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pinctrl: add explicit gpio_disable_free pinmux_op

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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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Stephen Warren 2011-10-21 12:25:53 -06:00 committed by Linus Walleij
parent d2f6a1c6fb
commit 3712a3c488
2 changed files with 28 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
drivers/pinctrl/pinmux.c
View File

@ -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 @@ static int pin_request(struct pinctrl_dev *pctldev,
* 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);
}
/**

3
include/linux/pinctrl/pinmux.h
View File

@ -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 */