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Date: Sat, 30 Nov 2024 20:28:49 +0000
From: Jonathan Cameron <jic23@kernel.org>
To: Ming Yu <a0282524688@gmail.com>
Cc: tmyu0@nuvoton.com, lars@metafoo.de, robh@kernel.org, krzk+dt@kernel.org,
 conor+dt@kernel.org, cmo@melexis.com, linux-iio@vger.kernel.org,
 devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Jean Delvare
 <jdelvare@suse.com>, Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH v1 0/2] Add Nuvoton NCT7718W IIO driver
Message-ID: <20241130202849.13eedb04@jic23-huawei>
In-Reply-To: <20241126074005.546447-1-tmyu0@nuvoton.com>
References: <20241126074005.546447-1-tmyu0@nuvoton.com>
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On Tue, 26 Nov 2024 15:40:03 +0800
Ming Yu <a0282524688@gmail.com> wrote:

> NCT7718W is an I2C based thermal sensor chip from Nuvoton.
Hi Ming Yu,

+CC Jean and Guenter,

Why an IIO driver rather than a HWMON one?  Superficially this looks like a hwmon
chip.  We do have the means to put a generic driver in IIO and bridge to hwmon, but
when a device is very much intended for monitoring of hardware temperatures etc
the IIO driver rarely has any purpose and a simpler hwmon only solution makes sense.

For temperature sensors IIO normally makes sense if:
1) They are part of a series of devices some of which have more functionality than temp
2) Fast devices where hwmon sysfs interfaces become a bottleneck - note you have to have
a usecase for reading them fast, not simply a device that is capable of it.
3) 'Unusual' temperature sensors such as infrared thermometers or very high precision
   thermocouple interfaces.

Any of those apply here?

Note that hwmon has better threshold and critical temperature handling than we can do
in IIO and it seems your part has those as well.

Thanks,

Jonathan


> 
> Ming Yu (2):
>   dt-bindings: iio: temperature: Add support for NCT7718W
>   iio: temperature: Add Nuvoton NCT7718W support
> 
>  .../iio/temperature/nuvoton,nct7718.yaml      |  44 ++
>  MAINTAINERS                                   |   7 +
>  drivers/iio/temperature/Kconfig               |  10 +
>  drivers/iio/temperature/Makefile              |   1 +
>  drivers/iio/temperature/nct7718.c             | 505 ++++++++++++++++++
>  5 files changed, 567 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/temperature/nuvoton,nct7718.yaml
>  create mode 100644 drivers/iio/temperature/nct7718.c
>