Re: [PATCH v2 00/13] serial: 8250_exar: Clean up the driver

[Andy Shevchenko]

On Fri, Sep 06, 2024 at 02:38:51PM -0400, Parker Newman wrote:
> On Fri, 6 Sep 2024 17:42:26 +0300
> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > On Fri, Sep 06, 2024 at 10:33:54AM -0400, Parker Newman wrote:
> > > On Fri, 6 Sep 2024 17:24:44 +0300
> > > Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > > > On Fri, Sep 06, 2024 at 09:51:41AM -0400, Parker Newman wrote:
> > > > > On Fri, 6 Sep 2024 15:46:51 +0300
> > > > > Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
> > > > > > On Fri, May 03, 2024 at 02:33:03PM -0400, Parker Newman wrote:

...

> > > > > > Sorry for blast from the past, but I have some instersting information
> > > > > > for you. We now have spi-gpio and 93c46 eeprom drivers available to be
> > > > > > used from others via software nodes, can you consider updating your code
> > > > > > to replace custom bitbanging along with r/w ops by the instantiating the
> > > > > > respective drivers?
> > > > >
> > > > > Hi Andy,
> > > > > The Exar UARTs don't actually use MPIO/GPIO for the EEPROM.
> > > > > They have a dedicated "EEPROM interface" which is accessed by the
> > > > > REGB (0x8E) register. It is a very simple bit-bang interface though,
> > > > > one bit per signal.
> > > > >
> > > > > I guess in theory I could either add  GPIO wrapper to toggle these bits
> > > > > and use the spi-gpio driver but I am not sure if that really improves things?
> > > > > Maybe using the spi-bitbang driver directly is more appropriate?
> > > > > What do you think?
> > > >
> > > > Yes, spi-bitbang seems better in this case.
> > >
> > > I will try to make some time to implement this... Or if someone else from the
> > > community wants to take this on in the mean time I am certainly happy to test
> > > and help out!
> >
> > Sure, I shared this thought due to having lack of time to look myself,
> > but I prepared the above mentioned drivers to make them work in this case.
> > (If you are curios, see the Git history for the last few releases with
> >  --author="Andy Shevchenko")
> >
> 
> Looking into it a bit more I think we could just use the eeprom_93cx6
> driver without any SPI layer. Just need to add simple register_read()
> and register_write() functions to read/write the REB register.
> 
> That should be a pretty easy change to make, I can try to make that
> change soon unless anyone has any objections to that method?

Thank you, this is pretty wonderful news!

-- 
With Best Regards,
Andy Shevchenko