Message-ID: <d4da4803-134c-72aa-a24c-cc6fc3d8acc5@linaro.org>
Date:   Fri, 27 Jan 2023 12:54:03 +0100
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Subject: Re: [PATCH v8 5/5] thermal: mediatek: try again if first temp read is
 bogus
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To:     Amjad Ouled-Ameur <aouledameur@baylibre.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Amit Kucheria <amitk@kernel.org>,
        Zhang Rui <rui.zhang@intel.com>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc:     linux-pm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org,
        Fabien Parent <fparent@baylibre.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>,
        Rob Herring <robh@kernel.org>,
        Markus Schneider-Pargmann <msp@baylibre.com>,
        Hsin-Yi Wang <hsinyi@chromium.org>,
        Michael Kao <michael.kao@mediatek.com>
References: <20221018-up-i350-thermal-bringup-v8-0-23e8fbb08837@baylibre.com>
 <20221018-up-i350-thermal-bringup-v8-5-23e8fbb08837@baylibre.com>
 <96e7aaf5-76ef-9356-84e2-ee1f747dafcd@linaro.org>
 <9b5911ec-9993-5540-6de5-c62c7c446274@baylibre.com>
From:   Daniel Lezcano <daniel.lezcano@linaro.org>
In-Reply-To: <9b5911ec-9993-5540-6de5-c62c7c446274@baylibre.com>
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Hi Amjad,

On 27/01/2023 11:50, Amjad Ouled-Ameur wrote:
> Hi Daniel,
> 
> On 1/25/23 11:58, Daniel Lezcano wrote:
>> On 25/01/2023 10:50, Amjad Ouled-Ameur wrote:
>>> In mtk_thermal_bank_temperature, return -EAGAIN instead of 0
>>> on the first read of sensor that often are bogus values.
>>>
>>> Signed-off-by: Michael Kao <michael.kao@mediatek.com>
>>> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
>>> Signed-off-by: Amjad Ouled-Ameur <aouledameur@baylibre.com>
>>> Reviewed-by: AngeloGioacchino Del Regno 
>>> <angelogioacchino.delregno@collabora.com>
>>> ---
>>>   drivers/thermal/mtk_thermal.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/thermal/mtk_thermal.c 
>>> b/drivers/thermal/mtk_thermal.c
>>> index b8e06f6c7c42..e7be450cd40a 100644
>>> --- a/drivers/thermal/mtk_thermal.c
>>> +++ b/drivers/thermal/mtk_thermal.c
>>> @@ -736,7 +736,7 @@ static int mtk_thermal_bank_temperature(struct 
>>> mtk_thermal_bank *bank)
>>>            * not immediately shut down.
>>>            */
>>>           if (temp > 200000)
>>> -            temp = 0;
>>> +            temp = -EAGAIN;
>>
>> Did you try to add a delay between the bank init and the thermal zone 
>> device register (eg. 1ms) ?
>>
>> May be the HW did not have time to initialize and capture a 
>> temperature before thermal_zone_device_register() is called (this one 
>> calls get_temp) ?
> 
> A delay of 29 ms actually fixed the issue, thanks for the suggestion. I 
> can send a V9 with this improvement.

I'm glad that helped.

Will you remove the "if (temp > 200000)" test ?

> Is there anything else to fix perhaps ?

Not in your changes

Thanks

   -- Daniel


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