diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index 5db0639d3b01..dfa8ab1ec80f 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -577,6 +577,7 @@ EXPORT_SYMBOL_GPL(spi_mem_adjust_op_freq);
  * spi_mem_calc_op_duration() - Derives the theoretical length (in ns) of an
  *			        operation. This helps finding the best variant
  *			        among a list of possible choices.
+ * @mem: the SPI memory
  * @op: the operation to benchmark
  *
  * Some chips have per-op frequency limitations, PCBs usually have their own