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authorLaxman Dewangan <ldewangan@nvidia.com>2012-02-17 20:26:21 +0530
committerGrant Likely <grant.likely@secretlab.ca>2012-03-05 07:49:44 -0700
commitaca5ce14eb773a75e5d935968b2e390dc5bd29c3 (patch)
tree7da20e783f03b076d41163aad82dfb6878964ff9 /include/linux/gpio.h
parent3d2ddfdcf05f5f816f829f81858c54827d7be5b4 (diff)
downloadop-kernel-dev-aca5ce14eb773a75e5d935968b2e390dc5bd29c3.zip
op-kernel-dev-aca5ce14eb773a75e5d935968b2e390dc5bd29c3.tar.gz
gpio: gpiolib: Support for open drain/collector gpios
Adding support for the open drain gpio on which client can specify the open drain property through GPIO flag GPIOF_OPEN_DRAIN at the time of gpio request. The open drain pins are normally pulled high and it cannot be driven to output with value of 1 and so when client request for setting the pin to HIGH, the gpio will be set to input direction to make pin in tristate and hence PULL-UP on pins will make the state to HIGH. The open drain pin can be driven to LOW by setting output with value of 0. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> Reviwed-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Diffstat (limited to 'include/linux/gpio.h')
-rw-r--r--include/linux/gpio.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/gpio.h b/include/linux/gpio.h
index 38ac48b..66a5b2e 100644
--- a/include/linux/gpio.h
+++ b/include/linux/gpio.h
@@ -14,6 +14,9 @@
#define GPIOF_OUT_INIT_LOW (GPIOF_DIR_OUT | GPIOF_INIT_LOW)
#define GPIOF_OUT_INIT_HIGH (GPIOF_DIR_OUT | GPIOF_INIT_HIGH)
+/* Gpio pin is open drain */
+#define GPIOF_OPEN_DRAIN (1 << 2)
+
/**
* struct gpio - a structure describing a GPIO with configuration
* @gpio: the GPIO number
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