Re: [PATCH v5 03/11] pinctrl: Add MAX7360 pinctrl driver

[Andy Shevchenko]

On Tue, Mar 18, 2025 at 05:26:19PM +0100, 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.

...

> +	help
> +	  Say Y here to enable Pin control support for Maxim MAX7360 keypad

s/Pin/pin/

> +	  controller.
> +	  This keypad controller has 8 GPIO pins that work as GPIO as well as

"...that may work as GPIO, or PWM, or..."

> +	  PWM or rotary encoder alternate modes.

...

+ array_size.h
+ dev_printk.h
+ device/devres.h // currently only in Linux Next
+ err.h

> +#include <linux/init.h>
> +#include <linux/mfd/max7360.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>

> +#include <linux/pinctrl/pinctrl.h>
> +#include <linux/pinctrl/pinconf-generic.h>
> +#include <linux/pinctrl/pinmux.h>

We usually move this group of inclusions...

> +#include <linux/regmap.h>
> +#include <linux/slab.h>

...to somewhere here.

> +#include "core.h"
> +#include "pinmux.h"

...

> +static const struct pingroup max7360_groups[] = {
> +	PINCTRL_PINGROUP("PORT0", port0_pins, ARRAY_SIZE(port0_pins)),
> +	PINCTRL_PINGROUP("PORT1", port1_pins, ARRAY_SIZE(port1_pins)),
> +	PINCTRL_PINGROUP("PORT2", port2_pins, ARRAY_SIZE(port2_pins)),
> +	PINCTRL_PINGROUP("PORT3", port3_pins, ARRAY_SIZE(port3_pins)),
> +	PINCTRL_PINGROUP("PORT4", port4_pins, ARRAY_SIZE(port4_pins)),
> +	PINCTRL_PINGROUP("PORT5", port5_pins, ARRAY_SIZE(port5_pins)),
> +	PINCTRL_PINGROUP("PORT6", port6_pins, ARRAY_SIZE(port6_pins)),
> +	PINCTRL_PINGROUP("PORT7", port7_pins, ARRAY_SIZE(port7_pins)),
> +	PINCTRL_PINGROUP("ROTARY", rotary_pins, ARRAY_SIZE(rotary_pins))

Leave trailing comma. Helps in the future in case of expansion.

> +};

...

> +static const char * const simple_groups[] = {"PORT0", "PORT1", "PORT2", "PORT3",
> +					     "PORT4", "PORT5", "PORT6", "PORT7"};

It's better to read when split as

static const char * const simple_groups[] = {
	"PORT0", "PORT1", "PORT2", "PORT3",
	"PORT4", "PORT5", "PORT6", "PORT7",
};

(also note the trailing comma).

…

> +static const char * const rotary_groups[] = {"ROTARY"};

Add spaces inside {}.

...

> +#define MAX7360_PINCTRL_FN_ROTARY	2
> +static const struct pinfunction max7360_functions[] = {
> +	PINCTRL_PINFUNCTION("gpio", simple_groups, ARRAY_SIZE(simple_groups)),
> +	PINCTRL_PINFUNCTION("pwm", simple_groups, ARRAY_SIZE(simple_groups)),
> +	[MAX7360_PINCTRL_FN_ROTARY] = PINCTRL_PINFUNCTION("rotary", rotary_groups,
> +							  ARRAY_SIZE(rotary_groups)),

Please make them all look the same, if indexed, than add indices to all.

> +};

...

> +static int max7360_set_mux(struct pinctrl_dev *pctldev, unsigned int selector,
> +			   unsigned int group)
> +{
> +	struct regmap *regmap;

> +	int ret = 0;

Variable is not needed, just return directly.

> +	int val;
> +
> +	/*
> +	 * GPIO and PWM functions are the same: we only need to handle the
> +	 * rotary encoder function, on pins 6 and 7.
> +	 */
> +	if (max7360_groups[group].pins[0] >= 6) {
> +		if (selector == MAX7360_PINCTRL_FN_ROTARY)
> +			val = MAX7360_GPIO_CFG_RTR_EN;
> +		else
> +			val = 0;
> +
> +		regmap = dev_get_regmap(pctldev->dev, NULL);
> +		ret = regmap_write_bits(regmap, MAX7360_REG_GPIOCFG, MAX7360_GPIO_CFG_RTR_EN, val);
> +	}
> +
> +	return ret;
> +}

...

> +static int max7360_pinctrl_probe(struct platform_device *pdev)
> +{

With

	struct device *dev = &pdev->dev;

the below will look better.

> +	struct regmap *regmap;
> +	struct pinctrl_desc *pd;
> +	struct max7360_pinctrl *chip;
> +
> +	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
> +	if (!chip)
> +		return -ENOMEM;
> +
> +	regmap = dev_get_regmap(pdev->dev.parent, NULL);
> +	if (!regmap)
> +		dev_err_probe(&pdev->dev, -ENODEV, "Could not get parent regmap\n");

Make it first check, in such a case you don't even need to allocate memory for
peanuts.

> +	pd = &chip->pinctrl_desc;
> +
> +	pd->pctlops = &max7360_pinctrl_ops;
> +	pd->pmxops = &max7360_pmxops;
> +	pd->name = dev_name(&pdev->dev);
> +	pd->pins = max7360_pins;
> +	pd->npins = MAX7360_MAX_GPIO;
> +	pd->owner = THIS_MODULE;
> +
> +	chip->pctldev = devm_pinctrl_register(pdev->dev.parent, pd, chip);
> +	if (IS_ERR(chip->pctldev))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(chip->pctldev),
> +			"can't register controller\n");
> +
> +	return 0;
> +}

-- 
With Best Regards,
Andy Shevchenko