+struct iio_backend *devm_iio_backend_get_by_index(struct device *dev, unsigned int index);
 struct iio_backend *devm_iio_backend_fwnode_get(struct device *dev,
 						const char *name,
 						struct fwnode_handle *fwnode);
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index d37f82678f71..745c98ef4e04 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -34,8 +34,16 @@ static inline int iio_push_to_buffers_with_timestamp(struct iio_dev *indio_dev,
 	void *data, int64_t timestamp)
 {
 	if (ACCESS_PRIVATE(indio_dev, scan_timestamp)) {
-		size_t ts_offset = indio_dev->scan_bytes / sizeof(int64_t) - 1;
-		((int64_t *)data)[ts_offset] = timestamp;
+		size_t ts_offset = ACCESS_PRIVATE(indio_dev, scan_timestamp_offset);
+
+		/*
+		 * The size of indio_dev->scan_bytes is always aligned to the
+		 * largest scan element's alignment (see iio_compute_scan_bytes()).
+		 * So there may be padding after the timestamp. ts_offset contains
+		 * the offset in bytes that was already computed for correctly
+		 * aligning the timestamp.
+		 */
+		*(int64_t *)(data + ts_offset) = timestamp;
 	}
 
 	return iio_push_to_buffers(indio_dev, data);
@@ -71,7 +79,7 @@ static inline int iio_push_to_buffers_with_ts(struct iio_dev *indio_dev,
 
 int iio_push_to_buffers_with_ts_unaligned(struct iio_dev *indio_dev,
 					  const void *data, size_t data_sz,
-					  int64_t timestamp);
+					  s64 timestamp);
 
 bool iio_validate_scan_mask_onehot(struct iio_dev *indio_dev,
 				   const unsigned long *mask);
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 2c91b7659ce9..711c00f67371 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -177,8 +177,31 @@ struct iio_event_spec {
 };
 
 /**
+ * define IIO_SCAN_FORMAT_SIGNED_INT - signed integer data format
+ *
+ * &iio_scan_type.format value for signed integers (two's complement).
+ */
+#define IIO_SCAN_FORMAT_SIGNED_INT	's'
+
+/**
+ * define IIO_SCAN_FORMAT_UNSIGNED_INT - unsigned integer data format
+ *
+ * &iio_scan_type.format value for unsigned integers.
+ */
+#define IIO_SCAN_FORMAT_UNSIGNED_INT	'u'
+
+/**
+ * define IIO_SCAN_FORMAT_FLOAT - floating-point data format
+ *
+ * &iio_scan_type.format value for IEEE 754 floating-point numbers.
+ */
+#define IIO_SCAN_FORMAT_FLOAT		'f'
+
+/**
  * struct iio_scan_type - specification for channel data format in buffer
- * @sign:		's' or 'u' to specify signed or unsigned
+ * @sign:		Deprecated, use @format instead.
+ * @format:		Data format, can have any of the IIO_SCAN_FORMAT_*
+ *			values.
  * @realbits:		Number of valid bits of data
  * @storagebits:	Realbits + padding
  * @shift:		Shift right by this before masking out realbits.
@@ -189,7 +212,10 @@ struct iio_event_spec {
  * @endianness:		little or big endian
  */
 struct iio_scan_type {
-	char	sign;
+	union {
+		char sign;
+		char format;
+	};
 	u8	realbits;
 	u8	storagebits;
 	u8	shift;
@@ -327,15 +353,15 @@ static inline bool iio_channel_has_available(const struct iio_chan_spec *chan,
 		(chan->info_mask_shared_by_all_available & BIT(type));
 }
 
-#define IIO_CHAN_SOFT_TIMESTAMP(_si) {					\
+#define IIO_CHAN_SOFT_TIMESTAMP(_si) (struct iio_chan_spec) {		\
 	.type = IIO_TIMESTAMP,						\
 	.channel = -1,							\
 	.scan_index = _si,						\
 	.scan_type = {							\
 		.sign = 's',						\
-		.realbits = 64,					\
+		.realbits = 64,						\
 		.storagebits = 64,					\
-		},							\
+	},								\
 }
 
 s64 iio_get_time_ns(const struct iio_dev *indio_dev);
@@ -584,6 +610,8 @@ struct iio_buffer_setup_ops {
  *			and owner
  * @buffer:		[DRIVER] any buffer present
  * @scan_bytes:		[INTERN] num bytes captured to be fed to buffer demux
+ * @scan_timestamp_offset: [INTERN] cache of the offset (in bytes) for the
+ *			   timestamp in the scan buffer
  * @available_scan_masks: [DRIVER] optional array of allowed bitmasks. Sort the
  *			   array in order of preference, the most preferred
  *			   masks first.
@@ -610,6 +638,7 @@ struct iio_dev {
 
 	struct iio_buffer		*buffer;
 	int				scan_bytes;
+	unsigned int			__private scan_timestamp_offset;
 
 	const unsigned long		*available_scan_masks;
 	unsigned int			__private masklength;