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| author | David Brownell <david-b@pacbell.net> | 2007-07-19 01:47:52 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-19 10:04:43 -0700 |
| commit | a0a9983509f45b2225ca87fdcf7b40ea916834ed (patch) | |
| tree | a70151c57f184bccd24175fa19a585021e297973 /Documentation/gpio.txt | |
| parent | e53252d97e670a38b1d2e9723b48077bba11ddda (diff) | |
| download | lwn-a0a9983509f45b2225ca87fdcf7b40ea916834ed.tar.gz lwn-a0a9983509f45b2225ca87fdcf7b40ea916834ed.zip | |
gpio calls don't need i/o barriers
Clarify that drivers using the GPIO operations don't need to issue io
barrier instructions themselves. Previously this wasn't clear, and at
least one platform assumed otherwise (and would thus break various
otherwise-portable drivers which don't issue barriers).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/gpio.txt')
| -rw-r--r-- | Documentation/gpio.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt index 36af58eba136..218a8650f48d 100644 --- a/Documentation/gpio.txt +++ b/Documentation/gpio.txt @@ -75,6 +75,9 @@ using the include file: If you stick to this convention then it'll be easier for other developers to see what your code is doing, and help maintain it. +Note that these operations include I/O barriers on platforms which need to +use them; drivers don't need to add them explicitly. + Identifying GPIOs ----------------- |