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-rw-r--r--Documentation/spi/spidev6
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
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