Commit 3712a3c4 authored by Stephen Warren's avatar Stephen Warren Committed by Linus Walleij
Browse files

pinctrl: add explicit gpio_disable_free pinmux_op 



Some pinctrl drivers (Tegra at least) program a pin to be a GPIO in a
completely different manner than they select which function to mux out of
that pin. In order to support a single "free" pinmux_op, the driver would
need to maintain a per-pin state of requested-for-gpio vs. requested-for-
function. However, that's a lot of work when the core already has explicit
separate paths for gpio request/free and function request/free.

So, add a gpio_disable_free op to struct pinmux_ops, and make pin_free()
call it when appropriate.

When doing this, I noticed that when calling pin_request():

    !!gpio == (gpio_range != NULL)

... and so I collapsed those two parameters in both pin_request(), and
when adding writing the new code in pin_free().

Also, for pin_free():

    !!free_func == (gpio_range != NULL)

However, I didn't want pin_free() to know about the GPIO function naming
special case, so instead, I reworked pin_free() to always return the pin's
previously requested function, and now pinmux_free_gpio() calls
kfree(function). This is much more balanced with the allocation having
been performed in pinmux_request_gpio().

Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent d2f6a1c6

drivers/pinctrl/pinmux.c

+25 −14
Original line number Diff line number Diff line
@@ -94,12 +94,11 @@ struct pinmux_hog { 
 * @function: a functional name to give to this pin, passed to the driver

 *	so it knows what function to mux in, e.g. the string "gpioNN"

 *	means that you want to mux in the pin for use as GPIO number NN

 * @gpio: if this request concerns a single GPIO pin

 * @gpio_range: the range matching the GPIO pin if this is a request for a

 *	single GPIO pin

 */

static int pin_request(struct pinctrl_dev *pctldev,

		       int pin, const char *function, bool gpio,

		       int pin, const char *function,

		       struct pinctrl_gpio_range *gpio_range)

{

	struct pin_desc *desc;
@@ -143,7 +142,7 @@ static int pin_request(struct pinctrl_dev *pctldev, 
	 * If there is no kind of request function for the pin we just assume

	 * we got it by default and proceed.

	 */

	if (gpio && ops->gpio_request_enable)

	if (gpio_range && ops->gpio_request_enable)

		/* This requests and enables a single GPIO pin */

		status = ops->gpio_request_enable(pctldev, gpio_range, pin);

	else if (ops->request)
@@ -173,29 +172,39 @@ out: 
 * pin_free() - release a single muxed in pin so something else can be muxed

 * @pctldev: pin controller device handling this pin

 * @pin: the pin to free

 * @free_func: whether to free the pin's assigned function name string

 * @gpio_range: the range matching the GPIO pin if this is a request for a

 *	single GPIO pin

 */

static void pin_free(struct pinctrl_dev *pctldev, int pin, int free_func)

static const char *pin_free(struct pinctrl_dev *pctldev, int pin,

			    struct pinctrl_gpio_range *gpio_range)

{

	const struct pinmux_ops *ops = pctldev->desc->pmxops;

	struct pin_desc *desc;

	const char *func;



	desc = pin_desc_get(pctldev, pin);

	if (desc == NULL) {

		dev_err(&pctldev->dev,

			"pin is not registered so it cannot be freed\n");

		return;

		return NULL;

	}



	if (ops->free)

	/*

	 * If there is no kind of request function for the pin we just assume

	 * we got it by default and proceed.

	 */

	if (gpio_range && ops->gpio_disable_free)

		ops->gpio_disable_free(pctldev, gpio_range, pin);

	else if (ops->free)

		ops->free(pctldev, pin);



	spin_lock(&desc->lock);

	if (free_func)

		kfree(desc->mux_function);

	func = desc->mux_function;

	desc->mux_function = NULL;

	spin_unlock(&desc->lock);

	module_put(pctldev->owner);



	return func;

}



/**
@@ -225,7 +234,7 @@ int pinmux_request_gpio(unsigned gpio) 
	if (!function)

		return -EINVAL;



	ret = pin_request(pctldev, pin, function, true, range);

	ret = pin_request(pctldev, pin, function, range);

	if (ret < 0)

		kfree(function);
@@ -243,6 +252,7 @@ void pinmux_free_gpio(unsigned gpio) 
	struct pinctrl_gpio_range *range;

	int ret;

	int pin;

	const char *func;



	ret = pinctrl_get_device_gpio_range(gpio, &pctldev, &range);

	if (ret)
@@ -251,7 +261,8 @@ void pinmux_free_gpio(unsigned gpio) 
	/* Convert to the pin controllers number space */

	pin = gpio - range->base;



	pin_free(pctldev, pin, true);

	func = pin_free(pctldev, pin, range);

	kfree(func);

}

EXPORT_SYMBOL_GPL(pinmux_free_gpio);
@@ -341,7 +352,7 @@ 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, false, NULL);

		ret = pin_request(pctldev, pins[i], func, NULL);

		if (ret) {

			dev_err(&pctldev->dev,

				"could not get pin %d for function %s "
@@ -351,7 +362,7 @@ static int acquire_pins(struct pinctrl_dev *pctldev, 
			/* On error release all taken pins */

			i--; /* this pin just failed */

			for (; i >= 0; i--)

				pin_free(pctldev, pins[i], false);

				pin_free(pctldev, pins[i], NULL);

			return -ENODEV;

		}

	}
@@ -381,7 +392,7 @@ static void release_pins(struct pinctrl_dev *pctldev, 
		return;

	}

	for (i = 0; i < num_pins; i++)

		pin_free(pctldev, pins[i], false);

		pin_free(pctldev, pins[i], NULL);

}



/**

include/linux/pinctrl/pinmux.h

+3 −0
Original line number Diff line number Diff line
@@ -73,6 +73,9 @@ struct pinmux_ops { 
	int (*gpio_request_enable) (struct pinctrl_dev *pctldev,

				    struct pinctrl_gpio_range *range,

				    unsigned offset);

	void (*gpio_disable_free) (struct pinctrl_dev *pctldev,

				   struct pinctrl_gpio_range *range,

				   unsigned offset);

};



/* External interface to pinmux */

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