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

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@codeaurora.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Akash Asthana <akashast@codeaurora.org>
---
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(-)

On Thu 10 Sep 12:53 UTC 2020, satya priya wrote:

> 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.
> 

Seems reasonable.

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

> Signed-off-by: satya priya <skakit@codeaurora.org>
> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Greg, I don't see this depending on anything else, will you pick this
patch through your tree? I will take the dts patches through the qcom
tree.

Regards,
Bjorn

> Reviewed-by: Akash Asthana <akashast@codeaurora.org>
> ---
> 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)
>  		uart_manual_rfr = UART_MANUAL_RFR_EN | UART_RFR_NOT_READY;
>  	writel(uart_manual_rfr, uport->membase + SE_UART_MANUAL_RFR);
>  }
> -- 
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
> of Code Aurora Forum, hosted by The Linux Foundation
>

On Thu, Sep 10, 2020 at 11:06:39PM +0000, Bjorn Andersson wrote:
> On Thu 10 Sep 12:53 UTC 2020, satya priya wrote:
> 
> > 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.
> > 
> 
> Seems reasonable.
> 
> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> 
> > Signed-off-by: satya priya <skakit@codeaurora.org>
> > Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> 
> Greg, I don't see this depending on anything else, will you pick this
> patch through your tree? I will take the dts patches through the qcom
> tree.

Sure, will pick it up now, thanks.

greg k-h