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| author | Paul Mundt <lethal@linux-sh.org> | 2009-04-22 09:27:47 +0900 |
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| committer | Paul Mundt <lethal@linux-sh.org> | 2009-04-22 09:27:47 +0900 |
| commit | 99ce567ba912109c78762246c964327f3f81f27d (patch) | |
| tree | 685265d60792c11d386db6c005ca8b8e714ecc23 /Documentation/spi/spi-summary | |
| parent | 8fb2bae4b41eb64f6e233e9bd3f3a789fbb04a06 (diff) | |
| parent | ccc5ff94c66e628d3c501b26ace5d4339667715d (diff) | |
| download | linux-99ce567ba912109c78762246c964327f3f81f27d.tar.bz2 | |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
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 |