[PATCH v3 0/2] reset: Make optional functions really optional.

[PATCH v3 0/2] reset: Make optional functions really optional.

[Ramiro Oliveira]

v3:
 - Improve description of changes ocurring in the patchset
 - Add 2 new return errors.

v2:
 - Make some comments more explicit
 - Add optional flag to reduce code duplication
 - Change shared flag from int to bool to match optional flag 

Up until now optional functions in the reset API were similar to the non
optional.

This patch corrects that, while maintaining compatibility with existing
drivers.

As suggested here: https://lkml.org/lkml/2016/12/14/502

Ramiro Oliveira (2):
  reset: Change shared flag from int to bool
  reset: make optional functions really optional

 drivers/reset/core.c  | 63 +++++++++++++++++++++++++++++++++++++++------------
 include/linux/reset.h | 45 ++++++++++++++++++++----------------
 2 files changed, 75 insertions(+), 33 deletions(-)

-- 
2.11.0

[PATCH v3 1/2] reset: Change shared flag from int to bool

[Ramiro Oliveira]

Since the new parameter being added is going to be a bool this patch
changes the shared flag from int to bool to match the new parameter.

Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
---
 drivers/reset/core.c  |  8 ++++----
 include/linux/reset.h | 32 ++++++++++++++++----------------
 2 files changed, 20 insertions(+), 20 deletions(-)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 10368ed8fd13..272c1e4ecb5c 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -41,7 +41,7 @@ struct reset_control {
 	struct list_head list;
 	unsigned int id;
 	unsigned int refcnt;
-	int shared;
+	bool shared;
 	atomic_t deassert_count;
 	atomic_t triggered_count;
 };
@@ -254,7 +254,7 @@ EXPORT_SYMBOL_GPL(reset_control_status);
 
 static struct reset_control *__reset_control_get(
 				struct reset_controller_dev *rcdev,
-				unsigned int index, int shared)
+				unsigned int index, bool shared)
 {
 	struct reset_control *rstc;
 
@@ -299,7 +299,7 @@ static void __reset_control_put(struct reset_control *rstc)
 }
 
 struct reset_control *__of_reset_control_get(struct device_node *node,
-				     const char *id, int index, int shared)
+				     const char *id, int index, bool shared)
 {
 	struct reset_control *rstc;
 	struct reset_controller_dev *r, *rcdev;
@@ -379,7 +379,7 @@ static void devm_reset_control_release(struct device *dev, void *res)
 }
 
 struct reset_control *__devm_reset_control_get(struct device *dev,
-				     const char *id, int index, int shared)
+				     const char *id, int index, bool shared)
 {
 	struct reset_control **ptr, *rstc;
 
diff --git a/include/linux/reset.h b/include/linux/reset.h
index 5daff15722d3..ec1d1fd28f5f 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -13,10 +13,10 @@ int reset_control_deassert(struct reset_control *rstc);
 int reset_control_status(struct reset_control *rstc);
 
 struct reset_control *__of_reset_control_get(struct device_node *node,
-				     const char *id, int index, int shared);
+				     const char *id, int index, bool shared);
 void reset_control_put(struct reset_control *rstc);
 struct reset_control *__devm_reset_control_get(struct device *dev,
-				     const char *id, int index, int shared);
+				     const char *id, int index, bool shared);
 
 int __must_check device_reset(struct device *dev);
 
@@ -69,14 +69,14 @@ static inline int device_reset_optional(struct device *dev)
 
 static inline struct reset_control *__of_reset_control_get(
 					struct device_node *node,
-					const char *id, int index, int shared)
+					const char *id, int index, bool shared)
 {
 	return ERR_PTR(-ENOTSUPP);
 }
 
 static inline struct reset_control *__devm_reset_control_get(
 					struct device *dev,
-					const char *id, int index, int shared)
+					const char *id, int index, bool shared)
 {
 	return ERR_PTR(-ENOTSUPP);
 }
@@ -132,19 +132,19 @@ __must_check reset_control_get_exclusive(struct device *dev, const char *id)
 static inline struct reset_control *reset_control_get_shared(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 1);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, true);
 }
 
 static inline struct reset_control *reset_control_get_optional_exclusive(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, false);
 }
 
 static inline struct reset_control *reset_control_get_optional_shared(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 1);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, true);
 }
 
