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

Frank Li
2024-06-05T15:52:27Z

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
>