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

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Date:   Wed, 9 Dec 2020 16:34:43 +0530
From:   Maulik Shah <mkshah@...eaurora.org>
To:     Doug Anderson <dianders@...omium.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 Doug,

On 12/4/2020 2:47 AM, Doug Anderson wrote:
> 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>

Thanks for the review, i will send v2 adding Fixes: tag.

Thanks,
Maulik

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