R518_I2C_CTL
reg_w(sd, R518_I2C_CTL, 0x01);
reg_r8(sd, R518_I2C_CTL);
reg_w(sd, R518_I2C_CTL, 0x03);
reg_r8(sd, R518_I2C_CTL);
reg_w(sd, R518_I2C_CTL, 0x05);
reg_r8(sd, R518_I2C_CTL);