arm64: dts: qcom: msm8998: Fixup uart3 gpio config for bluetooth

It turns out that the wcn3990 can float the gpio lines during bootup, etc
which will result in the uart core thinking there is incoming data.  This
results in the bluetooth stack getting garbage.  By applying a bias to
match what wcn3990 would drive, the issue is corrected.

Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com>
Link: https://lore.kernel.org/r/20191021161921.31825-1-jeffrey.l.hugo@gmail.com
[bjorn: Moved board specific pinctrl states to the end]
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

diff --git a/arch/arm64/boot/dts/qcom/msm8998-clamshell.dtsi b/arch/arm64/boot/dts/qcom/msm8998-clamshell.dtsi
index 0f84fa0894a4f41a28f56df6c8ea2d06129564ad..b3cf263f4a00aa87f474ba4f25a74a115366fd0f 100644 (file)
--- a/arch/arm64/boot/dts/qcom/msm8998-clamshell.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8998-clamshell.dtsi
@@ -301,3 +301,26 @@
        vdd-1.3-rfa-supply = <&vreg_l17a_1p3>;
        vdd-3.3-ch0-supply = <&vreg_l25a_3p3>;
 };
+
+/* PINCTRL - board-specific pinctrl */
+&blsp1_uart3_on {
+       rx {
+               /delete-property/ bias-disable;
+               /*
+                * Configure a pull-up on 45 (RX). This is needed to
+                * avoid garbage data when the TX pin of the Bluetooth
+                * module is in tri-state (module powered off or not
+                * driving the signal yet).
+                */
+               bias-pull-up;
+       };
+
+       cts {
+               /delete-property/ bias-disable;
+               /*
+                * Configure a pull-down on 47 (CTS) to match the pull
+                * of the Bluetooth module.
+                */
+               bias-pull-down;
+       };
+};

diff --git a/arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi b/arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi
index 1220756fb5b3134386b66174655310a57f7c892d..6835fbd9636ed05036f4bdf97536a6bcfe2f6ec2 100644 (file)
--- a/arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8998-mtp.dtsi
@@ -373,3 +373,26 @@
        vdd-1.3-rfa-supply = <&vreg_l17a_1p3>;
        vdd-3.3-ch0-supply = <&vreg_l25a_3p3>;
 };
+
+/* PINCTRL - board-specific pinctrl */
+&blsp1_uart3_on {
+       rx {
+               /delete-property/ bias-disable;
+               /*
+                * Configure a pull-up on 45 (RX). This is needed to
+                * avoid garbage data when the TX pin of the Bluetooth
+                * module is in tri-state (module powered off or not
+                * driving the signal yet).
+                */
+               bias-pull-up;
+       };
+
+       cts {
+               /delete-property/ bias-disable;
+               /*
+                * Configure a pull-down on 47 (CTS) to match the pull
+                * of the Bluetooth module.
+                */
+               bias-pull-down;
+       };
+};

diff --git a/arch/arm64/boot/dts/qcom/msm8998-pins.dtsi b/arch/arm64/boot/dts/qcom/msm8998-pins.dtsi
index e32d3ab395ea8d0b582ea6b09635e41ef7140fd8..7c222cbf19d9cf8688107f41578900fe7a3e5ac3 100644 (file)
--- a/arch/arm64/boot/dts/qcom/msm8998-pins.dtsi
+++ b/arch/arm64/boot/dts/qcom/msm8998-pins.dtsi
@@ -77,13 +77,30 @@
        };
 
        blsp1_uart3_on: blsp1_uart3_on {
-               mux {
-                       pins = "gpio45", "gpio46", "gpio47", "gpio48";
+               tx {
+                       pins = "gpio45";
                        function = "blsp_uart3_a";
+                       drive-strength = <2>;
+                       bias-disable;
                };
 
-               config {
-                       pins = "gpio45", "gpio46", "gpio47", "gpio48";
+               rx {
+                       pins = "gpio46";
+                       function = "blsp_uart3_a";
+                       drive-strength = <2>;
+                       bias-disable;
+               };
+
+               cts {
+                       pins = "gpio47";
+                       function = "blsp_uart3_a";
+                       drive-strength = <2>;
+                       bias-disable;
+               };
+
+               rfr {
+                       pins = "gpio48";
+                       function = "blsp_uart3_a";
                        drive-strength = <2>;
                        bias-disable;
                };