[PATCH v2 1/2] gpio: Add devm_fwnode_gpiod_get_optional() helpers

Krzysztof Kozlowski
2020-08-26T20:08:38Z

Add devm_fwnode_gpiod_get_optional() and
devm_fwnode_gpiod_get_index_optional() helpers, similar to regular
devm_gpiod optional versions. Drivers getting GPIOs from a firmware
node might use it to remove some boilerplate code.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

---

Changes since v1:
1. New patch
---
drivers/gpio/gpiolib-devres.c | 71 +++++++++++++++++++++++++++++++++++
include/linux/gpio/consumer.h | 30 +++++++++++++++
2 files changed, 101 insertions(+)

diff --git a/drivers/gpio/gpiolib-devres.c b/drivers/gpio/gpiolib-devres.c
index 7dbce4c4ebdf..f8476f6a65cc 100644
--- a/drivers/gpio/gpiolib-devres.c
+++ b/drivers/gpio/gpiolib-devres.c
@@ -184,6 +184,37 @@ struct gpio_desc *devm_gpiod_get_from_of_node(struct device *dev,
}
EXPORT_SYMBOL_GPL(devm_gpiod_get_from_of_node);

+/**
+ * devm_fwnode_gpiod_get_optional - Resource-managed fwnode_gpiod_get_index()
+ * for optional GPIO
+ * @dev: GPIO consumer
+ * @fwnode: firmware node containing GPIO reference
+ * @con_id: function within the GPIO consumer
+ * @flags: GPIO initialization flags
+ * @label: label to attach to the requested GPIO
+ *
+ * GPIO descriptors returned from this function are automatically disposed on
+ * driver detach.
+ *
+ * This is equivalent to devm_fwnode_gpiod_get_index(), except that when no
+ * GPIO with the specified index was assigned to the requested function it will
+ * return NULL. This is convenient for drivers that need to handle optional
+ * GPIOs.
+ *
+ * On successful request the GPIO pin is configured in accordance with
+ * provided @flags.
+ */
+struct gpio_desc *devm_fwnode_gpiod_get_optional(struct device *dev,
+ struct fwnode_handle *fwnode,
+ const char *con_id,
+ enum gpiod_flags flags,
+ const char *label)
+{
+ return devm_fwnode_gpiod_get_index_optional(dev, fwnode, con_id, 0,
+ flags, label);
+}
+EXPORT_SYMBOL_GPL(devm_fwnode_gpiod_get_optional);
+
/**
* devm_fwnode_gpiod_get_index - get a GPIO descriptor from a given node
* @dev: GPIO consumer
@@ -226,6 +257,46 @@ struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
}
EXPORT_SYMBOL_GPL(devm_fwnode_gpiod_get_index);

+/**
+ * devm_fwnode_gpiod_get_index_optional - Resource-managed fwnode_gpiod_get_index()
+ * for optional GPIO
+ * @dev: GPIO consumer
+ * @fwnode: firmware node containing GPIO reference
+ * @con_id: function within the GPIO consumer
+ * @index: index of the GPIO to obtain in the consumer
+ * @flags: GPIO initialization flags
+ * @label: label to attach to the requested GPIO
+ *
+ * GPIO descriptors returned from this function are automatically disposed on
+ * driver detach.
+ *
+ * This is equivalent to devm_fwnode_gpiod_get_index(), except that when no
+ * GPIO with the specified index was assigned to the requested function it will
+ * return NULL. This is convenient for drivers that need to handle optional
+ * GPIOs.
+ *
+ * On successful request the GPIO pin is configured in accordance with
+ * provided @flags.
+ */
+struct gpio_desc *devm_fwnode_gpiod_get_index_optional(struct device *dev,
+ struct fwnode_handle *fwnode,
+ const char *con_id, int index,
+ enum gpiod_flags flags,
+ const char *label)
+{
+ struct gpio_desc *desc;
+
+ desc = devm_fwnode_gpiod_get_index(dev, fwnode, con_id, index, flags,
+ label);
+ if (IS_ERR(desc)) {
+ if (PTR_ERR(desc) == -ENOENT)
+ return NULL;
+ }
+
+ return desc;
+}
+EXPORT_SYMBOL_GPL(devm_fwnode_gpiod_get_index_optional);
+
/**
* devm_gpiod_get_index_optional - Resource-managed gpiod_get_index_optional()
* @dev: GPIO consumer
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index 901aab89d025..2364c5ca9384 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -183,11 +183,21 @@ struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
const char *con_id, int index,
enum gpiod_flags flags,
const char *label);
+struct gpio_desc *devm_fwnode_gpiod_get_optional(struct device *dev,
+ struct fwnode_handle *fwnode,
+ const char *con_id,
+ enum gpiod_flags flags,
+ const char *label);
struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
struct fwnode_handle *child,
const char *con_id, int index,
enum gpiod_flags flags,
const char *label);
+struct gpio_desc *devm_fwnode_gpiod_get_index_optional(struct device *dev,
+ struct fwnode_handle *fwnode,
+ const char *con_id, int index,
+ enum gpiod_flags flags,
+ const char *label);

#else /* CONFIG_GPIOLIB */

@@ -562,6 +572,16 @@ struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
return ERR_PTR(-ENOSYS);
}

+static inline
+struct gpio_desc *devm_fwnode_gpiod_get_optional(struct device *dev,
+ struct fwnode_handle *fwnode,
+ const char *con_id,
+ enum gpiod_flags flags,
+ const char *label)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
static inline
struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
struct fwnode_handle *fwnode,
@@ -572,6 +592,16 @@ struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
return ERR_PTR(-ENOSYS);
}

+static inline
+struct gpio_desc *devm_fwnode_gpiod_get_index_optional(struct device *dev,
+ struct fwnode_handle *fwnode,
+ const char *con_id, int index,
+ enum gpiod_flags flags,
+ const char *label)
+{
+ return ERR_PTR(-ENOSYS);
+}
+
#endif /* CONFIG_GPIOLIB */

static inline
--
2.17.1