On Tue, Nov 27 2018 at 02:12 -0700, Stephen Boyd wrote:
Quoting Lina Iyer (2018-11-26 08:14:55)
On Wed, Nov 21 2018 at 14:36 -0700, Stephen Boyd wrote:
>Quoting Lina Iyer (2018-11-20 16:06:47)
>> SDM845 SoC has an always-on interrupt controller (PDC) with select GPIO
>> routed to the PDC as interrupts that can be used to wake the system up
>> from deep low power modes and suspend.
>>
>> Signed-off-by: Lina Iyer <ilina@xxxxxxxxxxxxxx>
>> ---
>> .../bindings/pinctrl/qcom,sdm845-pinctrl.txt | 31 ++++++++++++++++++-
>> 1 file changed, 30 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/pinctrl/qcom,sdm845-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/qcom,sdm845-pinctrl.txt
>> index 665aadb5ea28..bedfa0b57fa6 100644
>> --- a/Documentation/devicetree/bindings/pinctrl/qcom,sdm845-pinctrl.txt
>> +++ b/Documentation/devicetree/bindings/pinctrl/qcom,sdm845-pinctrl.txt
>> @@ -29,6 +29,17 @@ SDM845 platform.
>> Definition: must be 2. Specifying the pin number and flags, as defined
>> in <dt-bindings/interrupt-controller/irq.h>
>>
>> +- wakeup-parent:
>> + Usage: optional
>> + Value type: <phandle>
>> + Definition: A phandle to the wakeup interrupt controller for the SoC.
>> +
>> +- wakeup-irq:
>
>This shouldn't be needed. TLMM driver can probe for the possibility of
>wakeup capable irqs from irq allocation step. The only place we should
>need to know what TLMM pins map to what PDC lines is in the PDC driver.
>
Why? Every driver seems to translate the hardware IRQ and pass it to
it's parent. Why should this be any different ? The PDC is an interrupt
controller that just knows an interrupt port and maps it to the GIC. Not
sure, I understand the reasoning for this. It seems to add more
confusing relationship with the PDC interrupt controller, that way.
Two reasons. First, simplicity. The TLMM driver just needs to pass the
gpio number up to the PDC gpio domain and then that domain can figure
out what hwirq it maps to within the PDC hw irq space. I don't see any
reason why we have to know the hwirq of PDC within the TLMM driver
besides "let's not be different".
And second, it makes it easier for us to implement the MPM case in the
TLMM driver by letting the TLMM code just ask "should I mask the irq
here or not?" by passing that with a wrapper struct around the fwspec
and a dedicated domain in the PDC/MPM driver. Keeping less things in the
TLMM driver and not driving the decision from DT but from tables in the
PDC driver also keeps things simple and reduces DT parsing code/time.
Couldn't this be simply achieved by matching the compatible flags for
PDC/MPM bindings for the wakeup-parent in the TLMM driver?
Thanks,
Lina
