Re: [PATCH v2 02/11] PM / devfreq: Remove devfreq_get_devfreq_by_phandle function

[Leonard Crestez <leonard.crestez@nxp.com>]

On 20.12.2019 02:18, Chanwoo Choi wrote:
> Previously, devfreq core support 'devfreq' property in order to get
> the devfreq device by phandle. But, 'devfreq' property name is not proper
> on devicetree binding because this name doesn't mean the any h/w attribute.
> 
> The devfreq core hand over the right to decide the property name
> for getting the devfreq device on devicetree. Each devfreq driver
> will decide the property name on devicetree binding and then get
> the devfreq device by using devfreq_get_devfreq_by_node().
> 
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
>   drivers/devfreq/devfreq.c    | 35 -----------------------------------
>   drivers/devfreq/exynos-bus.c | 12 +++++++++++-
>   include/linux/devfreq.h      |  8 --------
>   3 files changed, 11 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> index cb8ca81c8973..c3d3c7c802a0 100644
> --- a/drivers/devfreq/devfreq.c
> +++ b/drivers/devfreq/devfreq.c
> @@ -991,48 +991,13 @@ struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
>   
>   	return ERR_PTR(-ENODEV);
>   }
> -
> -/*
> - * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
> - * @dev - instance to the given device
> - * @index - index into list of devfreq
> - *
> - * return the instance of devfreq device
> - */
> -struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
> -{
> -	struct device_node *node;
> -	struct devfreq *devfreq;
> -
> -	if (!dev)
> -		return ERR_PTR(-EINVAL);
> -
> -	if (!dev->of_node)
> -		return ERR_PTR(-EINVAL);
> -
> -	node = of_parse_phandle(dev->of_node, "devfreq", index);
> -	if (!node)
> -		return ERR_PTR(-ENODEV);
> -
> -	devfreq = devfreq_get_devfreq_by_node(node);
> -	of_node_put(node);
> -
> -	return devfreq;
> -}
> -
>   #else
>   struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
>   {
>   	return ERR_PTR(-ENODEV);
>   }
> -
> -struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index)
> -{
> -	return ERR_PTR(-ENODEV);
> -}
>   #endif /* CONFIG_OF */
>   EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
> -EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
>   
>   /**
>    * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
> diff --git a/drivers/devfreq/exynos-bus.c b/drivers/devfreq/exynos-bus.c
> index 7f5917d59072..1bc4e3c81115 100644
> --- a/drivers/devfreq/exynos-bus.c
> +++ b/drivers/devfreq/exynos-bus.c
> @@ -86,6 +86,16 @@ static int exynos_bus_get_event(struct exynos_bus *bus,
>   	return ret;
>   }
>   
> +static struct devfreq *exynos_bus_get_parent_devfreq(struct device_node *np)
> +{
> +	struct device_node *node = of_parse_phandle(np, "devfreq", 0);
> +
> +	if (!node)
> +		return ERR_PTR(-ENODEV);
> +
> +	return devfreq_get_devfreq_by_node(node);

You need to call of_node_put(node) here and in several other places.

The old devfreq_get_devfreq_by_phandle API handled this internally but 
devfreq_get_devfreq_by_node doesn't.

Maybe the _by_phandle API could be kept and just take the property name 
instead of always using "devfreq"?

> +}
> +
>   /*
>    * devfreq function for both simple-ondemand and passive governor
>    */
> @@ -353,7 +363,7 @@ static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
>   	profile->exit = exynos_bus_passive_exit;
>   
>   	/* Get the instance of parent devfreq device */
> -	parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
> +	parent_devfreq = exynos_bus_get_parent_devfreq(dev->of_node);
>   	if (IS_ERR(parent_devfreq))
>   		return -EPROBE_DEFER;
>   
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index 1dccc47acbce..a4351698fb64 100644
> --- a/include/linux/devfreq.h
> +++ b/include/linux/devfreq.h
> @@ -254,8 +254,6 @@ extern void devm_devfreq_unregister_notifier(struct device *dev,
>   				struct notifier_block *nb,
>   				unsigned int list);
>   extern struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node);
> -extern struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
> -						int index);
>   
>   #if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
>   /**
> @@ -413,12 +411,6 @@ static inline struct devfreq *devfreq_get_devfreq_by_node(struct device_node *no
>   	return ERR_PTR(-ENODEV);
>   }
>   
> -static inline struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
> -							int index)
> -{
> -	return ERR_PTR(-ENODEV);
> -}
> -
>   static inline int devfreq_update_stats(struct devfreq *df)
>   {
>   	return -EINVAL;
>