From patchwork Fri Mar 14 16:23:18 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxime Chevallier X-Patchwork-Id: 14017136 X-Patchwork-Delegate: kuba@kernel.org Received: from relay4-d.mail.gandi.net (relay4-d.mail.gandi.net [217.70.183.196]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B09AD202F93; Fri, 14 Mar 2025 16:23:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.196 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741969414; cv=none; b=IyrXbf1WbAy3Qd68WmSjHxtknHm1niVs9TIWXWyOlheZ7W4qCldAlDlfS1Xr1P3R7jCz1J35zFTgHSftbcvQINye+zmKziHGaTtzTwuH1Pml6FRw8CTMXKlkk/zCjioXhl3sacnHnCQoEXn49rI/NH6iiyKbSU0eCXLIOH3Szm8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741969414; c=relaxed/simple; bh=gq6fs21t7cSRukId97F+mIARUz3H+G4ZI0HcQILix+w=; 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d=bootlin.com; s=gm1; t=1741969404; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LyyfvQmKNl4kXTmIpUUFmaqUY/uk1Kr0n69NdQXeYYc=; b=ET+X0CJaJKyGJdKpsOZGNs3WFrKMdlnP+JIY3eV7p3enSwI5IU5UFSBWrRqvGX6L98Q7At rk0q2yMC5R1GcDWCxIguAC7zDKon907PMbLEJcSgwnqLiSol6v+QS5zFu+cxHLB4UuEjO+ eEX2AAalon3FWFtbVz+xwqw4R4uhL/6KEvuOIGhgncxo11gwIm/Qso4NlNTwyW5PP1uF66 wWVSrc4+JbM0MonUT3Ye6Sjh4N2yOH7vB5/jYPjAp1EO5vCSYmBqecVNE9tnLoHb2Fgy9J 6W1upBy+u3Ho8yHamzqfOxwveh1cMyQE6hEtO7ytMswGaAcX0qP7B/zO6JRPmw== From: Maxime Chevallier To: davem@davemloft.net, Andrew Lunn , Jakub Kicinski , Eric Dumazet , Paolo Abeni , Russell King , Heiner Kallweit Cc: Maxime Chevallier , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com, Florian Fainelli , =?utf-8?q?K=C3=B6ry_Maincent?= , Simon Horman , Romain Gantois , Antoine Tenart , =?utf-8?q?Marek_Beh=C3=BAn?= , Sean Anderson , =?utf-8?q?Bj=C3=B8rn_Mork?= Subject: [PATCH net-next v3 2/2] net: mdio: mdio-i2c: Add support for single-byte SMBus operations Date: Fri, 14 Mar 2025 17:23:18 +0100 Message-ID: <20250314162319.516163-3-maxime.chevallier@bootlin.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250314162319.516163-1-maxime.chevallier@bootlin.com> References: <20250314162319.516163-1-maxime.chevallier@bootlin.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgddufedufeduucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuifetpfffkfdpucggtfgfnhhsuhgsshgtrhhisggvnecuuegrihhlohhuthemuceftddunecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvfevufffkffojghfggfgsedtkeertdertddtnecuhfhrohhmpeforgigihhmvgcuvehhvghvrghllhhivghruceomhgrgihimhgvrdgthhgvvhgrlhhlihgvrhessghoohhtlhhinhdrtghomheqnecuggftrfgrthhtvghrnhepveegtdffleffleevueellefgjeefvedvjefhheegfefgffdvfeetgeevudetffdtnecukfhppedvrgdtudemtggsudelmeekugegheemgeeltddtmeeiheeikeemvdelsgdumeelvghfheemvgektgejnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepvdgrtddumegtsgduleemkegugeehmeegledttdemieehieekmedvlegsudemlegvfhehmegvkegtjedphhgvlhhopehfvgguohhrrgdqvddrhhhomhgvpdhmrghilhhfrhhomhepmhgrgihimhgvrdgthhgvvhgrlhhlihgvrhessghoohhtlhhinhdrtghomhdpnhgspghrtghpthhtohepudelpdhrtghpthhtohepuggrvhgvmhesuggrvhgvmhhlohhfthdrnhgvthdprhgtphhtthhopegrnhgurhgvfieslhhunhhnrdgthhdprhgtphhtthhopehkuhgsrgeskhgvrhhnvghlrdhorhhgpdhrtghpthhtohepvgguu hhmrgiivghtsehgohhoghhlvgdrtghomhdprhgtphhtthhopehprggsvghnihesrhgvughhrghtrdgtohhmpdhrtghpthhtoheplhhinhhugiesrghrmhhlihhnuhigrdhorhhgrdhukhdprhgtphhtthhopehhkhgrlhhlfigvihhtudesghhmrghilhdrtghomhdprhgtphhtthhopehmrgigihhmvgdrtghhvghvrghllhhivghrsegsohhothhlihhnrdgtohhm X-GND-Sasl: maxime.chevallier@bootlin.com X-Patchwork-Delegate: kuba@kernel.org PHYs that are within copper SFP modules have their MDIO bus accessible