linux-kernel - Re: [PATCH v1 1/3] pwm: dwc: Add 16 channel support for Intel Elkhart Lake

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Date: Sun, 28 Jan 2024 16:53:24 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Raag Jadav <raag.jadav@...el.com>
Cc: u.kleine-koenig@...gutronix.de, jarkko.nikula@...ux.intel.com,
	mika.westerberg@...ux.intel.com, lakshmi.sowjanya.d@...el.com,
	linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/3] pwm: dwc: Add 16 channel support for Intel
 Elkhart Lake

On Mon, Jan 22, 2024 at 08:32:36AM +0530, Raag Jadav wrote:
> Intel Elkhart Lake PSE includes two instances of PWM as a single PCI
> function with 8 channels each. Add support for the remaining channels.

..

> +static int dwc_pwm_init(struct device *dev, const struct dwc_pwm_info *info, void __iomem *base)
> +{
> +	/* Default values for single instance devices */
> +	unsigned int nr = 1, size = 0;
> +	int i, ret;
> +
> +	/* Fill up values from driver_data, if any */
> +	if (info) {
> +		nr = info->nr;
> +		size = info->size;
> +	}
> +
> +	for (i = 0; i < nr; i++) {
> +		struct dwc_pwm *dwc;
> +
> +		dwc = dwc_pwm_alloc(dev);
> +		if (!dwc)
> +			return -ENOMEM;
> +
> +		dwc->base = base + (i * size);
> +
> +		ret = devm_pwmchip_add(dev, &dwc->chip);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}

Why not doing this slightly differently?

First option: Always provide driver data (info is never NULL).

Second option, have the body of the for-loop be factored to a helper
dwc_pwm_init_one() and here

	if (!info)
		return dwc_pwm_init_one(..., 1, 0);

	for (i = 0; i < info->nr; i++) {
		ret = dwc_pwm_init_one(...);
		if (ret)
			return ret;
	}

-- 
With Best Regards,
Andy Shevchenko