diff options
| author |   Michael Buesch <mb@bu3sch.de> | 2009-02-20 15:38:49 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2009-02-20 17:57:49 -0800 |
| commit | 01b24fee285b098c74318a8be801ef3711ec18d7 (patch) | |
| tree | 60403f86f2198f4c5f81a1447e4bf3f107ede7d3 /include | |
| parent | vmalloc: call flush_cache_vunmap() from unmap_kernel_range() (diff) | |
| download | linux-dev-01b24fee285b098c74318a8be801ef3711ec18d7.tar.xz linux-dev-01b24fee285b098c74318a8be801ef3711ec18d7.zip | |
spi_bitbang: add more lowlevel function documentation
This adds more documentation of the lowlevel API to avoid future bugs.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Acked-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 'include')
| -rw-r--r-- | include/linux/spi/spi_bitbang.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/spi/spi_bitbang.h b/include/linux/spi/spi_bitbang.h index bf8de281b4ed..eed4254bd503 100644 --- a/include/linux/spi/spi_bitbang.h +++ b/include/linux/spi/spi_bitbang.h @@ -83,6 +83,13 @@ extern int spi_bitbang_stop(struct spi_bitbang *spi); * int getmiso(struct spi_device *); * void spidelay(unsigned); * + * setsck()'s is_on parameter is a zero/nonzero boolean. + * + * setmosi()'s is_on parameter is a zero/nonzero boolean. + * + * getmiso() is required to return 0 or 1 only. Any other value is invalid + * and will result in improper operation. + * * A non-inlined routine would call bitbang_txrx_*() routines. The * main loop could easily compile down to a handful of instructions, * especially if the delay is a NOP (to run at peak speed). |