[d-kernel] [PATCH 3/3] arm64: dts: rockchip: Adjust the HDMI DDC IO driver strength for rk3588

[Daniil Gnusarev <gnusarevda@basealt.ru>]

From: Andy Yan <andy.yan@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@rock-chips.com>
Tested-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://lore.kernel.org/r/20250522020537.1884771-1-andyshrk@163.com
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
(cherry picked from commit af9feb0b85f92d2972061224839c5fea5ee39f6d)
Signed-off-by: Daniil Gnusarev <gnusarevda@basealt.ru>
---
 .../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 d1368418502a5..e77907e637d44 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 244c66faa1614..fb48ddc04bcbd 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 5c645437b5072..b0475b7c655ae 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;
-- 
2.42.2