[PATCH V5 2/4] arm64: dts: qcom: sc7180: Add necessary pinctrl and interrupt config for BT UART

[satya priya]

Add a suitable sleep configuration for uart3 to support Bluetooth wakeup.

If QUP function is selected in sleep state, UART RTS/RFR is pulled high
during suspend and BT SoC not able to send wakeup bytes. So, configure
GPIO mode in sleep state to keep it low during suspend.

Signed-off-by: satya priya <skakit@xxxxxxxxxxxxxx>
Reviewed-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
---
Changes in V2:
 - This patch adds sleep state for BT UART. Newly added in V2.

Changes in V3:
 - Remove "output-high" for TX from both sleep and default states
   as it is not required. Configure pull-up for TX in sleep state.

Changes in V4:
 - As per Matthias's comment, removed drive-strength for sleep state
   and fixed nit-pick.

Changes in V5:
 - As per Matthias's comments, moved pinmux change for sleep state,
   pinctrl and interrupt config to the board specific file.

 arch/arm64/boot/dts/qcom/sc7180-idp.dts | 48 +++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sc7180-idp.dts b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
index 04888df..e529a41 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-idp.dts
+++ b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
@@ -344,6 +344,10 @@
 };
 
 &uart3 {
+	pinctrl-names = "default", "sleep";
+	pinctrl-1 = <&qup_uart3_sleep>;
+	interrupts-extended = <&intc GIC_SPI 604 IRQ_TYPE_LEVEL_HIGH>,
+				<&tlmm 41 IRQ_TYPE_EDGE_FALLING>;
 	status = "okay";
 
 	bluetooth: wcn3990-bt {
@@ -545,3 +549,47 @@
 	};
 };
 
+&tlmm {
+	qup_uart3_sleep: qup-uart3-sleep {
+		pinmux {
+			pins = "gpio38", "gpio39",
+			       "gpio40", "gpio41";
+			function = "gpio";
+		};
+
+		pinconf-cts {
+			/*
+			 * Configure a pull-down on CTS to match the pull of
+			 * the Bluetooth module.
+			 */
+			pins = "gpio38";
+			bias-pull-down;
+		};
+
+		pinconf-rts {
+			/*
+			 * Configure pull-down on RTS to make sure that the BT SoC can
+			 * wake up the system by sending wakeup bytes during suspend.
+			 */
+			 pins = "gpio39";
+			 bias-pull-down;
+		};
+
+		pinconf-tx {
+			/* Configure pull-up on TX when it isn't actively driven */
+			pins = "gpio40";
+			bias-pull-up;
+		};
+
+		pinconf-rx {
+			/*
+			 * Configure a pull-up on 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).
+			 */
+			pins = "gpio41";
+			bias-pull-up;
+		};
+	};
+};
-- 
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