diff options
| -rw-r--r-- | Documentation/pinctrl.txt | 32 | ||||
| -rw-r--r-- | drivers/pinctrl/pinmux.c | 61 | ||||
| -rw-r--r-- | include/linux/pinctrl/pinmux.h | 24 |
3 files changed, 108 insertions, 9 deletions
diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt index 43ba411d157..3846264c597 100644 --- a/Documentation/pinctrl.txt +++ b/Documentation/pinctrl.txt @@ -645,6 +645,17 @@ All the above functions are mandatory to implement for a pinmux driver. Pinmux interaction with the GPIO subsystem ========================================== +The public pinmux API contains two functions named pinmux_request_gpio() +and pinmux_free_gpio(). These two functions shall *ONLY* be called from +gpiolib-based drivers as part of their gpio_request() and +gpio_free() semantics. Likewise the pinmux_gpio_direction_[input|output] +shall only be called from within respective gpio_direction_[input|output] +gpiolib implementation. + +NOTE that platforms and individual drivers shall *NOT* request GPIO pins to be +muxed in. Instead, implement a proper gpiolib driver and have that driver +request proper muxing for its pins. + The function list could become long, especially if you can convert every individual pin into a GPIO pin independent of any other pins, and then try the approach to define every pin as a function. @@ -652,19 +663,24 @@ the approach to define every pin as a function. In this case, the function array would become 64 entries for each GPIO setting and then the device functions. -For this reason there is an additional function a pinmux driver can implement -to enable only GPIO on an individual pin: .gpio_request_enable(). The same -.free() function as for other functions is assumed to be usable also for -GPIO pins. +For this reason there are two functions a pinmux driver can implement +to enable only GPIO on an individual pin: .gpio_request_enable() and +.gpio_disable_free(). This function will pass in the affected GPIO range identified by the pin controller core, so you know which GPIO pins are being affected by the request operation. -Alternatively it is fully allowed to use named functions for each GPIO -pin, the pinmux_request_gpio() will attempt to obtain the function "gpioN" -where "N" is the global GPIO pin number if no special GPIO-handler is -registered. +If your driver needs to have an indication from the framework of whether the +GPIO pin shall be used for input or output you can implement the +.gpio_set_direction() function. As described this shall be called from the +gpiolib driver and the affected GPIO range, pin offset and desired direction +will be passed along to this function. + +Alternatively to using these special functions, it is fully allowed to use +named functions for each GPIO pin, the pinmux_request_gpio() will attempt to +obtain the function "gpioN" where "N" is the global GPIO pin number if no +special GPIO-handler is registered. Pinmux board/machine configuration diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c index 92aa13ee220..f3e4f031fe1 100644 --- a/drivers/pinctrl/pinmux.c +++ b/drivers/pinctrl/pinmux.c @@ -214,6 +214,10 @@ static const char *pin_free(struct pinctrl_dev *pctldev, int pin, /** * pinmux_request_gpio() - request a single pin to be muxed in as GPIO * @gpio: the GPIO pin number from the GPIO subsystem number space + * + * This function should *ONLY* be used from gpiolib-based GPIO drivers, + * as part of their gpio_request() semantics, platforms and individual drivers + * shall *NOT* request GPIO pins to be muxed in. */ int pinmux_request_gpio(unsigned gpio) { @@ -249,6 +253,10 @@ EXPORT_SYMBOL_GPL(pinmux_request_gpio); /** * pinmux_free_gpio() - free a single pin, currently used as GPIO * @gpio: the GPIO pin number from the GPIO subsystem number space + * + * This function should *ONLY* be used from gpiolib-based GPIO drivers, + * as part of their gpio_free() semantics, platforms and individual drivers + * shall *NOT* request GPIO pins to be muxed out. */ void pinmux_free_gpio(unsigned gpio) { @@ -270,6 +278,59 @@ void pinmux_free_gpio(unsigned gpio) } EXPORT_SYMBOL_GPL(pinmux_free_gpio); +static int pinmux_gpio_direction(unsigned gpio, bool input) +{ + struct pinctrl_dev *pctldev; + struct pinctrl_gpio_range *range; + const struct pinmux_ops *ops; + int ret; + int pin; + + ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range); + if (ret) + return ret; + + ops = pctldev->desc->pmxops; + + /* Convert to the pin controllers number space */ + pin = gpio - range->base + range->pin_base; + + if (ops->gpio_set_direction) + ret = ops->gpio_set_direction(pctldev, range, pin, input); + else + ret = 0; + + return ret; +} + +/** + * pinmux_gpio_direction_input() - request a GPIO pin to go into input mode + * @gpio: the GPIO pin number from the GPIO subsystem number space + * + * This function should *ONLY* be used from gpiolib-based GPIO drivers, + * as part of their gpio_direction_input() semantics, platforms and individual + * drivers shall *NOT* touch pinmux GPIO calls. + */ +int pinmux_gpio_direction_input(unsigned gpio) +{ + return pinmux_gpio_direction(gpio, true); +} +EXPORT_SYMBOL_GPL(pinmux_gpio_direction_input); + +/** + * pinmux_gpio_direction_output() - request a GPIO pin to go into output mode + * @gpio: the GPIO pin number from the GPIO subsystem number space + * + * This function should *ONLY* be used from gpiolib-based GPIO drivers, + * as part of their gpio_direction_output() semantics, platforms and individual + * drivers shall *NOT* touch pinmux GPIO calls. + */ +int pinmux_gpio_direction_output(unsigned gpio) +{ + return pinmux_gpio_direction(gpio, false); +} +EXPORT_SYMBOL_GPL(pinmux_gpio_direction_output); + /** * pinmux_register_mappings() - register a set of pinmux mappings * @maps: the pinmux mappings table to register diff --git a/include/linux/pinctrl/pinmux.h b/include/linux/pinctrl/pinmux.h index bb7a9792f1e..937b3e2fa36 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; |