Re: [PATCH v7 03/11] pinctrl: Add MAX7360 pinctrl driver

[Mathieu Dubois-Briand]

On Fri May 2, 2025 at 12:15 PM CEST, Andy Shevchenko wrote:
> On Mon, Apr 28, 2025 at 01:57:21PM +0200, Mathieu Dubois-Briand wrote:
>> Add driver for Maxim Integrated MAX7360 pinctrl on the PORT pins. Pins
>> can be used either for GPIO, PWM or rotary encoder functionalities.
>
>> +struct max7360_pinctrl {
>> +	struct pinctrl_dev *pctldev;
>> +	struct pinctrl_desc pinctrl_desc;
>
> Does`pahole` agree with your choice of layout?
>

I believe so. `pahole drivers/pinctrl/pinctrl-max7360.ko` says:
struct max7360_pinctrl {
        struct pinctrl_dev *       pctldev;              /*     0     4 */
        struct pinctrl_desc        pinctrl_desc;         /*     4    44 */

        /* XXX last struct has 3 bytes of padding */

        /* size: 48, cachelines: 1, members: 2 */
        /* paddings: 1, sum paddings: 3 */
        /* last cacheline: 48 bytes */
};

>> +	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
>> +	if (!chip)
>> +		return -ENOMEM;
>> +
>> +	pd = &chip->pinctrl_desc;
>> +
>> +	pd->pctlops = &max7360_pinctrl_ops;
>> +	pd->pmxops = &max7360_pmxops;
>> +	pd->name = dev_name(dev);
>> +	pd->pins = max7360_pins;
>> +	pd->npins = MAX7360_MAX_GPIO;
>> +	pd->owner = THIS_MODULE;
>> +
>> +	device_set_of_node_from_dev(dev, dev->parent);
>
> I don't like this, but I have no better idea right now. Perhaps add a comment
> on top to explain this call?
>

I'm adding this comment here, and a similar one in the PWM driver.

/*
 * This MFD sub-device does not have any associated device tree node:
 * properties are stored in the device node of the parent (MFD) device
 * and this same node is used in phandles of client devices.
 * Reuse this device tree node here, as otherwise the pinctrl subsystem
 * would be confused by this topology.
 */

OK for all other comments.

Thanks for your review.
Mathieu

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