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| author | Ingo Molnar <mingo@elte.hu> | 2009-04-29 14:46:59 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-04-29 14:47:05 +0200 |
| commit | e7fd5d4b3d240f42c30a9e3d20a4689c4d3a795a (patch) | |
| tree | 4ba588631dd8189a818a91c9e3976526071178b6 /Documentation/spi/spi-summary | |
| parent | 1130b0296184bc21806225fd06d533515a99d2db (diff) | |
| parent | 56a50adda49b2020156616c4eb15353e0f9ad7de (diff) | |
| download | kernel-crypto-e7fd5d4b3d240f42c30a9e3d20a4689c4d3a795a.tar.gz kernel-crypto-e7fd5d4b3d240f42c30a9e3d20a4689c4d3a795a.tar.xz kernel-crypto-e7fd5d4b3d240f42c30a9e3d20a4689c4d3a795a.zip | |
Merge branch 'linus' into perfcounters/core
Merge reason: This brach was on -rc1, refresh it to almost-rc4 to pick up
the latest upstream fixes.
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 0f5122eb282..4a02d2508bc 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 |