RE: [PATCH 0/2] Add reset deassertion for Aspeed MDIO

[Dylan Hung]

Hi Andrew,

> -----Original Message-----
> From: Andrew Lunn [mailto:andrew@xxxxxxx]
> Sent: 2022年3月21日 8:11 PM
> To: Dylan Hung <dylan_hung@xxxxxxxxxxxxxx>
> Cc: robh+dt@xxxxxxxxxx; joel@xxxxxxxxx; andrew@xxxxxxxx;
> hkallweit1@xxxxxxxxx; linux@xxxxxxxxxxxxxxx; davem@xxxxxxxxxxxxx;
> kuba@xxxxxxxxxx; pabeni@xxxxxxxxxx; p.zabel@xxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> linux-aspeed@xxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> netdev@xxxxxxxxxxxxxxx; BMC-SW <BMC-SW@xxxxxxxxxxxxxx>
> Subject: Re: [PATCH 0/2] Add reset deassertion for Aspeed MDIO
> 
> On Mon, Mar 21, 2022 at 03:01:29PM +0800, Dylan Hung wrote:
> > Add missing reset deassertion for Aspeed MDIO. There are 4 MDIOs
> > embedded in Aspeed AST2600 and share one reset control bit SCU50[3].
> 
> Is the reset limited to the MDIO bus masters, or are PHYs one the bus
> potentially also reset?

It is limited to the MDIO bus masters.

> 
> Who asserts the reset in the first place? 

The hardware asserts the reset by default.

> Don't you want the first MDIO bus to
> probe to assert and then deassert the reset in order that all the hardware is
> reset?

Do I still need to add a reset assertion/deassertion if the hardware asserts the reset by default?

> 
>     Andrew

--
Dylan