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Sender: Guenter Roeck <groeck7@gmail.com>
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Date:   Mon, 21 Feb 2022 08:23:20 -0800
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Subject: Re: [PATCH v3 2/4] hwmon: (lm90) Use hwmon_notify_event()
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To:     Jon Hunter <jonathanh@nvidia.com>,
        Dmitry Osipenko <digetx@gmail.com>,
        Jean Delvare <jdelvare@suse.com>
Cc:     linux-kernel@vger.kernel.org, linux-hwmon@vger.kernel.org,
        linux-tegra@vger.kernel.org
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From:   Guenter Roeck <linux@roeck-us.net>
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On 2/21/22 08:16, Jon Hunter wrote:
> 
> On 21/02/2022 16:02, Guenter Roeck wrote:
> 
> ...
> 
>>> The platform I see this on does use device-tree and it does have a node for the ti,tmp451 device which uses the lm90 device. This platform uses the device-tree source arch/arm64/boot/dts/nvidia/tegra194-p2972-0000.dts and the tmp451 node is in arch/arm64/boot/dts/nvidia/tegra194-p2888.dtsi.
>>>
>>
>> Interesting. It appears that the call to devm_thermal_zone_of_sensor_register()
>> in the hwmon core nevertheless returns -ENODEV which is not handled properly
>> in the hwmon core. I can see a number of reasons for this to happen:
>> - there is no devicetree node for the lm90 device
>> - there is no thermal-zones devicetree node
>> - there is no thermal zone entry in the thermal-zones node which matches
>>    the sensor
> 
> 
> So we definitely have the node for the lm90 device and a thermal-zones node, but I do not see a thermal-sensor node. Maybe this is what we are missing?
> 

Correct.

Guenter