RE: [PATCH 2/2] drm/exynos: Add device tree based discovery support for G2D

[Inki Dae <inki.dae@samsung.com>]

> -----Original Message-----
> From: Sylwester Nawrocki [mailto:sylvester.nawrocki@gmail.com]
> Sent: Thursday, January 31, 2013 5:51 AM
> To: Inki Dae
> Cc: Sachin Kamat; linux-media@vger.kernel.org; dri-
> devel@lists.freedesktop.org; devicetree-discuss@lists.ozlabs.org;
> patches@linaro.org; s.nawrocki@samsung.com
> Subject: Re: [PATCH 2/2] drm/exynos: Add device tree based discovery
> support for G2D
> 
> On 01/30/2013 09:50 AM, Inki Dae wrote:
> >> +static const struct of_device_id exynos_g2d_match[] = {
> >> +       { .compatible = "samsung,g2d-v41" },
> >
> > not only Exynos5 and also Exyno4 has the g2d gpu and drm-based g2d
> > driver shoud support for all Exynos SoCs. How about using
> > "samsung,exynos5-g2d" instead and adding a new property 'version' to
> > identify ip version more surely? With this, we could know which SoC
> > and its g2d ip version. The version property could have '0x14' or
> > others. And please add descriptions to dt document.
> 
> Err no. Are you suggesting using "samsung,exynos5-g2d" compatible string
> for Exynos4 specific IPs ? This would not be correct, and you still can

I assumed the version 'v41' is the ip for Exynos5 SoC. So if this version
means Exynos4 SoC then it should be "samsung,exynos4-g2d".

> match the driver with multiple different revisions of the IP and associate
> any required driver's private data with each corresponding compatible
> property.
> 

Right, and for why I prefer to use version property instead of embedded
version string, you can refer to the my comment I replied already to the
"drm/exynos: Get HDMI version from device tree" email thread.

> Perhaps it would make more sense to include the SoCs name in the
> compatible
> string, e.g. "samsung,exynos-g2d-v41", but appending revision of the IP
> seems acceptable to me. The revisions appear to be well documented and
> it's
> more or less clear which one corresponds to which SoC.
> 
> --
> 
> Thanks,
> Sylwester