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spi: omap2-mcspi: Disable multi-mode when the previous message kept CS asserted

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When the last transfer of a SPI message has the cs_change flag, the CS is kept
asserted after the message.
The next message can't use multi-mode because the CS will be briefly deasserted
before the first transfer.

Remove the early exit of the list_for_each_entry because the last transfer
actually needs to be always checked.

Fixes: d153ff4056 ("spi: omap2-mcspi: Add support for MULTI-mode")
Signed-off-by: Félix Piédallu <felix.piedallu@non.se.com>
Link: https://patch.msgid.link/20250606-cs_change_fix-v1-2-27191a98a2e5@non.se.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Félix Piédallu 2025-06-06 15:37:25 +02:00 committed by Mark Brown
parent a5bf527229
commit 10c24e0d2f
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GPG key ID: 24D68B725D5487D0
1 changed files with 10 additions and 10 deletions
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20
drivers/spi/spi-omap2-mcspi.c
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@ -134,6 +134,7 @@ struct omap2_mcspi {
size_t max_xfer_len; size_t max_xfer_len;
u32 ref_clk_hz; u32 ref_clk_hz;
bool use_multi_mode; bool use_multi_mode;
bool last_msg_kept_cs;
}; };
struct omap2_mcspi_cs { struct omap2_mcspi_cs {
@ -1269,6 +1270,10 @@ static int omap2_mcspi_prepare_message(struct spi_controller *ctlr,
* multi-mode is applicable. * multi-mode is applicable.
*/ */
mcspi->use_multi_mode = true; mcspi->use_multi_mode = true;
if (mcspi->last_msg_kept_cs)
mcspi->use_multi_mode = false;
list_for_each_entry(tr, &msg->transfers, transfer_list) { list_for_each_entry(tr, &msg->transfers, transfer_list) {
if (!tr->bits_per_word) if (!tr->bits_per_word)
bits_per_word = msg->spi->bits_per_word; bits_per_word = msg->spi->bits_per_word;
@ -1289,22 +1294,17 @@ static int omap2_mcspi_prepare_message(struct spi_controller *ctlr,
if (list_is_last(&tr->transfer_list, &msg->transfers)) { if (list_is_last(&tr->transfer_list, &msg->transfers)) {
/* Check if transfer asks to keep the CS status after the whole message */ /* Check if transfer asks to keep the CS status after the whole message */
if (tr->cs_change) if (tr->cs_change) {
mcspi->use_multi_mode = false; mcspi->use_multi_mode = false;
mcspi->last_msg_kept_cs = true;
} else {
mcspi->last_msg_kept_cs = false;
}
} else { } else {
/* Check if transfer asks to change the CS status after the transfer */ /* Check if transfer asks to change the CS status after the transfer */
if (!tr->cs_change) if (!tr->cs_change)
mcspi->use_multi_mode = false; mcspi->use_multi_mode = false;
} }
/*
* If at least one message is not compatible, switch back to single mode
*
* The bits_per_word of certain transfer can be different, but it will have no
* impact on the signal itself.
*/
if (!mcspi->use_multi_mode)
break;
} }
omap2_mcspi_set_mode(ctlr); omap2_mcspi_set_mode(ctlr);