Re: [PATCH 2/2] pwm: airoha: Add support for EN7581 SoC

[Krzysztof Kozlowski <krzk@kernel.org>]

On 10/08/2024 06:48, Lorenzo Bianconi wrote:
> From: Benjamin Larsson <benjamin.larsson@genexis.eu>
> 
> Introduce driver for PWM module available on EN7581 SoC.
> 
> Signed-off-by: Benjamin Larsson <benjamin.larsson@genexis.eu>
> Co-developed-by: Lorenzo Bianconi <lorenzo@kernel.org>
> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> ---


...

> +
> +static void airoha_pwm_config_flash_map(struct airoha_pwm *pc,
> +					unsigned int hwpwm, int index)
> +{
> +	u32 addr, mask, val;
> +
> +	if (hwpwm < PWM_NUM_GPIO) {
> +		addr = REG_GPIO_FLASH_MAP(hwpwm / 8);
> +	} else {
> +		addr = REG_SIPO_FLASH_MAP(hwpwm / 8);
> +		hwpwm -= PWM_NUM_GPIO;
> +	}
> +
> +	if (index < 0) {
> +		/* Change of waveform takes effect immediately but

This and other comments should be not netdev-style but general Linux style.

> +		 * disabling has some delay so to prevent glitching
> +		 * only the enable bit is touched when disabling
> +		 */
> +		airoha_pwm_flash_clear(pc, addr, GPIO_FLASH_EN(hwpwm % 8));
> +		return;

...


> +
> +static const struct of_device_id airoha_pwm_of_match[] = {
> +	{ .compatible = "airoha,en7581-pwm" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, airoha_pwm_of_match);
> +
> +static struct platform_driver airoha_pwm_driver = {
> +	.driver = {
> +		.name = "airoha-pwm",
> +		.of_match_table = airoha_pwm_of_match,
> +	},
> +	.probe = airoha_pwm_probe,
> +};
> +module_platform_driver(airoha_pwm_driver);
> +
> +MODULE_ALIAS("platform:airoha-pwm");

You should not need MODULE_ALIAS() in normal cases. If you need it,
usually it means your device ID table is wrong (e.g. misses either
entries or MODULE_DEVICE_TABLE()). MODULE_ALIAS() is not a substitute
for incomplete ID table.

Especially that it does not match compatible, so you cannot use excuse
module autoloading does not work for given OF node...


Best regards,
Krzysztof