spi: add transfer histogram statistics via sysfs

report transfer sizes as a histogram via the following files:
  /sys/class/spi_master/spi*/statistics/transfer_bytes_histo_*
  /sys/class/spi_master/spi*/spi*.*/statistics/transfer_bytes_histo_*

Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 269e8afd3e2a..5b6fdc48eba7 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -51,6 +51,8 @@ extern struct bus_type spi_bus_type;
  * @bytes_tx:      number of bytes sent to device
  * @bytes_rx:      number of bytes received from device
  *
+ * @transfer_bytes_histo:
+ *                 transfer bytes histogramm
  */
 struct spi_statistics {
         spinlock_t              lock; /* lock for the whole structure */
@@ -68,6 +70,8 @@ struct spi_statistics {
         unsigned long long      bytes_rx;
         unsigned long long      bytes_tx;
 
+#define SPI_STATISTICS_HISTO_SIZE 17
+        unsigned long transfer_bytes_histo[SPI_STATISTICS_HISTO_SIZE];
 };
 
 void spi_statistics_add_transfer_stats(struct spi_statistics *stats,