[PATCH] Documentation: dt: bindings: TI WiLink modules
Nishanth Menon
nm at ti.com
Thu Jun 27 22:51:32 EST 2013
On 11:47-20130627, Luciano Coelho wrote:
> (added mailing lists and everyone back to the thread)
>
> On Wed, 2013-06-26 at 23:38 -0500, Nishanth Menon wrote:
> > On 06/25/2013 03:35 AM, Luciano Coelho wrote:
> > > +Optional properties:
> > > +--------------------
> > > +
> > > +- refclock: the internal WLAN reference clock frequency (required for
> > > + WiLink6 and WiLink7; not used for WiLink8). Must be one of the
> > > + following:
> > > + 0 = 19.2 MHz
> > > + 1 = 26.0 MHz
> > > + 2 = 38.4 MHz
> > > + 3 = 52.0 MHz
> > > + 4 = 38.4 MHz, XTAL
> > > + 5 = 26.0 MHz, XTAL
> > > +
> > > +- tcxoclock: the internal WLAN TCXO clock frequency (required for
> > > + WiLink7 not used for WiLink6 and WiLink8). Must be one of the
> > > + following:
> > > + 0 = 19.200 MHz
> > > + 1 = 26.000 MHz
> > > + 2 = 38.400 MHz
> > > + 3 = 52.000 MHz
> > > + 4 = 16.368 MHz
> > > + 5 = 32.736 MHz
> > > + 6 = 16.800 MHz
> > > + 7 = 33.600 MHz
> > >
> > just a gentle query - why not use frequency itself here in Hz for
> > refclock and txoclk?
>
> I thought about using the actual frequencies, but I decided not to do
> so, because I'd have to convert them to these values anyway. These
> values are used to configure the firmware and it uses these
> "enumerations".
Could we not hide this under preprocessor macros instead? just wondering
of txoclock = <6>; kind of usage.. easy to make mistakes and easier to
confuse a new reader :).
just my 2 cents.
>
>
> > might not another option of using
> > node {
> > clocks=<&clk>;
> > }
> >
> > Usually refclock is an external clock source, no?
>
> No. In the WiLink case, both refclock and tcxoclock are internal
> clocks. They are in the module itself and what we need to do is tell
> the WiLink chip what the module's clocks look like.
>
>
> > the above allows you to do an devm_clk_get and clk_get_rate() to figure
> > out the exact clock frequency.
>
> No, we can't use these calls, because they are internal clocks.
>
> Please see my more complete explanation as an answer to Tony's email.
K thanks.
>
> Thanks for your review!
Glad to be of help.
--
Regards,
Nishanth Menon
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