dm: pinctrl: introduce PINCONF_RECURSIVE option

In the Linux pinctrl binding, the pin configuration nodes don't need to
be direct children of the pin controller device (may be grandchildren for
example). This behavior is managed with the pinconfig u-class which
recursively bind all the sub-node of the pin controller.

But for some binding (when pin configuration is only children of pin
controller) that is not necessary. U-Boot can save memory and reduce
the number of pinconf instance when this feature is deactivated
(for arch stm32mp for example for SPL).

This patch allows to control this feature with a new option
CONFIG_PINCONF_RECURSIVE when it is possible for each individual
pin controller device.

Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Fixed CONFIG_IF_ENABLED() condition, added __maybe_unused:
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index deee924..6b41f66 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -75,6 +75,22 @@
 	  configuration; you can save memory footprint when this feature is
 	  no needed.
 
+config PINCONF_RECURSIVE
+	bool "Support recursive binding for pin configuration nodes"
+	depends on PINCTRL_FULL
+	default n if ARCH_STM32MP
+	default y
+	help
+	  In the Linux pinctrl binding, the pin configuration nodes need not be
+	  direct children of the pin controller device (may be grandchildren for
+	  example). It is define is each individual pin controller device.
+	  Say Y here if you want to keep this behavior with the pinconfig
+	  u-class: all sub are recursivelly bounded.
+	  If the option is disabled, this behavior is deactivated and only
+	  the direct children of pin controller will be assumed as pin
+	  configuration; you can save memory footprint when this feature is
+	  no needed.
+
 config SPL_PINCTRL
 	bool "Support pin controllers in SPL"
 	depends on SPL && SPL_DM
@@ -129,6 +145,15 @@
 	  This option is an SPL-variant of the PINCONF_RECURSIVE option.
 	  See the help of PINCONF_RECURSIVE for details.
 
+config SPL_PINCONF_RECURSIVE
+	bool "Support recursive binding for pin configuration nodes in SPL"
+	depends on SPL_PINCTRL_FULL
+	default n if ARCH_STM32MP
+	default y
+	help
+	  This option is an SPL-variant of the PINCONF_RECURSIVE option.
+	  See the help of PINCONF_RECURSIVE for details.
+
 if PINCTRL || SPL_PINCTRL
 
 config PINCTRL_AR933X
diff --git a/drivers/pinctrl/pinctrl-uclass.c b/drivers/pinctrl/pinctrl-uclass.c
index a2da63f..0b1eb7f 100644
--- a/drivers/pinctrl/pinctrl-uclass.c
+++ b/drivers/pinctrl/pinctrl-uclass.c
@@ -403,7 +403,7 @@
  * @dev: pinctrl device
  * @return: 0 on success, or negative error code on failure
  */
-static int pinctrl_post_bind(struct udevice *dev)
+static int __maybe_unused pinctrl_post_bind(struct udevice *dev)
 {
 	const struct pinctrl_ops *ops = pinctrl_get_ops(dev);
 
@@ -426,7 +426,9 @@
 
 UCLASS_DRIVER(pinctrl) = {
 	.id = UCLASS_PINCTRL,
+#if CONFIG_IS_ENABLED(PINCONF_RECURSIVE)
 	.post_bind = pinctrl_post_bind,
+#endif
 	.flags = DM_UC_FLAG_SEQ_ALIAS,
 	.name = "pinctrl",
 };