Re: [PATCH v5 2/2] pinctrl: sunxi: fix gpiochip_lock_as_irq() failure when pinmux is unknown

[Andre Przywara <andre.przywara@arm.com>]

Hi Michal,

On 3/19/26 18:19, Michal Piekos wrote:
> 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 uninitialized 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.
> 
> Fixes: 01e10d0272b9 ("pinctrl: sunxi: Implement gpiochip::get_direction()")
> Signed-off-by: Michal Piekos <michal.piekos@mmpsystems.pl>
> ---
>   drivers/pinctrl/sunxi/pinctrl-sunxi.c | 21 +++++++++++++++++++--
>   drivers/pinctrl/sunxi/pinctrl-sunxi.h |  2 ++
>   2 files changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.c b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> index 685b79fc0bf8..e3aa2b70aa7d 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.c
> @@ -1092,15 +1092,32 @@ 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;
> +	u8 disabled_mux;

Iff you are going to respin, maybe use the inverted Christmas tree 
style, and group the u8 variables.

>   
>   	func = sunxi_pinctrl_desc_find_function_by_pin(pctl,
>   					pctl->irq_array[d->hwirq], "irq");
>   	if (!func)
>   		return -EINVAL;
>   
> -	ret = gpiochip_lock_as_irq(pctl->chip,
> -			pctl->irq_array[d->hwirq] - pctl->desc->pin_base);
> +	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 (pctl->flags & SUNXI_PINCTRL_NEW_REG_LAYOUT)
> +		disabled_mux = SUN4I_FUNC_DISABLED_NEW;
> +	else
> +		disabled_mux = SUN4I_FUNC_DISABLED_OLD;
> +	
> +	if (muxval == disabled_mux)

There is whitespace damage in three of the four lines above.
Maybe this can be fixed up while applying?

The patch still feels a bit arbitrary, and looking at the definition of 
SUN4I_FUNC_IRQ below we probably need another rework, but if that fixes 
the issues observed, we should take it now:

(with the w/s damage fixed:)
Reviewed-by: Andre Przywara <andre.przywara@arm.com>

Cheers,
Andre

> +		sunxi_pmx_set(pctl->pctl_dev, pctl->irq_array[d->hwirq],
> +			      SUN4I_FUNC_INPUT);
> +
> +	ret = gpiochip_lock_as_irq(pctl->chip, offset);
>   	if (ret) {
>   		dev_err(pctl->dev, "unable to lock HW IRQ %lu for IRQ\n",
>   			irqd_to_hwirq(d));
> diff --git a/drivers/pinctrl/sunxi/pinctrl-sunxi.h b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> index 22bffac1c3f0..0daf7600e2fb 100644
> --- a/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> +++ b/drivers/pinctrl/sunxi/pinctrl-sunxi.h
> @@ -86,6 +86,8 @@
>   
>   #define SUN4I_FUNC_INPUT	0
>   #define SUN4I_FUNC_IRQ		6
> +#define SUN4I_FUNC_DISABLED_OLD 7
> +#define SUN4I_FUNC_DISABLED_NEW 15
>   
>   #define SUNXI_PINCTRL_VARIANT_MASK	GENMASK(7, 0)
>   #define SUNXI_PINCTRL_NEW_REG_LAYOUT	BIT(8)
>