Re: [net-next v5 1/3] net: ethernet: mtk_eth_soc: support named IRQs

[Daniel Golle <daniel@makrotopia.org>]

On Wed, Jun 18, 2025 at 03:07:12PM +0200, Frank Wunderlich wrote:
> From: Frank Wunderlich <frank-w@public-files.de>
> 
> Add named interrupts and keep index based fallback for existing
> devicetrees.
> 
> Currently only rx and tx IRQs are defined to be used with mt7988, but
> later extended with RSS/LRO support.
> 
> Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
> Reviewed-by: Simon Horman <horms@kernel.org>
>  
> +static int mtk_get_irqs(struct platform_device *pdev, struct mtk_eth *eth)
> +{
> +	int i;
> +
> +	/* future SoCs beginning with MT7988 should use named IRQs in dts */
> +	eth->irq[1] = platform_get_irq_byname(pdev, "tx");
> +	eth->irq[2] = platform_get_irq_byname(pdev, "rx");
> +	if (eth->irq[1] >= 0 && eth->irq[2] >= 0)
> +		return 0;

I'd rather extend that logic and fall back to the legacy way only in case
of -ENXIO. Ie. add here:

if (eth->irq[1] != -ENXIO)
	return eth->irq[1];

if (eth->irq[2] != -ENXIO)
	return eth->irq[2];

Maybe also output a warning at this point in case MTK_SHARED_INT is no
set, to recommend users to update their device tree to named interrupts.

> +
> +	/* legacy way:
> +	 * On MTK_SHARED_INT SoCs (MT7621 + MT7628) the first IRQ is taken
> +	 * from devicetree and used for both RX and TX - it is shared.
> +	 * On SoCs with non-shared IRQs the first entry is not used,
> +	 * the second is for TX, and the third is for RX.
> +	 */
> +	for (i = 0; i < 3; i++) {
> +		if (MTK_HAS_CAPS(eth->soc->caps, MTK_SHARED_INT) && i > 0)
> +			eth->irq[i] = eth->irq[0];
> +		else
> +			eth->irq[i] = platform_get_irq(pdev, i);
> +
> +		if (eth->irq[i] < 0) {
> +			dev_err(&pdev->dev, "no IRQ%d resource found\n", i);
> +			return -ENXIO;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static irqreturn_t mtk_handle_irq_rx(int irq, void *_eth)
>  {
>  	struct mtk_eth *eth = _eth;
> @@ -5106,17 +5137,10 @@ static int mtk_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> -	for (i = 0; i < 3; i++) {
> -		if (MTK_HAS_CAPS(eth->soc->caps, MTK_SHARED_INT) && i > 0)
> -			eth->irq[i] = eth->irq[0];
> -		else
> -			eth->irq[i] = platform_get_irq(pdev, i);
> -		if (eth->irq[i] < 0) {
> -			dev_err(&pdev->dev, "no IRQ%d resource found\n", i);
> -			err = -ENXIO;
> -			goto err_wed_exit;
> -		}
> -	}
> +	err = mtk_get_irqs(pdev, eth);
> +	if (err)
> +		goto err_wed_exit;
> +
>  	for (i = 0; i < ARRAY_SIZE(eth->clks); i++) {
>  		eth->clks[i] = devm_clk_get(eth->dev,
>  					    mtk_clks_source_name[i]);
> -- 
> 2.43.0
> 
>