[U-Boot] [PATCH v2] serial: ns16550: Add register shift variable

[Tom Rini <trini@konsulko.com>]

On Tue, Jul 17, 2018 at 12:45:51PM +0000, Alexey Brodkin wrote:
> Hi Felix,
> 
> > -----Original Message-----
> > From: Felix Brack [mailto:fb at ltec.ch]
> > Sent: Tuesday, July 17, 2018 3:13 PM
> > To: Alexander Graf <agraf@suse.de>; Lokesh Vutla <lokeshvutla@ti.com>; u-boot at lists.denx.de
> > Cc: Wolfgang Denk <wd@denx.de>; Tom Rini <trini@konsulko.com>; Marek Vasut <marek.vasut@gmail.com>; Patrice Chotard
> > <patrice.chotard@st.com>; Michal Simek <michal.simek@xilinx.com>; Simon Glass <sjg@chromium.org>; Alexey Brodkin
> > <Alexey.Brodkin@synopsys.com>; Bin Meng <bmeng.cn@gmail.com>; Ley Foon Tan <ley.foon.tan@intel.com>; Patrick Delaunay
> > <patrick.delaunay@st.com>; Mario Six <mario.six@gdsys.cc>; Stefan Roese <sr@denx.de>; Bernhard Messerklinger
> > <bernhard.messerklinger@br-automation.com>
> > Subject: Re: [PATCH v2] serial: ns16550: Add register shift variable
> 
> [snip]
>  
> > Adding a separate PORT in ns16550_serial_ids for a particular
> > architecture, platform or SoC would be an option. However the patch I
> > posted is much more generic as it offers to set the reg-shift property
> > for no matter what architecture, platform or SoC. It can also easily be
> > extended by adding more conditional defaults to the Kconfig file.
> 
> I'd say we're dealing with just one corner-case here.
> If I understand a concept of Device Tree it is supposed to describe your
> hardware. Thus if reg shift exists in your HW it should be explicitly mentioned in
> your .dts. If for some [historical] reason you have to deal with "incorrect" .dts then
> I'd prefer to have mentioned quirk with a separate PORT in ns16550_serial_ids
> instead of adding yet another Kconfig option.

So, this is part of the problem I suppose.  I don't know _why_ we can't
just add the correct and valid reg-shift property to the dtsi file in
Linux and be done with it.  Then the U-Boot driver would work because we
parse that property.

-- 
Tom
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