Re: [PATCH v2] phy: core: Allow children node to be overridden

[Kishon Vijay Abraham I]

On Thursday 28 April 2016 07:01 PM, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
> 
> In order to more flexibly support device tree bindings, allow drivers to
> override the container of the child nodes. By default the device node of
> the PHY provider is assumed to be the parent for children, but bindings
> may decide to add additional levels for better organization.
> 
> Cc: Kishon Vijay Abraham I <kishon@xxxxxx>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>

Acked-by: Kishon Vijay Abraham I <kishon@xxxxxx>
> ---
> Hi Kishon,
> 
> I'm looking for an Acked-by from you on this patch. It's recently become
> a requirement for the new Tegra PHY driver. As a precaution and to speed
> things up I preemptively took it into linux-next and I think it's pretty
> well-cooked by now. I have this sitting in a branch that I can stabilize
> and send your way as a pull request.
> 
> Thanks,
> Thierry
> 
> Changes in v2:
> - check that specified node is a child (or further descendant) of the
>   PHY provider (Kishon)
> 
>  Documentation/phy.txt   | 16 ++++++++++++++--
>  drivers/phy/phy-core.c  | 50 +++++++++++++++++++++++++++++++++++++++++++------
>  include/linux/phy/phy.h | 31 ++++++++++++++++++++----------
>  3 files changed, 79 insertions(+), 18 deletions(-)
> 
> diff --git a/Documentation/phy.txt b/Documentation/phy.txt
> index b388c5af9e72..0aa994bd9a91 100644
> --- a/Documentation/phy.txt
> +++ b/Documentation/phy.txt
> @@ -31,16 +31,28 @@ should provide its own implementation of of_xlate. of_xlate is used only for
>  dt boot case.
>  
>  #define of_phy_provider_register(dev, xlate)    \
> -        __of_phy_provider_register((dev), THIS_MODULE, (xlate))
> +        __of_phy_provider_register((dev), NULL, THIS_MODULE, (xlate))
>  
>  #define devm_of_phy_provider_register(dev, xlate)       \
> -        __devm_of_phy_provider_register((dev), THIS_MODULE, (xlate))
> +        __devm_of_phy_provider_register((dev), NULL, THIS_MODULE, (xlate))
>  
>  of_phy_provider_register and devm_of_phy_provider_register macros can be used to
>  register the phy_provider and it takes device and of_xlate as
>  arguments. For the dt boot case, all PHY providers should use one of the above
>  2 macros to register the PHY provider.
>  
> +Often the device tree nodes associated with a PHY provider will contain a set
> +of children that each represent a single PHY. Some bindings may nest the child
> +nodes within extra levels for context and extensibility, in which case the low
> +level of_phy_provider_register_full() and devm_of_phy_provider_register_full()
> +macros can be used to override the node containing the children.
> +
> +#define of_phy_provider_register_full(dev, children, xlate) \
> +	__of_phy_provider_register(dev, children, THIS_MODULE, xlate)
> +
> +#define devm_of_phy_provider_register_full(dev, children, xlate) \
> +	__devm_of_phy_provider_register_full(dev, children, THIS_MODULE, xlate)
> +
>  void devm_of_phy_provider_unregister(struct device *dev,
>  	struct phy_provider *phy_provider);
>  void of_phy_provider_unregister(struct phy_provider *phy_provider);
> diff --git a/drivers/phy/phy-core.c b/drivers/phy/phy-core.c
> index e7e574dc667a..b72e9a3b6429 100644
> --- a/drivers/phy/phy-core.c
> +++ b/drivers/phy/phy-core.c
> @@ -141,7 +141,7 @@ static struct phy_provider *of_phy_provider_lookup(struct device_node *node)
>  		if (phy_provider->dev->of_node == node)
>  			return phy_provider;
>  
> -		for_each_child_of_node(phy_provider->dev->of_node, child)
> +		for_each_child_of_node(phy_provider->children, child)
>  			if (child == node)
>  				return phy_provider;
>  	}
> @@ -811,24 +811,59 @@ EXPORT_SYMBOL_GPL(devm_phy_destroy);
>  /**
>   * __of_phy_provider_register() - create/register phy provider with the framework
>   * @dev: struct device of the phy provider
> + * @children: device node containing children (if different from dev->of_node)
>   * @owner: the module owner containing of_xlate
>   * @of_xlate: function pointer to obtain phy instance from phy provider
>   *
>   * Creates struct phy_provider from dev and of_xlate function pointer.