 /**
@@ -185,7 +185,7 @@ static inline struct reset_control *of_reset_control_get_exclusive(
 static inline struct reset_control *of_reset_control_get_shared(
 				struct device_node *node, const char *id)
 {
-	return __of_reset_control_get(node, id, 0, 1);
+	return __of_reset_control_get(node, id, 0, true);
 }
 
 /**
@@ -202,7 +202,7 @@ static inline struct reset_control *of_reset_control_get_shared(
 static inline struct reset_control *of_reset_control_get_exclusive_by_index(
 					struct device_node *node, int index)
 {
-	return __of_reset_control_get(node, NULL, index, 0);
+	return __of_reset_control_get(node, NULL, index, false);
 }
 
 /**
@@ -230,7 +230,7 @@ static inline struct reset_control *of_reset_control_get_exclusive_by_index(
 static inline struct reset_control *of_reset_control_get_shared_by_index(
 					struct device_node *node, int index)
 {
-	return __of_reset_control_get(node, NULL, index, 1);
+	return __of_reset_control_get(node, NULL, index, true);
 }
 
 /**
@@ -252,7 +252,7 @@ __must_check devm_reset_control_get_exclusive(struct device *dev,
 #ifndef CONFIG_RESET_CONTROLLER
 	WARN_ON(1);
 #endif
-	return __devm_reset_control_get(dev, id, 0, 0);
+	return __devm_reset_control_get(dev, id, 0, false);
 }
 
 /**
@@ -267,19 +267,19 @@ __must_check devm_reset_control_get_exclusive(struct device *dev,
 static inline struct reset_control *devm_reset_control_get_shared(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, 1);
+	return __devm_reset_control_get(dev, id, 0, true);
 }
 
 static inline struct reset_control *devm_reset_control_get_optional_exclusive(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, 0);
+	return __devm_reset_control_get(dev, id, 0, false);
 }
 
 static inline struct reset_control *devm_reset_control_get_optional_shared(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, 1);
+	return __devm_reset_control_get(dev, id, 0, true);
 }
 
 /**
@@ -297,7 +297,7 @@ static inline struct reset_control *devm_reset_control_get_optional_shared(
 static inline struct reset_control *
 devm_reset_control_get_exclusive_by_index(struct device *dev, int index)
 {
-	return __devm_reset_control_get(dev, NULL, index, 0);
+	return __devm_reset_control_get(dev, NULL, index, false);
 }
 
 /**
@@ -313,7 +313,7 @@ devm_reset_control_get_exclusive_by_index(struct device *dev, int index)
 static inline struct reset_control *
 devm_reset_control_get_shared_by_index(struct device *dev, int index)
 {
-	return __devm_reset_control_get(dev, NULL, index, 1);
+	return __devm_reset_control_get(dev, NULL, index, true);
 }
 
 /*
-- 
2.11.0

[PATCH v3 2/2] reset: make optional functions really optional

[Ramiro Oliveira]

"The *_get_optional_* functions weren't really optional so this patch
makes them really optional.

These *_get_optional_* functions will now return NULL instead of an error
if no matching reset phandle is found in the DT, and all the
reset_control_* functions now accept NULL rstc pointers.

Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
---
 drivers/reset/core.c  | 59 ++++++++++++++++++++++++++++++++++++++++-----------
 include/linux/reset.h | 45 ++++++++++++++++++++++-----------------
 2 files changed, 73 insertions(+), 31 deletions(-)

diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index 272c1e4ecb5c..7b679b0bfef8 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -143,12 +143,18 @@ EXPORT_SYMBOL_GPL(devm_reset_controller_register);
  * a no-op.
  * Consumers must not use reset_control_(de)assert on shared reset lines when
  * reset_control_reset has been used.
+ *
+ * If rstc is NULL it is an optional reset and the function will just
+ * return 0.
  */
 int reset_control_reset(struct reset_control *rstc)
 {
 	int ret;
 
