linux-kernel - Re: [PATCH v4 06/10] regmap: irq: Add support for chips without separate IRQ status

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Message-ID: <Z69eue2dV37vw61v@smile.fi.intel.com>
Date: Fri, 14 Feb 2025 17:18:17 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Mathieu Dubois-Briand <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 v4 06/10] regmap: irq: Add support for chips without
 separate IRQ status

On Fri, Feb 14, 2025 at 12:49:56PM +0100, Mathieu Dubois-Briand wrote:
> Some GPIO chips allow to rise an IRQ on GPIO level changes but do not
> provide an IRQ status for each separate line: only the current gpio
> level can be retrieved.
> 
> Add support for these chips, emulating IRQ status by comparing GPIO
> levels with the levels during the previous interrupt.

Thanks, this will help to convert more drivers to regmap
(e.g., gpio-pca953x that seems use similar approach).

...

> +static irqreturn_t regmap_irq_thread(int irq, void *d)
> +{
> +	struct regmap_irq_chip_data *data = d;
> +	const struct regmap_irq_chip *chip = data->chip;
> +	struct regmap *map = data->map;
> +	int ret, i;

	unsigned int i;
?

> +	bool handled = false;
> +	u32 reg;
> +
> +	if (chip->handle_pre_irq)
> +		chip->handle_pre_irq(chip->irq_drv_data);
> +
> +	if (chip->runtime_pm) {
> +		ret = pm_runtime_get_sync(map->dev);
> +		if (ret < 0) {

> +			dev_err(map->dev, "IRQ thread failed to resume: %d\n",
> +				ret);

Can be one line.

> +			goto exit;
> +		}
> +	}
> +
> +	ret = read_irq_data(data);
> +	if (ret < 0)
> +		goto exit;
> +
> +	if (chip->status_is_level) {
> +		for (i = 0; i < data->chip->num_regs; i++) {
> +			unsigned int val = data->status_buf[i];
> +
> +			data->status_buf[i] ^= data->prev_status_buf[i];
> +			data->prev_status_buf[i] = val;
> +		}
> +	}

...

> +		for (i = 0; i < d->chip->num_regs; i++)
> +			d->prev_status_buf[i] = d->status_buf[i];

Hmm... Wouldn't memcpy() suffice?
But okay, this seems to be not a hot path and the intention is clear.

-- 
With Best Regards,
Andy Shevchenko