RE: [LINUX PATCH v2 1/3] clocksource: timer-cadence-ttc: Do not probe TTC device configured as PWM

[Sayyed, Mubin]

Hi Krzysztof,

> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx>
> Sent: Wednesday, November 15, 2023 5:41 PM
> To: Sayyed, Mubin <mubin.sayyed@xxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-pwm@xxxxxxxxxxxxxxx; git (AMD-Xilinx)
> <git@xxxxxxx>; mubin10@xxxxxxxxx; krzysztof.kozlowski+dt@xxxxxxxxxx;
> u.kleine-koenig@xxxxxxxxxxxxxx; thierry.reding@xxxxxxxxx;
> robh+dt@xxxxxxxxxx; conor+dt@xxxxxxxxxx; tglx@xxxxxxxxxxxxx;
> daniel.lezcano@xxxxxxxxxx; Simek, Michal <michal.simek@xxxxxxx>
> Subject: Re: [LINUX PATCH v2 1/3] clocksource: timer-cadence-ttc: Do not probe
> TTC device configured as PWM
> 
> On 15/11/2023 06:55, Sayyed, Mubin wrote:
> >>> +	/*
> >>> +	 * If pwm-cells property is present in TTC node,
> >>> +	 * it would be treated as PWM device.
> >>> +	 */
> >>> +	if (of_property_read_bool(timer, "#pwm-cells"))
> >>> +		return -ENODEV;
> >>
> >> You will introduce dmesg errors, so regressions.
> >>
> > [Mubin]: I will change it to "return 0" to avoid dmesg errors.
> 
> No, because solution is wrong.
> 
> >
> >> This does not look right. What you want is to bind one device driver
> >> and choose different functionality based on properties.
> > [Mubin]:  I am doing it based on earlier discussion related to AXI Timer PWM
> driver.  It was suggested to use #pwm-cells property for identifying role of
> device(PWM/clocksource) https://lore.kernel.org/linux-
> devicetree/20210513021631.GA878860@xxxxxxxxxxxxxxxxxx/.
> 
> You are mixing bindings with driver. I said here about driver and yes - you must
> use pwm-cells to differentiate that. It's obvious.
> 
> So again, one driver binding.
[Mubin]: I will explore whether mfd framework can be used to handle this.

Thanks,
Mubin
> 
> Wrap your emails to mailing list discussion style.
> 
> Best regards,
> Krzysztof