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authorRussell King <rmk+kernel@arm.linux.org.uk>2011-01-06 22:31:35 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2011-01-06 22:32:03 +0000
commit4ec3eb13634529c0bc7466658d84d0bbe3244aea (patch)
treeb491daac2ccfc7b8ca88e171a43f66888463568a /Documentation/gpio.txt
parent24056f525051a9e186af28904b396320e18bf9a0 (diff)
parent15095bb0fe779c0403091bda7adce5fb3bb9ca35 (diff)
Merge branch 'smp' into misc
Conflicts: arch/arm/kernel/entry-armv.S arch/arm/mm/ioremap.c
Diffstat (limited to 'Documentation/gpio.txt')
-rw-r--r--Documentation/gpio.txt10
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 9633da01ff46..792faa3c06cf 100644
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -617,6 +617,16 @@ and have the following read/write attributes:
is configured as an output, this value may be written;
any nonzero value is treated as high.
+ If the pin can be configured as interrupt-generating interrupt
+ and if it has been configured to generate interrupts (see the
+ description of "edge"), you can poll(2) on that file and
+ poll(2) will return whenever the interrupt was triggered. If
+ you use poll(2), set the events POLLPRI and POLLERR. If you
+ use select(2), set the file descriptor in exceptfds. After
+ poll(2) returns, either lseek(2) to the beginning of the sysfs
+ file and read the new value or close the file and re-open it
+ to read the value.
+
"edge" ... reads as either "none", "rising", "falling", or
"both". Write these strings to select the signal edge(s)
that will make poll(2) on the "value" file return.