Re: [PATCH 1/2] mfd: ucb1x00: register software node for GPIO controller

[Bartosz Golaszewski]

On Tue, 7 Jul 2026 01:08:04 +0200, Dmitry Torokhov
<dmitry.torokhov@xxxxxxxxx> said:
> Define a static software node for the UCB1x00 GPIO controller and attach
> it to the core MFD device in ucb1x00_probe(). This node will also be
> used by the created GPIO chip.
>
> This allows machine subdrivers (such as Assabet evaluation board
> support) to reference the UCB1x00 GPIO controller in property entries
> when converting legacy platform data to software nodes, resolving pin
> bindings directly via the attached firmware node without relying on
> name matching.
>
> Assisted-by: Antigravity:gemini-3.5-flash
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@xxxxxxxxx>
> ---
>  drivers/mfd/ucb1x00-core.c  | 12 ++++++++++++
>  include/linux/mfd/ucb1x00.h |  3 +++
>  2 files changed, 15 insertions(+)
>
> diff --git a/drivers/mfd/ucb1x00-core.c b/drivers/mfd/ucb1x00-core.c
> index 16f64e2b2f77..8d1c34c53955 100644
> --- a/drivers/mfd/ucb1x00-core.c
> +++ b/drivers/mfd/ucb1x00-core.c
> @@ -25,8 +25,13 @@
>  #include <linux/mutex.h>
>  #include <linux/mfd/ucb1x00.h>
>  #include <linux/pm.h>
> +#include <linux/property.h>
>  #include <linux/gpio/driver.h>
>
> +const struct software_node ucb1x00_gpiochip_node = {
> +	.name = "ucb1x00-gpio",
> +};
> +
>  static DEFINE_MUTEX(ucb1x00_mutex);
>  static LIST_HEAD(ucb1x00_drivers);
>  static LIST_HEAD(ucb1x00_devices);
> @@ -530,6 +535,10 @@ static int ucb1x00_probe(struct mcp *mcp)
>  	ucb->id  = id;
>  	ucb->mcp = mcp;
>
> +	ret = device_add_software_node(&ucb->dev, &ucb1x00_gpiochip_node);
> +	if (ret)
> +		goto err_swnode_add;
> +
>  	ret = device_add(&ucb->dev);
>  	if (ret)
>  		goto err_dev_add;
> @@ -604,6 +613,8 @@ static int ucb1x00_probe(struct mcp *mcp)
>   err_no_irq:
>  	device_del(&ucb->dev);
>   err_dev_add:
> +	device_remove_software_node(&ucb->dev);
> + err_swnode_add:
>  	put_device(&ucb->dev);
>   out:
>  	if (pdata && pdata->reset)
> @@ -630,6 +641,7 @@ static void ucb1x00_remove(struct mcp *mcp)
>
>  	irq_set_chained_handler(ucb->irq, NULL);
>  	irq_free_descs(ucb->irq_base, 16);
> +	device_remove_software_node(&ucb->dev);
>  	device_unregister(&ucb->dev);
>
>  	if (pdata && pdata->reset)
> diff --git a/include/linux/mfd/ucb1x00.h b/include/linux/mfd/ucb1x00.h
> index ede237384723..214c71a12e84 100644
> --- a/include/linux/mfd/ucb1x00.h
> +++ b/include/linux/mfd/ucb1x00.h
> @@ -103,6 +103,9 @@
>  #define UCB_MODE_DYN_VFLAG_ENA	(1 << 12)
>  #define UCB_MODE_AUD_OFF_CAN	(1 << 13)
>
> +struct software_node;

Like I commented elsewhere, my preference for forward declarations is to have
them right under the includes but I won't die on that hill.

Bart

> +extern const struct software_node ucb1x00_gpiochip_node;
> +
>  enum ucb1x00_reset {
>  	UCB_RST_PROBE,
>  	UCB_RST_RESUME,
>
> --
> 2.55.0.rc2.803.g1fd1e6609c-goog
>
>