Re: [PATCH v10 1/3] spi: export of_find_spi_controller_by_node()

[Cezary Rojewski <cezary.rojewski@intel.com>]

On 2025-12-16 8:18 AM, Oder Chiou wrote:
> Some devices are primarily described on another bus (e.g. I2C) but also
> have an additional SPI connection that serves as a transport for
> firmware loading. Export of_find_spi_controller_by_node() so drivers can
> obtain the SPI controller referenced by a DT phandle.

One nitpick below, otherwise looks good.

Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>

> 
> Signed-off-by: Oder Chiou <oder_chiou@realtek.com>
> ---
>   drivers/spi/spi.c       |  3 ++-
>   include/linux/spi/spi.h | 11 +++++++++++
>   2 files changed, 13 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> index e25df9990f82..ecb5281b04a2 100644
> --- a/drivers/spi/spi.c
> +++ b/drivers/spi/spi.c
> @@ -4771,7 +4771,7 @@ static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
>   }
>   
>   /* The spi controllers are not using spi_bus, so we find it with another way */
> -static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
> +struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
>   {
>   	struct device *dev;
>   
> @@ -4784,6 +4784,7 @@ static struct spi_controller *of_find_spi_controller_by_node(struct device_node
>   	/* Reference got in class_find_device */
>   	return container_of(dev, struct spi_controller, dev);
>   }
> +EXPORT_SYMBOL_GPL(of_find_spi_controller_by_node);
>   
>   static int of_spi_notify(struct notifier_block *nb, unsigned long action,
>   			 void *arg)
> diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
> index cb2c2df31089..1eb04a96cc1c 100644
> --- a/include/linux/spi/spi.h
> +++ b/include/linux/spi/spi.h
> @@ -882,6 +882,17 @@ extern int devm_spi_register_controller(struct device *dev,
>   					struct spi_controller *ctlr);
>   extern void spi_unregister_controller(struct spi_controller *ctlr);
>   
> +#if IS_ENABLED(CONFIG_OF_DYNAMIC)
> +extern struct spi_controller *of_find_spi_controller_by_node(
> +	struct device_node *node);
> +#else
> +static inline struct spi_controller *of_find_spi_controller_by_node(
> +	struct device_node *node)

For both declarations, just make them one-liners. Fits the limit, even 
for the inliner case:

static inline struct spi_controller 
*of_find_spi_controller_by_node(struct device_node *node)

> +{
> +	return NULL;
> +}
> +#endif
> +
>   #if IS_ENABLED(CONFIG_ACPI) && IS_ENABLED(CONFIG_SPI_MASTER)
>   extern struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
>   extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,