gpiolib: add gpiod_get_array and gpiod_put_array functions

Introduce new functions for conveniently obtaining and disposing of
an entire array of GPIOs with one function call.

ACPI parts tested by Mika Westerberg, DT parts tested by Rojhalat
Ibrahim.

Change log:
v5: move the ACPI functions to gpiolib-acpi.c
v4: - use shorter names for members of struct gpio_descs
    - rename lut_gpio_count to platform_gpio_count for clarity
    - add check for successful memory allocation
    - use ERR_CAST()
v3: - rebase on current linux-gpio devel branch
    - fix ACPI GPIO counting
    - allow for zero-sized arrays
    - make the flags argument mandatory for the new functions
    - clarify documentation
v2: change interface

Suggested-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Rojhalat Ibrahim <imr@rtschenk.de>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Rojhalat Ibrahim <imr@rtschenk.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 46 insertions, 0 deletions

diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index ed20759229eb..33eb52fd0932 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -16,6 +16,15 @@ struct device;
  */
 struct gpio_desc;
 
+/**
+ * Struct containing an array of descriptors that can be obtained using
+ * gpiod_get_array().
+ */
+struct gpio_descs {
+        unsigned int ndescs;
+        struct gpio_desc *desc[];
+};
+
 #define GPIOD_FLAGS_BIT_DIR_SET         BIT(0)
 #define GPIOD_FLAGS_BIT_DIR_OUT         BIT(1)
 #define GPIOD_FLAGS_BIT_DIR_VAL         BIT(2)
@@ -34,6 +43,9 @@ enum gpiod_flags {
 
 #ifdef CONFIG_GPIOLIB
 
+/* Return the number of GPIOs associated with a device / function */
+int gpiod_count(struct device *dev, const char *con_id);
+
 /* Acquire and dispose GPIOs */
 struct gpio_desc *__must_check __gpiod_get(struct device *dev,
                                          const char *con_id,
@@ -49,7 +61,14 @@ struct gpio_desc *__must_check __gpiod_get_index_optional(struct device *dev,
                                                         const char *con_id,
                                                         unsigned int index,
                                                         enum gpiod_flags flags);
+struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
+                                                const char *con_id,
+                                                enum gpiod_flags flags);
+struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev,
+                                                        const char *con_id,
+                                                        enum gpiod_flags flags);
 void gpiod_put(struct gpio_desc *desc);
+void gpiod_put_array(struct gpio_descs *descs);
 
 struct gpio_desc *__must_check __devm_gpiod_get(struct device *dev,
                                               const char *con_id,
@@ -114,6 +133,11 @@ struct gpio_desc *devm_get_gpiod_from_child(struct device *dev,
                                             struct fwnode_handle *child);
 #else /* CONFIG_GPIOLIB */
 
+static inline int gpiod_count(struct device *dev, const char *con_id)
+{
+        return 0;
+}
+
 static inline struct gpio_desc *__must_check __gpiod_get(struct device *dev,
                                                 const char *con_id,
                                                 enum gpiod_flags flags)
@@ -143,6 +167,20 @@ __gpiod_get_index_optional(struct device *dev, const char *con_id,
         return ERR_PTR(-ENOSYS);
 }
 
+static inline struct gpio_descs *__must_check
+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
+gpiod_get_array_optional(struct device *dev, const char *con_id,
+                         enum gpiod_flags flags)
+{
+        return ERR_PTR(-ENOSYS);
+}
+
 static inline void gpiod_put(struct gpio_desc *desc)
 {
         might_sleep();
@@ -151,6 +189,14 @@ static inline void gpiod_put(struct gpio_desc *desc)
         WARN_ON(1);
 }
 
+static inline void gpiod_put_array(struct gpio_descs *descs)
+{
+        might_sleep();
+
+        /* GPIO can never have been requested */
+        WARN_ON(1);
+}
+
 static inline struct gpio_desc *__must_check
 __devm_gpiod_get(struct device *dev,
                  const char *con_id,