-	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
 		return -EINVAL;
 
 	if (!rstc->rcdev->ops->reset)
@@ -182,10 +188,17 @@ EXPORT_SYMBOL_GPL(reset_control_reset);
  * internal state to be reset, but must be prepared for this to happen.
  * Consumers must not use reset_control_reset on shared reset lines when
  * reset_control_(de)assert has been used.
+ * return 0.
+ *
+ * If rstc is NULL it is an optional reset and the function will just
+ * return 0.
  */
 int reset_control_assert(struct reset_control *rstc)
 {
-	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
 		return -EINVAL;
 
 	if (!rstc->rcdev->ops->assert)
@@ -213,10 +226,17 @@ EXPORT_SYMBOL_GPL(reset_control_assert);
  * After calling this function, the reset is guaranteed to be deasserted.
  * Consumers must not use reset_control_reset on shared reset lines when
  * reset_control_(de)assert has been used.
+ * return 0.
+ *
+ * If rstc is NULL it is an optional reset and the function will just
+ * return 0.
  */
 int reset_control_deassert(struct reset_control *rstc)
 {
-	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
 		return -EINVAL;
 
 	if (!rstc->rcdev->ops->deassert)
@@ -237,12 +257,15 @@ EXPORT_SYMBOL_GPL(reset_control_deassert);
 /**
  * reset_control_status - returns a negative errno if not supported, a
  * positive value if the reset line is asserted, or zero if the reset
- * line is not asserted.
+ * line is not asserted or if the desc is NULL (optional reset).
  * @rstc: reset controller
  */
 int reset_control_status(struct reset_control *rstc)
 {
-	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
+	if (!rstc)
+		return 0;
+
+	if (WARN_ON(IS_ERR(rstc)))
 		return -EINVAL;
 
 	if (rstc->rcdev->ops->status)
@@ -299,7 +322,8 @@ static void __reset_control_put(struct reset_control *rstc)
 }
 
 struct reset_control *__of_reset_control_get(struct device_node *node,
-				     const char *id, int index, bool shared)
+				     const char *id, int index, bool shared,
+				     bool optional)
 {
 	struct reset_control *rstc;
 	struct reset_controller_dev *r, *rcdev;
@@ -313,14 +337,24 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
 	if (id) {
 		index = of_property_match_string(node,
 						 "reset-names", id);
-		if (index < 0)
-			return ERR_PTR(-ENOENT);
+		if (index < 0) {
+			if (optional)
+				return NULL;
+			else
+				return (index == -EILSEQ) ?
+					ERR_PTR(index) : ERR_PTR(-ENOENT);
+		}
 	}
 
 	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
 					 index, &args);
-	if (ret)
-		return ERR_PTR(ret);
+	if (ret) {
+		if (optional)
+			return NULL;
+		else
+			return (index == -EINVAL) ?
+				ERR_PTR(index) : ERR_PTR(-ENOENT);
+	}
 
 	mutex_lock(&reset_list_mutex);
 	rcdev = NULL;
@@ -379,7 +413,8 @@ static void devm_reset_control_release(struct device *dev, void *res)
 }
 
 struct reset_control *__devm_reset_control_get(struct device *dev,
-				     const char *id, int index, bool shared)
+				     const char *id, int index, bool shared,
+				     bool optional)
 {
 	struct reset_control **ptr, *rstc;
 
@@ -389,7 +424,7 @@ struct reset_control *__devm_reset_control_get(struct device *dev,
 		return ERR_PTR(-ENOMEM);
 
 	rstc = __of_reset_control_get(dev ? dev->of_node : NULL,
-				      id, index, shared);
+				      id, index, shared, optional);
 	if (!IS_ERR(rstc)) {
 		*ptr = rstc;
 		devres_add(dev, ptr);
diff --git a/include/linux/reset.h b/include/linux/reset.h
index ec1d1fd28f5f..86b4ed75359e 100644
--- a/include/linux/reset.h
+++ b/include/linux/reset.h
@@ -13,10 +13,12 @@ int reset_control_deassert(struct reset_control *rstc);
 int reset_control_status(struct reset_control *rstc);
 
 struct reset_control *__of_reset_control_get(struct device_node *node,
-				     const char *id, int index, bool shared);
+				     const char *id, int index, bool shared,
+				     bool optional);
 void reset_control_put(struct reset_control *rstc);
 struct reset_control *__devm_reset_control_get(struct device *dev,
-				     const char *id, int index, bool shared);
+				     const char *id, int index, bool shared,
+				     bool optional);
 
 int __must_check device_reset(struct device *dev);
 
