[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20221110152925.3gkkp5opf74oqrxb@skbuf>
Date: Thu, 10 Nov 2022 15:29:26 +0000
From: Vladimir Oltean <vladimir.oltean@....com>
To: Sean Anderson <sean.anderson@...o.com>
CC: Vladimir Oltean <olteanv@...il.com>,
Heiner Kallweit <hkallweit1@...il.com>,
Russell King <linux@...linux.org.uk>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>,
Jakub Kicinski <kuba@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Andrew Lunn <andrew@...n.ch>,
Ioana Ciornei <ioana.ciornei@....com>,
Madalin Bucur <madalin.bucur@....com>,
"David S . Miller" <davem@...emloft.net>,
Alexandre Belloni <alexandre.belloni@...tlin.com>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Claudiu Manoil <claudiu.manoil@....com>,
Florian Fainelli <f.fainelli@...il.com>,
Frank Rowand <frowand.list@...il.com>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Leo Li <leoyang.li@....com>,
Michael Ellerman <mpe@...erman.id.au>,
Paul Mackerras <paulus@...ba.org>,
Rob Herring <robh+dt@...nel.org>,
Saravana Kannan <saravanak@...gle.com>,
Shawn Guo <shawnguo@...nel.org>,
"UNGLinuxDriver@...rochip.com" <UNGLinuxDriver@...rochip.com>,
Vivien Didelot <vivien.didelot@...il.com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH net-next v2 00/11] net: pcs: Add support for devices
probed in the "usual" manner
On Thu, Nov 10, 2022 at 09:55:32AM -0500, Sean Anderson wrote:
> On 11/9/22 17:41, Vladimir Oltean wrote:
> > On Thu, Nov 03, 2022 at 05:06:39PM -0400, Sean Anderson wrote:
> >> Several (later) patches in this series cannot be applied until a stable
> >> release has occured containing the dts updates.
> >
> > New kernels must remain compatible with old device trees.
>
> Well, this binding is not present in older device trees, so it needs to
> be added before these patches can be applied. It also could be possible
> to manually bind the driver using e.g. a helper function (like what is
> done with lynx_pcs_create_on_bus). Of course this would be tricky,
> because we would need to unbind any generic phy driver attached, but
> avoid unbinding an existing Lynx PCS driver.
If you know the value of the MII_PHYSID1 and MII_PHYSID2 registers for
these PCS devices, would it be possible to probe them in a generic way
as MDIO devices, if they lack a compatible string?
> As I understand it, kernels must be compatible with device trees from a
> few kernels before and after. There is not a permanent guarantee of
> backwards compatibility (like userspace has) because otherwise we would
> never be able to make internal changes (such as what is done in this
> series). I have suggested deferring these patches until after an LTS
> release as suggested by Rob last time [1].
>
> --Sean
>
> [1] https://lore.kernel.org/netdev/20220718194444.GA3377770-robh@kernel.org/
Internal changes limit themselves to what doesn't break compatibility
with device trees in circulation. DT bindings are ABI. Compared to the
lifetime of DPAA2 SoCs (and especially DPAA1), 1 LTS release is nothing,
sorry. The kernel has to continue probing them as Lynx PCS devices even
in lack of a compatible string.
Powered by blists - more mailing lists