linux-kernel - Re: [PATCH v7 10/11] input: misc: Add support for MAX7360 rotary

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Message-Id: <D9LQ7NV1LJM9.F2GF0YEEDFEY@bootlin.com>
Date: Fri, 02 May 2025 15:58:04 +0200
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>, "Michael Walle"
 <mwalle@...nel.org>, "Mark Brown" <broonie@...nel.org>, "Greg
 Kroah-Hartman" <gregkh@...uxfoundation.org>, "Rafael J. Wysocki"
 <rafael@...nel.org>, "Danilo Krummrich" <dakr@...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 v7 10/11] input: misc: Add support for MAX7360 rotary

On Fri May 2, 2025 at 12:52 PM CEST, Andy Shevchenko wrote:
> On Mon, Apr 28, 2025 at 01:57:28PM +0200, Mathieu Dubois-Briand wrote:
>> Add driver for Maxim Integrated MAX7360 rotary encoder controller,
>> supporting a single rotary switch.
>
> ...
>
>> +struct max7360_rotary {
>> +	struct input_dev *input;
>> +	unsigned int debounce_ms;
>> +	struct regmap *regmap;
>> +
>> +	u32 steps;
>> +	u32 axis;
>> +	bool relative_axis;
>> +	bool rollover;
>> +
>> +	unsigned int pos;
>> +};
>
> I believe `pahole` can recommend better layout (look for the better position
> of debounce_ms).
>
> ...
>

Oh yes it does on arm64. Moving it after the regmap pointer, it should
be better.

>> +static void max7360_rotaty_report_event(struct max7360_rotary *max7360_rotary, int steps)
>> +{
>> +	if (max7360_rotary->relative_axis) {
>> +		input_report_rel(max7360_rotary->input, max7360_rotary->axis, steps);
>> +	} else {
>> +		unsigned int pos = max7360_rotary->pos;
>> +
>> +		if (steps < 0) {
>> +			/* turning counter-clockwise */
>> +			if (max7360_rotary->rollover)
>> +				pos += max7360_rotary->steps + steps;
>> +			else
>
>> +				pos = max(0, (int)pos + steps);
>
> Please, no castings for min()/max()/clamp(). It diminishes the use of those
> macros.
>

Sorry, I'm not sure to get the point. Should I use MIN_T() instead?

>
> ...
>
>> +static int max7360_rotary_probe(struct platform_device *pdev)
>> +{
>> +	struct max7360_rotary *max7360_rotary;
>> +	struct device *dev = &pdev->dev;
>> +	struct input_dev *input;
>> +	struct regmap *regmap;
>> +	int irq;
>> +	int error;
>> +
>> +	regmap = dev_get_regmap(dev->parent, NULL);
>> +	if (!regmap)
>> +		dev_err_probe(dev, -ENODEV, "Could not get parent regmap\n");
>
> Missing return. Copy'n'paste error over all drivers?
>

Probably more an error while replacing all dev_err()+return by
dev_err_probe(), but yes. I will look for similar issues.

> ...

OK with all other comments.

Thanks for your review.
Mathieu

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