On Mon, Dec 17, 2018 at 03:37:43PM -0800, Stephen Boyd wrote:
> Quoting Jorge Ramirez-Ortiz (2018-12-17 01:46:22)
> > Allow accessing the parent clock names required for the driver
> > operation by using the device tree node.
> >
> > This permits extending the driver to other platforms without having to
> > modify its source code.
> >
> > For backwards compatibility leave previous values as default.
>
> Why do we need to maintain backwards compatibility? Isn't is required
> that the nodes have clocks properties?
>
Hello Stephen,
This is the existing DT nodes for msm8916:
a53pll: clock@b016000 {
compatible = "qcom,msm8916-a53pll";
reg = <0xb016000 0x40>;
#clock-cells = <0>;
};
apcs: mailbox@b011000 {
compatible = "qcom,msm8916-apcs-kpss-global", "syscon";
reg = <0xb011000 0x1000>;
#mbox-cells = <1>;
clocks = <&a53pll>;
#clock-cells = <0>;
};
This is the (suggested) DT nodes for qcs404:
apcs_hfpll: clock-controller@0b016000 {
compatible = "qcom,hfpll";
reg = <0x0b016000 0x30>;
#clock-cells = <0>;
clock-output-names = "apcs_hfpll";
clocks = <&xo_board>;
clock-names = "xo";
};
apcs_glb: mailbox@b011000 {
compatible = "qcom,qcs404-apcs-apps-global", "syscon";
reg = <0x0b011000 0x1000>;
#mbox-cells = <1>;
clocks = <&gcc GCC_GPLL0_AO_OUT_MAIN>, <&apcs_hfpll>;
clock-names = "aux", "pll";
#clock-cells = <0>;
};
qcs404 specifies two clocks, with an accompanied clock-name for each clock.
msm8916 specifies a single clock, without an accompanied clock-name.
It is possible to append clock-names = "pll" for the existing clock,
as well as to define the aux clock in the apcs node in the msm8916 DT:
clocks = <&gcc GPLL0_VOTE>;
clock-names = "aux";
However, since the DT is treated as an ABI, the existing DT for msm8916 must
still work, so I don't think that it is possible to ignore having backwards
compability in the apcs clock driver.
Kind regards,
Niklas
