linux-kernel - Re: [PATCH v2 4/6] clk: qcom: Use HW_CTRL_TRIGGER flag to switch video GDSC to HW mode

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Message-ID: <ZOXiUzxfs1cj3SWT@linaro.org>
Date:   Wed, 23 Aug 2023 13:41:23 +0300
From:   Abel Vesa <abel.vesa@...aro.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>
Cc:     "Rafael J . Wysocki" <rafael@...nel.org>,
        Kevin Hilman <khilman@...nel.org>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Pavel Machek <pavel@....cz>, Len Brown <len.brown@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Andy Gross <agross@...nel.org>,
        Mike Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Taniya Das <tdas@....qualcomm.com>, linux-pm@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm@...r.kernel.org,
        Jagadeesh Kona <quic_jkona@...cinc.com>
Subject: Re: [PATCH v2 4/6] clk: qcom: Use HW_CTRL_TRIGGER flag to switch
 video GDSC to HW mode

On 23-08-16 19:56:46, Konrad Dybcio wrote:
> On 16.08.2023 16:57, Abel Vesa wrote:
> > From: Jagadeesh Kona <quic_jkona@...cinc.com>
> > 
> > The current HW_CTRL flag switches the video GDSC to HW control mode as
> > part of GDSC enable itself, instead of that use HW_CTRL_TRIGGER flag to
> > give consumer drivers more control and switch the GDSC mode as and when
> > required.
> > 
> > HW_CTRL_TRIGGER flag allows consumer drivers to switch the video GDSC to
> > HW/SW control modes at runtime using dev_pm_genpd_set_hwmode API.
> > 
> > Signed-off-by: Jagadeesh Kona <quic_jkona@...cinc.com>
> > Signed-off-by: Abel Vesa <abel.vesa@...aro.org>
> > ---
> Do we have any use for the HW_CTRL flag?
> 
> Perhaps it should be renamed to HW_CTRL_ALWAYS?
> 
> Or even better, *if and only if* that is necessary, add a common
> property like "always_hw_managed" to the genpd code?

The HW_CTRL flag is still needed for the consumers that expect the GDSC
to be have the HW control bit set right after it gets enabled.

AFAIU, for the HW_CTRL_TRIGGER, the switch to HW control will only be
done by the consumer (not on enable).

> 
> Konrad