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author | Ingo Molnar <mingo@elte.hu> | 2009-05-07 13:17:13 +0400 |
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committer | Ingo Molnar <mingo@elte.hu> | 2009-05-07 13:17:34 +0400 |
commit | 44347d947f628060b92449702071bfe1d31dfb75 (patch) | |
tree | c6ed74610d5b3295df4296659f80f5feb94b28cc /Documentation/spi/spi-summary | |
parent | d94fc523f3c35bd8013f04827e94756cbc0212f4 (diff) | |
parent | 413f81eba35d6ede9289b0c8a920c013a84fac71 (diff) | |
download | linux-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-summary | 6 |
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 |