[PATCH] gpio: sa1100: defer GPIO chip registration to postcore_initcall

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

Registering the software node and the GPIO chip for the SA-1100 GPIO
controller during early IRQ initialization causes boot hangs on
SA-1100 platforms because the software node subsystem has not yet
been initialized. At that early boot stage, attempting to register
software nodes dereferences a NULL kset pointer before console or
driver model initialization.

Nothing on SA-1100 platforms requests GPIO lines via gpiolib during
early boot before initcalls run; only the GPIO IRQ controller and
domain must be initialized during init_IRQ(). Defer registering the
software node, assigning its firmware node, and registering the GPIO
chip with gpiolib to postcore_initcall, running after driver and
gpiolib device initialization and before board consumers register.

Fixes: e4671f292ebb ("gpio: sa1100: register software node for GPIO controller")
Cc: stable@vger.kernel.org
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/r/2a561a27-a3bf-4cac-a4dc-bfbc5c859f45@roeck-us.net
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/gpio/gpio-sa1100.c | 32 +++++++++++++++++++++++++++-----
 1 file changed, 27 insertions(+), 5 deletions(-)

diff --git a/drivers/gpio/gpio-sa1100.c b/drivers/gpio/gpio-sa1100.c
index e4f3bf949b87..1916200ebbd5 100644
--- a/drivers/gpio/gpio-sa1100.c
+++ b/drivers/gpio/gpio-sa1100.c
@@ -8,6 +8,7 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/io.h>
+#include <linux/printk.h>
 #include <linux/syscore_ops.h>
 #include <soc/sa1100/pwer.h>
 #include <mach/hardware.h>
@@ -322,7 +323,6 @@ static const int sa1100_gpio_irqs[] __initconst = {
 void __init sa1100_init_gpio(void)
 {
 	struct sa1100_gpio_chip *sgc = &sa1100_gpio_chip;
-	struct gpio_chip *gc = &sgc->chip;
 	int i;
 
 	/* clear all GPIO edge detects */
@@ -330,10 +330,6 @@ void __init sa1100_init_gpio(void)
 	writel_relaxed(0, sgc->membase + R_GRER);
 	writel_relaxed(-1, sgc->membase + R_GEDR);
 
-	software_node_register(&sa1100_gpiochip_node);
-	gc->fwnode = software_node_fwnode(&sa1100_gpiochip_node);
-	gpiochip_add_data(gc, NULL);
-
 	sa1100_gpio_irqdomain = irq_domain_create_simple(NULL,
 			28, IRQ_GPIO0,
 			&sa1100_gpio_irqdomain_ops, sgc);
@@ -342,3 +338,29 @@ void __init sa1100_init_gpio(void)
 		irq_set_chained_handler_and_data(sa1100_gpio_irqs[i],
 						 sa1100_gpio_handler, sgc);
 }
+
+static int __init sa1100_gpio_init_chip(void)
+{
+	struct gpio_chip *gc = &sa1100_gpio_chip.chip;
+	int error;
+
+	error = software_node_register(&sa1100_gpiochip_node);
+	if (error) {
+		pr_err("failed to register sa1100 gpiochip software node: %d\n",
+		       error);
+		return error;
+	}
+
+	gc->fwnode = software_node_fwnode(&sa1100_gpiochip_node);
+
+	error = gpiochip_add_data(gc, NULL);
+	if (error) {
+		pr_err("failed to add sa1100 gpiochip: %d\n", error);
+		gc->fwnode = NULL;
+		software_node_unregister(&sa1100_gpiochip_node);
+		return error;
+	}
+
+	return 0;
+}
+postcore_initcall(sa1100_gpio_init_chip);

---
base-commit: 6d0933ae9d46674a6ea63a87e9e9ab4e662670c9
change-id: 20261029-sa1100-swnode-fix-11499713eb7a

Thanks.

-- 
Dmitry