gpio: regmap: Allow to provide init_valid_mask callback

Allows to populate the gpio_regmap_config structure with
init_valid_mask() callback to set on the final gpio_chip structure.

Reviewed-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Link: https://lore.kernel.org/r/20250824-mdb-max7360-support-v14-6-435cfda2b1ea@bootlin.com
Signed-off-by: Lee Jones <lee@kernel.org>

Author: mbriand

drivers/gpio/gpio-regmap.c

@@ -261,6 +261,7 @@ 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->init_valid_mask = config->init_valid_mask;
 
 	chip->request = gpiochip_generic_request;
 	chip->free = gpiochip_generic_free;

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 +41,8 @@ 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).
+ * @init_valid_mask:	(Optional) Routine to initialize @valid_mask, to be used
+ *			if not all GPIOs are valid.
  * @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.
@@ -93,6 +96,10 @@ struct gpio_regmap_config {
 			      unsigned int offset, unsigned int *reg,
 			      unsigned int *mask);
 
+	int (*init_valid_mask)(struct gpio_chip *gc,
+			       unsigned long *valid_mask,
+			       unsigned int ngpios);
+
 	void *drvdata;
 };