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Date: Mon, 14 Nov 2011 13:08:00 +0200
From: Igor Grinberg <grinberg@...pulab.co.il>
To: Linus Walleij <linus.walleij@...ricsson.com>
CC: linux-kernel@...r.kernel.org, Stephen Warren <swarren@...dia.com>,
Grant Likely <grant.likely@...retlab.ca>,
Barry Song <21cnbao@...il.com>,
Shawn Guo <shawn.guo@...escale.com>,
Thomas Abraham <thomas.abraham@...aro.org>,
Linus Walleij <linus.walleij@...aro.org>
Subject: Re: [PATCH] pinctrl: indicate GPIO direction on single GPIO request
Hi Linus,
On 11/14/11 11:10, Linus Walleij wrote:
> From: Linus Walleij <linus.walleij@...aro.org>
>
> 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 pass this info along for the gpio_request_enable()
> function, we assume this is not needed for the gpio_free_disable()
> function for the time being.
>
> Suggested-by: Thomas Abraham <thomas.abraham@...aro.org>
> Signed-off-by: Linus Walleij <linus.walleij@...aro.org>
> ---
> drivers/pinctrl/pinmux.c | 16 +++++++++++-----
> include/linux/pinctrl/pinmux.h | 14 ++++++++++----
> 2 files changed, 21 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
> index d27b77d..ef2f812 100644
> --- a/drivers/pinctrl/pinmux.c
> +++ b/drivers/pinctrl/pinmux.c
> @@ -100,10 +100,13 @@ struct pinmux_hog {
> * means that you want to mux in the pin for use as GPIO number NN
> * @gpio_range: the range matching the GPIO pin if this is a request for a
> * single GPIO pin
> + * @gpio_direction: if the pin is muxed for GPIO, this provides the direction
> + * of the GPIO @true means output, @false means input
can this be gpio_direction_out (throughout the patch)?
so the true/false values will make more sense?
> */
> static int pin_request(struct pinctrl_dev *pctldev,
> int pin, const char *function,
> - struct pinctrl_gpio_range *gpio_range)
> + struct pinctrl_gpio_range *gpio_range,
> + bool gpio_direction)
> {
> struct pin_desc *desc;
> const struct pinmux_ops *ops = pctldev->desc->pmxops;
> @@ -148,7 +151,8 @@ static int pin_request(struct pinctrl_dev *pctldev,
> */
> if (gpio_range && ops->gpio_request_enable)
> /* This requests and enables a single GPIO pin */
> - status = ops->gpio_request_enable(pctldev, gpio_range, pin);
> + status = ops->gpio_request_enable(pctldev, gpio_range, pin,
> + gpio_direction);
> else if (ops->request)
> status = ops->request(pctldev, pin);
> else
> @@ -218,8 +222,10 @@ 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
> + * @direction: the direction of the GPIO, @true means output, @false
> + * means input
> */
> -int pinmux_request_gpio(unsigned gpio)
> +int pinmux_request_gpio(unsigned gpio, bool direction)
> {
> char gpiostr[16];
> const char *function;
> @@ -242,7 +248,7 @@ int pinmux_request_gpio(unsigned gpio)
> if (!function)
> return -EINVAL;
>
> - ret = pin_request(pctldev, pin, function, range);
> + ret = pin_request(pctldev, pin, function, range, direction);
> if (ret < 0)
> kfree(function);
>
> @@ -360,7 +366,7 @@ static int acquire_pins(struct pinctrl_dev *pctldev,
>
> /* Try to allocate all pins in this group, one by one */
> for (i = 0; i < num_pins; i++) {
> - ret = pin_request(pctldev, pins[i], func, NULL);
> + ret = pin_request(pctldev, pins[i], func, NULL, false);
> if (ret) {
> dev_err(&pctldev->dev,
> "could not get pin %d for function %s "
> diff --git a/include/linux/pinctrl/pinmux.h b/include/linux/pinctrl/pinmux.h
> index bb7a979..7d3841f 100644
> --- a/include/linux/pinctrl/pinmux.h
> +++ b/include/linux/pinctrl/pinmux.h
> @@ -54,7 +54,12 @@ 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. Since
> + * controllers may be needing different configurations depending on
> + * whether the GPIO is configured as input or output, a direction
> + * indicator is passed along
> + * @gpio_disable_free: free up GPIO muxing on a certain pin, the reverse of
> + * @gpio_request_enable
> */
> struct pinmux_ops {
> int (*request) (struct pinctrl_dev *pctldev, unsigned offset);
> @@ -72,14 +77,15 @@ struct pinmux_ops {
> unsigned group_selector);
> int (*gpio_request_enable) (struct pinctrl_dev *pctldev,
> struct pinctrl_gpio_range *range,
> - unsigned offset);
> + unsigned offset,
> + bool direction);
> void (*gpio_disable_free) (struct pinctrl_dev *pctldev,
> struct pinctrl_gpio_range *range,
> unsigned offset);
> };
>
> /* External interface to pinmux */
> -extern int pinmux_request_gpio(unsigned gpio);
> +extern int pinmux_request_gpio(unsigned gpio, bool direction);
> extern void pinmux_free_gpio(unsigned gpio);
> extern struct pinmux * __must_check pinmux_get(struct device *dev, const char *name);
> extern void pinmux_put(struct pinmux *pmx);
> @@ -88,7 +94,7 @@ extern void pinmux_disable(struct pinmux *pmx);
>
> #else /* !CONFIG_PINMUX */
>
> -static inline int pinmux_request_gpio(unsigned gpio)
> +static inline int pinmux_request_gpio(unsigned gpio, bool direction)
> {
> return 0;
> }
--
Regards,
Igor.
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