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[1/2] spi: omap2-mcspi: Disable multi mode when CS should be kept asserted after message

Message ID 20250606-cs_change_fix-v1-1-27191a98a2e5@non.se.com
State New
Headers show
Series SPI: omap2-mcspi: Fix SPI CS behaviour around cs_change in SPI transfers | expand

Commit Message

Félix Piédallu via B4 Relay June 6, 2025, 1:37 p.m. UTC 
From: Félix Piédallu <felix.piedallu@non.se.com>

When the last transfer of a SPI message has the cs_change flag, the CS is kept
asserted after the message.
Multi-mode can't respect this as CS is deasserted by the hardware at the end of
the message.

Disable multi-mode when not applicable to the current message.

Fixes: d153ff4056cb ("spi: omap2-mcspi: Add support for MULTI-mode")
Signed-off-by: Félix Piédallu <felix.piedallu@non.se.com>
---
 drivers/spi/spi-omap2-mcspi.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
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Patch

diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 532b2e9c31d0d..05766b98de36f 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -1287,9 +1287,15 @@  static int omap2_mcspi_prepare_message(struct spi_controller *ctlr,
 			mcspi->use_multi_mode = false;
 		}
 
-		/* Check if transfer asks to change the CS status after the transfer */
-		if (!tr->cs_change)
-			mcspi->use_multi_mode = false;
+		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)
+				mcspi->use_multi_mode = 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