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: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
index 3b542097f93ad379adaf25f5883ce164b8c1216a..06bee1b733bb28830882db66c16b7c2cbcbc934a 100644 (file)
--- a/drivers/pinctrl/pinmux.c
+++ b/drivers/pinctrl/pinmux.c
@@ -98,12 +98,11 @@ 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;
@@ -147,7 +146,7 @@ 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)
@@ -177,29 +176,39 @@ 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;
 }
 
 /**
@@ -229,7 +238,7 @@ 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);
 
@@ -247,6 +256,7 @@ 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)
@@ -255,7 +265,8 @@ 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);
 
@@ -345,7 +356,7 @@ 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 "
@@ -355,7 +366,7 @@ 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;
                }
        }
@@ -385,7 +396,7 @@ 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);
 }
 
 /**

diff --git a/include/linux/pinctrl/pinmux.h b/include/linux/pinctrl/pinmux.h
index 3c430e797efc7397d7363e5c421bd8746ef520b4..350e32a98c6aadcdc93ae1d7c12c0b3e3426d506 100644 (file)
--- a/include/linux/pinctrl/pinmux.h
+++ b/include/linux/pinctrl/pinmux.h
@@ -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 */