gpu: host1x: mipi: Set MIPI_CAL_BIAS_PAD_CFG1 register

During calibration, sets the "internal reference level for drive pull-
down" to the value specified in the Tegra TRM.
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Thierry Reding <treding@nvidia.com>

drivers/gpu/host1x/mipi.c

@@ -72,6 +72,7 @@
 #define MIPI_CAL_BIAS_PAD_E_VCLAMP_REF	(1 << 0)
 
 #define MIPI_CAL_BIAS_PAD_CFG1		0x17
+#define MIPI_CAL_BIAS_PAD_DRV_DN_REF(x) (((x) & 0x7) << 16)
 
 #define MIPI_CAL_BIAS_PAD_CFG2		0x18
 #define MIPI_CAL_BIAS_PAD_PDVREG	(1 << 1)
@@ -203,6 +204,9 @@ int tegra_mipi_calibrate(struct tegra_mipi_device *device)
 	value |= MIPI_CAL_BIAS_PAD_E_VCLAMP_REF;
 	tegra_mipi_writel(device->mipi, value, MIPI_CAL_BIAS_PAD_CFG0);
 
+	tegra_mipi_writel(device->mipi, MIPI_CAL_BIAS_PAD_DRV_DN_REF(2),
+			  MIPI_CAL_BIAS_PAD_CFG1);
+
 	value = tegra_mipi_readl(device->mipi, MIPI_CAL_BIAS_PAD_CFG2);
 	value &= ~MIPI_CAL_BIAS_PAD_PDVREG;
 	tegra_mipi_writel(device->mipi, value, MIPI_CAL_BIAS_PAD_CFG2);