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authorLinus Walleij <linus.walleij@linaro.org>2011-11-14 10:06:22 +0100
committerLinus Walleij <linus.walleij@linaro.org>2012-01-03 09:10:01 +0100
commit542e704f3ffee1dc4539c9e8191e4dc215220f5e (patch)
treeda2f8aae8bedb6e3216b4808dc743eb94c3270e3 /include/linux/pinctrl
parent75d6642a3ee1dfe2552028997cdcc2c4207bec8f (diff)
downloadop-kernel-dev-542e704f3ffee1dc4539c9e8191e4dc215220f5e.zip
op-kernel-dev-542e704f3ffee1dc4539c9e8191e4dc215220f5e.tar.gz
pinctrl: GPIO direction support for muxing
When requesting a single GPIO pin to be muxed in, some controllers will need to poke a different value into the control register depending on whether the pin will be used for GPIO output or GPIO input. So create pinmux counterparts to gpio_direction_[input|output] in the pinctrl framework. ChangeLog v1->v2: - This also amends the documentation to make it clear the this function and associated machinery is *ONLY* intended as a backend to gpiolib machinery, not for everyone and his dog to start playing around with pins. ChangeLog v2->v3: - Don't pass an argument to the common request function, instead provide pinmux_* counterparts to the gpio_direction_[input|output] calls, simpler and anyone can understand it. ChangeLog v3->v4: - Fix numerous spelling mistakes and dangling text in documentation. Add Ack and Rewewed-by. Cc: Igor Grinberg <grinberg@compulab.co.il> Acked-by: Stephen Warren <swarren@nvidia.com> Reviewed-by: Thomas Abraham <thomas.abraham@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'include/linux/pinctrl')
-rw-r--r--include/linux/pinctrl/pinmux.h24
1 files changed, 23 insertions, 1 deletions
diff --git a/include/linux/pinctrl/pinmux.h b/include/linux/pinctrl/pinmux.h
index bb7a979..937b3e2 100644
--- a/include/linux/pinctrl/pinmux.h
+++ b/include/linux/pinctrl/pinmux.h
@@ -54,7 +54,13 @@ struct pinctrl_dev;
* Implement this only if you can mux every pin individually as GPIO. The
* affected GPIO range is passed along with an offset(pin number) into that
* specific GPIO range - function selectors and pin groups are orthogonal
- * to this, the core will however make sure the pins do not collide
+ * to this, the core will however make sure the pins do not collide.
+ * @gpio_disable_free: free up GPIO muxing on a certain pin, the reverse of
+ * @gpio_request_enable
+ * @gpio_set_direction: Since controllers may need different configurations
+ * depending on whether the GPIO is configured as input or output,
+ * a direction selector function may be implemented as a backing
+ * to the GPIO controllers that need pin muxing.
*/
struct pinmux_ops {
int (*request) (struct pinctrl_dev *pctldev, unsigned offset);
@@ -76,11 +82,17 @@ struct pinmux_ops {
void (*gpio_disable_free) (struct pinctrl_dev *pctldev,
struct pinctrl_gpio_range *range,
unsigned offset);
+ int (*gpio_set_direction) (struct pinctrl_dev *pctldev,
+ struct pinctrl_gpio_range *range,
+ unsigned offset,
+ bool input);
};
/* External interface to pinmux */
extern int pinmux_request_gpio(unsigned gpio);
extern void pinmux_free_gpio(unsigned gpio);
+extern int pinmux_gpio_direction_input(unsigned gpio);
+extern int pinmux_gpio_direction_output(unsigned gpio);
extern struct pinmux * __must_check pinmux_get(struct device *dev, const char *name);
extern void pinmux_put(struct pinmux *pmx);
extern int pinmux_enable(struct pinmux *pmx);
@@ -97,6 +109,16 @@ static inline void pinmux_free_gpio(unsigned gpio)
{
}
+static inline int pinmux_gpio_direction_input(unsigned gpio)
+{
+ return 0;
+}
+
+static inline int pinmux_gpio_direction_output(unsigned gpio)
+{
+ return 0;
+}
+
static inline struct pinmux * __must_check pinmux_get(struct device *dev, const char *name)
{
return NULL;
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