Re: [PATCH 2/5] drivers: spi: spidev: add compatible for arduino spi mcu interface

[Krzysztof Kozlowski <krzk@kernel.org>]

On 06/11/2025 16:31, Riccardo Mereu wrote:
> Add compatible entry in spidev describing in Arduino boards one of the
> interfaces between microprocessor and  microcontroller.
> 
> Signed-off-by: Riccardo Mereu <r.mereu@arduino.cc>


Please use subject prefixes matching the subsystem. You can get them for
example with `git log --oneline -- DIRECTORY_OR_FILE` on the directory
your patch is touching. For bindings, the preferred subjects are
explained here:
https://www.kernel.org/doc/html/latest/devicetree/bindings/submitting-patches.html#i-for-patch-submitters

It is almost never "drivers" (with one or two exceptions).

> ---
>  drivers/spi/spidev.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
> index 5300c942a2a4..f0dd516c2083 100644
> --- a/drivers/spi/spidev.c
> +++ b/drivers/spi/spidev.c
> @@ -704,6 +704,7 @@ static const struct class spidev_class = {
>   */
>  static const struct spi_device_id spidev_spi_ids[] = {
>  	{ .name = /* abb */ "spi-sensor" },
> +	{ .name = /* arduino */ "mcu" },
>  	{ .name = /* cisco */ "spi-petra" },
>  	{ .name = /* dh */ "dhcom-board" },
>  	{ .name = /* elgin */ "jg10309-01" },
> @@ -737,6 +738,7 @@ static int spidev_of_check(struct device *dev)
>  
>  static const struct of_device_id spidev_dt_ids[] = {
>  	{ .compatible = "abb,spi-sensor", .data = &spidev_of_check },
> +	{ .compatible = "arduino,mcu", .data = &spidev_of_check },

That's way too generic, IMO. First, I am not aware of Arduino boards
mounted on top of regular development boards, so basically you are not
describing actual hardware setup but what could be potentially plugged
into box with Linux... and then it is like saying "you can plug
anything" because MCU covers everything, like calling it "Raspberry
Pi-clone".

Best regards,
Krzysztof