linux-kernel - Re: [PATCH v2 4/7] gpio: max7360: Add MAX7360 gpio support

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Message-Id: <D78MG8EQMSBU.2U6T5DXG2YJXI@bootlin.com>
Date: Wed, 22 Jan 2025 14:04:35 +0100
From: "Mathieu Dubois-Briand" <mathieu.dubois-briand@...tlin.com>
To: "Andy Shevchenko" <andriy.shevchenko@...el.com>
Cc: "Lee Jones" <lee@...nel.org>, "Rob Herring" <robh@...nel.org>,
 "Krzysztof Kozlowski" <krzk+dt@...nel.org>, "Conor Dooley"
 <conor+dt@...nel.org>, "Kamel Bouhara" <kamel.bouhara@...tlin.com>, "Linus
 Walleij" <linus.walleij@...aro.org>, "Bartosz Golaszewski" <brgl@...ev.pl>,
 "Dmitry Torokhov" <dmitry.torokhov@...il.com>,
 Uwe Kleine-König <ukleinek@...nel.org>,
 <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
 <linux-gpio@...r.kernel.org>, <linux-input@...r.kernel.org>,
 <linux-pwm@...r.kernel.org>, Grégory Clement
 <gregory.clement@...tlin.com>, "Thomas Petazzoni"
 <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v2 4/7] gpio: max7360: Add MAX7360 gpio support

On Tue Jan 21, 2025 at 4:20 PM CET, Andy Shevchenko wrote:
> On Mon, Dec 23, 2024 at 05:42:36PM +0100, Mathieu Dubois-Briand wrote:

Hi Andy,

Thanks for your review. I'm not sure you have seen it, but there is a v3
of this series. V3 of this patch can be seen here:
https://lore.kernel.org/all/20250113-mdb-max7360-support-v3-4-9519b4acb0b1@bootlin.com/

Yet, your comments are still valid for the v3.

> > Add driver for Maxim Integrated MAX7360 GPIO/GPO controller.
> > 
> > Two sets of GPIOs are provided by the device:
> > - Up to 8 GPIOs, shared with the PWM and rotary encoder functionalities.
> >   These GPIOs also provide interrupts on input changes.
> > - Up to 6 GPOs, on unused keypad columns pins.
>
> May I ask if you researched for the existing drivers that may host this without
> much to modify?
>

I did had a look at the existing drivers and in particular at all
gpio-max* drivers. Unfortunately, I believe none of them target chipsets
similar to the MAX7360.

The only similarity I noted, is with the MAX732x chipsets, on the IRQ
side: both lack of dedicated bits for each line, leading to some logic
to try to recover the corresponding lines on interrupt. My code is
partly based on the MAX732x code on this specific point.

> Second, please, avoid OF-centric APIs in a new code. Use fwnode and/or device
> property APIs. (This stands for the whole series and any new contributions)

Yes, I definitely need to remove these of_property_read_*() calls. I'm
going to replace them with device_property_read_*() calls.

Best regards,
Mathieu

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com