Re: [PATCH 1/1] ARM: imx: make the imx timer driver implementation independent of SoCs.

[Baruch Siach <baruch-NswTu9S1W3P6gbPvEgmw2w@public.gmane.org>]

Hi Shenwei Wang,
On Wed, Apr 29, 2015 at 03:19:19PM +0000, Shenwei Wang wrote:
> > -----Original Message-----
> > From: Baruch Siach [mailto:baruch-NswTu9S1W3P6gbPvEgmw2w@public.gmane.org]
> > Sent: 2015年4月29日 10:08
> > To: Wang Shenwei-B38339
> > Cc: shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org; linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org;
> > devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> > Subject: Re: [PATCH 1/1] ARM: imx: make the imx timer driver implementation
> > independent of SoCs.
> >
> > When several SoC share the same IP block the usual convention is to name 
> > it in
> > the compatible property string after the first SoC it appeared on. Just look at
> > some binding documentation from Documentation/devicetree/bindings/timer/ to
> > find examples. The allwinner,sun5i-a13-hstimer property is shared by A10s and
> > A13 SoCs. The amlogic,meson6-timer is shared by Meson6 and Meson8 SoCs, and
> > so on.
>
> If the same IP block is shared with several SoCs, why we gave them different compatible 
> strings? If no changes in an IP block, I assume no changes in the relating driver as well. 
> In this assumption, I don't see any need to introduce a new compatible string for an 
> unchanged IP block in a new SoC.

That is exactly what I meant to say. Sorry that I was not clear enough.

When the same IP block is used in a newer generation SoC the same compatible 
property string is used. For that reason you can find in sun5i-a10s.dtsi the 
line

	compatible = "allwinner,sun5i-a13-hstimer";

baruch

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