@@ -69,14 +71,15 @@ static inline int device_reset_optional(struct device *dev)
 
 static inline struct reset_control *__of_reset_control_get(
 					struct device_node *node,
-					const char *id, int index, bool shared)
+					const char *id, int index, bool shared,
+					bool optional)
 {
 	return ERR_PTR(-ENOTSUPP);
 }
 
 static inline struct reset_control *__devm_reset_control_get(
-					struct device *dev,
-					const char *id, int index, bool shared)
+					struct device *dev, const char *id,
+					int index, bool shared, bool optional)
 {
 	return ERR_PTR(-ENOTSUPP);
 }
@@ -104,7 +107,8 @@ __must_check reset_control_get_exclusive(struct device *dev, const char *id)
 #ifndef CONFIG_RESET_CONTROLLER
 	WARN_ON(1);
 #endif
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, 0);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, false,
+									false);
 }
 
 /**
@@ -132,19 +136,22 @@ __must_check reset_control_get_exclusive(struct device *dev, const char *id)
 static inline struct reset_control *reset_control_get_shared(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, true);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, true,
+									false);
 }
 
 static inline struct reset_control *reset_control_get_optional_exclusive(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, false);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, false,
+									true);
 }
 
 static inline struct reset_control *reset_control_get_optional_shared(
 					struct device *dev, const char *id)
 {
-	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, true);
+	return __of_reset_control_get(dev ? dev->of_node : NULL, id, 0, true,
+									true);
 }
 
 /**
@@ -160,7 +167,7 @@ static inline struct reset_control *reset_control_get_optional_shared(
 static inline struct reset_control *of_reset_control_get_exclusive(
 				struct device_node *node, const char *id)
 {
-	return __of_reset_control_get(node, id, 0, 0);
+	return __of_reset_control_get(node, id, 0, false, false);
 }
 
 /**
@@ -185,7 +192,7 @@ static inline struct reset_control *of_reset_control_get_exclusive(
 static inline struct reset_control *of_reset_control_get_shared(
 				struct device_node *node, const char *id)
 {
-	return __of_reset_control_get(node, id, 0, true);
+	return __of_reset_control_get(node, id, 0, true, false);
 }
 
 /**
@@ -202,7 +209,7 @@ static inline struct reset_control *of_reset_control_get_shared(
 static inline struct reset_control *of_reset_control_get_exclusive_by_index(
 					struct device_node *node, int index)
 {
-	return __of_reset_control_get(node, NULL, index, false);
+	return __of_reset_control_get(node, NULL, index, false, false);
 }
 
 /**
@@ -230,7 +237,7 @@ static inline struct reset_control *of_reset_control_get_exclusive_by_index(
 static inline struct reset_control *of_reset_control_get_shared_by_index(
 					struct device_node *node, int index)
 {
-	return __of_reset_control_get(node, NULL, index, true);
+	return __of_reset_control_get(node, NULL, index, true, false);
 }
 
 /**
@@ -252,7 +259,7 @@ __must_check devm_reset_control_get_exclusive(struct device *dev,
 #ifndef CONFIG_RESET_CONTROLLER
 	WARN_ON(1);
 #endif
-	return __devm_reset_control_get(dev, id, 0, false);
+	return __devm_reset_control_get(dev, id, 0, false, false);
 }
 
 /**
@@ -267,19 +274,19 @@ __must_check devm_reset_control_get_exclusive(struct device *dev,
 static inline struct reset_control *devm_reset_control_get_shared(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, true);
+	return __devm_reset_control_get(dev, id, 0, true, false);
 }
 
 static inline struct reset_control *devm_reset_control_get_optional_exclusive(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, false);
+	return __devm_reset_control_get(dev, id, 0, false, true);
 }
 
 static inline struct reset_control *devm_reset_control_get_optional_shared(
 					struct device *dev, const char *id)
 {
-	return __devm_reset_control_get(dev, id, 0, true);
+	return __devm_reset_control_get(dev, id, 0, true, true);
 }
 
