Add sleep state for BT uart to support the wakeup feature.

Signed-off-by: satya priya <[email protected]>
Reviewed-by: Akash Asthana <[email protected]>
---
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.

 arch/arm64/boot/dts/qcom/sc7180-idp.dts | 37 +++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/sc7180-idp.dts 
b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
index cecac3e..77e3523 100644
--- a/arch/arm64/boot/dts/qcom/sc7180-idp.dts
+++ b/arch/arm64/boot/dts/qcom/sc7180-idp.dts
@@ -507,6 +507,43 @@
        };
 };
 
+&qup_uart3_sleep {
+       pinconf-cts {
+               /*
+                * Configure no-pull on CTS. As this is driven by BT, do not
+                * specify any pull in order to not conflict with BT pulls.
+                */
+               pins = "gpio38";
+               bias-disable;
+       };
+
+       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;
+       };
+};
+
 &qup_uart8_default {
        pinconf-tx {
                pins = "gpio44";
-- 
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