[PATCH v2] pinctrl: renesas: r906g032: handle pin subgroups

[PATCH v2] pinctrl: renesas: r906g032: handle pin subgroups

[Ralph Siemsen]

Add simple recursion support to the .set_state method. This makes it
possible to use subgroups in the device tree, which in turn allows
setting multiple pins with different bias/drive-strength properties.

Fixes: e4aea57fa773 ("pinctrl: renesas: add R906G032 driver")
Signed-off-by: Ralph Siemsen <ralph.siemsen@linaro.org>
---
Changes in v2:
- split out of the series "Renesas RZ/N1 additional drivers"
  https://lore.kernel.org/u-boot/20260731-rzn1-2026-07-v1-1-af2ce80db9d8@linaro.org/
- fix typos in commit message
- use device_foreach_child() to iterate child nodes
- move recursion to top of function, ahead of the early return in the
  case of no direct pinmux entries, instead of removing early return.
- dev_err() in case of failure during recursion
---
 drivers/pinctrl/renesas/pinctrl-rzn1.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/pinctrl/renesas/pinctrl-rzn1.c b/drivers/pinctrl/renesas/pinctrl-rzn1.c
index fdc43c8e714..6c8d40e9639 100644
--- a/drivers/pinctrl/renesas/pinctrl-rzn1.c
+++ b/drivers/pinctrl/renesas/pinctrl-rzn1.c
@@ -298,11 +298,24 @@ static int rzn1_pinconf_set(struct rzn1_pinctrl_priv *priv, unsigned int pin,
 static int rzn1_pinctrl_set_state(struct udevice *dev, struct udevice *config)
 {
 	struct rzn1_pinctrl_priv *priv = dev_get_priv(dev);
+	struct udevice *child;
 	int size;
 	int ret;
 	u32 val;
 	u32 bias;
 
+	/*
+	 * Handle subnodes recursively, so that pin groups work.
+	 * Note that properties are *NOT* inherited from parent.
+	 */
+	device_foreach_child(child, config) {
+		ret = rzn1_pinctrl_set_state(dev, child);
+		if (ret) {
+			dev_err(dev, "failed node '%s'\n", child->name);
+			return ret;
+		}
+	}
+
 	/* Pullup/down bias, common to all pins in group */
 	bias = PIN_CONFIG_BIAS_PULL_UP;
 	if (dev_read_bool(config, "bias-disable"))

---
base-commit: 36c377b9859ffb53eb1e39ea31e8d96d1e0fe1e5
change-id: 20260810-rzn1-2026-10-pinctrl-cf97d3baf307

Best regards,
--  
Ralph Siemsen <ralph.siemsen@linaro.org>

Re: [PATCH v2] pinctrl: renesas: r906g032: handle pin subgroups

[Marek Vasut via U-Boot]

On 8/14/26 8:26 PM, Ralph Siemsen wrote:
> Add simple recursion support to the .set_state method. This makes it
> possible to use subgroups in the device tree, which in turn allows
> setting multiple pins with different bias/drive-strength properties.
> 
> Fixes: e4aea57fa773 ("pinctrl: renesas: add R906G032 driver")
> Signed-off-by: Ralph Siemsen <ralph.siemsen@linaro.org>
> ---
> Changes in v2:
> - split out of the series "Renesas RZ/N1 additional drivers"
>    https://lore.kernel.org/u-boot/20260731-rzn1-2026-07-v1-1-af2ce80db9d8@linaro.org/
> - fix typos in commit message
> - use device_foreach_child() to iterate child nodes
> - move recursion to top of function, ahead of the early return in the
>    case of no direct pinmux entries, instead of removing early return.
> - dev_err() in case of failure during recursion
> ---
>   drivers/pinctrl/renesas/pinctrl-rzn1.c | 13 +++++++++++++
>   1 file changed, 13 insertions(+)
> 
> diff --git a/drivers/pinctrl/renesas/pinctrl-rzn1.c b/drivers/pinctrl/renesas/pinctrl-rzn1.c
> index fdc43c8e714..6c8d40e9639 100644
> --- a/drivers/pinctrl/renesas/pinctrl-rzn1.c
> +++ b/drivers/pinctrl/renesas/pinctrl-rzn1.c
> @@ -298,11 +298,24 @@ static int rzn1_pinconf_set(struct rzn1_pinctrl_priv *priv, unsigned int pin,
>   static int rzn1_pinctrl_set_state(struct udevice *dev, struct udevice *config)
>   {
>   	struct rzn1_pinctrl_priv *priv = dev_get_priv(dev);
> +	struct udevice *child;
>   	int size;
>   	int ret;
>   	u32 val;
>   	u32 bias;
>   
> +	/*
> +	 * Handle subnodes recursively, so that pin groups work.
> +	 * Note that properties are *NOT* inherited from parent.
> +	 */
> +	device_foreach_child(child, config) {
> +		ret = rzn1_pinctrl_set_state(dev, child);
Can there really be infinite nested subgroups , or are there always only 
groups with subgroups and that is where it ends ? Linux 
Documentation/devicetree/bindings/pinctrl/renesas,rzn1-pinctrl.yaml 
makes it look like the later, so maybe the recursion is not necessary 
here, instead call device_foreach_child() { device_foreach_child() { .. 
} } to prevent the possibility of infinite recursion ?

