[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <4351a85a-ab53-acf8-9e80-e65b2ebfab66@gmail.com>
Date: Mon, 2 Oct 2023 12:16:12 -0700
From: Florian Fainelli <f.fainelli@...il.com>
To: Vladimir Oltean <vladimir.oltean@....com>, netdev@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-phy@...ts.infradead.org
Cc: "Russell King (Oracle)" <rmk+kernel@...linux.org.uk>,
Heiner Kallweit <hkallweit1@...il.com>,
Andrew Lunn <andrew@...n.ch>,
Madalin Bucur <madalin.bucur@....com>,
Ioana Ciornei <ioana.ciornei@....com>,
Camelia Groza <camelia.groza@....com>,
Li Yang <leoyang.li@....com>, Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor@...nel.org>,
Sean Anderson <sean.anderson@...o.com>,
Maxime Chevallier <maxime.chevallier@...tlin.com>,
Vinod Koul <vkoul@...nel.org>,
Kishon Vijay Abraham I <kishon@...nel.org>
Subject: Re: [RFC PATCH v2 net-next 01/15] phy: introduce phy_get_status() and
use it to report CDR lock
On 9/23/23 06:48, Vladimir Oltean wrote:
> Some modules, like the MTIP AN/LT block used as a copper backplane PHY
> driver, need this extra information from the SerDes PHY as another
> source of "link up" information.
>
> Namely, the 25GBase-R PCS does not have a MDIO_CTRL1_LPOWER bit
> implemented in its MDIO_MMD_PCS:MDIO_CTRL1 register. That bit is
> typically set from phy_suspend() or phylink_pcs_disable() implementations,
> and that is supposed to cause a link drop event on the link partner.
> But here it does not happen.
>
> By implementing the networking phylink_pcs_disable() as phy_power_off(),
> we are able to actually power down the lane in a way that is visible to
> the remote end. Where it is visible is the CDR lock, so we introduce
> PHY_STATUS_TYPE_CDR_LOCK as an extra link indication, we are able to
> detect that condition and signal it to upper layers of the network
> stack.
>
> A more high-level and generic phy_get_status() operation was chosen
> instead of the more specific phy_get_cdr_lock() alternative, because I
> saw this as being more in the spirit of the generic PHY API.
> Also, phy_get_status() is more extensible and reusable for other
> purposes as well.
>
> Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
Reviewed-by: Florian Fainelli <florian.fainelli@...adcom.com>
--
Florian
Powered by blists - more mailing lists