through address 0x56 (usually) on the i2c bus. The MDIO-I2C bridge is desgned for 16 bits accesses, but we can also perform 8bits accesses by reading/writing the high and low bytes sequentially. This commit adds support for this type of accesses, thus supporting smbus controllers such as the one in the VSC8552. This was only tested on Copper SFP modules that embed a Marvell 88e1111 PHY. Tested-by: Sean Anderson Signed-off-by: Maxime Chevallier --- drivers/net/mdio/mdio-i2c.c | 79 ++++++++++++++++++++++++++++++++++++- 1 file changed, 78 insertions(+), 1 deletion(-) diff --git a/drivers/net/mdio/mdio-i2c.c b/drivers/net/mdio/mdio-i2c.c index da2001ea1f99..202f486e71f1 100644 --- a/drivers/net/mdio/mdio-i2c.c +++ b/drivers/net/mdio/mdio-i2c.c @@ -106,6 +106,62 @@ static int i2c_mii_write_default_c22(struct mii_bus *bus, int phy_id, int reg, return i2c_mii_write_default_c45(bus, phy_id, -1, reg, val); } +static int smbus_byte_mii_read_default_c22(struct mii_bus *bus, int phy_id, + int reg) +{ + struct i2c_adapter *i2c = bus->priv; + union i2c_smbus_data smbus_data; + int val = 0, ret; + + if (!i2c_mii_valid_phy_id(phy_id)) + return 0; + + ret = i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0, + I2C_SMBUS_READ, reg, + I2C_SMBUS_BYTE_DATA, &smbus_data); + if (ret < 0) + return ret; + + val = ((smbus_data.byte & 0xff) << 8); + + ret = i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0, + I2C_SMBUS_READ, reg, + I2C_SMBUS_BYTE_DATA, &smbus_data); + if (ret < 0) + return ret; + + val |= (smbus_data.byte & 0xff); + + return val; +} + +static int smbus_byte_mii_write_default_c22(struct mii_bus *bus, int phy_id, + int reg, u16 val) +{ + struct i2c_adapter *i2c = bus->priv; + union i2c_smbus_data smbus_data; + int ret; + + if (!i2c_mii_valid_phy_id(phy_id)) + return 0; + + smbus_data.byte = ((val & 0xff00) >> 8); + + ret = i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0, + I2C_SMBUS_WRITE, reg, + I2C_SMBUS_BYTE_DATA, &smbus_data); + if (ret < 0) + return ret; + + smbus_data.byte = val & 0xff; + + ret = i2c_smbus_xfer(i2c, i2c_mii_phy_addr(phy_id), 0, + I2C_SMBUS_WRITE, reg, + I2C_SMBUS_BYTE_DATA, &smbus_data); + + return ret < 0 ? ret : 0; +} + /* RollBall SFPs do not access internal PHY via I2C address 0x56, but * instead via address 0x51, when SFP page is set to 0x03 and password to * 0xffffffff. @@ -378,13 +434,26 @@ static int i2c_mii_init_rollball(struct i2c_adapter *i2c) return 0; } +static bool mdio_i2c_check_functionality(struct i2c_adapter *i2c, + enum mdio_i2c_proto protocol) +{ + if (i2c_check_functionality(i2c, I2C_FUNC_I2C)) + return true; + + if (i2c_check_functionality(i2c, I2C_FUNC_SMBUS_BYTE_DATA) && + protocol == MDIO_I2C_MARVELL_C22) + return true; + + return false; +} + struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c, enum mdio_i2c_proto protocol) { struct mii_bus *mii; int ret; - if (!i2c_check_functionality(i2c, I2C_FUNC_I2C)) + if (!mdio_i2c_check_functionality(i2c, protocol)) return ERR_PTR(-EINVAL); mii = mdiobus_alloc(); @@ -395,6 +464,14 @@ struct mii_bus *mdio_i2c_alloc(struct device *parent, struct i2c_adapter *i2c, mii->parent = parent; mii->priv = i2c; + /* Only use SMBus if we have no other choice */ + if (i2c_check_functionality(i2c, I2C_FUNC_SMBUS_BYTE_DATA) && + !i2c_check_functionality(i2c, I2C_FUNC_I2C)) { + mii->read = smbus_byte_mii_read_default_c22; + mii->write = smbus_byte_mii_write_default_c22; + return mii; + } + switch (protocol) { case MDIO_I2C_ROLLBALL: ret = i2c_mii_init_rollball(i2c);