[RFC][PATCH] ARM: imx: verdin-imx8mm: Set CAN oscillator frequency based on model

[Francesco Dolcini]

On Sat, Jan 13, 2024 at 09:45:42PM +0100, Francesco Dolcini wrote:
> On Sat, Jan 13, 2024 at 06:40:19PM +0000, Marcel Ziswiler wrote:
> > Hi Marek
> > 
> > Thanks, seems like a decent idea. I guess we just did not do it as those previous revisions were just samples
> > but with this change can still be used much easier (e.g. without requiring manual intervention).
> > 
> > On Sat, 2024-01-13 at 19:33 +0100, Marek Vasut wrote:
> > > The older i.MX8M Mini Verdin SoMs before rev. 1.1C came with 20 MHz SPI CAN
> > > controller oscillator, the newer SoMs use 40 MHz oscillator. Handle both by
> > > overriding the oscillator frequency just before booting the kernel.
> > > 
> > > Signed-off-by: Marek Vasut <marex at denx.de>
> > > ---
> > > Cc: "NXP i.MX U-Boot Team" <uboot-imx at nxp.com>
> > > Cc: Fabio Estevam <festevam at gmail.com>
> > > Cc: Francesco Dolcini <francesco.dolcini at toradex.com>
> > > Cc: Marcel Ziswiler <marcel.ziswiler at toradex.com>
> > > Cc: Philippe Schenker <philippe.schenker at toradex.com>
> > > Cc: Stefano Babic <sbabic at denx.de>
> > 
> > Acked-by: Marcel Ziswiler <marcel.ziswiler at toradex.com>
> 
> Marcel, that patch is buggy.
> 
> The assembly version makes sense only for a specific major/minor
> hardware version.
> 
> So what you need to check if revision < 1.1C, while the code from Marek
> check just for the assembly version C.

And in the general case even my suggested test is not enough.  We
started having assembly version that are not linearly increasing since
some time.

I am fine on finding a solution to dynamically handle the different
oscillator frequency, but let's do it right.

I will reply Monday with some more details so we can have a working
solution.

Francesco