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| author | James Morris <jmorris@namei.org> | 2009-05-08 17:56:47 +1000 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2009-05-08 17:56:47 +1000 |
| commit | d254117099d711f215e62427f55dfb8ebd5ad011 (patch) | |
| tree | 0848ff8dd74314fec14a86497f8d288c86ba7c65 /Documentation/spi/spi-summary | |
| parent | 07ff7a0b187f3951788f64ae1f30e8109bc8e9eb (diff) | |
| parent | 8c9ed899b44c19e81859fbb0e9d659fe2f8630fc (diff) | |
| download | kernel_samsung_tuna-d254117099d711f215e62427f55dfb8ebd5ad011.zip kernel_samsung_tuna-d254117099d711f215e62427f55dfb8ebd5ad011.tar.gz kernel_samsung_tuna-d254117099d711f215e62427f55dfb8ebd5ad011.tar.bz2 | |
Merge branch 'master' into next
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 0f5122e..4a02d25 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 |