Re: [PATCH net-next v2 3/9] net: ethernet: oa_tc6: implement OA TC6 configuration function

[<Parthiban.Veerasooran@microchip.com>]

Hi Andrew,

On 27/10/23 1:36 am, Andrew Lunn wrote:
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> 
>>>> -struct oa_tc6 *oa_tc6_init(struct spi_device *spi, bool prote)
>>>> +struct oa_tc6 *oa_tc6_init(struct spi_device *spi)
>>>
>>> Was there a reason to have prote initially, and then remove it here?
>> The reason is, control communication uses "protect". But in the first
>> patch there was no dt used. Later in this patch, dt used for all the
>> configuration parameters and this also part of that. That's why removed
>> and moved this to dt configuration.
>>
>> What's your opinion? shall I keep as it is like this? or remove the
>> protect in the first two patches and introduce in this patch?
> 
> It will actually depend on what goes into the DT binding. If using
> protections costs very little, i would just hard code it on. Maybe you
> can run some iperf tests and see if it makes a measurable difference.
> 
> How fast an SPI bus are you using on your development board? If you
> have a 50Mbps SPI bus, it does not even matter, since the media
> bandwidth is just 10Mbps.
Actually protection is only used for control communication to read/write 
registers. It is not used in data communication where ethernet frame 
transfer performed. So it doesn't hurt data traffic. But of course in 
between data communication I may perform some control transfer for 
register read/write but they are not big and will not affect the speed. 
In my development board I use 15MHz speed SPI bus.

As this is given as a configurable parameter in the OPEN Alliance 
specification, I have implemented it in the DT binding for user 
input/choice.

Best Regards,
Parthiban V
> 
>      Andrew