path: root/Documentation/spi
diff options
authorGeert Uytterhoeven <geert+renesas@linux-m68k.org>2014-02-25 11:40:17 +0100
committerMark Brown <broonie@linaro.org>2014-02-27 13:51:29 +0900
commitdc64d39b54c1e9db97a6fb1ca52598c981728157 (patch)
tree4e68275a6ecd75f7ea65bd9d7d66c4007e1b1754 /Documentation/spi
parente6456186cae76f80446ba911f77eb2f85d3d927e (diff)
spi: spidev: Add support for Dual/Quad SPI Transfers
Add support for Dual/Quad SPI Transfers to the spidev API. As this uses SPI mode bits that don't fit in a single byte, two new ioctls (SPI_IOC_RD_MODE32 and SPI_IOC_WR_MODE32) are introduced. Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org> Signed-off-by: Mark Brown <broonie@linaro.org>
Diffstat (limited to 'Documentation/spi')
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/spi/spidev b/Documentation/spi/spidev
index ed2da5e5b28a..3d14035b1766 100644
--- a/Documentation/spi/spidev
+++ b/Documentation/spi/spidev
@@ -85,6 +85,12 @@ settings for data transfer parameters:
SPI_MODE_0..SPI_MODE_3; or if you prefer you can combine SPI_CPOL
(clock polarity, idle high iff this is set) or SPI_CPHA (clock phase,
sample on trailing edge iff this is set) flags.
+ Note that this request is limited to SPI mode flags that fit in a
+ single byte.
+ SPI_IOC_RD_MODE32, SPI_IOC_WR_MODE32 ... pass a pointer to a uin32_t
+ which will return (RD) or assign (WR) the full SPI transfer mode,
+ not limited to the bits that fit in one byte.
SPI_IOC_RD_LSB_FIRST, SPI_IOC_WR_LSB_FIRST ... pass a pointer to a byte
which will return (RD) or assign (WR) the bit justification used to