Re: [PATCH 03/14] DEVICETREE: Add PIC32 clock binding documentation

From: Rob Herring
Date: Mon Nov 30 2015 - 16:47:31 EST


On Wed, Nov 25, 2015 at 10:36:55PM -0700, Joshua Henderson wrote:
> Hi Rob,
>
> On 11/22/2015 2:31 PM, Rob Herring wrote:
> > On Fri, Nov 20, 2015 at 05:17:15PM -0700, Joshua Henderson wrote:
> >> From: Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>
> >>
> >> Document the devicetree bindings for the clock driver found on Microchip
> >> PIC32 class devices.
> >>
> >> Signed-off-by: Purna Chandra Mandal <purna.mandal@xxxxxxxxxxxxx>
> >> Signed-off-by: Joshua Henderson <joshua.henderson@xxxxxxxxxxxxx>
> >> ---
> >> .../devicetree/bindings/clock/microchip,pic32.txt | 263 ++++++++++++++++++++
> >> 1 file changed, 263 insertions(+)
> >> create mode 100644 Documentation/devicetree/bindings/clock/microchip,pic32.txt
> >>
> >> diff --git a/Documentation/devicetree/bindings/clock/microchip,pic32.txt b/Documentation/devicetree/bindings/clock/microchip,pic32.txt
> >> new file mode 100644
> >> index 0000000..4cef72d
> >> --- /dev/null
> >> +++ b/Documentation/devicetree/bindings/clock/microchip,pic32.txt
> >> @@ -0,0 +1,263 @@
> >> +Binding for a Clock hardware block found on
> >> +certain Microchip PIC32 MCU devices.
> >> +
> >> +Microchip SoC clocks-node consists of few oscillators, PLL, multiplexer
> >> +and few divider nodes.
> >
> > [...]
> >
> >> +Required properties:
> >> +- compatible : should have "microchip,pic32-clk".

BTW, this should list out the actual compatible strings.

> > There is some discussion about this upstream with "critical-clocks"
> > binding. Can you use and wait for that?
> >
>
> The way this is going, we might not have to wait. :) Is there a patch available yet to try it out?

Yes, googling "Lee Jones critical-clocks" should find it.

> >> +- microchip,status-bit-mask: bitmask for status check. This will be used to confirm
> >> + particular operation by clock sub-node is completed. It is dependent sub-node.
> >> +- microchip,bit-mask: enable mask, similar to microchip,status-bit-mask.
> >
> > We've generally decided not to describe clocks at this level of detail
> > in DT. It's fine though for simple clock trees. This one seems to be
> > borderline IMO.
> >
>
> The binding example is the entire clock tree. These masks are right from the datasheet. For reference, do you have an example of a better alternative?

Okay, like I said, borderline. If this is complete, then it is fine.
Adding more clocks or a newer version of the SoC with more clocks would
change that opinion.

Rob
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