gpiolib: add devm_gpiod_get_array and devm_gpiod_put_array functions

Add device managed variants of gpiod_get_array() / gpiod_put_array()
functions for conveniently obtaining and disposing of an entire array
of GPIOs with one function call.

Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

3 files changed, 131 insertions, 2 deletions

diff --git a/Documentation/gpio/consumer.txt b/Documentation/gpio/consumer.txt
index 2924f2ffcd91..d29a9725c9e5 100644
--- a/Documentation/gpio/consumer.txt
+++ b/Documentation/gpio/consumer.txt
@@ -102,11 +102,19 @@ Device-managed variants of these functions are also defined:
                                                   const char *con_id,
                                                   enum gpiod_flags flags)
 
-        struct gpio_desc * devm_gpiod_get_index_optional(struct device *dev,
+        struct gpio_desc *devm_gpiod_get_index_optional(struct device *dev,
                                                         const char *con_id,
                                                         unsigned int index,
                                                         enum gpiod_flags flags)
 
+        struct gpio_descs *devm_gpiod_get_array(struct device *dev,
+                                                const char *con_id,
+                                                enum gpiod_flags flags)
+
+        struct gpio_descs *devm_gpiod_get_array_optional(struct device *dev,
+                                                         const char *con_id,
+                                                         enum gpiod_flags flags)
+
 A GPIO descriptor can be disposed of using the gpiod_put() function:
 
         void gpiod_put(struct gpio_desc *desc)
@@ -119,10 +127,12 @@ It is strictly forbidden to use a descriptor after calling these functions.
 It is also not allowed to individually release descriptors (using gpiod_put())
 from an array acquired with gpiod_get_array().
 
-The device-managed variant is, unsurprisingly:
+The device-managed variants are, unsurprisingly:
 
         void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
 
+        void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs)
+
 
 Using GPIOs
 ===========
diff --git a/drivers/gpio/devres.c b/drivers/gpio/devres.c
index 12c2082f968e..ec24da2418b3 100644
--- a/drivers/gpio/devres.c
+++ b/drivers/gpio/devres.c
@@ -35,6 +35,20 @@ static int devm_gpiod_match(struct device *dev, void *res, void *data)
         return *this == *gpio;
 }
 
+static void devm_gpiod_release_array(struct device *dev, void *res)
+{
+        struct gpio_descs **descs = res;
+
+        gpiod_put_array(*descs);
+}
+
+static int devm_gpiod_match_array(struct device *dev, void *res, void *data)
+{
+        struct gpio_descs **this = res, **gpios = data;
+
+        return *this == *gpios;
+}
+
 /**
  * devm_gpiod_get - Resource-managed gpiod_get()
  * @dev:        GPIO consumer
@@ -186,6 +200,66 @@ struct gpio_desc *__must_check __devm_gpiod_get_index_optional(struct device *de
 EXPORT_SYMBOL(__devm_gpiod_get_index_optional);
 
