From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v3 0/5] phy: core: rework phy_set_mode to accept phy mode and submode Date: Mon, 17 Dec 2018 15:06:23 +0100 Message-ID: <20181217140623.2zze2kfclup7wjti@flea> References: <20181120012424.11802-1-grygorii.strashko@ti.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="553g4on6q5epsg5z" Return-path: Content-Disposition: inline In-Reply-To: <20181120012424.11802-1-grygorii.strashko@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: Grygorii Strashko Cc: "David S. Miller" , Kishon Vijay Abraham I , Antoine Tenart , Quentin Schulz , Russell King - ARM Linux , Maxime Chevallier , netdev@vger.kernel.org, Sekhar Nori , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Tony Lindgren , linux-amlogic@lists.infradead.org, linux-mediatek@lists.infradead.org, Alexandre Belloni , Vivek Gautam , Chen-Yu Tsai , Carlo Caione , Chunfeng Yun , Matthias Brugger , Manu Gautam List-Id: linux-mediatek@lists.infradead.org --553g4on6q5epsg5z Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Grygorii, Kishon, On Mon, Nov 19, 2018 at 07:24:19PM -0600, Grygorii Strashko wrote: > Thank you for your review. > I've not added "Tested-by"/"Acked-by" tags due to code changes in v3. >=20 > As was discussed in [1] I'm posting series which introduces rework of > phy_set_mode to accept phy mode and submode. I've dropped TI specific pat= ches as > this change is pretty big by itself. >=20 > Patch 1 is cumulative change which refactors PHY framework code to > support dual level PHYs mode configuration - PHY mode and PHY submode. It > extends .set_mode() callback to support additional parameter "int submode" > and converts all corresponding PHY drivers to support new .set_mode() > callback declaration. > The new extended PHY API > int phy_set_mode_ext(struct phy *phy, enum phy_mode mode, int submode) > is introduced to support dual level PHYs mode configuration and existing > phy_set_mode() API is converted to macros, so PHY framework consumers do > not need to be changed (~21 matches). >=20 > Patches 2-4: Add new PHY's mode to be used by Ethernet PHY interface driv= ers or > multipurpose PHYs like serdes and convert ocelot-serdes and mvebu-cp110-c= omphy > PHY drivers to use recently introduced PHY_MODE_ETHERNET and phy_set_mode= _ext(). >=20 > Patch 5 - removes unused, ethernet specific phy modes from enum phy_mode. >=20 > Testing: > - series tested on TI am335x/am437x/am5(dra7) paltforms. > - other driver build tested. I realise I'm a bit late to the party, but while working on the D-PHY support, I noticed a few things that could be improved. I guess the main issue is that the sub-mode is completely opaque to the generic phy framework now. This might not be a big issue, and I assume that it has been done that way because the net framework already has a define for the submode it wants. However, this creates a bunch of drawbacks at the phy framework level: - phy_set_mode will now pass a submode of 0, all the time. This means that the behaviour is undefined for all the modes not using the submodes at the moment, and phy_interface_t seems to have the value PHY_INTERFACE_MODE_NA matching 0, but I guess this could change in the future (or the guarantee is not documented anywhere). - on a similar note, there's no documentation for which value to pass to phy_set_mode_ext when used with something else than a PHY_MODE_ETHERNET. - at the provider level, if you're supporting a phy that isn't using the submodes, you have no way to filter out or reject any subnode, since you have no idea what the "no submode" value is. I guess this can be addressed by: A) defining a generic phy framework wide unused / invalid phy submode, that wouldn't collide with the subnode values (such as -1?), and making phy_set_mode_ext use that. B) moving the phy submodes definition to the generic phy headers. This would allow to have a documented, obvious link between a mode and its subnodes, for all the actors involved (consumer, provider, and framework) without prior knowledge. C) Document what the submodes expectations are What do you think? Maxime --=20 Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --553g4on6q5epsg5z Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXBetXwAKCRDj7w1vZxhR xeUGAQCR50AQDteX+9l+EKki80/VMKbK438CYL7PPVfr3Qu84AEAjDNV9Y+LVbAp XRC0B5OfKDq6wnecuDvlw4UyOlmKWAo= =hd40 -----END PGP SIGNATURE----- --553g4on6q5epsg5z--