netdev - Re: [PATCH v5 net-next 05/12] dt-bindings: net: ti: add new cpsw switch driver bindings

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Date:   Fri, 1 Nov 2019 19:25:49 +0200
From:   Grygorii Strashko <grygorii.strashko@...com>
To:     Florian Fainelli <f.fainelli@...il.com>, <netdev@...r.kernel.org>,
        Ilias Apalodimas <ilias.apalodimas@...aro.org>,
        Andrew Lunn <andrew@...n.ch>,
        "David S . Miller" <davem@...emloft.net>,
        Ivan Khoronzhuk <ivan.khoronzhuk@...aro.org>,
        Jiri Pirko <jiri@...nulli.us>
CC:     Sekhar Nori <nsekhar@...com>, <linux-kernel@...r.kernel.org>,
        <linux-omap@...r.kernel.org>,
        Murali Karicheri <m-karicheri2@...com>,
        Ivan Vecera <ivecera@...hat.com>,
        Rob Herring <robh+dt@...nel.org>, <devicetree@...r.kernel.org>
Subject: Re: [PATCH v5 net-next 05/12] dt-bindings: net: ti: add new cpsw
 switch driver bindings

Hi Florian,

On 25/10/2019 20:47, Florian Fainelli wrote:
> On 10/24/19 3:09 AM, Grygorii Strashko wrote:
>> Add bindings for the new TI CPSW switch driver. Comparing to the legacy
>> bindings (net/cpsw.txt):
>> - ports definition follows DSA bindings (net/dsa/dsa.txt) and ports can be
>> marked as "disabled" if not physically wired.
>> - all deprecated properties dropped;
>> - all legacy propertiies dropped which represent constant HW cpapbilities
>> (cpdma_channels, ale_entries, bd_ram_size, mac_control, slaves,
>> active_slave)
>> - TI CPTS DT properties are reused as is, but grouped in "cpts" sub-node
>> - TI Davinci MDIO DT bindings are reused as is, because Davinci MDIO is
>> reused.
>>
>> Signed-off-by: Grygorii Strashko <grygorii.strashko@...com>
>> ---
> 
> [snip]
>> +- mdio : CPSW MDIO bus block description
>> +	- bus_freq : MDIO Bus frequency
> 
> clock-frequency is a more typical property to describe the bus clock's
> frequency, that is what i2c and spi do.

The MDIO is re-used here unchanged (including bindings).
i think, I could try to add standard optional property "bus-frequency" to MDIO bindings
as separate series, and deprecate "bus_freq".

> 
>> +	See bindings/net/mdio.txt and davinci-mdio.txt
>> +
>> +- cpts : The Common Platform Time Sync (CPTS) module description
>> +	- clocks : should contain the CPTS reference clock
>> +	- clock-names : should be "cpts"
>> +	See bindings/clock/clock-bindings.txt
>> +
>> +	Optional properties - all ports:
>> +	- cpts_clock_mult : Numerator to convert input clock ticks into ns
>> +	- cpts_clock_shift : Denominator to convert input clock ticks into ns
>> +			  Mult and shift will be calculated basing on CPTS
>> +			  rftclk frequency if both cpts_clock_shift and
>> +			  cpts_clock_mult properties are not provided.
> 
> Why would those two be needed that would be modeled in the Linux Common
> Clock Framework?

The CPTS is re-used here unchanged (including bindings).

This is very specific tuning options for PHC clock (cyclecounter) which intended to be used
in very rare cases with some ref frequencies when automatic calculation is not working properly.



-- 
Best regards,
grygorii