 /**
+ * devm_gpiod_get_array - Resource-managed gpiod_get_array()
+ * @dev:        GPIO consumer
+ * @con_id:     function within the GPIO consumer
+ * @flags:      optional GPIO initialization flags
+ *
+ * Managed gpiod_get_array(). GPIO descriptors returned from this function are
+ * automatically disposed on driver detach. See gpiod_get_array() for detailed
+ * information about behavior and return values.
+ */
+struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev,
+                                                     const char *con_id,
+                                                     enum gpiod_flags flags)
+{
+        struct gpio_descs **dr;
+        struct gpio_descs *descs;
+
+        dr = devres_alloc(devm_gpiod_release_array,
+                          sizeof(struct gpio_descs *), GFP_KERNEL);
+        if (!dr)
+                return ERR_PTR(-ENOMEM);
+
+        descs = gpiod_get_array(dev, con_id, flags);
+        if (IS_ERR(descs)) {
+                devres_free(dr);
+                return descs;
+        }
+
+        *dr = descs;
+        devres_add(dev, dr);
+
+        return descs;
+}
+EXPORT_SYMBOL(devm_gpiod_get_array);
+
+/**
+ * devm_gpiod_get_array_optional - Resource-managed gpiod_get_array_optional()
+ * @dev:        GPIO consumer
+ * @con_id:     function within the GPIO consumer
+ * @flags:      optional GPIO initialization flags
+ *
+ * Managed gpiod_get_array_optional(). GPIO descriptors returned from this
+ * function are automatically disposed on driver detach.
+ * See gpiod_get_array_optional() for detailed information about behavior and
+ * return values.
+ */
+struct gpio_descs *__must_check
+devm_gpiod_get_array_optional(struct device *dev, const char *con_id,
+                              enum gpiod_flags flags)
+{
+        struct gpio_descs *descs;
+
+        descs = devm_gpiod_get_array(dev, con_id, flags);
+        if (IS_ERR(descs) && (PTR_ERR(descs) == -ENOENT))
+                return NULL;
+
+        return descs;
+}
+EXPORT_SYMBOL(devm_gpiod_get_array_optional);
+
+/**
  * devm_gpiod_put - Resource-managed gpiod_put()
  * @desc:       GPIO descriptor to dispose of
  *
@@ -200,6 +274,21 @@ void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
 }
 EXPORT_SYMBOL(devm_gpiod_put);
 
+/**
+ * devm_gpiod_put_array - Resource-managed gpiod_put_array()
+ * @descs:      GPIO descriptor array to dispose of
+ *
+ * Dispose of an array of GPIO descriptors obtained with devm_gpiod_get_array().
+ * Normally this function will not be called as the GPIOs will be disposed of
+ * by the resource management code.
+ */
+void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs)
+{
+        WARN_ON(devres_release(dev, devm_gpiod_release_array,
+                               devm_gpiod_match_array, &descs));
+}
+EXPORT_SYMBOL(devm_gpiod_put_array);
+
 
 
 
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 33eb52fd0932..3a7c9ffd5ab9 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -83,7 +83,14 @@ struct gpio_desc *__must_check __devm_gpiod_get_optional(struct device *dev,
 struct gpio_desc *__must_check
 __devm_gpiod_get_index_optional(struct device *dev, const char *con_id,
                               unsigned int index, enum gpiod_flags flags);
+struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev,
+                                                     const char *con_id,
+                                                     enum gpiod_flags flags);
+struct gpio_descs *__must_check
+devm_gpiod_get_array_optional(struct device *dev, const char *con_id,
+                              enum gpiod_flags flags);
 void devm_gpiod_put(struct device *dev, struct gpio_desc *desc);
+void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs);
 
 int gpiod_get_direction(struct gpio_desc *desc);
 int gpiod_direction_input(struct gpio_desc *desc);
@@ -228,6 +235,20 @@ __devm_gpiod_get_index_optional(struct device *dev, const char *con_id,
         return ERR_PTR(-ENOSYS);
 }
 
+static inline struct gpio_descs *__must_check
+devm_gpiod_get_array(struct device *dev, const char *con_id,
+                     enum gpiod_flags flags)
+{
+        return ERR_PTR(-ENOSYS);
+}
+
+static inline struct gpio_descs *__must_check
+devm_gpiod_get_array_optional(struct device *dev, const char *con_id,
+                              enum gpiod_flags flags)
+{
+        return ERR_PTR(-ENOSYS);
+}
+
 static inline void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
 {
         might_sleep();
@@ -236,6 +257,15 @@ static inline void devm_gpiod_put(struct device *dev, struct gpio_desc *desc)
         WARN_ON(1);
 }
 
+static inline void devm_gpiod_put_array(struct device *dev,
+                                        struct gpio_descs *descs)
+{
+        might_sleep();
+
+        /* GPIO can never have been requested */
+        WARN_ON(1);
+}
+
 
 static inline int gpiod_get_direction(const struct gpio_desc *desc)
 {