Subject: Re: [RFC net-next PATCH 08/16] net: macb: Clean up macb_validate

From: Nicolas Ferre <[email-masked]>
Date: Thu, 7 Oct 2021 15:22:04 +0200

On 04/10/2021 at 21:15, Sean Anderson wrote:
> While we're on the subject, could someone clarify the relationship
> between the various speed capabilities? What's the difference between
> MACB_CAPS_GIGABIT_MODE_AVAILABLE, MACB_CAPS_HIGH_SPEED, MACB_CAPS_PCS,
> and macb_is_gem()? Would there ever be a GEM without GIGABIT_MODE?

Yes. GEM is a new revision of the IP that is capable of doing Gigabit 
mode or not. sama7g5_emac_config is typically one of those doing only 
10/100.

> HIGH_SPEED without PCS? Why doesn't SGMII care if we're a gem (I think
> this one is a bug, because it cares later on)?

MACB_CAPS_HIGH_SPEED and MACB_CAPS_PCS were added by 
e4e143e26ce8f5f57c60a994bdc63d0ddce3a823 ("net: macb: add support for 
high speed interface"). In this commit it is said that "This controller 
has separate MAC's and PCS'es for low and high speed paths." Maybe it's 
a hint.

Best regards,
   Nicolas

-- 
Nicolas Ferre