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author | Linus Walleij <linus.walleij@linaro.org> | 2011-11-14 09:06:22 (GMT) |
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committer | Linus Walleij <linus.walleij@linaro.org> | 2012-01-03 08:10:01 (GMT) |
commit | 542e704f3ffee1dc4539c9e8191e4dc215220f5e (patch) | |
tree | da2f8aae8bedb6e3216b4808dc743eb94c3270e3 /drivers | |
parent | 75d6642a3ee1dfe2552028997cdcc2c4207bec8f (diff) | |
download | linux-542e704f3ffee1dc4539c9e8191e4dc215220f5e.tar.xz |
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 'drivers')
-rw-r--r-- | drivers/pinctrl/pinmux.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c index 92aa13e..f3e4f03 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 |