[PATCH 4/9] ARM: i.MX: extend drivers for i.MX8MN (Nano) support

[Trent Piepho]

On Sun, Sep 5, 2021 at 6:52 AM Ahmad Fatoum <a.fatoum at pengutronix.de> wrote:
>
> Extend match tables and function definitions for i.MX USB, ATF,
> MCI, NVMEM, pinctrl and serial drivers for the i.MX8M Nano.
>
> There is no special handling required for those, compared with
> the mini.

It shouldn't be necessary to add them when there is no special
handling.  The device tree should list the earlier type they are
compatible with as well.  For example, every fsl,imx8*-usdhc I see in
a device tree then lists fsl,imx7d-usdhc additionally.

Though the Barebox driver does NOT list fsl,imx7d-usdhc.  It works on
the fsl,imx7d-usdhc because that is compatible with the
fsl,imx6sl-usdhc.

Really, the error would seem to be the NXP devicetrees only listing
imx7d as a compatible instead of going back to imx6sl.

It is also interesting that in Barebox, the imx7d uses the imx6sl
compat entry, and that entry includes ESDHC_FLAG_ERR004536.  While the
imx8* is supposedly imx7d compatible, it uses the imx6sx entry that
lacks that flag.  I think the error here is that imx7d does not have
this erratum.