linux-kernel - Re: [PATCH v6 04/12] pwm: max7360: Add MAX7360 PWM support

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Message-ID: <Z_anx4eiPB9DJ97J@smile.fi.intel.com>
Date: Wed, 9 Apr 2025 20:00:55 +0300
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: mathieu.dubois-briand@...tlin.com
Cc: Lee Jones <lee@...nel.org>, Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Kamel Bouhara <kamel.bouhara@...tlin.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Bartosz Golaszewski <brgl@...ev.pl>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Uwe Kleine-König <ukleinek@...nel.org>,
	Michael Walle <mwalle@...nel.org>, Mark Brown <broonie@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael@...nel.org>,
	Danilo Krummrich <dakr@...nel.org>, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
	linux-input@...r.kernel.org, linux-pwm@...r.kernel.org,
	Grégory Clement <gregory.clement@...tlin.com>,
	Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v6 04/12] pwm: max7360: Add MAX7360 PWM support

On Wed, Apr 09, 2025 at 04:55:51PM +0200, mathieu.dubois-briand@...tlin.com wrote:
> From: Kamel Bouhara <kamel.bouhara@...tlin.com>
> 
> Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to
> 8 independent PWM outputs.

...

> +static void max7360_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> +	struct regmap *regmap;
> +	struct device *dev;
> +
> +	regmap = pwmchip_get_drvdata(chip);
> +	dev = regmap_get_device(regmap);
> +}

This will produce compiler warnings. Why do you have this at all?

...

> +static int max7360_pwm_round_waveform_tohw(struct pwm_chip *chip,
> +					   struct pwm_device *pwm,
> +					   const struct pwm_waveform *wf,
> +					   void *_wfhw)
> +{
> +	struct max7360_pwm_waveform *wfhw = _wfhw;
> +	u64 duty_steps;
> +
> +	/*
> +	 * Ignore user provided values for period_length_ns and duty_offset_ns:
> +	 * we only support fixed period of MAX7360_PWM_PERIOD_NS and offset of 0.
> +	 */
> +	duty_steps = mul_u64_u64_div_u64(wf->duty_length_ns, MAX7360_PWM_MAX_RES,
> +					 MAX7360_PWM_PERIOD_NS);
> +
> +	wfhw->duty_steps = min(MAX7360_PWM_MAX_RES, duty_steps);

> +	wfhw->enabled = (wf->duty_length_ns != 0);

Can be written as

	wfhw->enabled = wf->duty_length_ns;

Or if you want really to be picky about rules,

	wfhw->enabled = !!wf->duty_length_ns;

> +	return 0;
> +}

...

> +static int max7360_pwm_read_waveform(struct pwm_chip *chip,
> +				     struct pwm_device *pwm,
> +				     void *_wfhw)
> +{
> +	struct max7360_pwm_waveform *wfhw = _wfhw;
> +	struct regmap *regmap;
> +	unsigned int val;
> +	int ret;

> +	regmap = pwmchip_get_drvdata(chip);

Why not move this to the definition block above?

	struct regmap *regmap = pwmchip_get_drvdata(chip);


> +	ret = regmap_read(regmap, MAX7360_REG_GPIOCTRL, &val);
> +	if (ret)
> +		return ret;
> +
> +	if (val & BIT(pwm->hwpwm)) {
> +		wfhw->enabled = true;
> +		ret = regmap_read(regmap, MAX7360_REG_PWM(pwm->hwpwm), &val);

		if (ret)
			return ret;

> +		if (!ret)
> +			wfhw->duty_steps = val;
> +	} else {
> +		wfhw->enabled = false;
> +		wfhw->duty_steps = 0;
> +	}
> +
> +	return ret;

	return 0;

> +}

...

> +	device_set_of_node_from_dev(dev, dev->parent);

This needs broader discussion.

-- 
With Best Regards,
Andy Shevchenko