linux-kernel - Re: [PATCH v3 3/6] drm/msm/dsi: Don't set a load before disabling a regulator

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Date:   Wed, 3 Aug 2022 10:07:18 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Douglas Anderson <dianders@...omium.org>,
        Rob Clark <robdclark@...il.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>
Cc:     dri-devel@...ts.freedesktop.org, Mark Brown <broonie@...nel.org>,
        linux-arm-msm@...r.kernel.org, freedreno@...ts.freedesktop.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...ainline.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Jonathan Marek <jonathan@...ek.ca>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        Loic Poulain <loic.poulain@...aro.org>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        Rajeev Nandan <quic_rajeevny@...cinc.com>,
        Sean Paul <sean@...rly.run>,
        Stephen Boyd <swboyd@...omium.org>,
        Vinod Koul <vkoul@...nel.org>,
        Vladimir Lypak <vladimir.lypak@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/6] drm/msm/dsi: Don't set a load before disabling a
 regulator

On 03/08/2022 01:37, Douglas Anderson wrote:
> As of commit 5451781dadf8 ("regulator: core: Only count load for
> enabled consumers"), a load isn't counted for a disabled
> regulator. That means all the code in the DSI driver to specify and
> set loads before disabling a regulator is not actually doing anything
> useful. Let's remove it.
> 
> It should be noted that all of the loads set that were being specified
> were pointless noise anyway. The only use for this number is to pick
> between low power and high power modes of regulators. Regulators
> appear to do this changeover at loads on the order of 10000 uA. You
> would need a lot of clients of the same rail for that 100 uA number to
> count for anything.
> 
> Note that now that we get rid of the setting of the load at disable
> time, we can just set the load once when we first get the regulator
> and then forget it.
> 
> It should also be noted that the regulator functions
> regulator_bulk_enable() and regulator_set_load() already print error
> messages when they encounter problems so while moving things around we
> get rid of some extra error prints.
> 
> Signed-off-by: Douglas Anderson <dianders@...omium.org>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>

> ---
> 
> Changes in v3:
> - Fix typo in commit message.
> - Just directly call the bulk commands; get rid of the wrapper.
> 
>   drivers/gpu/drm/msm/dsi/dsi.h                 |  1 -
>   drivers/gpu/drm/msm/dsi/dsi_cfg.c             | 52 +++++++-------
>   drivers/gpu/drm/msm/dsi/dsi_host.c            | 71 ++++---------------
>   drivers/gpu/drm/msm/dsi/phy/dsi_phy.c         | 52 ++------------
>   drivers/gpu/drm/msm/dsi/phy/dsi_phy_10nm.c    |  4 +-
>   drivers/gpu/drm/msm/dsi/phy/dsi_phy_14nm.c    |  6 +-
>   drivers/gpu/drm/msm/dsi/phy/dsi_phy_20nm.c    |  4 +-
>   drivers/gpu/drm/msm/dsi/phy/dsi_phy_28nm.c    |  6 +-
>   .../gpu/drm/msm/dsi/phy/dsi_phy_28nm_8960.c   |  2 +-
>   drivers/gpu/drm/msm/dsi/phy/dsi_phy_7nm.c     |  6 +-
>   10 files changed, 60 insertions(+), 144 deletions(-)
> 


-- 
With best wishes
Dmitry