From 83596fbeb5d28e8cb8878786133945d4dc7c0090 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Mon, 14 Apr 2014 19:39:53 +0200 Subject: spi: core: Ignore unsupported Dual/Quad Transfer Mode bits The availability of SPI Dual or Quad Transfer Mode as indicated by the "spi-tx-bus-width" and "spi-rx-bus-width" properties in the device tree is a hardware property of the SPI master, SPI slave, and board wiring. Hence the SPI core should not reject an SPI slave because an SPI master driver doesn't (yet) support Dual or Quad Transfer Mode. Change the lack of Dual or Quad Transfer Mode support in the SPI master driver from an error condition to a warning condition, and ignore the unsupported mode bits, falling back to Single Transfer Mode, to avoid breakages when running old kernels with new device trees. Fixes: f477b7fb13df (spi: DUAL and QUAD support) Signed-off-by: Geert Uytterhoeven Signed-off-by: Mark Brown Cc: stable@vger.kernel.org --- drivers/spi/spi.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'drivers/spi') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 4eb9bf02996c..1534fa1dac34 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1756,7 +1756,7 @@ EXPORT_SYMBOL_GPL(spi_busnum_to_master); */ int spi_setup(struct spi_device *spi) { - unsigned bad_bits; + unsigned bad_bits, ugly_bits; int status = 0; /* check mode to prevent that DUAL and QUAD set at the same time @@ -1776,6 +1776,15 @@ int spi_setup(struct spi_device *spi) * that aren't supported with their current master */ bad_bits = spi->mode & ~spi->master->mode_bits; + ugly_bits = bad_bits & + (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD); + if (ugly_bits) { + dev_warn(&spi->dev, + "setup: ignoring unsupported mode bits %x\n", + ugly_bits); + spi->mode &= ~ugly_bits; + bad_bits &= ~ugly_bits; + } if (bad_bits) { dev_err(&spi->dev, "setup: unsupported mode bits %x\n", bad_bits); -- cgit v1.2.1