diff mbox series

[net-next,v3,06/14] net: mdio-i2c: add support for Clause 45 accesses

Message ID E1iezfI-0002yD-2U@rmk-PC.armlinux.org.uk
State Accepted
Delegated to: David Miller
Headers show
Series Add support for SFP+ copper modules | expand

Commit Message

Russell King (Oracle) Dec. 11, 2019, 10:56 a.m. UTC
Some SFP+ modules have PHYs on them just like SFP modules do, except
they are Clause 45 PHYs.  The I2C protocol used to access them is
modified slightly in order to send the device address and 16-bit
register index.

Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 drivers/net/phy/mdio-i2c.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/phy/mdio-i2c.c b/drivers/net/phy/mdio-i2c.c
index 0dce67672548..0746e2cc39ae 100644
--- a/drivers/net/phy/mdio-i2c.c
+++ b/drivers/net/phy/mdio-i2c.c
@@ -33,17 +33,24 @@  static int i2c_mii_read(struct mii_bus *bus, int phy_id, int reg)
 {
 	struct i2c_adapter *i2c = bus->priv;
 	struct i2c_msg msgs[2];
-	u8 data[2], dev_addr = reg;
+	u8 addr[3], data[2], *p;
 	int bus_addr, ret;
 
 	if (!i2c_mii_valid_phy_id(phy_id))
 		return 0xffff;
 
+	p = addr;
+	if (reg & MII_ADDR_C45) {
+		*p++ = 0x20 | ((reg >> 16) & 31);
+		*p++ = reg >> 8;
+	}
+	*p++ = reg;
+
 	bus_addr = i2c_mii_phy_addr(phy_id);
 	msgs[0].addr = bus_addr;
 	msgs[0].flags = 0;
-	msgs[0].len = 1;
-	msgs[0].buf = &dev_addr;
+	msgs[0].len = p - addr;
+	msgs[0].buf = addr;
 	msgs[1].addr = bus_addr;
 	msgs[1].flags = I2C_M_RD;
 	msgs[1].len = sizeof(data);
@@ -61,18 +68,23 @@  static int i2c_mii_write(struct mii_bus *bus, int phy_id, int reg, u16 val)
 	struct i2c_adapter *i2c = bus->priv;
 	struct i2c_msg msg;
 	int ret;
-	u8 data[3];
+	u8 data[5], *p;
 
 	if (!i2c_mii_valid_phy_id(phy_id))
 		return 0;
 
-	data[0] = reg;
-	data[1] = val >> 8;
-	data[2] = val;
+	p = data;
+	if (reg & MII_ADDR_C45) {
+		*p++ = (reg >> 16) & 31;
+		*p++ = reg >> 8;
+	}
+	*p++ = reg;
+	*p++ = val >> 8;
+	*p++ = val;
 
 	msg.addr = i2c_mii_phy_addr(phy_id);
 	msg.flags = 0;
-	msg.len = 3;
+	msg.len = p - data;
 	msg.buf = data;
 
 	ret = i2c_transfer(i2c, &msg, 1);