[PATCH v2] arm64: dts: rockchip: Adjust the HDMI DDC IO driver strength for rk3588

[Andy Yan]

From: Andy Yan <andy.yan at rock-chips.com>

For the RK3588 HDMI controller, the falling edge of DDC SDA and SCL
almost coincide and cannot be adjusted by HDMI registrer, resulting
in poor compatibility of DDC communication.

An improvement of the compatibility of DDC can be done by increasing
the driver strength of SCL and decreasing the driver strength of SDA
to increase the slope of the falling edge.

It should be noted that the maximum driving strength of hdmim0_tx1_scl
is only 3, which is different from that of the other IOs.

Signed-off-by: Andy Yan <andy.yan at rock-chips.com>

---

Changes in v2:
- Correct the max drive level of hdmim0_tx1_scl.

 .../dts/rockchip/rk3588-base-pinctrl.dtsi     | 20 +++++------
 .../dts/rockchip/rk3588-extra-pinctrl.dtsi    |  5 +--
 .../boot/dts/rockchip/rockchip-pinconf.dtsi   | 35 +++++++++++++++++++
 3 files changed, 48 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/boot/dts/rockchip/rk3588-base-pinctrl.dtsi b/arch/arm64/boot/dts/rockchip/rk3588-base-pinctrl.dtsi
index 7f874c77410c..6584d73660f6 100644
--- a/arch/arm64/boot/dts/rockchip/rk3588-base-pinctrl.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3588-base-pinctrl.dtsi
@@ -578,14 +578,14 @@ hdmim0_tx0_hpd: hdmim0-tx0-hpd {
 		hdmim0_tx0_scl: hdmim0-tx0-scl {
 			rockchip,pins =
 				/* hdmim0_tx0_scl */
-				<4 RK_PB7 5 &pcfg_pull_none>;
+				<4 RK_PB7 5 &pcfg_pull_none_drv_level_5_smt>;
 		};
 
 		/omit-if-no-ref/
 		hdmim0_tx0_sda: hdmim0-tx0-sda {
 			rockchip,pins =
 				/* hdmim0_tx0_sda */
-				<4 RK_PC0 5 &pcfg_pull_none>;
+				<4 RK_PC0 5 &pcfg_pull_none_drv_level_1_smt>;
 		};
 
 		/omit-if-no-ref/
@@ -640,14 +640,14 @@ hdmim1_tx0_hpd: hdmim1-tx0-hpd {
 		hdmim1_tx0_scl: hdmim1-tx0-scl {
 			rockchip,pins =
 				/* hdmim1_tx0_scl */
-				<0 RK_PD5 11 &pcfg_pull_none>;
+				<0 RK_PD5 11 &pcfg_pull_none_drv_level_5_smt>;
 		};
 
 		/omit-if-no-ref/
 		hdmim1_tx0_sda: hdmim1-tx0-sda {
 			rockchip,pins =
 				/* hdmim1_tx0_sda */
-				<0 RK_PD4 11 &pcfg_pull_none>;
+				<0 RK_PD4 11 &pcfg_pull_none_drv_level_1_smt>;
 		};
 
 		/omit-if-no-ref/
@@ -668,14 +668,14 @@ hdmim1_tx1_hpd: hdmim1-tx1-hpd {
 		hdmim1_tx1_scl: hdmim1-tx1-scl {
 			rockchip,pins =
 				/* hdmim1_tx1_scl */
-				<3 RK_PC6 5 &pcfg_pull_none>;
+				<3 RK_PC6 5 &pcfg_pull_none_drv_level_5_smt>;
 		};
 
 		/omit-if-no-ref/
 		hdmim1_tx1_sda: hdmim1-tx1-sda {
 			rockchip,pins =
 				/* hdmim1_tx1_sda */
-				<3 RK_PC5 5 &pcfg_pull_none>;
+				<3 RK_PC5 5 &pcfg_pull_none_drv_level_1_smt>;
 		};
 		/omit-if-no-ref/
 		hdmim2_rx_cec: hdmim2-rx-cec {
@@ -709,14 +709,14 @@ hdmim2_rx_sda: hdmim2-rx-sda {
 		hdmim2_tx0_scl: hdmim2-tx0-scl {
 			rockchip,pins =
 				/* hdmim2_tx0_scl */
-				<3 RK_PC7 5 &pcfg_pull_none>;
+				<3 RK_PC7 5 &pcfg_pull_none_drv_level_5_smt>;
 		};
 
