Re: [PATCH v11 19/19] h8300: devicetree source

[Yoshinori Sato <ysato@users.sourceforge.jp>]

At Fri, 8 May 2015 17:50:00 +0100,
Mark Rutland wrote:
> 
> Hi,
> 
> > +++ b/Documentation/devicetree/bindings/h8300/cpu.txt
> > @@ -0,0 +1,17 @@
> > +* H8/300 CPU bindings
> > +
> > +Required properties:
> > +
> > +- compatible: Compatible property value should be "renesas,h8300".
> > +- reg: Contains CPU index.
> 
> What does the "CPU index" correspond to physically on the CPU?
> 
> Can h8300 support SMP?

No.
It's unnecessary.

> > +- clock-frequency: Contains the clock frequency for CPU, in Hz.
> 
> Is this strictly necessary?

Yes.
There are no ways to calculate.

> > +- renesas,bus-width: Contain the memory bus width.
> 
> What's this needed for?

Hmm...
This value can get bus controller setting.
It's considered.

> 
> [...]
> 
> > +++ b/Documentation/devicetree/bindings/interrupt-controller/renesas,h8300h-intc.txt
> > @@ -0,0 +1,20 @@
> > +* H8/300H Interrupt controller
> > +
> > +Required properties:
> > +
> > +- compatible: has to be "renesas,h8300h-intc", "renesas,h8300-intc" as fallback.
> > +- #interrupt-cells: has to be <1>: an interrupt index and flags, as defined in
> > +  interrupts.txt in this directory
> 
> Surely you need two cells to encode index and flags?

That's right.
flag field needed.

> 
> > +
> > +Optional properties:
> > +
> > +- any properties, listed in interrupts.txt, and any standard resource allocation
> > +  properties
> > +
> > +Example:
> > +
> > +	h8intc: intc@0 {
> 
> Nit: call this "interrupt-controller" rather than "ntc".

OK.
Updated.

> Without a reg you shouldn't have a unit-address (the '@0' part).
> 
> How does the CPU communicate with this controller? I assume it's not
> MMIO.

Interrupt controller is MMIO.
It set base address.

> These comments also apply to "renesas,h8s-intc".

OK.

> > diff --git a/arch/h8300/boot/dts/edosk2674.dts b/arch/h8300/boot/dts/edosk2674.dts
> > new file mode 100644
> > index 0000000..60e73b9
> > --- /dev/null
> > +++ b/arch/h8300/boot/dts/edosk2674.dts
> > @@ -0,0 +1,109 @@
> > +#include <dt-bindings/clock/renesas,8bit-timer.h>
> > +
> > +/dts-v1/;
> > +/ {
> > +	compatible = "renesas,edosk2674";
> > +	#address-cells = <1>;
> > +	#size-cells = <1>;
> > +	interrupt-parent = <&h8intc>;
> > +
> > +	chosen {
> > +		bootargs = "console=ttySC2,38400";
> > +	};
> 
> It would be great if you could use stdout-path from the start rather
> than passing console= in bootargs. That makes things far less fragile
> w.r.t. physical vs logical naming, and keeps console and earlycon in
> sync.
> 
> It also means that a user can replace bootargs and still expect the
> console to work by default (unless overridden explicitly).

OK.

> > +	aliases {
> > +		serial0 = &sci0;
> > +		serial1 = &sci1;
> > +		serial2 = &sci2;
> > +	};
> > +
> > +	clocks {
> > +		ranges;
> > +		#address-cells = <1>;
> > +		#size-cells = <1>;
> 
> Please get rid of the clocks container node and place the clocks
> directly under the root node. There's nothing magic about a /clocks
> node, and it's not been listed as a bus of any sort.

OK.

> > +		pllclk: pllclk {
> > +			compatible = "renesas,h8s2678-pll-clock";
> > +			clocks = <&xclk>;
> > +			#clock-cells = <0>;
> > +			reg = <0xfee03b 2>, <0xfee045 2>;
> > +		};
> > +		cclk: cclk {
> > +			compatible = "renesas,h8300-div-clock";
> > +			clocks = <&pllclk>;
> > +			#clock-cells = <0>;
> > +			reg = <0xfee03b 2>;
> > +			renesas,width = <3>;
> > +		};
> 
> Are there existing bindings for these? I didn't see any as part of the
> portion of the series I was Cc'd for.

No.
It new clock bindings.
Please refer Message-Id: <1431097479-21101-18-git-send-email-ysato@users.sourceforge.jp>

> > +	memory@0 {
> 
> Nit: the unit-address should math the address in the reg entry (here it
> should be 400000 rather than 0).

OK.

> [...]
> 
> > +	chosen {
> > +		bootargs = "earlyprintk=h8300-sim console=ttySC0";
> > +	};
> 
> If you implement earlycon you'd only need a single stdout-path entry
> here, which would make this much nicer.

OK.

> Thanks,
> Mark.

Thanks comment.
It was helpful.

-- 
Yoshinori Sato
<ysato@users.sourceforge.jp>