Unverified Commit 10c24e0d authored by Félix Piédallu's avatar Félix Piédallu Committed by Mark Brown
Browse files

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



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: d153ff40 ("spi: omap2-mcspi: Add support for MULTI-mode")
Signed-off-by: default avatarFélix Piédallu <felix.piedallu@non.se.com>
Link: https://patch.msgid.link/20250606-cs_change_fix-v1-2-27191a98a2e5@non.se.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent a5bf5272

drivers/spi/spi-omap2-mcspi.c

+10 −10
Original line number Diff line number Diff line
@@ -134,6 +134,7 @@ struct omap2_mcspi { 
	size_t			max_xfer_len;

	u32			ref_clk_hz;

	bool			use_multi_mode;

	bool			last_msg_kept_cs;

};



struct omap2_mcspi_cs {
@@ -1269,6 +1270,10 @@ static int omap2_mcspi_prepare_message(struct spi_controller *ctlr, 
	 * multi-mode is applicable.

	 */

	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) {

		if (!tr->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)) {

			/* 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->last_msg_kept_cs = true;

			} else {

				mcspi->last_msg_kept_cs = false;

			}

		} else {

			/* Check if transfer asks to change the CS status after the transfer */

			if (!tr->cs_change)

				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);