linux-kernel - Re: [PATCH v2 04/22] rtc: pm8xxx: drop bogus locking

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Message-ID: <1eef640f-7d3d-6213-fd5b-6731283b3049@quicinc.com>
Date:   Mon, 6 Feb 2023 19:14:44 -0800
From:   David Collins <quic_collinsd@...cinc.com>
To:     Johan Hovold <johan+linaro@...nel.org>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Bjorn Andersson <andersson@...nel.org>
CC:     Andy Gross <agross@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Alessandro Zummo <a.zummo@...ertech.it>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Maximilian Luz <luzmaximilian@...il.com>,
        <linux-arm-msm@...r.kernel.org>, <linux-rtc@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 04/22] rtc: pm8xxx: drop bogus locking

On 2/2/23 07:54, Johan Hovold wrote:
> Since commit c8d523a4b053 ("drivers/rtc/rtc-pm8xxx.c: rework to support
> pm8941 rtc") which removed the shadow control register there is no need
> for a driver lock.
> 
> Specifically, the rtc ops are serialised by rtc core and the interrupt
> handler only unconditionally disables the alarm using the alarm_ctrl
> register.
> 
> Note that since only the alarm enable bit of alarm_ctrl is used after
> enabling the RTC at probe, the locking was not needed when doing open
> coded read-modify-write cycles either.
> 
> Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
> ---
>  drivers/rtc/rtc-pm8xxx.c | 67 +++++++++++++---------------------------
>  1 file changed, 21 insertions(+), 46 deletions(-)

Reviewed-by: David Collins <quic_collinsd@...cinc.com>

Take care,
David