On Mon, Jul 1, 2019 at 3:47 AM <Anson.Huang@xxxxxxx> wrote: > > From: Anson Huang <Anson.Huang@xxxxxxx> 'dt-bindings: timer: ...' for the subject. > > Systems which use platform driver model for clock driver require the > clock frequency to be supplied via device tree when system counter > driver is enabled. This is a DT binding. What's a platform driver? > > This is necessary as in the platform driver model the of_clk operations > do not work correctly because system counter driver is initialized in > early phase of system boot up, and clock driver using platform driver > model is NOT ready at that time, it will cause system counter driver > initialization failed. > > Add clock-frequency property to the device tree bindings of the NXP > system counter, so the driver can tell timer-of driver to get clock > frequency from DT directly instead of doing of_clk operations via > clk APIs. While you've now given a good explanation why you need this, it all sounds like linux specific issues and a DT change should not be necessary. Presumably, 'clocks' points to a fixed-clock node, right? Just parse the 'clocks' phandle and fetch the frequency from that node if you need to get the frequency 'early'. > Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx> > --- > No change. > --- > .../devicetree/bindings/timer/nxp,sysctr-timer.txt | 15 +++++++++------ > 1 file changed, 9 insertions(+), 6 deletions(-) > > diff --git a/Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt b/Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt > index d576599..7088a0e 100644 > --- a/Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt > +++ b/Documentation/devicetree/bindings/timer/nxp,sysctr-timer.txt > @@ -11,15 +11,18 @@ Required properties: > - reg : Specifies the base physical address and size of the comapre > frame and the counter control, read & compare. > - interrupts : should be the first compare frames' interrupt > -- clocks : Specifies the counter clock. > -- clock-names: Specifies the clock's name of this module > +- clocks : Specifies the counter clock, mutually exclusive with clock-frequency. > +- clock-names : Specifies the clock's name of this module, mutually exclusive with > + clock-frequency. > +- clock-frequency : Specifies system counter clock frequency, mutually exclusive with > + clocks/clock-names. It doesn't really work to say one or the other is needed unless you make the OS support both cases. Rob