 		/omit-if-no-ref/
 		hdmim2_tx0_sda: hdmim2-tx0-sda {
 			rockchip,pins =
 				/* hdmim2_tx0_sda */
-				<3 RK_PD0 5 &pcfg_pull_none>;
+				<3 RK_PD0 5 &pcfg_pull_none_drv_level_1_smt>;
 		};
 
 		/omit-if-no-ref/
@@ -730,14 +730,14 @@ hdmim2_tx1_cec: hdmim2-tx1-cec {
 		hdmim2_tx1_scl: hdmim2-tx1-scl {
 			rockchip,pins =
 				/* hdmim2_tx1_scl */
-				<1 RK_PA4 5 &pcfg_pull_none>;
+				<1 RK_PA4 5 &pcfg_pull_none_drv_level_5_smt>;
 		};
 
 		/omit-if-no-ref/
 		hdmim2_tx1_sda: hdmim2-tx1-sda {
 			rockchip,pins =
 				/* hdmim2_tx1_sda */
-				<1 RK_PA3 5 &pcfg_pull_none>;
+				<1 RK_PA3 5 &pcfg_pull_none_drv_level_1_smt>;
 		};
 
 		/omit-if-no-ref/
diff --git a/arch/arm64/boot/dts/rockchip/rk3588-extra-pinctrl.dtsi b/arch/arm64/boot/dts/rockchip/rk3588-extra-pinctrl.dtsi
index 244c66faa161..fb48ddc04bcb 100644
--- a/arch/arm64/boot/dts/rockchip/rk3588-extra-pinctrl.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rk3588-extra-pinctrl.dtsi
@@ -160,14 +160,15 @@ hdmim0_tx1_cec: hdmim0-tx1-cec {
 		hdmim0_tx1_scl: hdmim0-tx1-scl {
 			rockchip,pins =
 				/* hdmim0_tx1_scl */
-				<2 RK_PB5 4 &pcfg_pull_none>;
+				<2 RK_PB5 4 &pcfg_pull_none_drv_level_3_smt>;
 		};
 
 		/omit-if-no-ref/
 		hdmim0_tx1_sda: hdmim0-tx1-sda {
 			rockchip,pins =
 				/* hdmim0_tx1_sda */
-				<2 RK_PB4 4 &pcfg_pull_none>;
+				<2 RK_PB4 4 &pcfg_pull_none_drv_level_1_smt>;
+
 		};
 	};
 
diff --git a/arch/arm64/boot/dts/rockchip/rockchip-pinconf.dtsi b/arch/arm64/boot/dts/rockchip/rockchip-pinconf.dtsi
index 5c645437b507..b0475b7c655a 100644
--- a/arch/arm64/boot/dts/rockchip/rockchip-pinconf.dtsi
+++ b/arch/arm64/boot/dts/rockchip/rockchip-pinconf.dtsi
@@ -332,6 +332,41 @@ pcfg_pull_none_drv_level_0_smt: pcfg-pull-none-drv-level-0-smt {
 		input-schmitt-enable;
 	};
 
+	/omit-if-no-ref/
+	pcfg_pull_none_drv_level_1_smt: pcfg-pull-none-drv-level-1-smt {
+		bias-disable;
+		drive-strength = <1>;
+		input-schmitt-enable;
+	};
+
+	/omit-if-no-ref/
+	pcfg_pull_none_drv_level_2_smt: pcfg-pull-none-drv-level-2-smt {
+		bias-disable;
+		drive-strength = <2>;
+		input-schmitt-enable;
+	};
+
+	/omit-if-no-ref/
+	pcfg_pull_none_drv_level_3_smt: pcfg-pull-none-drv-level-3-smt {
+		bias-disable;
+		drive-strength = <3>;
+		input-schmitt-enable;
+	};
+
+	/omit-if-no-ref/
+	pcfg_pull_none_drv_level_4_smt: pcfg-pull-none-drv-level-4-smt {
+		bias-disable;
+		drive-strength = <4>;
+		input-schmitt-enable;
+	};
+
+	/omit-if-no-ref/
+	pcfg_pull_none_drv_level_5_smt: pcfg-pull-none-drv-level-5-smt {
+		bias-disable;
+		drive-strength = <5>;
+		input-schmitt-enable;
+	};
+
 	/omit-if-no-ref/
 	pcfg_output_high: pcfg-output-high {
 		output-high;
-- 
2.43.0

base-commit: 897af18e5d75e7ebf137044d57fed6522c46ae74
branch: linux-rockchip-next