diff mbox

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

Message ID 1438155122-2923-1-git-send-email-larper@axis.com (mailing list archive)
State Accepted
Commit 26a67ec47a4c58fe79c6421c3dc3d697d322d2d6
Headers show

Commit Message

Lars Persson July 29, 2015, 7:32 a.m. UTC 
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.

Signed-off-by: Lars Persson <larper@axis.com>
---
 drivers/spi/spi-bitbang-txrx.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/drivers/spi/spi-bitbang-txrx.h b/drivers/spi/spi-bitbang-txrx.h
index 06b34e5..47bb9b89 100644
--- 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 *spi,
 {
 	/* 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 *spi,
 {
 	/* 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--) {