Re: [PATCH v2] pinctrl: renesas: r906g032: handle pin subgroups

[Ralph Siemsen]

On Sat, Aug 15, 2026 at 12:00:23AM +0200, Marek Vasut wrote:
>>diff --git a/drivers/pinctrl/renesas/pinctrl-rzn1.c 
>>b/drivers/pinctrl/renesas/pinctrl-rzn1.c
>>index fdc43c8e714..6c8d40e9639 100644
>>--- a/drivers/pinctrl/renesas/pinctrl-rzn1.c
>>+++ b/drivers/pinctrl/renesas/pinctrl-rzn1.c
>>@@ -298,11 +298,24 @@ static int rzn1_pinconf_set(struct rzn1_pinctrl_priv *priv, unsigned int pin,
>>  static int rzn1_pinctrl_set_state(struct udevice *dev, struct udevice *config)
>>  {
>>  	struct rzn1_pinctrl_priv *priv = dev_get_priv(dev);
>>+	struct udevice *child;
>>  	int size;
>>  	int ret;
>>  	u32 val;
>>  	u32 bias;
>>+	/*
>>+	 * Handle subnodes recursively, so that pin groups work.
>>+	 * Note that properties are *NOT* inherited from parent.
>>+	 */
>>+	device_foreach_child(child, config) {
>>+		ret = rzn1_pinctrl_set_state(dev, child);

>Can there really be infinite nested subgroups , or are there always 
>only groups with subgroups and that is where it ends ? Linux 
>Documentation/devicetree/bindings/pinctrl/renesas,rzn1-pinctrl.yaml 
>makes it look like the later, so maybe the recursion is not necessary 
>here, instead call device_foreach_child() { device_foreach_child() { .. 
>} } to prevent the possibility of infinite recursion ?

Realistically there will only be groups with one level of subgroups.
Perhaps if there was a phandle it could go a few levels deeper.

Unbounded recursion is not really possible here unless:
- the device tree is infinitely deep, or
- there is a very serious bug in device_foreach_child()

As these both seem unlikely, I opted for the simple recursive call, but 
I am happy to change it if you feel it is better.

Ralph

Re: [PATCH v2] pinctrl: renesas: r906g032: handle pin subgroups

[Marek Vasut via U-Boot]

On 8/15/26 3:53 PM, Ralph Siemsen wrote:
> On Sat, Aug 15, 2026 at 12:00:23AM +0200, Marek Vasut wrote:
>>> diff --git a/drivers/pinctrl/renesas/pinctrl-rzn1.c b/drivers/ 
>>> pinctrl/renesas/pinctrl-rzn1.c
>>> index fdc43c8e714..6c8d40e9639 100644
>>> --- a/drivers/pinctrl/renesas/pinctrl-rzn1.c
>>> +++ b/drivers/pinctrl/renesas/pinctrl-rzn1.c
>>> @@ -298,11 +298,24 @@ static int rzn1_pinconf_set(struct 
>>> rzn1_pinctrl_priv *priv, unsigned int pin,
>>>  static int rzn1_pinctrl_set_state(struct udevice *dev, struct 
>>> udevice *config)
>>>  {
>>>      struct rzn1_pinctrl_priv *priv = dev_get_priv(dev);
>>> +    struct udevice *child;
>>>      int size;
>>>      int ret;
>>>      u32 val;
>>>      u32 bias;
>>> +    /*
>>> +     * Handle subnodes recursively, so that pin groups work.
>>> +     * Note that properties are *NOT* inherited from parent.
>>> +     */
>>> +    device_foreach_child(child, config) {
>>> +        ret = rzn1_pinctrl_set_state(dev, child);
> 
>> Can there really be infinite nested subgroups , or are there always 
>> only groups with subgroups and that is where it ends ? Linux 
>> Documentation/devicetree/bindings/pinctrl/renesas,rzn1-pinctrl.yaml 
>> makes it look like the later, so maybe the recursion is not necessary 
>> here, instead call device_foreach_child() { device_foreach_child() 
>> { .. } } to prevent the possibility of infinite recursion ?
> 
> Realistically there will only be groups with one level of subgroups.
> Perhaps if there was a phandle it could go a few levels deeper.
> 
> Unbounded recursion is not really possible here unless:
> - the device tree is infinitely deep, or
> - there is a very serious bug in device_foreach_child()
> 
> As these both seem unlikely, I opted for the simple recursive call, but 
> I am happy to change it if you feel it is better.
Let's go with bounded one-level-deep parsing, that's what the bindings 
describe too.