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Message-ID: <0a56fde2-3190-4f65-9fc5-b1d5ff0da6a8@microchip.com>
Date: Fri, 27 Oct 2023 07:10:42 +0000
From: <Parthiban.Veerasooran@...rochip.com>
To: <andrew@...n.ch>
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Subject: Re: [PATCH net-next v2 3/9] net: ethernet: oa_tc6: implement OA TC6
configuration function
Hi Andrew,
On 27/10/23 1:36 am, Andrew Lunn wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
>>>> -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
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