spi: rspi: Fix sequencer reset during initialization

[ Upstream commit 26843bb128590edd7eba1ad7ce22e4b9f1066ce3 ]

While the sequencer is reset after each SPI message since commit
880c6d114fd79a69 ("spi: rspi: Add support for Quad and Dual SPI
Transfers on QSPI"), it was never reset for the first message, thus
relying on reset state or bootloader settings.

Fix this by initializing it explicitly during configuration.

Fixes: 0b2182ddac4b8837 ("spi: add support for Renesas RSPI")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/spi/spi-rspi.c

@@ -279,7 +279,8 @@ static int rspi_set_config_register(struct rspi_data *rspi, int access_size)
 	/* Sets parity, interrupt mask */
 	rspi_write8(rspi, 0x00, RSPI_SPCR2);
 
-	/* Sets SPCMD */
+	/* Resets sequencer */
+	rspi_write8(rspi, 0, RSPI_SPSCR);
 	rspi->spcmd |= SPCMD_SPB_8_TO_16(access_size);
 	rspi_write16(rspi, rspi->spcmd, RSPI_SPCMD0);
 
@@ -323,7 +324,8 @@ static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size)
 	rspi_write8(rspi, 0x00, RSPI_SSLND);
 	rspi_write8(rspi, 0x00, RSPI_SPND);
 
-	/* Sets SPCMD */
+	/* Resets sequencer */
+	rspi_write8(rspi, 0, RSPI_SPSCR);
 	rspi->spcmd |= SPCMD_SPB_8_TO_16(access_size);
 	rspi_write16(rspi, rspi->spcmd, RSPI_SPCMD0);
 
@@ -374,7 +376,8 @@ static int qspi_set_config_register(struct rspi_data *rspi, int access_size)
 	/* Sets buffer to allow normal operation */
 	rspi_write8(rspi, 0x00, QSPI_SPBFCR);
 
-	/* Sets SPCMD */
+	/* Resets sequencer */
+	rspi_write8(rspi, 0, RSPI_SPSCR);
 	rspi_write16(rspi, rspi->spcmd, RSPI_SPCMD0);
 
 	/* Sets RSPI mode */