linux-kernel - Re: [PATCH v4] drm/msm/dp: do not initialize phy until plugin interrupt received

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Date:   Fri, 19 Nov 2021 08:54:12 -0800
From:   Kuogee Hsieh <quic_khsieh@...cinc.com>
To:     Stephen Boyd <swboyd@...omium.org>, <agross@...nel.org>,
        <airlied@...ux.ie>, <bjorn.andersson@...aro.org>,
        <daniel@...ll.ch>, <dmitry.baryshkov@...aro.org>,
        <robdclark@...il.com>, <sean@...rly.run>, <vkoul@...nel.org>
CC:     <quic_abhinavk@...cinc.com>, <aravindh@...eaurora.org>,
        <freedreno@...ts.freedesktop.org>,
        <dri-devel@...ts.freedesktop.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Kuogee Hsieh <khsieh@...eaurora.org>
Subject: Re: [PATCH v4] drm/msm/dp: do not initialize phy until plugin
 interrupt received


On 11/18/2021 5:20 PM, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2021-11-09 13:38:13)
>> From: Kuogee Hsieh <khsieh@...eaurora.org>
>>
>> Current DP drivers have regulators, clocks, irq and phy are grouped
>> together within a function and executed not in a symmetric manner.
>> This increase difficulty of code maintenance and limited code scalability.
>> This patch divided the driver life cycle of operation into four states,
>> resume (including booting up), dongle plugin, dongle unplugged and suspend.
>> Regulators, core clocks and irq are grouped together and enabled at resume
>> (or booting up) so that the DP controller is armed and ready to receive HPD
>> plugin interrupts. HPD plugin interrupt is generated when a dongle plugs
>> into DUT (device under test). Once HPD plugin interrupt is received, DP
>> controller will initialize phy so that dpcd read/write will function and
>> following link training can be proceeded successfully. DP phy will be
>> disabled after main link is teared down at end of unplugged HPD interrupt
>> handle triggered by dongle unplugged out of DUT. Finally regulators, code
>> clocks and irq are disabled at corresponding suspension.
>>
>> Changes in V2:
>> -- removed unnecessary dp_ctrl NULL check
>> -- removed unnecessary phy init_count and power_count DRM_DEBUG_DP logs
>> -- remove flip parameter out of dp_ctrl_irq_enable()
>> -- add fixes tag
>>
>> Changes in V3:
>> -- call dp_display_host_phy_init() instead of dp_ctrl_phy_init() at
>>          dp_display_host_init() for eDP
>>
>> Changes in V4:
>> -- rewording commit text to match this commit changes
>>
>> Fixes: e91e3065a806 ("drm/msm/dp: Add DP compliance tests on Snapdragon Chipsets")
>>
>> Signed-off-by: Kuogee Hsieh <quic_khsieh@...cinc.com>
>> ---
> What commit is this patch based on?

It base on Bjorn's patch,

https://patchwork.freedesktop.org/series/92992/