F_SCL_FREQ
ret = regmap_field_write(i2c->fields[F_SCL_FREQ], chan->bus_freq);
[F_SCL_FREQ] = MST_REG_FIELD(RTL9300_I2C_MST_CTRL2, 0, 1),
[F_SCL_FREQ] = MST_REG_FIELD(RTL9310_I2C_MST_CTRL, 30, 31),