CSI2_PHY_TST_CTRL1
writel(0x0, csi2->base + CSI2_PHY_TST_CTRL1);
writel(PHY_TESTEN | test_code, csi2->base + CSI2_PHY_TST_CTRL1);
writel(test_data, csi2->base + CSI2_PHY_TST_CTRL1);
readl(csi2->base + CSI2_PHY_TST_CTRL1));