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spi: spi-mem: Mark dummy transfers by setting dummy_data bit

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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 <skomatineni@nvidia.com>
Link: https://lore.kernel.org/r/1608585459-17250-6-git-send-email-skomatineni@nvidia.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Sowjanya Komatineni 2020-12-21 13:17:35 -08:00 committed by Mark Brown
parent 921fc1838f
commit 98621ed011
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GPG key ID: 24D68B725D5487D0
2 changed files with 3 additions and 0 deletions
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1
drivers/spi/spi-mem.c
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@ -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;

2
include/linux/spi/spi.h
View file

@ -825,6 +825,7 @@ 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
@ -937,6 +938,7 @@ 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;