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authorIngo Molnar <mingo@elte.hu>2009-05-08 10:50:00 +0200
committerIngo Molnar <mingo@elte.hu>2009-05-08 10:50:00 +0200
commitf066a155334642b8a206eec625b1925d88c48aeb (patch)
treecb12975e60b70d1dae3b7397bab955de78a4d01e /Documentation/spi/spi-summary
parente7c064889606aab3569669078c69b87b2c527e72 (diff)
parent33df4db04a79660150e1948e3296eeb451ac121b (diff)
downloadblackbird-op-linux-f066a155334642b8a206eec625b1925d88c48aeb.tar.gz
blackbird-op-linux-f066a155334642b8a206eec625b1925d88c48aeb.zip
Merge branch 'x86/urgent' into x86/xen
Conflicts: arch/frv/include/asm/pgtable.h arch/x86/include/asm/required-features.h arch/x86/xen/mmu.c Merge reason: x86/xen was on a .29 base still, move it to a fresher branch and pick up Xen fixes as well, plus resolve conflicts Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/spi/spi-summary')
-rw-r--r--Documentation/spi/spi-summary6
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
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