[PATCH V5 4/4] tty: serial: qcom_geni_serial: Fix the UART wakeup issue

From: satya priya
Date: Thu Sep 10 2020 - 17:43:58 EST

As a part of system suspend uart_port_suspend is called from the
Serial driver, which calls set_mctrl passing mctrl as 0. This
makes RFR high(NOT_READY) during suspend.

Due to this BT SoC is not able to send wakeup bytes to UART during
suspend. Include if check for non-suspend case to keep RFR low
during suspend.

Signed-off-by: satya priya <skakit@xxxxxxxxxxxxxx>
Acked-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Akash Asthana <akashast@xxxxxxxxxxxxxx>
Changes in V2:
- This patch fixes the UART flow control issue during suspend.
Newly added in V2.

Changes in V3:
- As per Matthias's comment removed the extra parentheses.

Changes in V4:
- No change.

Changes in V5:
- As per Matthias comment, fixed nit-pick in commit text.

drivers/tty/serial/qcom_geni_serial.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c
index 3aa29d2..bc63c54 100644
--- a/drivers/tty/serial/qcom_geni_serial.c
+++ b/drivers/tty/serial/qcom_geni_serial.c
@@ -242,7 +242,7 @@ static void qcom_geni_serial_set_mctrl(struct uart_port *uport,
if (mctrl & TIOCM_LOOP)
port->loopback = RX_TX_CTS_RTS_SORTED;

- if (!(mctrl & TIOCM_RTS))
+ if (!(mctrl & TIOCM_RTS) && !uport->suspended)
writel(uart_manual_rfr, uport->membase + SE_UART_MANUAL_RFR);
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