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

Sayyed, Mubin mubin.sayyed at amd.com
Fri Nov 24 03:03:24 PST 2023


Hi Krzysztof,

> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski at linaro.org>
> Sent: Wednesday, November 15, 2023 5:41 PM
> To: Sayyed, Mubin <mubin.sayyed at amd.com>
> Cc: linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org;
> devicetree at vger.kernel.org; linux-pwm at vger.kernel.org; git (AMD-Xilinx)
> <git at amd.com>; mubin10 at gmail.com; krzysztof.kozlowski+dt at linaro.org;
> u.kleine-koenig at pengutronix.de; thierry.reding at gmail.com;
> robh+dt at kernel.org; conor+dt at kernel.org; tglx at linutronix.de;
> daniel.lezcano at linaro.org; Simek, Michal <michal.simek at amd.com>
> 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 at robh.at.kernel.org/.
> 
> 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



More information about the linux-arm-kernel mailing list