Allows to populate the gpio_regmap_config structure with request() and
free() callbacks to set on the final gpio_chip structure.

Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
---
 drivers/gpio/gpio-regmap.c  | 2 ++
 include/linux/gpio/regmap.h | 7 +++++++
 2 files changed, 9 insertions(+)

diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c
index 05f8781b5204..ba72c23bcf97 100644
--- a/drivers/gpio/gpio-regmap.c
+++ b/drivers/gpio/gpio-regmap.c
@@ -261,6 +261,8 @@ struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config
 	chip->names = config->names;
 	chip->label = config->label ?: dev_name(config->parent);
 	chip->can_sleep = regmap_might_sleep(config->regmap);
+	chip->request = config->request;
+	chip->free = config->free;
 
 	chip->request = gpiochip_generic_request;
 	chip->free = gpiochip_generic_free;
diff --git a/include/linux/gpio/regmap.h b/include/linux/gpio/regmap.h
index a9f7b7faf57b..16f0c33df75d 100644
--- a/include/linux/gpio/regmap.h
+++ b/include/linux/gpio/regmap.h
@@ -6,6 +6,7 @@
 struct device;
 struct fwnode_handle;
 struct gpio_regmap;
+struct gpio_chip;
 struct irq_domain;
 struct regmap;
 
@@ -40,6 +41,10 @@ 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).
+ * @request:		(Optional) Hook for chip-specific activation, such as
+ *			enabling module power and clock
+ * @free:		(Optional) Hook for chip-specific deactivation, such as
+ *			disabling module power and clock
  *
  * 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
@@ -83,6 +88,8 @@ struct gpio_regmap_config {
 			      unsigned int *mask);
 
 	void *drvdata;
+	int (*request)(struct gpio_chip *gc, unsigned int offset);
+	void (*free)(struct gpio_chip *gc, unsigned int offset);
 };
 
 struct gpio_regmap *gpio_regmap_register(const struct gpio_regmap_config *config);

-- 
2.39.5

Hi Mathieu,

On Fri, 2025-02-14 at 12:49 +0100, Mathieu Dubois-Briand wrote:
> Allows to populate the gpio_regmap_config structure with request() and
> free() callbacks to set on the final gpio_chip structure.
> 
> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
> ---
>  drivers/gpio/gpio-regmap.c  | 2 ++
>  include/linux/gpio/regmap.h | 7 +++++++
>  2 files changed, 9 insertions(+)
> 
> diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c
> index 05f8781b5204..ba72c23bcf97 100644
> --- a/drivers/gpio/gpio-regmap.c
> +++ b/drivers/gpio/gpio-regmap.c
> @@ -261,6 +261,8 @@ struct gpio_regmap *gpio_regmap_register(const struct
> gpio_regmap_config *config
>  	chip->names = config->names;
>  	chip->label = config->label ?: dev_name(config->parent);
>  	chip->can_sleep = regmap_might_sleep(config->regmap);
> +	chip->request = config->request;
> +	chip->free = config->free;
>  
>  	chip->request = gpiochip_generic_request;
>  	chip->free = gpiochip_generic_free;

You probably have a bad rebase here, as the chip->{request,free} functions are immediately
overwritten by gpiochip_generic_{request,free}. Perhaps those can actually be used if you
provide a pinctrl driver for the MFD.


Best,
Sander

On Sun Feb 16, 2025 at 2:17 PM CET, Sander Vanheule wrote:
> Hi Mathieu,
>
> On Fri, 2025-02-14 at 12:49 +0100, Mathieu Dubois-Briand wrote:
> > Allows to populate the gpio_regmap_config structure with request() and
> > free() callbacks to set on the final gpio_chip structure.
> > 
> > Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
> > ---
> >  drivers/gpio/gpio-regmap.c  | 2 ++
> >  include/linux/gpio/regmap.h | 7 +++++++
> >  2 files changed, 9 insertions(+)
> > 
> > diff --git a/drivers/gpio/gpio-regmap.c b/drivers/gpio/gpio-regmap.c
> > index 05f8781b5204..ba72c23bcf97 100644
> > --- a/drivers/gpio/gpio-regmap.c
> > +++ b/drivers/gpio/gpio-regmap.c
> > @@ -261,6 +261,8 @@ struct gpio_regmap *gpio_regmap_register(const struct
> > gpio_regmap_config *config
> >  	chip->names = config->names;
> >  	chip->label = config->label ?: dev_name(config->parent);
> >  	chip->can_sleep = regmap_might_sleep(config->regmap);
> > +	chip->request = config->request;
> > +	chip->free = config->free;
> >  
> >  	chip->request = gpiochip_generic_request;
> >  	chip->free = gpiochip_generic_free;
>
> You probably have a bad rebase here, as the chip->{request,free} functions are immediately
> overwritten by gpiochip_generic_{request,free}. Perhaps those can actually be used if you
> provide a pinctrl driver for the MFD.
>

Thanks, indeed I missed this rebase issue. It's fixed now.

-- 
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

On Fri, Feb 14, 2025 at 12:49:54PM +0100, Mathieu Dubois-Briand wrote:
> Allows to populate the gpio_regmap_config structure with request() and
> free() callbacks to set on the final gpio_chip structure.

Yeah, I understand the intention, but I have mixed feelings about this.
OOH it helps with the cases like yours, OTO it sounds like a hack instead
of proper implementation of the pin muxing. Yes, I know there are some
drivers in the kernel do similar things, but it most likely historically
and not always having the same HW capabilities as this chip.

-- 
With Best Regards,
Andy Shevchenko