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| author | Ingo Molnar <mingo@elte.hu> | 2009-06-07 12:22:15 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-06-07 12:22:15 +0200 |
| commit | 5f4457a4f62cc9d78e04c0eb12ff0540899aad89 (patch) | |
| tree | 0b973d527ea6b2ae31e08da0746b4965a3c5a6d8 /Documentation/spi/spi-summary | |
| parent | 9b94b3a19b13e094c10f65f24bc358f6ffe4eacd (diff) | |
| parent | b87297fb405ef13cac375f202d114323b076a56d (diff) | |
Merge branch 'linus' into x86/cpu
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 |