Re: [PATCH 2/5] drm/exynos: mixer: Use platform_get_irq() to get the interrupt

From: Inki Dae <inki.dae@samsung.com>
To: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Joonyoung Shim <jy0922.shim@samsung.com>,
	Seung-Woo Kim <sw0312.kim@samsung.com>,
	Kyungmin Park <kyungmin.park@samsung.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org,
	linux-samsung-soc@vger.kernel.org
Cc: Rob Herring <robh+dt@kernel.org>,
	linux-kernel@vger.kernel.org,
	Prabhakar <prabhakar.csengg@gmail.com>
Subject: Re: [PATCH 2/5] drm/exynos: mixer: Use platform_get_irq() to get the interrupt
Date: Fri, 14 Jan 2022 20:20:05 +0900	[thread overview]
Message-ID: <a95b74fd-7118-b0fe-26b9-4665c719f1a0@samsung.com> (raw)
In-Reply-To: <20211222190134.24866-3-prabhakar.mahadev-lad.rj@bp.renesas.com>

Hi Lad Prabhakar,

21. 12. 23. 오전 4:01에 Lad Prabhakar 이(가) 쓴 글:
> platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
> allocation of IRQ resources in DT core code, this causes an issue
> when using hierarchical interrupt domains using "interrupts" property
> in the node as this bypassed the hierarchical setup and messed up the
> irq chaining.
> 
> In preparation for removal of static setup of IRQ resource from DT core
> code use platform_get_irq().
> 
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> Hi,
> 
> Ideally I would expect the mixer_resources_init() to be called from probe
> instead from the bind callback. If platform_get_irq() returns -EPROBE_DEFER
> the bind callback will fail :(

If the bind callback failed then probe function of exynos drm driver will call -EPROBE_DEFER like below so it must be no problem :),
--------------------------------------------
in exynos_drm_platform_probe function
    component_master_add_with_match()

in component_master_add_with_match function
    try_to_bring_up_master()

Thanks,
Inki Dae

> 
> Cheers,
> Prabhakar
> ---
>  drivers/gpu/drm/exynos/exynos_mixer.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_mixer.c b/drivers/gpu/drm/exynos/exynos_mixer.c
> index 41c54f1f60bc..e5204be86093 100644
> --- a/drivers/gpu/drm/exynos/exynos_mixer.c
> +++ b/drivers/gpu/drm/exynos/exynos_mixer.c
> @@ -809,19 +809,17 @@ static int mixer_resources_init(struct mixer_context *mixer_ctx)
>  		return -ENXIO;
>  	}
>  
> -	res = platform_get_resource(mixer_ctx->pdev, IORESOURCE_IRQ, 0);
> -	if (res == NULL) {
> -		dev_err(dev, "get interrupt resource failed.\n");
> -		return -ENXIO;
> -	}
> +	ret = platform_get_irq(mixer_ctx->pdev, 0);
> +	if (ret < 0)
> +		return ret;
> +	mixer_ctx->irq = ret;
>  
> -	ret = devm_request_irq(dev, res->start, mixer_irq_handler,
> -						0, "drm_mixer", mixer_ctx);
> +	ret = devm_request_irq(dev, mixer_ctx->irq, mixer_irq_handler,
> +			       0, "drm_mixer", mixer_ctx);
>  	if (ret) {
>  		dev_err(dev, "request interrupt failed.\n");
>  		return ret;
>  	}
> -	mixer_ctx->irq = res->start;
>  
>  	return 0;
>  }
> 