pinctrl: add function to retrieve range from pin

This adds a function to the pinctrl core to retrieve the GPIO
range associated with a certain pin for a certain controller.
This is needed when a pinctrl driver want to look up the
corresponding struct gpio_chip for a certain pin. As the
GPIO drivers can now create these ranges themselves, the
pinctrl driver no longer knows about all its associated GPIO
chips.

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

2 files changed, 27 insertions, 0 deletions

diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c
index 33af811a6a3c..5cdee8669ea3 100644
--- a/drivers/pinctrl/core.c
+++ b/drivers/pinctrl/core.c
@@ -364,6 +364,30 @@ struct pinctrl_dev *pinctrl_find_and_add_gpio_range(const char *devname,
 EXPORT_SYMBOL_GPL(pinctrl_find_and_add_gpio_range);
 
 /**
+ * pinctrl_find_gpio_range_from_pin() - locate the GPIO range for a pin
+ * @pctldev: the pin controller device to look in
+ * @pin: a controller-local number to find the range for
+ */
+struct pinctrl_gpio_range *
+pinctrl_find_gpio_range_from_pin(struct pinctrl_dev *pctldev,
+                                 unsigned int pin)
+{
+        struct pinctrl_gpio_range *range = NULL;
+
+        /* Loop over the ranges */
+        list_for_each_entry(range, &pctldev->gpio_ranges, node) {
+                /* Check if we're in the valid range */
+                if (pin >= range->pin_base &&
+                    pin < range->pin_base + range->npins) {
+                        return range;
+                }
+        }
+
+        return NULL;
+}
+EXPORT_SYMBOL_GPL(pinctrl_find_gpio_range_from_pin);
+
+/**
  * pinctrl_remove_gpio_range() - remove a range of GPIOs fro a pin controller
  * @pctldev: pin controller device to remove the range from
  * @range: the GPIO range to remove
diff --git a/include/linux/pinctrl/pinctrl.h b/include/linux/pinctrl/pinctrl.h
index 7dee9acbd271..04d6700d99af 100644
--- a/include/linux/pinctrl/pinctrl.h
+++ b/include/linux/pinctrl/pinctrl.h
@@ -139,6 +139,9 @@ extern void pinctrl_remove_gpio_range(struct pinctrl_dev *pctldev,
 
 extern struct pinctrl_dev *pinctrl_find_and_add_gpio_range(const char *devname,
                 struct pinctrl_gpio_range *range);
+extern struct pinctrl_gpio_range *
+pinctrl_find_gpio_range_from_pin(struct pinctrl_dev *pctldev,
+                                 unsigned int pin);
 
 #ifdef CONFIG_OF
 extern struct pinctrl_dev *of_pinctrl_get(struct device_node *np);