[v3,24/27] gpio: Add devm_fwnode_gpiod_get_optional() helpers

Commit Message

Krzysztof Kozlowski Aug. 27, 2020, 6:58 p.m. UTC

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 <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>

---

Changes since v2:
1. Return NULL

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

Comments

Linus Walleij Aug. 28, 2020, 2:31 p.m. UTC | #1

On Thu, Aug 27, 2020 at 9:00 PM Krzysztof Kozlowski <[e-mail]> wrote:

> 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 <[e-mail]>
> Reviewed-by: Andy Shevchenko <[e-mail]>

OK then, I suppose this gets merged with the rest?

Reviewed-by: Linus Walleij <[e-mail]>

Yours,
Linus Walleij

Krzysztof Kozlowski Aug. 28, 2020, 2:45 p.m. UTC | #2

On Fri, 28 Aug 2020 at 16:31, Linus Walleij <[e-mail]> wrote:
>
> On Thu, Aug 27, 2020 at 9:00 PM Krzysztof Kozlowski <[e-mail]> wrote:
>
> > 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 <[e-mail]>
> > Reviewed-by: Andy Shevchenko <[e-mail]>
>
> OK then, I suppose this gets merged with the rest?
>
> Reviewed-by: Linus Walleij <[e-mail]>

That's the easiest unless you expect some conflicts. Only one next
patch depends on this so worst case it could wait one cycle.

Best regards,
Krzysztof

Andy Shevchenko Aug. 28, 2020, 2:56 p.m. UTC | #3

On Fri, Aug 28, 2020 at 5:45 PM Krzysztof Kozlowski <[e-mail]> wrote:
> On Fri, 28 Aug 2020 at 16:31, Linus Walleij <[e-mail]> wrote:
> > On Thu, Aug 27, 2020 at 9:00 PM Krzysztof Kozlowski <[e-mail]> wrote:
> >
> > > 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 <[e-mail]>
> > > Reviewed-by: Andy Shevchenko <[e-mail]>
> >
> > OK then, I suppose this gets merged with the rest?
> >
> > Reviewed-by: Linus Walleij <[e-mail]>
>
> That's the easiest unless you expect some conflicts. Only one next
> patch depends on this so worst case it could wait one cycle.

I believe Dmitry and Linus are familiar with the concept of immutable
branches, so it won't be a problem to create one and share.

Patch

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..7854d80b1e9a 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 NULL;
+}
+
 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 NULL;
+}
+
 #endif /* CONFIG_GPIOLIB */
 
 static inline