[PATCH 2/5] spi: core: allow reporting the effectivly used speed_hz for a transfer

[kernel@xxxxxxxxxxxxxxxx]

From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>

Provide a means for the spi bus driver to report the effectively used
spi clock frequency used for each spi_transfer.

Signed-off-by: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
---
 drivers/spi/spi.c       | 1 +
 include/linux/spi/spi.h | 5 +++++
 2 files changed, 6 insertions(+)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 90659eb29660..5a4616894d57 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -3004,6 +3004,7 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message)
 	 */
 	message->frame_length = 0;
 	list_for_each_entry(xfer, &message->transfers, transfer_list) {
+		xfer->effective_speed_hz = 0;
 		message->frame_length += xfer->len;
 		if (!xfer->bits_per_word)
 			xfer->bits_per_word = spi->bits_per_word;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index f2ce1fb403ef..f503a712423d 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -711,6 +711,9 @@ extern void spi_res_release(struct spi_controller *ctlr,
  *	the next transfer or completing this @spi_message.
  * @word_delay: clock cycles to inter word delay after each word size
  *	(set by bits_per_word) transmission.
+ * @effective_speed_hz: the effective SCK-speed that was used to
+ *      transfer this transfer. Set to 0 if the spi bus driver does
+ *      not support it.
  * @transfer_list: transfers are sequenced through @spi_message.transfers
  * @tx_sg: Scatterlist for transmit, currently not for client use
  * @rx_sg: Scatterlist for receive, currently not for client use
@@ -799,6 +802,8 @@ struct spi_transfer {
 	u32		speed_hz;
 	u16		word_delay;

+	u32		effective_speed_hz;
+
 	struct list_head transfer_list;
 };

--
2.11.0