 /**
@@ -297,7 +304,7 @@ static inline struct reset_control *devm_reset_control_get_optional_shared(
 static inline struct reset_control *
 devm_reset_control_get_exclusive_by_index(struct device *dev, int index)
 {
-	return __devm_reset_control_get(dev, NULL, index, false);
+	return __devm_reset_control_get(dev, NULL, index, false, false);
 }
 
 /**
@@ -313,7 +320,7 @@ devm_reset_control_get_exclusive_by_index(struct device *dev, int index)
 static inline struct reset_control *
 devm_reset_control_get_shared_by_index(struct device *dev, int index)
 {
-	return __devm_reset_control_get(dev, NULL, index, true);
+	return __devm_reset_control_get(dev, NULL, index, true, false);
 }
 
 /*
-- 
2.11.0

Re: [PATCH v3 2/2] reset: make optional functions really optional

[Philipp Zabel]

Hi Ramiro,

Am Donnerstag, den 12.01.2017, 18:34 +0000 schrieb Ramiro Oliveira:
> "The *_get_optional_* functions weren't really optional so this patch
> makes them really optional.
> 
> These *_get_optional_* functions will now return NULL instead of an error
> if no matching reset phandle is found in the DT, and all the
> reset_control_* functions now accept NULL rstc pointers.
> 
> Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
> ---
>  drivers/reset/core.c  | 59 ++++++++++++++++++++++++++++++++++++++++-----------
>  include/linux/reset.h | 45 ++++++++++++++++++++++-----------------
>  2 files changed, 73 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
> index 272c1e4ecb5c..7b679b0bfef8 100644
> --- a/drivers/reset/core.c
> +++ b/drivers/reset/core.c
> @@ -143,12 +143,18 @@ EXPORT_SYMBOL_GPL(devm_reset_controller_register);
>   * a no-op.
>   * Consumers must not use reset_control_(de)assert on shared reset lines when
>   * reset_control_reset has been used.
> + *
> + * If rstc is NULL it is an optional reset and the function will just
> + * return 0.
>   */
>  int reset_control_reset(struct reset_control *rstc)
>  {
>  	int ret;
>  
> -	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
> +	if (!rstc)
> +		return 0;
> +
> +	if (WARN_ON(IS_ERR(rstc)))
>  		return -EINVAL;
>  
>  	if (!rstc->rcdev->ops->reset)
> @@ -182,10 +188,17 @@ EXPORT_SYMBOL_GPL(reset_control_reset);
>   * internal state to be reset, but must be prepared for this to happen.
>   * Consumers must not use reset_control_reset on shared reset lines when
>   * reset_control_(de)assert has been used.
> + * return 0.
> + *
> + * If rstc is NULL it is an optional reset and the function will just
> + * return 0.
>   */
>  int reset_control_assert(struct reset_control *rstc)
>  {
> -	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
> +	if (!rstc)
> +		return 0;
> +
> +	if (WARN_ON(IS_ERR(rstc)))
>  		return -EINVAL;
>  
>  	if (!rstc->rcdev->ops->assert)
> @@ -213,10 +226,17 @@ EXPORT_SYMBOL_GPL(reset_control_assert);
>   * After calling this function, the reset is guaranteed to be deasserted.
>   * Consumers must not use reset_control_reset on shared reset lines when
>   * reset_control_(de)assert has been used.
> + * return 0.
> + *
> + * If rstc is NULL it is an optional reset and the function will just
> + * return 0.
>   */
>  int reset_control_deassert(struct reset_control *rstc)
>  {
> -	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
> +	if (!rstc)
> +		return 0;
> +
> +	if (WARN_ON(IS_ERR(rstc)))
>  		return -EINVAL;
>  
>  	if (!rstc->rcdev->ops->deassert)
> @@ -237,12 +257,15 @@ EXPORT_SYMBOL_GPL(reset_control_deassert);
>  /**
>   * reset_control_status - returns a negative errno if not supported, a
>   * positive value if the reset line is asserted, or zero if the reset
> - * line is not asserted.
> + * line is not asserted or if the desc is NULL (optional reset).
>   * @rstc: reset controller
>   */
>  int reset_control_status(struct reset_control *rstc)
>  {
> -	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
> +	if (!rstc)
> +		return 0;
> +
> +	if (WARN_ON(IS_ERR(rstc)))
>  		return -EINVAL;
>  
>  	if (rstc->rcdev->ops->status)
> @@ -299,7 +322,8 @@ static void __reset_control_put(struct reset_control *rstc)
>  }
>  
>  struct reset_control *__of_reset_control_get(struct device_node *node,
> -				     const char *id, int index, bool shared)
> +				     const char *id, int index, bool shared,
> +				     bool optional)
>  {
>  	struct reset_control *rstc;
>  	struct reset_controller_dev *r, *rcdev;
> @@ -313,14 +337,24 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
>  	if (id) {
>  		index = of_property_match_string(node,
>  						 "reset-names", id);
> -		if (index < 0)
> -			return ERR_PTR(-ENOENT);
> +		if (index < 0) {
> +			if (optional)
> +				return NULL;
> +			else
> +				return (index == -EILSEQ) ?
> +					ERR_PTR(index) : ERR_PTR(-ENOENT);

