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From:   Amit Kucheria <amit.kucheria@verdurent.com>
Date:   Tue, 3 Dec 2019 22:34:37 +0530
Message-ID: <CAHLCerOCt9VBizAHu+y+CmzFmz-ktqCJgcB_NeC3WC4W9YBvAQ@mail.gmail.com>
Subject: Re: [PATCH v3 3/7] thermal: core: Add late init hook to cooling
 device ops
To:     Thara Gopinath <thara.gopinath@linaro.org>
Cc:     Eduardo Valentin <edubezval@gmail.com>,
        Zhang Rui <rui.zhang@intel.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Andy Gross <agross@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Linux PM list <linux-pm@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Thu, Oct 17, 2019 at 1:07 AM Thara Gopinath
<thara.gopinath@linaro.org> wrote:
>
> Add a hook in thermal_cooling_device_ops to be called after
> the cooling device has been initialized and registered
> but before binding it to a thermal zone.
>
> In this patch series it is used to hook up a power domain
> to the device pointer of cooling device.
>
> It can be used for any other relevant late initializations
> of a cooling device as well.

Please describe WHY this hook is needed.

> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
> ---
>  drivers/thermal/thermal_core.c | 13 +++++++++++++
>  include/linux/thermal.h        |  1 +
>  2 files changed, 14 insertions(+)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 886e8fa..c2ecb73 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -994,6 +994,19 @@ __thermal_cooling_device_register(struct device_node *np,
>         list_add(&cdev->node, &thermal_cdev_list);
>         mutex_unlock(&thermal_list_lock);
>
> +       /* Call into cdev late initialization if defined */
> +       if (cdev->ops->late_init) {
> +               result = cdev->ops->late_init(cdev);
> +               if (result) {
> +                       ida_simple_remove(&thermal_cdev_ida, cdev->id);
> +                       put_device(&cdev->device);
> +                       mutex_lock(&thermal_list_lock);
> +                       list_del(&cdev->node);
> +                       mutex_unlock(&thermal_list_lock);
> +                       return ERR_PTR(result);
> +               }
> +       }
> +
>         /* Update binding information for 'this' new cdev */
>         bind_cdev(cdev);
>
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index e45659c..e94b3de 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -125,6 +125,7 @@ struct thermal_cooling_device_ops {
>                            struct thermal_zone_device *, unsigned long, u32 *);
>         int (*power2state)(struct thermal_cooling_device *,
>                            struct thermal_zone_device *, u32, unsigned long *);
> +       int (*late_init)(struct thermal_cooling_device *);
>  };
>
>  struct thermal_cooling_device {
> --
> 2.1.4
>