Re: [PATCH 2/9] PM / devfreq: Remove devfreq_get_devfreq_by_phandle function

From: Leonard Crestez <leonard.crestez@nxp.com>
To: Chanwoo Choi <cw00.choi@samsung.com>,
	"krzk@kernel.org" <krzk@kernel.org>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>
Cc: "mark.rutland@arm.com" <mark.rutland@arm.com>,
	"heiko@sntech.de" <heiko@sntech.de>,
	"lukasz.luba@arm.com" <lukasz.luba@arm.com>,
	"a.swigon@samsung.com" <a.swigon@samsung.com>,
	"m.szyprowski@samsung.com" <m.szyprowski@samsung.com>,
	"kgene@kernel.org" <kgene@kernel.org>,
	"myungjoo.ham@samsung.com" <myungjoo.ham@samsung.com>,
	"kyungmin.park@samsung.com" <kyungmin.park@samsung.com>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	"linux-samsung-soc@vger.kernel.org" 
	<linux-samsung-soc@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-rockchip@lists.infradead.org" 
	<linux-rockchip@lists.infradead.org>
Subject: Re: [PATCH 2/9] PM / devfreq: Remove devfreq_get_devfreq_by_phandle function
Date: Tue, 17 Dec 2019 14:33:52 +0000	[thread overview]
Message-ID: <VI1PR04MB70231FA16F12ACA3A3C01772EE500@VI1PR04MB7023.eurprd04.prod.outlook.com> (raw)
In-Reply-To: 20191217055738.28445-3-cw00.choi@samsung.com

On 17.12.2019 07:51, 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 | 14 ++++++++++++--
>   include/linux/devfreq.h      |  8 --------
>   3 files changed, 12 insertions(+), 45 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..9aac2db956d5 100644
> --- a/drivers/devfreq/exynos-bus.c
> +++ b/drivers/devfreq/exynos-bus.c
> @@ -146,6 +146,16 @@ static int exynos_bus_get_dev_status(struct device *dev,
>   	return ret;
>   }
>   
> +static struct devfreq *get_parent_devfreq_by_node(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);
> +}

The _by_node suffix here is confusing because it actually fetches a 
property of the node unlike devfreq_get_devfreq_by_node. Maybe call this 
get_parent_devfreq_from_node?

Since it's a static function it could just be called get_parent_devfreq?

> +
>   static void exynos_bus_exit(struct device *dev)
>   {
>   	struct exynos_bus *bus = dev_get_drvdata(dev);
> @@ -353,8 +363,8 @@ 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);
> -	if (IS_ERR(parent_devfreq))
> +	parent_devfreq = get_parent_devfreq_by_node(dev->of_node);
> +	if (IS_ERR(parent_devfreq)) {
>   		return -EPROBE_DEFER;
>   
>   	passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
> diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
> index e3633ae43349..3ed96426302e 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 @@ struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
>   	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;
> 