Re: [PATCH net-next v4 1/4] net: phy: mdio-i2c: support I2C MDIO protocol for RollBall SFP modules

[Andrew Lunn]

> +static int i2c_transfer_rollball(struct i2c_adapter *i2c,
> +                              struct i2c_msg *msgs, int num)
> +{
> +     u8 saved_page;
> +     int ret;
> +
> +     i2c_lock_bus(i2c, I2C_LOCK_SEGMENT);
> +
> +     /* save original page */
> +     ret = __i2c_rollball_get_page(i2c, msgs->addr, &saved_page);
> +     if (ret)
> +             goto unlock;
> +
> +     /* change to RollBall MDIO page */
> +     ret = __i2c_rollball_set_page(i2c, msgs->addr, SFP_PAGE_ROLLBALL_MDIO);
> +     if (ret)
> +             goto unlock;
> +
> +     /* do the transfer */
> +     ret = __i2c_transfer_err(i2c, msgs, num);
> +     if (ret)
> +             goto unlock;

If get page and set page worked, and you get an error in during the
actual data transfer, i wonder if you should try restoring the page
before returning with the error?

> +
> +     /* restore original page */
> +     ret = __i2c_rollball_set_page(i2c, msgs->addr, saved_page);
> +
> +unlock:
> +     i2c_unlock_bus(i2c, I2C_LOCK_SEGMENT);
> +
> +     return ret;
> +}