Re: [PATCH v6 09/12] gpio: max7360: Add MAX7360 gpio support

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Wed, Apr 09, 2025 at 04:55:56PM +0200, Mathieu Dubois-Briand wrote:
> 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.

...

> +#include <linux/bitfield.h>
> +#include <linux/bitmap.h>
> +#include <linux/err.h>
> +#include <linux/gpio/driver.h>
> +#include <linux/gpio/regmap.h>
> +#include <linux/init.h>
> +#include <linux/interrupt.h>
> +#include <linux/mfd/max7360.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/property.h>
> +#include <linux/regmap.h>

> +#include <linux/slab.h>

I don't think you use this header directly.

...

> +static int max7360_gpio_probe(struct platform_device *pdev)
> +{
> +	struct regmap_irq_chip *irq_chip;
> +	struct gpio_regmap_config gpio_config = { };
> +	struct device *dev = &pdev->dev;
> +	unsigned long gpio_function;
> +	struct regmap *regmap;
> +	unsigned int outconf;
> +	int ret;
> +
> +	regmap = dev_get_regmap(dev->parent, NULL);
> +	if (!regmap)
> +		return dev_err_probe(dev, -ENODEV, "could not get parent regmap\n");

> +	gpio_function = (uintptr_t)device_get_match_data(dev);

Somebody pointed me out the Linus' rant on uintptr_t, so he prefers not to see
this in the entire kernel. He suggested to use (unsigned long), but ideally one
should operate with the info structures instead.

...

> +	if (gpio_function == MAX7360_GPIO_PORT) {
> +		if (device_property_read_bool(dev, "interrupt-controller")) {
> +			/*
> +			 * Port GPIOs with interrupt-controller property: add IRQ
> +			 * controller.
> +			 */
> +			gpio_config.regmap_irq_flags = IRQF_ONESHOT | IRQF_SHARED;
> +			gpio_config.regmap_irq_irqno =
> +				fwnode_irq_get_byname(dev_fwnode(dev->parent), "inti");
> +			if (gpio_config.regmap_irq_irqno < 0)
> +				return dev_err_probe(dev, gpio_config.regmap_irq_irqno,
> +						     "Failed to get IRQ\n");
> +
> +			irq_chip = devm_kzalloc(dev, sizeof(*irq_chip), GFP_KERNEL);
> +			gpio_config.regmap_irq_chip = irq_chip;
> +			if (!irq_chip)
> +				return -ENOMEM;
> +
> +			irq_chip->name = dev_name(dev);
> +			irq_chip->status_base = MAX7360_REG_GPIOIN;
> +			irq_chip->status_is_level = true;
> +			irq_chip->num_regs = 1;
> +			irq_chip->num_irqs = MAX7360_MAX_GPIO;
> +			irq_chip->irqs = max7360_regmap_irqs;
> +			irq_chip->handle_mask_sync = max7360_handle_mask_sync;
> +			irq_chip->irq_drv_data = regmap;
> +
> +			for (unsigned int i = 0; i < MAX7360_MAX_GPIO; i++) {
> +				ret = regmap_write_bits(regmap, MAX7360_REG_PWMCFG(i),
> +							MAX7360_PORT_CFG_INTERRUPT_EDGES,
> +							MAX7360_PORT_CFG_INTERRUPT_EDGES);
> +				if (ret)
> +					return dev_err_probe(dev, ret,
> +							     "Failed to enable interrupts\n");
> +			}
> +		}
> +
> +		/*
> +		 * Port GPIOs: set output mode configuration (constant-current or not).
> +		 * This property is optional.
> +		 */
> +		outconf = 0;
> +		ret = device_property_read_u32(dev, "maxim,constant-current-disable", &outconf);
> +		if (!ret) {
> +			ret = regmap_write(regmap, MAX7360_REG_GPIOOUTM, outconf);
> +			if (ret)
> +				return dev_err_probe(dev, ret,
> +						     "Failed to set constant-current configuration\n");
> +		}

This will look better as if-else:

		ret = device_property_read_u32(dev, "maxim,constant-current-disable", &outconf);
		if (ret) {
			outconf = 0;
		} else {
			ret = regmap_write(regmap, MAX7360_REG_GPIOOUTM, outconf);
			if (ret)
				return dev_err_probe(dev, ret,
						     "Failed to set constant-current configuration\n");
		}

> +	}
> +
> +	/* Add gpio device. */
> +	gpio_config.parent = dev;
> +	gpio_config.regmap = regmap;
> +	if (gpio_function == MAX7360_GPIO_PORT) {
> +		gpio_config.ngpio = MAX7360_MAX_GPIO;
> +		gpio_config.reg_dat_base = GPIO_REGMAP_ADDR(MAX7360_REG_GPIOIN);
> +		gpio_config.reg_set_base = GPIO_REGMAP_ADDR(MAX7360_REG_PWMBASE);
> +		gpio_config.reg_dir_out_base = GPIO_REGMAP_ADDR(MAX7360_REG_GPIOCTRL);
> +		gpio_config.ngpio_per_reg = MAX7360_MAX_GPIO;
> +		gpio_config.reg_mask_xlate = max7360_gpio_reg_mask_xlate;
> +	} else {
> +		ret = max7360_set_gpos_count(dev, regmap);
> +		if (ret)
> +			return dev_err_probe(dev, ret, "Failed to set GPOS pin count\n");
> +
> +		gpio_config.reg_set_base = GPIO_REGMAP_ADDR(MAX7360_REG_PORTS);
> +		gpio_config.ngpio = MAX7360_MAX_KEY_COLS;
> +		gpio_config.init_valid_mask = max7360_gpo_init_valid_mask;
> +	}
> +
> +	return PTR_ERR_OR_ZERO(devm_gpio_regmap_register(dev, &gpio_config));
> +}

-- 
With Best Regards,
Andy Shevchenko