That is not what I meant. I think reset_control_get should return an
error on EILSEQ even if optional is true, since that means there are
resets specified in the DT, but the reset-names property is broken.
How about:
		if (index == -EILSEQ)
			return ERR_PTR(index);
		if (index < 0)
			return optional ? NULL : ERR_PTR(-ENOENT);

> +		}
>  	}
>  
>  	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
>  					 index, &args);
> -	if (ret)
> -		return ERR_PTR(ret);
> +	if (ret) {
> +		if (optional)
> +			return NULL;
> +		else
> +			return (index == -EINVAL) ?
> +				ERR_PTR(index) : ERR_PTR(-ENOENT);
> +	}

That is not what I meant either. If the phandle parsing fails with
of_phandle_iterator_next returning -EINVAL, that should be passed along
in the optional case: that happens when we've already found a matching
entry in reset-names, but the resets property is broken.
How about:
	if (ret == -EINVAL)
		return ERR_PTR(ret);
	if (ret)
		return optional ? NULL : ERR_PTR(ret);

regards
Philipp

Re: [PATCH v3 2/2] reset: make optional functions really optional

[Ramiro Oliveira]

Hi Philipp

On 1/13/2017 9:11 AM, Philipp Zabel wrote:
> Hi Ramiro,
> 
> Am Donnerstag, den 12.01.2017, 18:34 +0000 schrieb Ramiro Oliveira:
>> "The *_get_optional_* functions weren't really optional so this patch
>> makes them really optional.
>>
>> These *_get_optional_* functions will now return NULL instead of an error
>> if no matching reset phandle is found in the DT, and all the
>> reset_control_* functions now accept NULL rstc pointers.
>>
>> Signed-off-by: Ramiro Oliveira <Ramiro.Oliveira@synopsys.com>
>> ---
>>  drivers/reset/core.c  | 59 ++++++++++++++++++++++++++++++++++++++++-----------
>>  include/linux/reset.h | 45 ++++++++++++++++++++++-----------------
>>  2 files changed, 73 insertions(+), 31 deletions(-)
>>
>> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
>> index 272c1e4ecb5c..7b679b0bfef8 100644
>> --- a/drivers/reset/core.c
>> +++ b/drivers/reset/core.c
>> @@ -143,12 +143,18 @@ EXPORT_SYMBOL_GPL(devm_reset_controller_register);
>>   * a no-op.
>>   * Consumers must not use reset_control_(de)assert on shared reset lines when
>>   * reset_control_reset has been used.
>> + *
>> + * If rstc is NULL it is an optional reset and the function will just
>> + * return 0.
>>   */
>>  int reset_control_reset(struct reset_control *rstc)
>>  {
>>  	int ret;
>>  
>> -	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
>> +	if (!rstc)
>> +		return 0;
>> +
>> +	if (WARN_ON(IS_ERR(rstc)))
>>  		return -EINVAL;
>>  
>>  	if (!rstc->rcdev->ops->reset)
>> @@ -182,10 +188,17 @@ EXPORT_SYMBOL_GPL(reset_control_reset);
>>   * internal state to be reset, but must be prepared for this to happen.
>>   * Consumers must not use reset_control_reset on shared reset lines when
>>   * reset_control_(de)assert has been used.
>> + * return 0.
>> + *
>> + * If rstc is NULL it is an optional reset and the function will just
>> + * return 0.
>>   */
>>  int reset_control_assert(struct reset_control *rstc)
>>  {
>> -	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
>> +	if (!rstc)
>> +		return 0;
>> +
>> +	if (WARN_ON(IS_ERR(rstc)))
>>  		return -EINVAL;
>>  
>>  	if (!rstc->rcdev->ops->assert)
>> @@ -213,10 +226,17 @@ EXPORT_SYMBOL_GPL(reset_control_assert);
