apalis-tk1: lvds: allow setting LVDS drive strength in dt

Hardcoded value was used before. This allows setting
drive strength values in the devicetree.

Signed-off-by: Dominik Sliwa <dominik.sliwa@toradex.com>
Acked-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>

6 files changed, 36 insertions, 1 deletions

diff --git a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-displays.dtsi b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-displays.dtsi
index 0ef2503b7e77..211905e74ff2 100644
--- a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-displays.dtsi
+++ b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-displays.dtsi
@@ -13,6 +13,7 @@
 
 		lvds:lvds {
 			status = "okay";
+			lvds-drive-strength = <0x40 0x40 0x40 0x40>;
 			display {
 				status = "okay";
 				disp-default-out {
diff --git a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-displays.dtsi b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-displays.dtsi
index da0f82024ce0..3670e63a2033 100644
--- a/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-displays.dtsi
+++ b/arch/arm/boot/dts/tegra124-platforms/tegra124-apalis-v1.2-displays.dtsi
@@ -13,6 +13,7 @@
 
 		lvds:lvds {
 			status = "okay";
+			lvds-drive-strength = <0x40 0x40 0x40 0x40>;
 			display {
 				status = "okay";
 				disp-default-out {
diff --git a/arch/arm/mach-tegra/include/mach/dc.h b/arch/arm/mach-tegra/include/mach/dc.h
index 880545833270..6eafba0101df 100644
--- a/arch/arm/mach-tegra/include/mach/dc.h
+++ b/arch/arm/mach-tegra/include/mach/dc.h
@@ -578,6 +578,7 @@ struct tegra_dc_out {
 	struct tegra_hdmi_out		*hdmi_out;
 	struct tegra_dp_out		*dp_out;
 	struct tegra_stereo_out		*stereo;
+	u32				lvds_drive_strength;
 
 	unsigned			height; /* mm */
 	unsigned			width; /* mm */
diff --git a/drivers/video/tegra/dc/of_dc.c b/drivers/video/tegra/dc/of_dc.c
index aed0fda91299..4e071cf9f139 100644
--- a/drivers/video/tegra/dc/of_dc.c
+++ b/drivers/video/tegra/dc/of_dc.c
@@ -246,6 +246,29 @@ parse_tmds_fail:
 	return -EINVAL;
 }
 
+static u32 parse_dt_lvds_drive_strength(struct device_node *np)
+{
+	u32 temp[4];
+	u32 drive_strength = 0;
+
+	if(of_property_read_u32_array(np, "lvds-drive-strength",
+				temp, 4)) {
+		OF_DC_LOG("No lvds-drive-strength entry\n");
+		return 0;
+	}
+
+	for (int i = 0; i < 4;i++) {
+		if (temp[i] < 0x100) {
+			drive_strength += (temp[i] << i*8);
+		} else {
+			OF_DC_LOG("Invalid LVDS driver strength for lane %d\n", i);
+			return 0;
+		}
+	}
+
+	return drive_strength;
+}
+
 static int parse_dt_lt(struct device_node *np,
 	u8 *addr)
 {
@@ -1803,6 +1826,8 @@ struct tegra_dc_platform_data
 			pr_err("lvds/display node is NOT valid\n");
 			goto fail_parse;
 		}
+		pdata->default_out->lvds_drive_strength =
+				parse_dt_lvds_drive_strength(np_target_disp);
 		pdata->default_out->enable = dc_lvds_enable;
 		pdata->default_out->disable = dc_lvds_disable;
 
diff --git a/drivers/video/tegra/dc/sor.c b/drivers/video/tegra/dc/sor.c
index 5fee008d122a..f80d9e8f7ac0 100644
--- a/drivers/video/tegra/dc/sor.c
+++ b/drivers/video/tegra/dc/sor.c
@@ -1277,8 +1277,14 @@ void tegra_dc_sor_enable_lvds(struct tegra_dc_sor_data *sor,
 		reg_val |= (NV_SOR_LVDS_PD_TXDA_3_DISABLE);
 
 	tegra_sor_writel(sor, NV_SOR_LVDS, reg_val);
-	tegra_sor_writel(sor, NV_SOR_LANE_DRIVE_CURRENT(sor->portnum),
+	if (sor->dc->pdata->default_out->lvds_drive_strength > 0 ) {
+		tegra_sor_writel(sor, NV_SOR_LANE_DRIVE_CURRENT(sor->portnum),
+			sor->dc->pdata->default_out->lvds_drive_strength);
+	} else {
+		tegra_sor_writel(sor, NV_SOR_LANE_DRIVE_CURRENT(sor->portnum),
 		0x40404040);
+	}
+
 	if (!conforming && (sor->dc->pdata->default_out->depth == 24)) {
 		tegra_sor_write_field(sor, NV_SOR_LVDS,
 			NV_SOR_LVDS_ROTDAT_DEFAULT_MASK,
diff --git a/drivers/video/tegra/dc/sor.h b/drivers/video/tegra/dc/sor.h
index 261716950372..e7282d2fd36b 100644
--- a/drivers/video/tegra/dc/sor.h
+++ b/drivers/video/tegra/dc/sor.h
@@ -93,6 +93,7 @@ struct tegra_dc_sor_data {
 
 	u8					 portnum;	/* 0 or 1 */
 	const struct tegra_dc_dp_link_config	*link_cfg;
+	u32	lvds_drive_strength;
 
 	bool   power_is_up;