>   * This is used in the case of dt boot for finding the phy instance from
>   * phy provider.
> + *
> + * If the PHY provider doesn't nest children directly but uses a separate
> + * child node to contain the individual children, the @children parameter
> + * can be used to override the default. If NULL, the default (dev->of_node)
> + * will be used. If non-NULL, the device node must be a child (or further
> + * descendant) of dev->of_node. Otherwise an ERR_PTR()-encoded -EINVAL
> + * error code is returned.
>   */
>  struct phy_provider *__of_phy_provider_register(struct device *dev,
> -	struct module *owner, struct phy * (*of_xlate)(struct device *dev,
> -	struct of_phandle_args *args))
> +	struct device_node *children, struct module *owner,
> +	struct phy * (*of_xlate)(struct device *dev,
> +				 struct of_phandle_args *args))
>  {
>  	struct phy_provider *phy_provider;
>  
> +	/*
> +	 * If specified, the device node containing the children must itself
> +	 * be the provider's device node or a child (or further descendant)
> +	 * thereof.
> +	 */
> +	if (children) {
> +		struct device_node *parent = of_node_get(children), *next;
> +
> +		while (parent) {
> +			if (parent == dev->of_node)
> +				break;
> +
> +			next = of_get_parent(parent);
> +			of_node_put(parent);
> +			parent = next;
> +		}
> +
> +		if (!parent)
> +			return ERR_PTR(-EINVAL);
> +
> +		of_node_put(parent);
> +	} else {
> +		children = dev->of_node;
> +	}
> +
>  	phy_provider = kzalloc(sizeof(*phy_provider), GFP_KERNEL);
>  	if (!phy_provider)
>  		return ERR_PTR(-ENOMEM);
>  
>  	phy_provider->dev = dev;
> +	phy_provider->children = of_node_get(children);
>  	phy_provider->owner = owner;
>  	phy_provider->of_xlate = of_xlate;
>  
> @@ -854,8 +889,9 @@ EXPORT_SYMBOL_GPL(__of_phy_provider_register);
>   * on the devres data, then, devres data is freed.
>   */
>  struct phy_provider *__devm_of_phy_provider_register(struct device *dev,
> -	struct module *owner, struct phy * (*of_xlate)(struct device *dev,
> -	struct of_phandle_args *args))
> +	struct device_node *children, struct module *owner,
> +	struct phy * (*of_xlate)(struct device *dev,
> +				 struct of_phandle_args *args))
>  {
>  	struct phy_provider **ptr, *phy_provider;
>  
> @@ -863,7 +899,8 @@ struct phy_provider *__devm_of_phy_provider_register(struct device *dev,
>  	if (!ptr)
>  		return ERR_PTR(-ENOMEM);
>  
> -	phy_provider = __of_phy_provider_register(dev, owner, of_xlate);
> +	phy_provider = __of_phy_provider_register(dev, children, owner,
> +						  of_xlate);
>  	if (!IS_ERR(phy_provider)) {
>  		*ptr = phy_provider;
>  		devres_add(dev, ptr);
> @@ -888,6 +925,7 @@ void of_phy_provider_unregister(struct phy_provider *phy_provider)
>  
>  	mutex_lock(&phy_provider_mutex);
>  	list_del(&phy_provider->list);
> +	of_node_put(phy_provider->children);
>  	kfree(phy_provider);
>  	mutex_unlock(&phy_provider_mutex);
>  }
> diff --git a/include/linux/phy/phy.h b/include/linux/phy/phy.h
> index 8cf05e341cff..a810f2a18842 100644
