Re: [PATCH v12 1/3] drm: rockchip: Add basic drm driver

From: Daniel Vetter <daniel@ffwll.ch>
To: Mark Yao <mark.yao@rock-chips.com>
Cc: heiko@sntech.de,
	Boris BREZILLON <boris.brezillon@free-electrons.com>,
	David Airlie <airlied@gmail.com>, Rob Clark <robdclark@gmail.com>,
	Daniel Vetter <daniel@ffwll.ch>, Rob Herring <robh+dt@kernel.org>,
	Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	Randy Dunlap <rdunlap@infradead.org>,
	Grant Likely <grant.likely@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	John Stultz <john.stultz@linaro.org>,
	Rom Lemarchand <romlem@google.com>,
	devicetree@vger.kernel.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-api@vger.kernel.org, linux-rockchip@lists.infradead.org,
	dianders@chromium.org, marcheu@chromium.org, dbehr@chromium.org,
	olof@lixom.net, djkurtz@chromium.org, cf@rock-chips.com,
	xxm@rock-chips.com, huangtao@rock-chips.com,
	kever.yang@rock-chips.com, yxj@rock-chips.com, xw@rock-chips.com
Subject: Re: [PATCH v12 1/3] drm: rockchip: Add basic drm driver
Date: Tue, 18 Nov 2014 09:32:34 +0100	[thread overview]
Message-ID: <20141118083234.GZ25711@phenom.ffwll.local> (raw)
In-Reply-To: <1416297629-19024-1-git-send-email-mark.yao@rock-chips.com>

On Tue, Nov 18, 2014 at 04:00:29PM +0800, Mark Yao wrote:
> From: Mark yao <mark.yao@rock-chips.com>
> 
> This patch adds the basic structure of a DRM Driver for Rockchip Socs.
> 
> Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
> Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
> Acked-by: Daniel Vetter <daniel@ffwll.ch>
> Reviewed-by: Rob Clark <robdclark@gmail.com>
> ---
> Changes in v2:
> - use the component framework to defer main drm driver probe
>   until all VOP devices have been probed.
> - use dma-mapping API with ARM_DMA_USE_IOMMU, create dma mapping by
>   master device and each vop device can shared the drm dma mapping.
> - use drm_crtc_init_with_planes and drm_universal_plane_init.
> - remove unnecessary middle layers.
> - add cursor set, move funcs to rockchip drm crtc.
> - use vop reset at first init
> - reference framebuffer when used and unreference when swap out vop
> 
> Changes in v3:
> - change "crtc->fb" to "crtc->primary-fb"
> Adviced by Daniel Vetter
> - init cursor plane with universal api, remove unnecessary cursor set,move 
> 
> Changes in v4:
> Adviced by David Herrmann
> - remove drm_platform_*() usage, use register drm device directly.

Minor fixup for that part below.

[snip]

> +static int rockchip_drm_bind(struct device *dev)
> +{
> +	struct drm_device *drm;
> +	int ret;
> +
> +	drm = drm_dev_alloc(&rockchip_drm_driver, dev);
> +	if (!drm)
> +		return -ENOMEM;
> +
> +	ret = drm_dev_set_unique(drm, "%s", dev_name(dev));
> +	if (ret)
> +		goto err_free;

Please call rockchip_drm_load here directly and don't put it as the ->load
function into the driver vtable. The point of the alloc/register split is
that the driver can be completely set up _before_ we register anything.
But for backwards compat and historical reasons ->load is called somewhere
in the middle (so that you could access the minor nodes if needed, since
some drivers do that).

Cheers, Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch