[U-Boot] Add support for imxrt

[Fabio Estevam]

Hi Giulio,

On Wed, Oct 9, 2019 at 12:59 PM Giulio Benetti
<giulio.benetti at benettiengineering.com> wrote:
>
> Hi Fabio and Stefano,
>
> On 9/29/19 9:40 PM, Fabio Estevam wrote:
> > We try to use DM in U-Boot proper as much as possible, but using DM in
> > SPL is currently not a requirement, especially due to internal RAM
> > size constraints.
> IOMUXC and LPUART(using 24Mhz clock) work correctly using DM.
>
> About clk drivers, I've seen all around that they are very shrinked
> Linux's version drivers. Would it make sense to add complete clk driver
> in u-boot starting from Linux one(i.e. vf610) or it would only grow
> size? I mean, after adding initial support I would like to add Lcd
> controller driver etc. etc. so a complete driver would be useful.
> Instead what I see on IMX6 clk driver is only a subsection of all PLLs
> and ref_sel to start Linux up.

Yes, since you are adding this from scratch, I would suggest adding a
complete clock driver, which is close to the Linux driver.

Regards,

Fabio Estevam