Re: [PATCH 1/2] dt-bindings: counter: Add new ti,omap-dmtimer-cap compatible

[Gokul Praveen]

Hi Krzysztof,


On 07/10/25 12:05, Krzysztof Kozlowski wrote:
> On 26/09/2025 18:06, Gokul Praveen wrote:
> > > > +
> > > > +  ti,timers:
> > > > +    description: Timer instance phandle for the Capture
> > >
> > > So the only resource is phandle? That's completely fake device then. NAK.
> >
> >
> > The OMAP Timer IP can operate in 3 modes: Timer, PWM mode or capture
> > (mutually exclusive).
> > The timer/ti,timer-dm.yaml file describes the timer mode of operation.
> > It encapsulates base IP block and reg property is also part the same
> > binding.
> >
> > This node represents the capture mode with phandle reference to the
> > timer DT node. This is modeled all the same lines as how PWM
> > functionality is implemented in pwm/ti,omap-dmtimer-pwm.yaml
>
> Different modes do not have their own device nodes. It is still one
> device, so one device node.
>
> > Now, if this needs to change, please suggest alternate.
> >
> > One solution is perhaps to add a new property to ti,timer-dm.yaml itself
> > to indicate the mode of IP?
>
> Not sure, depends what this really is and how it is used. I can also
> imagine that consumer defines the mod of operation.

For a timer operating in capture mode, there are no consumers actually 
and the only way we use it is through sysfs.

Would it be good enough if I have a separate "mode" property for the 
dmtimer device node just like how it is done for USB as follows where 
the usb device node has a "dr_mode" property to decide on whether the 
usb should act in host, device or otg mode.

&usb0 {
	status = "okay";
	dr_mode = "host";
};


> Or mode of operation could be even configured runtime, thus not suitable
> for DT at all.
>
> Best regards,
> Krzysztof