linux-kernel - Re: [PATCH] iio: light: bh1750: Add hardware reset support via GPIO

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Message-ID: <c9fb19c4-aa7a-4114-ace4-764d15a2d795@kernel.org>
Date: Tue, 18 Mar 2025 14:28:50 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Sergio Perez Alegre <sergio@...eznus.es>
Cc: tduszyns@...il.com, jic23@...nel.org, lars@...afoo.de, robh@...nel.org,
 conor+dt@...nel.org, linux-iio@...r.kernel.org,
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH] iio: light: bh1750: Add hardware reset support via GPIO

On 18/03/2025 14:16, Sergio Perez Alegre wrote:
> El 17 mar. 2025, a las 8:24, Krzysztof Kozlowski <krzk@...nel.org> escribieron: On 16/03/2025 15:55, Sergio Perez wrote: Some BH1750 sensors require a hardware reset before they can be detected on the I2C bus. This patch adds support for an optional reset GPIO that can be specified in the device tree. The reset sequence pulls the GPIO low and then high before initializing the sensor, which enables proper detection with tools like i2cdetect. Update the devicetree binding documentation to include the new reset-gpios property with examples. Signed-off-by: Sergio Perez <sergio@...eznus.es> Please run scripts/checkpatch.pl and fix reported warnings. After that, run also `scripts/checkpatch.pl --strict` and (probably) fix more warnings. Some warnings can be ignored, especially from --strict run, but the code here looks like it needs a fix. Feel free to get in touch if the warning is not clear. <form letter> Please use scripts/get_maintainers.pl to get a list of necessary people and lists to CC. It might happen, that command when run on an older kernel, gives you outdated entries. Therefore please be sure you base your patches on recent Linux kernel. Tools like b4 or scripts/get_maintainer.pl provide you proper list of people, so fix your workflow. Tools might also fail if you work on some ancient tree (don't, instead use mainline) or work on fork of kernel (don't, instead use mainline). Just use b4 and everything should be fine, although remember about `b4 prep --auto-to-cc` if you added new patches to the patchset. You missed at least devicetree list (maybe more), so this won't be tested by automated tooling. Performing review on untested code might be a waste of time. Please kindly resend and include all necessary To/Cc entries. </form letter> Sorry, I had run the scripts/get_maintainer.pl tool and got fewer recipients than necessary. I have redone everything in a clean installation and now I have obtained more recipients. Any fixes I make in the patch I send to this same thread or should I send it with git send-mail? I say this because perhaps I have done it incorrectly and possibly created 3 versions, I apologize. My latest version (v3) includes all the suggestions mentioned but due to my ignorance of the procedure I thought they should be sent to the list again as before. --- .../devicetree/bindings/iio/light/bh1750.yaml | 20 +++- drivers/iio/light/bh1750.c | 113 ++++++++++++------ ... and please go through your patch and see what happened there. 2 files changed, 95 insertions(+), 38 deletions(-) diff --git a/Documentation/devicetree/bindings/iio/light/bh1750.yaml b/Documentation/devicetree/bindings/iio/light/bh1750.yaml index 1a88b3c253d5..d53b221eb84b 100644 --- a/Documentation/devicetree/bindings/iio/light/bh1750.yaml +++ b/Documentation/devicetree/bindings/iio/light/bh1750.yaml @@ -11,6 +11,9 @@ maintainers: description: | Ambient light sensor with an i2c interface. + + Some BH1750 sensors require a hardware reset before being properly detected + on the I2C bus. This can be done using the optional reset-gpios property. properties: compatible: @@ -23,6 +26,10 @@ properties: reg: maxItems: 1 + + reset-gpios: + description: GPIO connected to the sensor's reset line (active low) + maxItems: 1 required: - compatible @@ -41,5 +48,16 @@ examples: reg = <0x23>; }; }; + - | + i2c { + #address-cells = <1>; + #size-cells = <0>; + + light-sensor@23 { + compatible = "rohm,bh1750"; + reg = <0x23>; + reset-gpios = <&gpio2 17 GPIO_ACTIVE_HIGH>; + }; + }; -... +... \ No newline at end of file You have unrelated changed all over the place. Best regards, Krzysztof


Hm? No clue what this means, sorry, unreadable.

Best regards,
Krzysztof