Re: [PATCH 02/18] dmaengine: bcm2835: Support common dma-channel-mask

[Frank Li <Frank.li@nxp.com>]

On Fri, May 24, 2024 at 07:26:46PM +0100, Dave Stevenson wrote:
> From: Stefan Wahren <stefan.wahren@i2se.com>
> 
> Nowadays there is a generic property for dma-channel-mask in the DMA
> controller binding. So prefer this one instead of the old vendor specific
> one. Print a warning in case the old one is used. Btw use the result of
> of_property_read_u32() as return code in error case.

Use generic 'dma-channel-mask' property. Print a warning in case the
old brcm,dma-channel-mask is used.

Did you update binding doc?

> 
> Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
> ---
>  drivers/dma/bcm2835-dma.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
> index 9d74fe97452e..528c4593b45a 100644
> --- a/drivers/dma/bcm2835-dma.c
> +++ b/drivers/dma/bcm2835-dma.c
> @@ -941,12 +941,19 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
>  	}
>  
>  	/* Request DMA channel mask from device tree */
> -	if (of_property_read_u32(pdev->dev.of_node,
> -			"brcm,dma-channel-mask",
> -			&chans_available)) {
> -		dev_err(&pdev->dev, "Failed to get channel mask\n");
> -		rc = -EINVAL;
> -		goto err_no_dma;
> +	rc = of_property_read_u32(pdev->dev.of_node, "dma-channel-mask",
> +				  &chans_available);
> +
> +	if (rc) {
> +		/* Try deprecated property */
> +		if (of_property_read_u32(pdev->dev.of_node,
> +					 "brcm,dma-channel-mask",
> +					 &chans_available)) {
> +			dev_err(&pdev->dev, "Failed to get channel mask\n");
> +			goto err_no_dma;
> +		}
> +
> +		dev_warn(&pdev->dev, "brcm,dma-channel-mask deprecated - please update DT\n");
>  	}
>  
>  	/* get irqs for each channel that we support */
> -- 
> 2.34.1
>