From 2638b50b18ad78c8fc0433c05270d3c7d62a6e03 Mon Sep 17 00:00:00 2001 From: Matthias Fuchs Date: Sat, 14 Jan 2012 02:25:25 +0000 Subject: [PATCH] mx28: fix i.MX28 spi driver The generic spi flash driver (drivers/mtd/spi/spi_flash.c) uses the spi low level driver's spi_xfer() function with len=0 to deassert the SPI flash' chip select. But the i.MX28 spi driver rejects this call due to len=0. This patch implements an exception for len=0 with the SPI_XFER_END flag set. This results in an extra read with the chip select being deasserted afterwards. There seems to be no way to deassert the signal by hand. Signed-off-by: Matthias Fuchs Tested-by: Fabio Estevam --- drivers/spi/mxs_spi.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c index 4c27fef3d1..adb9ca8ec8 100644 --- a/drivers/spi/mxs_spi.c +++ b/drivers/spi/mxs_spi.c @@ -129,9 +129,15 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, int len = bitlen / 8; const char *tx = dout; char *rx = din; - - if (bitlen == 0) - return 0; + char dummy; + + if (bitlen == 0) { + if (flags & SPI_XFER_END) { + rx = &dummy; + len = 1; + } else + return 0; + } if (!rx && !tx) return 0; -- 2.39.5