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authorIngo Molnar <mingo@elte.hu>2009-05-07 13:17:13 +0400
committerIngo Molnar <mingo@elte.hu>2009-05-07 13:17:34 +0400
commit44347d947f628060b92449702071bfe1d31dfb75 (patch)
treec6ed74610d5b3295df4296659f80f5feb94b28cc /Documentation/spi/spi-summary
parentd94fc523f3c35bd8013f04827e94756cbc0212f4 (diff)
parent413f81eba35d6ede9289b0c8a920c013a84fac71 (diff)
downloadlinux-44347d947f628060b92449702071bfe1d31dfb75.tar.xz
Merge branch 'linus' into tracing/core
Merge reason: tracing/core was on a .30-rc1 base and was missing out on on a handful of tracing fixes present in .30-rc5-almost. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/spi/spi-summary')
-rw-r--r--Documentation/spi/spi-summary6
1 files changed, 6 insertions, 0 deletions
diff --git a/Documentation/spi/spi-summary b/Documentation/spi/spi-summary
index 0f5122eb282b..4a02d2508bc8 100644
--- a/Documentation/spi/spi-summary
+++ b/Documentation/spi/spi-summary
@@ -511,10 +511,16 @@ SPI MASTER METHODS
This sets up the device clock rate, SPI mode, and word sizes.
Drivers may change the defaults provided by board_info, and then
call spi_setup(spi) to invoke this routine. It may sleep.
+
Unless each SPI slave has its own configuration registers, don't
change them right away ... otherwise drivers could corrupt I/O
that's in progress for other SPI devices.
+ ** BUG ALERT: for some reason the first version of
+ ** many spi_master drivers seems to get this wrong.
+ ** When you code setup(), ASSUME that the controller
+ ** is actively processing transfers for another device.
+
master->transfer(struct spi_device *spi, struct spi_message *message)
This must not sleep. Its responsibility is arrange that the
transfer happens and its complete() callback is issued. The two