Hello Matthias,
On Wed, Feb 5, 2014 at 6:02 PM, Matthias Brugger <matthias.bgg@xxxxxxxxx> wrote:
> Hi,
>
> I'm stuck with dts problem. Whenever I try to find a clock for my
> device, the of_get_clk returns an error "Kernel panic - not syncing:
> Can't get timer clock"
>
> My DTS looks like this (reduced to relevant parts for easier reading):
>
Could you give more details about your platform?
I would take a look to Documentation/devicetree/bindings/clock/<your
platform>-clock.txt to be sure that you are using the bindings
correctly.
> #include <dt-bindings/interrupt-controller/irq.h>
> #include <dt-bindings/interrupt-controller/arm-gic.h>
> #include "skeleton.dtsi"
>
> / {
>
> [...]
>
> soc {
> #address-cells = <1>;
> #size-cells = <1>;
> compatible = "simple-bus";
> ranges;
>
> gic: interrupt-controller@10212000 {
> compatible = "arm,cortex-a9-gic";
> interrupt-controller;
> #interrupt-cells = <3>;
> reg = <0x10211000 0x1000>,
> <0x10212000 0x1000>;
> };
>
> osc: oscillator {
> compatible = "fixed-clock";
> #clock-cells = <1>;
Looking at Documentation/devicetree/bindings/clock/fixed-clock.txt it says:
#clock-cells : from common clock binding; shall be set to 0
while your are setting your clock-cells to 1.
> clock-frequency = <15000000>;
> clock-output-names = "osc";
> };
>
> timer: timer-mysoc {
> compatible = "mysoc,mysoc-timer";
> reg = <0x10008000 0x30>;
> interrupts = <GIC_SPI 113 IRQ_TYPE_EDGE_RISING>;
> clocks = <&osc 0>;
> clock-names = "system15m";
> };
> };
Documentation/devicetree/bindings/clock/clock-bindings.txt also says:
==Clock consumers==
Required properties:
clocks: List of phandle and clock specifier pairs, one pair
for each clock input to the device. Note: if the
clock provider specifies '0' for #clock-cells, then
only the phandle portion of the pair will appear.
So my educated guess is that you should use #clock-cells = <0>; your
your clock provider device node and clocks = <&osc> on your clock
consumer device node.
By looking at DTS and DTSI that uses the fixed-clock binding I see
that all platforms don't have their clocks providers device nodes
under soc {} but on a separate clocks {} node. I didn't find on the
clock-bindings.txt DT bindings documentation that this is a
requirement so probably that is not issue in your case but still
something to keep in mind.
> };
>
>
> my /drivers/clocksource/mysoc-timer.c looks like this (reduced to
> relevant parts for easier reading):
>
> [...]
>
> static void __init mysoc_timer_init(struct device_node *node)
> {
> unsigned long rate = 0;
> struct clk *clk;
> int ret, irq;
> u32 val;
>
> gpt_base = of_iomap(node, 0);
> if (!gpt_base)
> panic("Can't map registers");
>
> irq = irq_of_parse_and_map(node, 0);
> if (irq <= 0)
> panic("Can't parse IRQ");
>
> clk = of_clk_get(node, 0);
> if (IS_ERR(clk))
> panic("Can't get timer clock");
> clk_prepare_enable(clk);
>
> rate = clk_get_rate(clk);
>
> }
> CLOCKSOURCE_OF_DECLARE(mtk_mt6589, "mysoc,mysoc-timer",
> mysoc_timer_init);
>
>
> What I'm missing? I seems as if the clock "osc" is not found in the
> device tree. Any idea why. Building the DTB works without errors, but
> I suppose that doesn't mean too much anyway.
>
> Cheers,
> Matthias
>
> --
> motzblog.wordpress.com
Hope it helps,
Javier
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