linux-kernel - Re: [PATCH v2] arm64: dts: imx8mp: use correct clock for eqos timestamping counter

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Message-ID: <8a5686f8-8c86-8242-b1b0-881b55a35489@pengutronix.de>
Date:   Mon, 24 Jul 2023 14:42:51 +0200
From:   Johannes Zink <j.zink@...gutronix.de>
To:     Fabio Estevam <festevam@...il.com>
Cc:     devicetree@...r.kernel.org, Conor Dooley <conor+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        linux-kernel@...r.kernel.org, Rob Herring <robh+dt@...nel.org>,
        NXP Linux Team <linux-imx@....com>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, patchwork-jzi@...gutronix.de
Subject: Re: [PATCH v2] arm64: dts: imx8mp: use correct clock for eqos
 timestamping counter

Hi everyone,

On 7/22/23 03:49, Fabio Estevam wrote:
> On Fri, Jul 21, 2023 at 12:51 AM Johannes Zink <j.zink@...gutronix.de> wrote:
>>
>> The i.MX8MP Reference Manual rev 1 06/2021, section 11.7.2.5 "Timestamp
>> Support" indicates the PTP timestamp clock expects a typical frequency
>> of 125MHz.
>>
>> As this also improves the precision of the measured timestamps: assign
>> appropriate 125MHz Clock parent. As no one except the timestamping
>> counter uses this clock, there are no side-effects of this change in
>> other peripherals.
>>
>> Signed-off-by: Johannes Zink <j.zink@...gutronix.de>
> 
> Reviewed-by: Fabio Estevam <festevam@...il.com>
> 
> 

please scratch this patch, the PTP Timestamping clock cannot be supplied with a 
125MHz clock, there is no 125MHz source in the MUX input and I misinterpreted 
the clocksummary when testing this patch.

Sorry for the noise,
Johannes


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