>>   * After calling this function, the reset is guaranteed to be deasserted.
>>   * Consumers must not use reset_control_reset on shared reset lines when
>>   * reset_control_(de)assert has been used.
>> + * return 0.
>> + *
>> + * If rstc is NULL it is an optional reset and the function will just
>> + * return 0.
>>   */
>>  int reset_control_deassert(struct reset_control *rstc)
>>  {
>> -	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
>> +	if (!rstc)
>> +		return 0;
>> +
>> +	if (WARN_ON(IS_ERR(rstc)))
>>  		return -EINVAL;
>>  
>>  	if (!rstc->rcdev->ops->deassert)
>> @@ -237,12 +257,15 @@ EXPORT_SYMBOL_GPL(reset_control_deassert);
>>  /**
>>   * reset_control_status - returns a negative errno if not supported, a
>>   * positive value if the reset line is asserted, or zero if the reset
>> - * line is not asserted.
>> + * line is not asserted or if the desc is NULL (optional reset).
>>   * @rstc: reset controller
>>   */
>>  int reset_control_status(struct reset_control *rstc)
>>  {
>> -	if (WARN_ON(IS_ERR_OR_NULL(rstc)))
>> +	if (!rstc)
>> +		return 0;
>> +
>> +	if (WARN_ON(IS_ERR(rstc)))
>>  		return -EINVAL;
>>  
>>  	if (rstc->rcdev->ops->status)
>> @@ -299,7 +322,8 @@ static void __reset_control_put(struct reset_control *rstc)
>>  }
>>  
>>  struct reset_control *__of_reset_control_get(struct device_node *node,
>> -				     const char *id, int index, bool shared)
>> +				     const char *id, int index, bool shared,
>> +				     bool optional)
>>  {
>>  	struct reset_control *rstc;
>>  	struct reset_controller_dev *r, *rcdev;
>> @@ -313,14 +337,24 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
>>  	if (id) {
>>  		index = of_property_match_string(node,
>>  						 "reset-names", id);
>> -		if (index < 0)
>> -			return ERR_PTR(-ENOENT);
>> +		if (index < 0) {
>> +			if (optional)
>> +				return NULL;
>> +			else
>> +				return (index == -EILSEQ) ?
>> +					ERR_PTR(index) : ERR_PTR(-ENOENT);
> 
> That is not what I meant. I think reset_control_get should return an
> error on EILSEQ even if optional is true, since that means there are
> resets specified in the DT, but the reset-names property is broken.
> How about:
> 		if (index == -EILSEQ)
> 			return ERR_PTR(index);
> 		if (index < 0)
> 			return optional ? NULL : ERR_PTR(-ENOENT);
> 

When you first suggested I wasn't entirely sure what you meant, but now it makes
total sense to me.

I should have asked you about it before implementing it.

>> +		}
>>  	}
>>  
>>  	ret = of_parse_phandle_with_args(node, "resets", "#reset-cells",
>>  					 index, &args);
>> -	if (ret)
>> -		return ERR_PTR(ret);
>> +	if (ret) {
>> +		if (optional)
>> +			return NULL;
>> +		else
>> +			return (index == -EINVAL) ?
>> +				ERR_PTR(index) : ERR_PTR(-ENOENT);
>> +	}
> 
> That is not what I meant either. If the phandle parsing fails with
> of_phandle_iterator_next returning -EINVAL, that should be passed along
> in the optional case: that happens when we've already found a matching
> entry in reset-names, but the resets property is broken.
> How about:
> 	if (ret == -EINVAL)
> 		return ERR_PTR(ret);
> 	if (ret)
> 		return optional ? NULL : ERR_PTR(ret);
> 

Same as above.

> regards
> Philipp
> 

I'll refactor the code and send a new patch ASAP.

BRs,
Ramiro