diff options
author | Steve French <sfrench@us.ibm.com> | 2009-04-30 11:36:52 -0400 |
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committer | Steve French <sfrench@us.ibm.com> | 2009-04-30 11:36:52 -0400 |
commit | 912bc6ae3de99c7bada4577d4341ace4ee59b5be (patch) | |
tree | 28fd1a4bb9e4b05aa833285b46df169f12c0e24d /Documentation/spi/spi-summary | |
parent | d37dc42ab6f040b8f0f2962ab219c5b2accf748d (diff) | |
parent | 091438dd5668396328a3419abcbc6591159eb8d1 (diff) |
Merge branch 'master' of /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 | |||
511 | This sets up the device clock rate, SPI mode, and word sizes. | 511 | This sets up the device clock rate, SPI mode, and word sizes. |
512 | Drivers may change the defaults provided by board_info, and then | 512 | Drivers may change the defaults provided by board_info, and then |
513 | call spi_setup(spi) to invoke this routine. It may sleep. | 513 | call spi_setup(spi) to invoke this routine. It may sleep. |
514 | |||
514 | Unless each SPI slave has its own configuration registers, don't | 515 | Unless each SPI slave has its own configuration registers, don't |
515 | change them right away ... otherwise drivers could corrupt I/O | 516 | change them right away ... otherwise drivers could corrupt I/O |
516 | that's in progress for other SPI devices. | 517 | that's in progress for other SPI devices. |
517 | 518 | ||
519 | ** BUG ALERT: for some reason the first version of | ||
520 | ** many spi_master drivers seems to get this wrong. | ||
521 | ** When you code setup(), ASSUME that the controller | ||
522 | ** is actively processing transfers for another device. | ||
523 | |||
518 | master->transfer(struct spi_device *spi, struct spi_message *message) | 524 | master->transfer(struct spi_device *spi, struct spi_message *message) |
519 | This must not sleep. Its responsibility is arrange that the | 525 | This must not sleep. Its responsibility is arrange that the |
520 | transfer happens and its complete() callback is issued. The two | 526 | transfer happens and its complete() callback is issued. The two |