> +/* 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.
> + * Since current SFP code does not modify SFP_PAGE, we set it to 0x03 only at
> + * bus creation time, and expect it to remain set to 0x03 throughout the
> + * lifetime of the module plugged into the system. If the SFP code starts
> + * modifying SFP_PAGE in the future, this code will need to change.
...
> +/* In order to not interfere with other SFP code (which possibly may
> manipulate
> + * SFP_PAGE), for every transfer we do this:
> + * 1. lock the bus
> + * 2. save content of SFP_PAGE
> + * 3. set SFP_PAGE to 3
> + * 4. do the transfer
> + * 5. restore original SFP_PAGE
> + * 6. unlock the bus
These two comments seem to contradict each other?
> +static int i2c_rollball_mii_poll(struct mii_bus *bus, int bus_addr, u8 *buf,
> + size_t len)
> +{
> + struct i2c_adapter *i2c = bus->priv;
> + struct i2c_msg msgs[2];
> + u8 cmd_addr, tmp, *res;
> + int i, ret;
> +
> + cmd_addr = ROLLBALL_CMD_ADDR;
> +
> + res = buf ? buf : &tmp;
> + len = buf ? len : 1;
> +
> + msgs[0].addr = bus_addr;
> + msgs[0].flags = 0;
> + msgs[0].len = 1;
> + msgs[0].buf = &cmd_addr;
> +
> + msgs[1].addr = bus_addr;
> + msgs[1].flags = I2C_M_RD;
> + msgs[1].len = len;
> + msgs[1].buf = res;
> +
> + /* By experiment it takes up to 70 ms to access a register for these
> + * SFPs. Sleep 20ms between iteratios and try 10 times.
> + */
iterations
> +static int i2c_mii_read_rollball(struct mii_bus *bus, int phy_id, int reg)
> +{
> + u8 buf[4], res[6];
> + int bus_addr, ret;
> + u16 val;
> +
> + if (!(reg & MII_ADDR_C45))
> + return -EOPNOTSUPP;
> +
> + bus_addr = i2c_mii_phy_addr(phy_id);
> + if (bus_addr != ROLLBALL_PHY_I2C_ADDR)
> + return 0xffff;
> +
> + buf[0] = ROLLBALL_DATA_ADDR;
> + buf[1] = (reg >> 16) & 0x1f;
> + buf[2] = (reg >> 8) & 0xff;
> + buf[3] = reg & 0xff;
This looks odd. There are only 32 registers for C22 transactions, so
it fits in one byte. You can set buf[1] and buf[2] to zero.
C45 transactions allow for 65536 registers, and has the devtype field,
so would need 3 bytes. Which suggests that C45 might actually be
supported? At least by the protocol, if not the device.
> + dev_dbg(&bus->dev, "read reg %02x:%04x = %04x\n", (reg >> 16) & 0x1f,
> + reg & 0xffff, val);
There is a tracepoint that allows access to this information, so you
can probably remove this.
Andrew
