[PATCH 09/10] dts: versatile: add clock tree

On Tue, May 20, 2014 at 11:09 PM, Rob Herring [off-list ref] wrote:

From: Rob Herring <robh@kernel.org>

The versatile dts is missing any clock data. Add the clocks.

It is not clear from the documentation where pclk comes from, so for
now it is a dummy clock which is sufficient for things to work.

AFAICT (from experiments and measurements on some boards, during which
I destroyed some boards) that is actually just the 24MHz clock right off.

Signed-off-by: Rob Herring <robh@kernel.org>

+       core-module at 10000000 {
+               compatible = "arm,core-module-versatile";
+               reg = <0x10000000 0x200>;
+
+               osc24M: oscillator at 24M {
+                       #clock-cells = <0>;
+                       compatible = "fixed-clock";
+                       clock-frequency = <24000000>;
+               };

Please follow the naming convention from the Integrator DTS, I am
pretty sure this is a chrystal:

        /* 24 MHz chrystal on the core module */
        xtal24mhz: xtal24mhz at 24M {
                #clock-cells = <0>;
                compatible = "fixed-clock";
                clock-frequency = <24000000>;
        };

+               /* OSC1 on AB, OSC4 on PB */
+               osc1: cm_aux_osc at 24M {
+                       #clock-cells = <0>;
+                       compatible = "arm,versatile-cm-auxosc";
+                       clocks = <&osc24M>;
+               };

Name xtal, also: why is this inside the core module node?
You're explicitly saying it is on the PB (platform baseboard)
and *not* on the core module!

+               /* The timer clock is the 24 MHz oscillator divided to 1MHz */
+               timclk: timclk at 1M {
+                       #clock-cells = <0>;
+                       compatible = "fixed-factor-clock";
+                       clock-div = <24>;
+                       clock-mult = <1>;
+                       clocks = <&osc24M>;
+               };
+
+               /* Actually hclk ? */
+               pclk: pclk at 0 {
+                       #clock-cells = <0>;
+                       compatible = "fixed-clock";
+                       clock-frequency = <0>;
+               };

I strongly suspect it's like this:

        pclk: pclk at 0 {
                #clock-cells = <0>;
                compatible = "fixed-factor-clock";
                clock-div = <1>;
                clock-mult = <1>;
                clocks = <&xtal24mhz>;
        };

                timer at 101e2000 {
                        compatible = "arm,sp804", "arm,primecell";
                        reg = <0x101e2000 0x1000>;
                        interrupts = <4>;
+                       clocks = <&timclk>, <&pclk>;
+                       clock-names = "tmrclk", "apb_pclk";
                };

We recently had some fight over the names of these clocks.
The DT bindings say they should be named "timer0" "timer1"
etc, see
Documentation/devicetree/bindings/timer/arm,sp804.txt

                timer at 101e3000 {
                        compatible = "arm,sp804", "arm,primecell";
                        reg = <0x101e3000 0x1000>;
                        interrupts = <5>;
+                       clocks = <&timclk>, <&pclk>;
+                       clock-names = "tmrclk", "apb_pclk";

Dito.

                ssp at 101f4000 {
                        compatible = "arm,pl022", "arm,primecell";
                        reg = <0x101f4000 0x1000>;
                        interrupts = <11>;
+                       clocks = <&osc24M>, <&pclk>;
+                       clock-names = "sspclk", "apb_pclk";

Should be SSPCLK all capitals.

Yours,
Linus Walleij