Re: [PATCH v4 3/4] dmaengine: mediatek-cqdma: fix compatible

[Matthias Brugger]

On 28/05/2020 11:57, EastL wrote:
> This patch fixes mediatek-cqdma compatible to common.
> 
> Signed-off-by: EastL <EastL.Lee@xxxxxxxxxxxx>
> ---
>  drivers/dma/mediatek/mtk-cqdma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/dma/mediatek/mtk-cqdma.c b/drivers/dma/mediatek/mtk-cqdma.c
> index 905bbcb..bca7118 100644
> --- a/drivers/dma/mediatek/mtk-cqdma.c
> +++ b/drivers/dma/mediatek/mtk-cqdma.c
> @@ -544,7 +544,7 @@ static void mtk_cqdma_hw_deinit(struct mtk_cqdma_device *cqdma)
>  }
>  
>  static const struct of_device_id mtk_cqdma_match[] = {
> -	{ .compatible = "mediatek,mt6765-cqdma" },
> +	{ .compatible = "mediatek,cqdma" },

We can't just delete and old compatible. If other cqdma IP blocks are the same
as mt6795, we should instead add entries in the binding description with
fallback compatible. For example for mt6779 the DTS would look like this:
compatible = "mediatek,mt6779-cqdma", "mediatek,mt6765-cqdma";

This way we the kernel will take care to bind the device against the driver with
mt7665-cqdma, but leaves us the posibillity to add any changes to the driver in
the future if we find some bugs/features for mt6779 that are not present in mt6765.

Regards,
Matthias

>  	{ /* sentinel */ }
>  };
>  MODULE_DEVICE_TABLE(of, mtk_cqdma_match);
>