Patch "spi: Fix regression in spi-bitbang-txrx.h" has been added to the 4.1-stable tree

Patch "spi: Fix regression in spi-bitbang-txrx.h" has been added to the 4.1-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    spi: Fix regression in spi-bitbang-txrx.h

to the 4.1-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     spi-fix-regression-in-spi-bitbang-txrx.h.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 26a67ec47a4c58fe79c6421c3dc3d697d322d2d6 Mon Sep 17 00:00:00 2001
From: Lars Persson <lars.persson@axis.com>
Date: Wed, 29 Jul 2015 09:32:02 +0200
Subject: spi: Fix regression in spi-bitbang-txrx.h

From: Lars Persson <lars.persson@axis.com>

commit 26a67ec47a4c58fe79c6421c3dc3d697d322d2d6 upstream.

This patch fixes a regression introduced by commit 232a5adc5199 ("spi:
bitbang: only toggle bitchanges"). The attempt to optimize writes of
consecutive bit patterns broke most of the combinations of word size
and SPI modes due to selecting the wrong bit as the MSB value.

Fixes: 232a5adc5199 (spi: bitbang: only toggle bitchanges)
Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/spi/spi-bitbang-txrx.h |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/spi/spi-bitbang-txrx.h
+++ b/drivers/spi/spi-bitbang-txrx.h
@@ -49,7 +49,7 @@ bitbang_txrx_be_cpha0(struct spi_device
 {
 	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */
 
-	bool oldbit = !(word & 1);
+	u32 oldbit = (!(word & (1<<(bits-1)))) << 31;
 	/* clock starts at inactive polarity */
 	for (word <<= (32 - bits); likely(bits); bits--) {
 
@@ -81,7 +81,7 @@ bitbang_txrx_be_cpha1(struct spi_device
 {
 	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */
 
-	bool oldbit = !(word & (1 << 31));
+	u32 oldbit = (!(word & (1<<(bits-1)))) << 31;
 	/* clock starts at inactive polarity */
 	for (word <<= (32 - bits); likely(bits); bits--) {
 


Patches currently in stable-queue which might be from lars.persson@axis.com are

queue-4.1/spi-fix-regression-in-spi-bitbang-txrx.h.patch