Re: [PATCH V3 1/3] arm64: dts: sc7180: Add wakeup support over UART RX

From: skakit
Date: Wed Sep 02 2020 - 09:16:54 EST


Hi Matthias,

On 2020-08-21 21:56, Matthias Kaehlcke wrote:
On Thu, Aug 20, 2020 at 07:21:05PM +0530, satya priya wrote:
Add the necessary pinctrl and interrupts to make UART
wakeup capable.

Signed-off-by: satya priya <skakit@xxxxxxxxxxxxxx>
Reviewed-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
---
Changes in V2:
- As per Matthias's comment added wakeup support for all the UARTs
of SC7180.

Changes in V3:
- No change.

arch/arm64/boot/dts/qcom/sc7180.dtsi | 98 ++++++++++++++++++++++++++++++------
1 file changed, 84 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/sc7180.dtsi b/arch/arm64/boot/dts/qcom/sc7180.dtsi
index d46b383..855b13e 100644
--- a/arch/arm64/boot/dts/qcom/sc7180.dtsi
+++ b/arch/arm64/boot/dts/qcom/sc7180.dtsi

...

+ qup_uart0_sleep: qup-uart0-sleep {
+ pinmux {
+ pins = "gpio34", "gpio35",
+ "gpio36", "gpio37";
+ function = "gpio";

What is the reason that the GPIO function needs to be selected in sleep mode
to support wakeup?

This should be explained in the commit message unless it is evident.

When QUP function is selected in sleep state, RTS/RFR is pulled high as soon as we enter suspend and not receiving wakeup bytes from BT SoC to wakeup device. Whereas in GPIO mode it is staying low and receiving data.

Thanks,
Satya Priya