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

Shenwei Wang
2015-04-30T15:16:42Z

> -----Original Message-----
> From: Sascha Hauer [mailto:s.hauer at pengutronix.de]
> Sent: 2015?4?30? 0:16
> To: Wang Shenwei-B38339
> Cc: shawn.guo at linaro.org; linux-arm-kernel at lists.infradead.org
> Subject: Re: [PATCH 1/1] ARM: imx: make the imx timer driver implementation
> independent of SoCs.
>
>
> The policy so far is:
>
> - use the exact SoC name as primary compatible string
> - Use the oldest SoC we *think* is compatible at the time of writing as
> secondary compatible.
>
> This way we can always match to the oldest compatible in the driver (Thus i.MX7
> could get a "i.MX6sx" compatible or whatever). Should we realize later that there
> are slight differences between timers that we thought would be identical, then
> we can still change the driver to match against the exact compatible string.
>
> Whether we use the SoC name or Vxy doesn't matter at all. With Vxy we still
> need to increase the counter with each new SoC since there might be differences
> discovered later. We can't really say for sure that there only four versions of the
> timer, only that by now we have identified four versions. On i.MX we chose to
> match to the SoC name not only for the timer but for all other devices aswell, so
> let's keep it that way.
>
> That i.MX6q has two different versions of the timer is unfortunate, that needs a
> new compatible string, but whether that is fsl,imx-gpt-v3 or
> fsl,imx6q-gpt-newone again doesn't matter.

As it is a rule, we should follow it. But I don?t' think it is a good idea to bind the SoC name
with the IP block. It seems even ugly especially in this case. You will have to create a new
string for each new SoC even the IP block has no changes at all. Otherwise, you will
have to re-use a string containing another SoC's name.

>
> Sascha
>
> --
> Pengutronix e.K. |
> |
> Industrial Linux Solutions | http://www.pengutronix.de/ |
> Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
> Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555
> |