Re: [PATCH v5 2/3] tty: serial: qcom_geni_serial: Wakeup over UART RX

Akash Asthana
2019-11-22T06:46:34Z

On 11/16/2019 1:11 AM, Stephen Boyd wrote:
> Quoting Akash Asthana (2019-11-15 02:00:44)
>> On 11/14/2019 11:10 PM, Stephen Boyd wrote:
>>> Quoting Akash Asthana (2019-11-13 02:48:56)
>>>> Add system wakeup capability over UART RX line for wakeup capable UART.
>>>> When system is suspended, RX line act as an interrupt to wakeup system
>>>> for any communication requests from peer.
>>> How does the RX line get remuxed as a GPIO interrupt here? Is that
>>> through some pinctrl magic in DT or just via enabling/disabling the
>>> interrupt?
>> Yes, For wakeup capable UART node, we have registered UART RX line with
>> TLMM interrupt controller in DT file . Example: if GPIO48 is UART RX line
>>
>> interrupts-extended =  <&intc GIC_SPI 607 IRQ_TYPE_LEVEL_HIGH>,  <&tlmm
>> 48 IRQ_TYPE_EDGE_FALLING>;
> Right. So is gpio48 muxed as 'uart' function forever and the interrupt
> logic in tlmm is connected to that pad regardless of the function
> selected? I thought that gpios through TLMM had to be muxed as function
> 0, i.e. gpio function, so that interrupts worked. But maybe that's wrong
> and it can work without that.

Yes, gpio48 is muxed as "uart' function function forever. There is no
need to mux gpio48 to

gpio function, interrupts can work without that.