[PATCH v3] pinctrl: sunxi: fix gpiochip_lock_as_irq() failure when pinmux is unknown

[Michal Piekos]

Fixes kernel hang during boot due to inability to set up IRQ on AXP313a.

The issue is caused by gpiochip_lock_as_irq() which is failing when gpio
is in unitialized state.

Solution is to set pinmux to GPIO INPUT in
sunxi_pinctrl_irq_request_resources() if it wasn't initialized
earlier.

Tested on Orange Pi Zero 3.

Signed-off-by: Michal Piekos <michal.piekos at mmpsystems.pl>
Suggested-by: Chen-Yu Tsai <wens at kernel.org>
---
Changes in v3:
- Drop v2 solution which was returning input instead of error when pin
  is not initialized.
- Add checking pinmux configuration in
  sunxi_pinctrl_irq_request_resources() and set pin to input if
  uninitialized
- Link to v2: https://lore.kernel.org/r/20260308-rc2-boot-hang-v2-1-516fdb820953@mmpsystems.pl

Changes in v2:
- Dropped the previous faulty solution which was forcing the axp313 to
  use r_pio as interrupt controller as pointed out by Jernej Škrabec.
- Implemented suggestion from Andrey Skvortsov to return default
  direction as input
- Link to v1: https://lore.kernel.org/r/20260308-rc2-boot-hang-v1-0-d792d1a78dfd@mmpsystems.pl
---
 drivers/pinctrl/sunxi/pinctrl-sunxi.c | 13 +++++++++++++
 drivers/pinctrl/sunxi/pinctrl-sunxi.h |  1 +
 2 files changed, 14 insertions(+)

diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
index c990b6118172..7d46f7613672 100644
--- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
+++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
@@ -1089,6 +1089,9 @@ static int sunxi_pinctrl_irq_request_resources(struct irq_data *d)
 {
 	struct sunxi_pinctrl *pctl = irq_data_get_irq_chip_data(d);
 	struct sunxi_desc_function *func;
+	unsigned int offset;
+	u32 reg, shift, mask;
+	u8 muxval;
 	int ret;
 
 	func = sunxi_pinctrl_desc_find_function_by_pin(pctl,
@@ -1096,6 +1099,16 @@ static int sunxi_pinctrl_irq_request_resources(struct irq_data *d)
 	if (!func)
 		return -EINVAL;
 
+	offset = pctl->irq_array[d->hwirq] - pctl->desc->pin_base;
+	sunxi_mux_reg(pctl, offset, &reg, &shift, &mask);
+	muxval = (readl(pctl->membase + reg) & mask) >> shift;
+
+	/* Change muxing to GPIO INPUT mode if at reset value */
+	if (muxval == SUN4I_FUNC_IO_DISABLE) {
+		sunxi_pmx_set(pctl->pctl_dev, pctl->irq_array[d->hwirq],
+			      SUN4I_FUNC_INPUT);
+	}
+
 	ret = gpiochip_lock_as_irq(pctl->chip,
 			pctl->irq_array[d->hwirq] - pctl->desc->pin_base);
 	if (ret) {
diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.h b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
index ad26e4de16a8..22c527fc6ae2 100644
--- a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
+++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
@@ -86,6 +86,7 @@
 
 #define SUN4I_FUNC_INPUT	0
 #define SUN4I_FUNC_IRQ		6
+#define SUN4I_FUNC_IO_DISABLE	7
 
 #define SUNXI_PINCTRL_VARIANT_MASK	GENMASK(7, 0)
 #define SUNXI_PINCTRL_NEW_REG_LAYOUT	BIT(8)

---
base-commit: 4ae12d8bd9a830799db335ee661d6cbc6597f838
change-id: 20260308-rc2-boot-hang-269e8546635b

Best regards,
-- 
Michal Piekos <michal.piekos at mmpsystems.pl>