> --- a/include/linux/phy/phy.h
> +++ b/include/linux/phy/phy.h
> @@ -77,6 +77,7 @@ struct phy {
>   */
>  struct phy_provider {
>  	struct device		*dev;
> +	struct device_node	*children;
>  	struct module		*owner;
>  	struct list_head	list;
>  	struct phy * (*of_xlate)(struct device *dev,
> @@ -93,10 +94,16 @@ struct phy_lookup {
>  #define	to_phy(a)	(container_of((a), struct phy, dev))
>  
>  #define	of_phy_provider_register(dev, xlate)	\
> -	__of_phy_provider_register((dev), THIS_MODULE, (xlate))
> +	__of_phy_provider_register((dev), NULL, THIS_MODULE, (xlate))
>  
>  #define	devm_of_phy_provider_register(dev, xlate)	\
> -	__devm_of_phy_provider_register((dev), THIS_MODULE, (xlate))
> +	__devm_of_phy_provider_register((dev), NULL, THIS_MODULE, (xlate))
> +
> +#define of_phy_provider_register_full(dev, children, xlate) \
> +	__of_phy_provider_register(dev, children, THIS_MODULE, xlate)
> +
> +#define devm_of_phy_provider_register_full(dev, children, xlate) \
> +	__devm_of_phy_provider_register(dev, children, THIS_MODULE, xlate)
>  
>  static inline void phy_set_drvdata(struct phy *phy, void *data)
>  {
> @@ -147,11 +154,13 @@ struct phy *devm_phy_create(struct device *dev, struct device_node *node,
>  void phy_destroy(struct phy *phy);
>  void devm_phy_destroy(struct device *dev, struct phy *phy);
>  struct phy_provider *__of_phy_provider_register(struct device *dev,
> -	struct module *owner, struct phy * (*of_xlate)(struct device *dev,
> -	struct of_phandle_args *args));
> +	struct device_node *children, struct module *owner,
> +	struct phy * (*of_xlate)(struct device *dev,
> +				 struct of_phandle_args *args));
>  struct phy_provider *__devm_of_phy_provider_register(struct device *dev,
> -	struct module *owner, struct phy * (*of_xlate)(struct device *dev,
> -	struct of_phandle_args *args));
> +	struct device_node *children, struct module *owner,
> +	struct phy * (*of_xlate)(struct device *dev,
> +				 struct of_phandle_args *args));
>  void of_phy_provider_unregister(struct phy_provider *phy_provider);
>  void devm_of_phy_provider_unregister(struct device *dev,
>  	struct phy_provider *phy_provider);
> @@ -312,15 +321,17 @@ static inline void devm_phy_destroy(struct device *dev, struct phy *phy)
>  }
>  
>  static inline struct phy_provider *__of_phy_provider_register(
> -	struct device *dev, struct module *owner, struct phy * (*of_xlate)(
> -	struct device *dev, struct of_phandle_args *args))
> +	struct device *dev, struct device_node *children, struct module *owner,
> +	struct phy * (*of_xlate)(struct device *dev,
> +				 struct of_phandle_args *args))
>  {
>  	return ERR_PTR(-ENOSYS);
>  }
>  
>  static inline struct phy_provider *__devm_of_phy_provider_register(struct device
> -	*dev, struct module *owner, struct phy * (*of_xlate)(struct device *dev,
> -	struct of_phandle_args *args))
> +	*dev, struct device_node *children, struct module *owner,
> +	struct phy * (*of_xlate)(struct device *dev,
> +				 struct of_phandle_args *args))
>  {
>  	return ERR_PTR(-ENOSYS);
>  }
>