linux-kernel - Re: [PATCH] drivers: qcom: rpmh-rsc: Do not read back the register write on trigger

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Message-ID: <CAD=FV=XafiNR+vZc2nM6JzhU7xPm9v3eeeR5SMhBM3k3mmsZDQ@mail.gmail.com>
Date:   Thu, 3 Dec 2020 13:17:00 -0800
From:   Doug Anderson <dianders@...omium.org>
To:     Maulik Shah <mkshah@...eaurora.org>
Cc:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Lina Iyer <ilina@...eaurora.org>,
        Srinivas Rao L <lsrao@...eaurora.org>,
        Stephen Boyd <swboyd@...omium.org>
Subject: Re: [PATCH] drivers: qcom: rpmh-rsc: Do not read back the register
 write on trigger

Hi,

On Thu, Dec 3, 2020 at 1:15 PM Doug Anderson <dianders@...omium.org> wrote:
>
> Hi,
>
> On Tue, Nov 24, 2020 at 1:53 AM Maulik Shah <mkshah@...eaurora.org> wrote:
> >
> > From: Lina Iyer <ilina@...eaurora.org>
> >
> > When triggering a TCS to send its contents, reading back the trigger
> > value may return an incorrect value. That is because, writing the
> > trigger may raise an interrupt which could be handled immediately and
> > the trigger value could be reset in the interrupt handler.
> >
> > A write_tcs_reg_sync() would read back the value that is written and try
> > to match it to the value written to ensure that the value is written,
> > but if that value is different, we may see false error for same.
> >
> > Signed-off-by: Lina Iyer <ilina@...eaurora.org>
> > Signed-off-by: Maulik Shah <mkshah@...eaurora.org>
> > ---
> >  drivers/soc/qcom/rpmh-rsc.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
>
> Fixes: 658628e7ef78 ("drivers: qcom: rpmh-rsc: add RPMH controller for
> QCOM SoCs")
> Signed-off-by: Douglas Anderson <dianders@...omium.org>

Ugh, brain-fart.  Not Signed-off-by, but:

Reviewed-by: Douglas Anderson <dianders@...omium.org>