This patch marks dummy transfer by setting dummy_data bit to 1.
Controllers supporting dummy transfer by hardware use this bit field
to skip software transfer of dummy bytes and use hardware dummy bytes
transfer.
Signed-off-by: Sowjanya Komatineni <[email protected]>
---
drivers/spi/spi-mem.c | 1 +
include/linux/spi/spi.h | 2 ++
2 files changed, 3 insertions(+)
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index f3a3f19..c64371c 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -354,6 +354,7 @@ int spi_mem_exec_op(struct spi_mem *mem, const struct spi_mem_op *op)
xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
xfers[xferpos].len = op->dummy.nbytes;
xfers[xferpos].tx_nbits = op->dummy.buswidth;
+ xfers[xferpos].dummy_data = 1;
spi_message_add_tail(&xfers[xferpos], &msg);
xferpos++;
totalxferlen += op->dummy.nbytes;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index aa09fdc..708f2f5 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -827,6 +827,7 @@ extern void spi_res_release(struct spi_controller *ctlr,
* transfer. If 0 the default (from @spi_device) is used.
* @bits_per_word: select a bits_per_word other than the device default
* for this transfer. If 0 the default (from @spi_device) is used.
+ * @dummy_data: indicates transfer is dummy bytes transfer.
* @cs_change: affects chipselect after this transfer completes
* @cs_change_delay: delay between cs deassert and assert when
* @cs_change is set and @spi_transfer is not the last in @spi_message
@@ -939,6 +940,7 @@ struct spi_transfer {
struct sg_table tx_sg;
struct sg_table rx_sg;
+ unsigned dummy_data:1;
unsigned cs_change:1;
unsigned tx_nbits:3;
unsigned rx_nbits:3;
--
2.7.4