linux-kernel - RE: [PATCH v3 4/5] drm/panfrost: devfreq: set opp to the recommended one to configure and enable regulator

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Date:   Mon, 5 Sep 2022 18:17:09 +0000
From:   Biju Das <biju.das.jz@...renesas.com>
To:     Clément Péron <peron.clem@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Chen-Yu Tsai <wens@...e.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Samuel Holland <samuel@...lland.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        Steven Price <steven.price@....com>,
        Alyssa Rosenzweig <alyssa.rosenzweig@...labora.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Bjorn Andersson <andersson@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Arnd Bergmann <arnd@...db.de>,
        Marcel Ziswiler <marcel.ziswiler@...adex.com>,
        Vinod Koul <vkoul@...nel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Rob Herring <robh@...nel.org>
CC:     "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-sunxi@...ts.linux.dev" <linux-sunxi@...ts.linux.dev>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        Viresh Kumar <viresh.kumar@...aro.org>
Subject: RE: [PATCH v3 4/5] drm/panfrost: devfreq: set opp to the recommended
 one to configure and enable regulator

Hi,

Thanks for the patch.

> Subject: [PATCH v3 4/5] drm/panfrost: devfreq: set opp to the recommended
> one to configure and enable regulator
> 
> devm_pm_opp_set_regulators() doesn't enable regulator, which make
> regulator framework switching it off during regulator_late_cleanup().

In that case, why not regulator_get()for 
Dynamic regulator(non fixed regulator)??

> 
> Call dev_pm_opp_set_opp() with the recommend OPP in
> panfrost_devfreq_init() to enable the regulator and avoid any switch off
> by regulator_late_cleanup().
> 
> Suggested-by: Viresh Kumar <viresh.kumar@...aro.org>
> Signed-off-by: Clément Péron <peron.clem@...il.com>
> ---
>  drivers/gpu/drm/panfrost/panfrost_devfreq.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> index 5110cd9b2425..67b242407156 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
> @@ -131,6 +131,14 @@ int panfrost_devfreq_init(struct panfrost_device
> *pfdev)
>  		return PTR_ERR(opp);
> 
>  	panfrost_devfreq_profile.initial_freq = cur_freq;
> +
> +	/* Setup and enable regulator */
> +	ret = dev_pm_opp_set_opp(dev, opp);
> +	if (ret) {
> +		DRM_DEV_ERROR(dev, "Couldn't set recommended OPP\n");
> +		return ret;
> +	}


FYI,
On RZ/G2L mali gpu, we have fixed regulator and
I was able to do GPU OPP transition without any issues previously.

root@...rc-rzg2l:~# cat /sys/class/devfreq/11840000.gpu/trans_stat
     From  :   To
           :  50000000  62500000 100000000 125000000 200000000 250000000 400000000 500000000   time(ms)
*  50000000:         0         0         0         0         0         0         0         1       144
   62500000:         0         0         0         0         0         0         0         0         0
  100000000:         0         0         0         0         0         0         0         9       524
  125000000:         0         0         9         0         0         0         0         3      2544
  200000000:         0         0         0        11         0         0         0        46      3304
  250000000:         1         0         0         0        33         0         0         0      7496
  400000000:         0         0         0         0        16        19         0         0      2024
  500000000:         1         0         0         1         8        15        35         0      4032
Total transition : 208

Cheers,
Biju