Re: [PATCH v4 3/6] ARM: at91/dt: define sama5d3 clocks

[boris brezillon]

On 09/12/2013 17:48, Arnd Bergmann wrote:
> On Monday 09 December 2013, boris brezillon wrote:
> > Hello Arnd,
> >
> > On 09/12/2013 16:48, Arnd Bergmann wrote:
> > > On Monday 09 December 2013, boris brezillon wrote:
> > > > > You are adding "clock-names" properties in a lot of cases. Are you sure you
> > > > > are using the strings that are documented in the respective device bindings
> > > > > for each name? In a lot of cases, drivers just want an anonymous clock
> > > > > and we don't name them.
> > > > I rechecked it, and almost all drivers call [devm_]clk_get with a
> > > > specific clock
> > > > name, and as a result we must specify the "clock-names" property.
> > > > The only exceptions I found are the spi and PIT (Periodic Interval
> > > > Timer) drivers,
> > > > and "clock-names" property is not defined in these nodes.
> > > Yes, I understood that the *drivers* use the names, but are they actually
> > > documented in the device bindings? If not, it might be better to change the
> > > drivers.
> > We have to keep both clk system working for at91 platform (new CCF based
> > clk implementations and old clk implementations) for two reasons:
> > 1) the new clk implemetations are only compatible with DT enabled boards
> >       and some at91 boards are not yet ported to DT.
> > 2) we decided to move to the new clk implementations in multiple steps
> > (one SoC
> >       family after another) in order to ease PATCH review.
> >
> > If we change the drivers to avoid specific clock name request
> > ([devm]_clk_get(dev, NULL)),
> > we will have to change the old static clk lookup tables
> > (i.e.
> > http://lxr.free-electrons.com/source/arch/arm/mach-at91/at91sam9g45.c#L226,
> > http://lxr.free-electrons.com/source/arch/arm/mach-at91/at91sam9260.c#L202,
> > ...).
> Yes, that is a bit painful, but we really need to ensure that the drivers
> implement the documented binding. If they don't match we have to either
> review and change all the binding documents, or change the static clock
> tables and the drivers.
>
> Note that I have not checked your binding documents for the devices in
> question. If they already document these names, we don't need to change
> anything.

Are you talking about drivers or clk binding documentation ?
In either cases they're not defined :-), but I'd like to know which 
file(s) I
should update.

I'd rather not change the static clock lookup tables, but if you prefer this
approach (and Nicolas agrees), I'll propose a series modifying the drivers
and clk lookup table.

Whatever solution is choosen, I guess I'll have to update the drivers dt
binding documentation anyway ;-).

Best Regards,

Boris

> 	Arnd

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/