From c20c57d9868d7f9fd1b2904c7801b07e128f6322 Mon Sep 17 00:00:00 2001
From: Christophe Leroy <christophe.leroy@csgroup.eu>
Date: Sat, 1 Apr 2023 19:59:46 +0200
Subject: [PATCH] spi: fsl-spi: Fix CPM/QE mode Litte Endian
Git-commit: c20c57d9868d7f9fd1b2904c7801b07e128f6322
Patch-mainline: v6.4-rc1
References: git-fixes

CPM has the same problem as QE so for CPM also use the fix added
by commit 0398fb70940e ("spi/spi_mpc8xxx: Fix QE mode Litte Endian"):

  CPM mode uses Little Endian so words > 8 bits are byte swapped.
  Workaround this by always enforcing wordsize 8 for 16 and 32 bits
  words. Unfortunately this will not work for LSB transfers
  where wordsize is > 8 bits so disable these for now.

Also limit the workaround to 16 and 32 bits words because it can
only work for multiples of 8-bits.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joakim Tjernlund <Joakim.Tjernlund@infinera.com>
Fixes: 0398fb70940e ("spi/spi_mpc8xxx: Fix QE mode Litte Endian")
Link: https://lore.kernel.org/r/1b7d3e84b1128f42c1887dd2fb9cdf390f541bc1.1680371809.git.christophe.leroy@csgroup.eu
Signed-off-by: Mark Brown <broonie@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/spi/spi-fsl-spi.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi-fsl-spi.c b/drivers/spi/spi-fsl-spi.c
index 702756c25aa7..4651f65c9046 100644
--- a/drivers/spi/spi-fsl-spi.c
+++ b/drivers/spi/spi-fsl-spi.c
@@ -181,8 +181,8 @@ static int mspi_apply_qe_mode_quirks(struct spi_mpc8xxx_cs *cs,
 				struct spi_device *spi,
 				int bits_per_word)
 {
-	/* QE uses Little Endian for words > 8
-	 * so transform all words > 8 into 8 bits
+	/* CPM/QE uses Little Endian for words > 8
+	 * so transform 16 and 32 bits words into 8 bits
 	 * Unfortnatly that doesn't work for LSB so
 	 * reject these for now */
 	/* Note: 32 bits word, LSB works iff
@@ -190,9 +190,11 @@ static int mspi_apply_qe_mode_quirks(struct spi_mpc8xxx_cs *cs,
 	if (spi->mode & SPI_LSB_FIRST &&
 	    bits_per_word > 8)
 		return -EINVAL;
-	if (bits_per_word > 8)
+	if (bits_per_word <= 8)
+		return bits_per_word;
+	if (bits_per_word == 16 || bits_per_word == 32)
 		return 8; /* pretend its 8 bits */
-	return bits_per_word;
+	return -EINVAL;
 }
 
 static int fsl_spi_setup_transfer(struct spi_device *spi,
@@ -222,7 +224,7 @@ static int fsl_spi_setup_transfer(struct spi_device *spi,
 		bits_per_word = mspi_apply_cpu_mode_quirks(cs, spi,
 							   mpc8xxx_spi,
 							   bits_per_word);
-	else if (mpc8xxx_spi->flags & SPI_QE)
+	else
 		bits_per_word = mspi_apply_qe_mode_quirks(cs, spi,
 							  bits_per_word);
 
-- 
2.35.3