Re: [PATCH 03/24] arm64: dts: qcom: Introduce Glymur base dtsi and CRD dts

Dmitry Baryshkov
2025-10-29T10:36:48Z

On Wed, Oct 29, 2025 at 03:30:54PM +0530, Taniya Das wrote:
>
>
> On 9/25/2025 3:46 PM, Konrad Dybcio wrote:
> >> + tcsrcc: clock-controller@1fd5044 {
> >> + compatible = "qcom,glymur-tcsr";
> >> + reg = <0x0 0x1fd5044 0x0 0x48>;
> > We can map 0x1fd5000 - 0x1fd5094 inclusive, as that seems like a
> > logical subblock (this would require adjusting the driver)
> >
>
> Konrad, we encountered issues when trying to map regions beyond just the
> clock reference registers. Normally, we map the entire address range of
> a clock controller (CC) module in the device tree. However, for TCSRCC
> where CLKREF_EN registers are located within shared modules like TCSR or
> TLMM—we don't own the whole address space, and mapping the full range
> can overlap with other devices.
> To avoid this, we propose defining the base address as the first
> register actually used, and the size to only include up to the last
> register we use. This ensures we only map the relevant subblock,
> preventing conflicts with other device nodes.

Then you need to behave slightly differently: map the full range at the
basic device (TLMM, TCSR, etc.) and then create TCSRCC as a child device
to that node (and use paren't regmap to access the registers).

>
> So want to keep the mapping same from the start of clockref clocks.
>
> > There's also a laaaarge pool of various TCSR_ registers between
> > the previous node and this one.. but we can leave that in case we
> > need to describe it in a specific way some day
> >> + #clock-cells = <1>;
> >> + #reset-cells = <1>;
> >> + };
> >> +
>
> --
> Thanks,
> Taniya Das
>

--
With best wishes
Dmitry