linux-kernel - Re: [PATCH] devfreq: Register devfreq as a cooling device

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Message-ID: <23db1b13-9418-91f5-4871-f45b983f6e3c@arm.com>
Date:   Fri, 5 Mar 2021 08:12:21 +0000
From:   Steven Price <steven.price@....com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>, cwchoi00@...il.com,
        kyungmin.park@...sung.com, myungjoo.ham@...sung.com
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Chanwoo Choi <cw00.choi@...sung.com>,
        Qiang Yu <yuq825@...il.com>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        Rob Herring <robh@...nel.org>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        Alyssa Rosenzweig <alyssa.rosenzweig@...labora.com>,
        "open list:DRM DRIVERS FOR LIMA" <dri-devel@...ts.freedesktop.org>,
        "moderated list:DRM DRIVERS FOR LIMA" <lima@...ts.freedesktop.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <linux-arm-msm@...r.kernel.org>,
        "open list:DRM DRIVER FOR MSM ADRENO GPU" 
        <freedreno@...ts.freedesktop.org>
Subject: Re: [PATCH] devfreq: Register devfreq as a cooling device

On 04/03/2021 12:50, Daniel Lezcano wrote:
> Currently the default behavior is to manually having the devfreq
> backend to register themselves as a devfreq cooling device.
> 
> There are no so many and actually it makes more sense to register the
> devfreq device when adding it.
> 
> Consequently, every devfreq becomes a cooling device like cpufreq is.
> 
> Having a devfreq being registered as a cooling device can not mitigate
> a thermal zone if it is not bound to this one. Thus, the current
> configurations are not impacted by this change.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
> ---
>   drivers/devfreq/devfreq.c                   |  8 ++++++++
>   drivers/gpu/drm/lima/lima_devfreq.c         | 13 -------------
>   drivers/gpu/drm/lima/lima_devfreq.h         |  2 --
>   drivers/gpu/drm/msm/msm_gpu.c               | 11 -----------
>   drivers/gpu/drm/msm/msm_gpu.h               |  2 --
>   drivers/gpu/drm/panfrost/panfrost_devfreq.c | 13 -------------
>   include/linux/devfreq.h                     |  3 +++
>   7 files changed, 11 insertions(+), 41 deletions(-)
> 
[...]
> diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> index 56b3f5935703..2cb6300de1f1 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> @@ -3,7 +3,6 @@
>   
>   #include <linux/clk.h>
>   #include <linux/devfreq.h>
> -#include <linux/devfreq_cooling.h>
>   #include <linux/platform_device.h>
>   #include <linux/pm_opp.h>
>   
> @@ -90,7 +89,6 @@ int panfrost_devfreq_init(struct panfrost_device *pfdev)
>   	struct device *dev = &pfdev->pdev->dev;
>   	struct devfreq *devfreq;
>   	struct opp_table *opp_table;
> -	struct thermal_cooling_device *cooling;
>   	struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
>   
>   	opp_table = dev_pm_opp_set_regulators(dev, pfdev->comp->supply_names,
> @@ -139,12 +137,6 @@ int panfrost_devfreq_init(struct panfrost_device *pfdev)
>   	}
>   	pfdevfreq->devfreq = devfreq;
>   
> -	cooling = devfreq_cooling_em_register(devfreq, NULL);
> -	if (IS_ERR(cooling))
> -		DRM_DEV_INFO(dev, "Failed to register cooling device\n");
> -	else
> -		pfdevfreq->cooling = cooling;
> -
>   	return 0;
>   
>   err_fini:
> @@ -156,11 +148,6 @@ void panfrost_devfreq_fini(struct panfrost_device *pfdev)
>   {
>   	struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
>   
> -	if (pfdevfreq->cooling) {
> -		devfreq_cooling_unregister(pfdevfreq->cooling);
> -		pfdevfreq->cooling = NULL;
> -	}
> -
>   	if (pfdevfreq->opp_of_table_added) {
>   		dev_pm_opp_of_remove_table(&pfdev->pdev->dev);
>   		pfdevfreq->opp_of_table_added = false;

You've removed all references to pfdevfreq->cooling, so please also 
remove the member from struct panfrost_devfreq (as already done with 
lima and msm).

Thanks,

Steve