Re: [PATCH v5] serial: support for 16550A serial ports on LP-8x4x

Sergei Ianovich
2015-12-16T08:06:19Z

On Tue, 2015-12-15 at 22:51 +0100, Arnd Bergmann wrote:
> On Wednesday 16 December 2015 00:04:45 Sergei Ianovich wrote:
> > index 0000000..5f9a4c1
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/serial/lp8x4x-serial.txt
> > @@ -0,0 +1,35 @@
> > +UART ports on ICP DAS LP-8x4x
> > +
> > +ICP DAS LP-8x4x contains three additional serial ports interfaced
> > via
> > +Analog Devices ADM213EA chips in addition to 3 serial ports on PXA
> > CPU.
> > +
> > +Required properties:
> > +- compatible : should be "icpdas,uart-lp8x4x"
>
> Compatible strings should not include a 'x' wildcard like this, better
> use
> the specific chip name.
>
> Also, it sounds like you named them after the board vendor, which
> sounds
> wrong as the vendor part of the compatible string should be the
> whoever
> made that part (analog?)

The chips themselves are standard, they would work with 8250_core if
properly connected. However, they are not connected normally. Al least
some of their config pins are wired to a different address region. So
the driver is board-specific.

'x' wildcards in the name of the board seem important. There are devices
made by the same vendor without 8 or 4 in their name. Those devices
either are not shipped with linux or are base on a x86 platform.

Does this justify the choice of the compatible string?

> > +- reg : should provide 16 byte man IO memory region and 1 byte
> > region for
> > +       termios
> > +
> > +- interrupts : should provide interrupt
> > +
> > +- interrupt-parent : should provide a link to interrupt controller
> > either
> > +                    explicitly or implicitly from a parent node
>
> interrupt-parent should be an optional property, or you can leave it
> out,
> as this is a standard property that can always be there when there is
> interrupts.

ok

> > +Examples (from pxa27x-lp8x4x.dts):
> > +
> > +               uart@9050 {
>
> By convention, the name should be 'serial', not 'uart'.

ok