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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Mon, 15 Jun 2020 13:25:00 +0200
Message-ID: <CAPDyKFrdzcf5e98EM0VvwxnR0zDFQ851PDLOZ9wpe-LO6n4Abw@mail.gmail.com>
Subject: Re: [PATCH v4 4/4] thermal: cpuidle: Register cpuidle cooling device
To:     Daniel Lezcano <daniel.lezcano@linaro.org>
Cc:     Zhang Rui <rui.zhang@intel.com>, lukasz.luba@arm.com,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Sudeep Holla <sudeep.holla@arm.com>,
        "open list:CPU IDLE TIME MANAGEMENT FRAMEWORK" 
        <linux-pm@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:CPUIDLE DRIVER - ARM PSCI" 
        <linux-arm-kernel@lists.infradead.org>
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On Wed, 29 Apr 2020 at 12:37, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
>
> The cpuidle driver can be used as a cooling device by injecting idle
> cycles. The DT binding for the idle state added an optional
>
> When the property is set, register the cpuidle driver with the idle
> state node pointer as a cooling device. The thermal framework will do
> the association automatically with the thermal zone via the
> cooling-device defined in the device tree cooling-maps section.
>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
>  - V4:
>    - Do not check the return value as the function does no longer return one
> ---
>  drivers/cpuidle/cpuidle-arm.c  | 3 +++
>  drivers/cpuidle/cpuidle-psci.c | 3 +++
>  2 files changed, 6 insertions(+)
>
> diff --git a/drivers/cpuidle/cpuidle-arm.c b/drivers/cpuidle/cpuidle-arm.c
> index 9e5156d39627..8c758920d699 100644
> --- a/drivers/cpuidle/cpuidle-arm.c
> +++ b/drivers/cpuidle/cpuidle-arm.c
> @@ -8,6 +8,7 @@
>
>  #define pr_fmt(fmt) "CPUidle arm: " fmt
>
> +#include <linux/cpu_cooling.h>
>  #include <linux/cpuidle.h>
>  #include <linux/cpumask.h>
>  #include <linux/cpu_pm.h>
> @@ -124,6 +125,8 @@ static int __init arm_idle_init_cpu(int cpu)
>         if (ret)
>                 goto out_kfree_drv;
>
> +       cpuidle_cooling_register(drv);
> +
>         return 0;
>
>  out_kfree_drv:
> diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c
> index bae9140a65a5..1f38e0dfc9b2 100644
> --- a/drivers/cpuidle/cpuidle-psci.c
> +++ b/drivers/cpuidle/cpuidle-psci.c
> @@ -9,6 +9,7 @@
>  #define pr_fmt(fmt) "CPUidle PSCI: " fmt
>
>  #include <linux/cpuhotplug.h>
> +#include <linux/cpu_cooling.h>
>  #include <linux/cpuidle.h>
>  #include <linux/cpumask.h>
>  #include <linux/cpu_pm.h>
> @@ -313,6 +314,8 @@ static int __init psci_idle_init_cpu(int cpu)
>         if (ret)
>                 goto out_kfree_drv;
>
> +       cpuidle_cooling_register(drv);
> +

Apologies for the late reply, but just noticed this change in v5.8-rc1.

Don't you need a cpuidle_cooling_unregister function? For example,
cpuidle-psci may fail and then calls cpuidle_unregister() to cleans up
things.

Is that okay?

Kind regards
Uffe