linux-kernel - Re: [PATCH v5 06/11] gpio: regmap: Allow to allocate regmap-irq device

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Message-Id: <D8K23TCWC5TO.3T1YPKL3G0OY5@kernel.org>
Date: Wed, 19 Mar 2025 08:15:57 +0100
From: "Michael Walle" <mwalle@...nel.org>
To: "Mathieu Dubois-Briand" <mathieu.dubois-briand@...tlin.com>, "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>, "Mark Brown" <broonie@...nel.org>, "Greg
 Kroah-Hartman" <gregkh@...uxfoundation.org>, "Rafael J. Wysocki"
 <rafael@...nel.org>, "Danilo Krummrich" <dakr@...nel.org>
Cc: <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
 <linux-gpio@...r.kernel.org>, <linux-input@...r.kernel.org>,
 <linux-pwm@...r.kernel.org>, <andriy.shevchenko@...el.com>,
 Grégory Clement <gregory.clement@...tlin.com>, "Thomas
 Petazzoni" <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v5 06/11] gpio: regmap: Allow to allocate regmap-irq
 device

Hi,

> GPIO controller often have support for IRQ: allow to easily allocate
> both gpio-regmap and regmap-irq in one operation.
>
> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@...tlin.com>
> ---
>  drivers/gpio/gpio-regmap.c  | 23 +++++++++++++++++++++--
>  include/linux/gpio/regmap.h | 15 +++++++++++++++
>  2 files changed, 36 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c
> index 05f8781b5204..61d5f48b445d 100644
> --- a/drivers/gpio/gpio-regmap.c
> +++ b/drivers/gpio/gpio-regmap.c
> @@ -203,6 +203,7 @@ EXPORT_SYMBOL_GPL(gpio_regmap_get_drvdata);
>   */
>  struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config)
>  {
> +	struct irq_domain *irq_domain;
>  	struct gpio_regmap *gpio;
>  	struct gpio_chip *chip;
>  	int ret;
> @@ -280,8 +281,26 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
>  	if (ret < 0)
>  		goto err_free_gpio;
>  
> -	if (config->irq_domain) {
> -		ret = gpiochip_irqchip_add_domain(chip, config->irq_domain);
> +	irq_domain = config->irq_domain;
> +#ifdef CONFIG_GPIOLIB_IRQCHIP

Why do we need this ifdef?

> +	if (config->regmap_irq_chip) {
> +		struct regmap_irq_chip_data *irq_chip_data;
> +
> +		ret = devm_regmap_add_irq_chip_fwnode(config->parent, dev_fwnode(config->parent),
> +						      config->regmap, config->regmap_irq_irqno,
> +						      config->regmap_irq_flags, 0,
> +						      config->regmap_irq_chip, &irq_chip_data);
> +		if (ret)
> +			goto err_free_gpio;
> +
> +		irq_domain = regmap_irq_get_domain(irq_chip_data);
> +		if (config->regmap_irq_chip_data)
> +			*config->regmap_irq_chip_data = irq_chip_data;

I'm not a fan of misusing the config to return any data. Can we have
a normal gpio_regmap_get_...()? Usually, the config is on the stack
of the caller, what if you need to get irq_chip_data afterwards?
Then your caller has to save it somewhere.

Also, what is the advantage of this? Your caller doesn't have to
call devm_regmap_add_irq_chip_fwnode(), but on the flip side you
have to cram all its parameters in the gpio_regmap config. I'd like
to keep that small and simple (but still extensible!). IMHO just
setting the irq_domain is enough to achieve that.

-michael

> +	}
> +#endif
> +
> +	if (irq_domain) {
> +		ret = gpiochip_irqchip_add_domain(chip, irq_domain);
>  		if (ret)
>  			goto err_remove_gpiochip;
>  	}
> diff --git a/include/linux/gpio/regmap.h b/include/linux/gpio/regmap.h
> index a9f7b7faf57b..55df2527b982 100644
> --- a/include/linux/gpio/regmap.h
> +++ b/include/linux/gpio/regmap.h
> @@ -40,6 +40,14 @@ struct regmap;
>   * @drvdata:		(Optional) Pointer to driver specific data which is
>   *			not used by gpio-remap but is provided "as is" to the
>   *			driver callback(s).
> + * @regmap_irq_chip:	(Optional) Pointer on an regmap_irq_chip structure. If
> + *			set, a regmap-irq device will be created and the IRQ
> + *			domain will be set accordingly.
> + * @regmap_irq_chip_data: (Optional) Pointer on an regmap_irq_chip_data
> + *                      structure pointer. If set, it will be populated with a
> + *                      pointer on allocated regmap_irq data.
> + * @regmap_irq_irqno	(Optional) The IRQ the device uses to signal interrupts.
> + * @regmap_irq_flags	(Optional) The IRQF_ flags to use for the interrupt.
>   *
>   * The ->reg_mask_xlate translates a given base address and GPIO offset to
>   * register and mask pair. The base address is one of the given register
> @@ -78,6 +86,13 @@ struct gpio_regmap_config {
>  	int ngpio_per_reg;
>  	struct irq_domain *irq_domain;
>  
> +#ifdef CONFIG_GPIOLIB_IRQCHIP
> +	struct regmap_irq_chip *regmap_irq_chip;
> +	struct regmap_irq_chip_data **regmap_irq_chip_data;
> +	int regmap_irq_irqno;
> +	unsigned long regmap_irq_flags;
> +#endif
> +
>  	int (*reg_mask_xlate)(struct gpio_regmap *gpio, unsigned int base,
>  			      unsigned int offset, unsigned int *reg,
>  			      unsigned int *mask);