Re: [PATCH v4 1/4] hwmon: lm75: Add lm75 to of_match list

From: Guenter Roeck <linux@roeck-us.net>
To: "Matwey V. Kornilov" <matwey@sai.msu.ru>,
	Jean Delvare <jdelvare@suse.com>,
	Rob Herring <robh+dt@kernel.org>,
	"open list:HARDWARE MONITORING" <linux-hwmon@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 1/4] hwmon: lm75: Add lm75 to of_match list
Date: Sat, 6 Feb 2021 08:46:16 -0800	[thread overview]
Message-ID: <164495f0-9b53-2523-f178-bd52bbb40ae6@roeck-us.net> (raw)
In-Reply-To: <20210206095121.20625-2-matwey@sai.msu.ru>

On 2/6/21 1:51 AM, Matwey V. Kornilov wrote:
> Currently, many boards use just 'lm75' as a compatible string.
> 
> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
> ---
>  Documentation/devicetree/bindings/hwmon/lm75.yaml | 1 +
>  drivers/hwmon/lm75.c                              | 4 ++++
>  2 files changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/lm75.yaml b/Documentation/devicetree/bindings/hwmon/lm75.yaml
> index 96eed5cc7841..aec8edd1e0c6 100644
> --- a/Documentation/devicetree/bindings/hwmon/lm75.yaml
> +++ b/Documentation/devicetree/bindings/hwmon/lm75.yaml
> @@ -13,6 +13,7 @@ maintainers:
>  properties:
>    compatible:
>      enum:
> +      - lm75

Please split the .yaml file changes into a single patch, separate
from the code changes. Also please make sure that the subject indicates
that this is a bindings change.

For this change, we'll definitely need feedback from Rob. I am not sure
if such a generic compatible string is permitted or if we need to change
the dts files instead.

On a higher level, while lm75 is an extreme case, I see a few other
violators as well.

drivers/macintosh/windfarm_ad7417_sensor.c:     { .compatible = "ad7417", },
drivers/macintosh/windfarm_max6690_sensor.c:    { .compatible = "max6690", },
arch/arm/boot/dts/socfpga_arria10_socdk.dtsi:           compatible = "ltc2977";
arch/arm/boot/dts/aspeed-bmc-arm-centriq2400-rep.dts:                           compatible = "tmp421";
arch/arm/boot/dts/nuvoton-npcm750-evb.dts:              compatible = "tmp100";
arch/arm/boot/dts/nuvoton-npcm750-evb.dts:              compatible = "tmp100";

so it would be good to know how to handle those in general.

Note that there is also:

Documentation/devicetree/bindings/display/repaper.txt:          compatible = "lm75b";

but maybe that doesn't matter as much since it is not actually
used in dts files.

Thanks,
Guenter