Enhancement: Improve PD power class detection approach

[vthakur7f]

Product: (OC-SDR, OC-LTE, OC-LTE, OC-Power, others)

OC-SDR

Component: (PSU, GBC, BBU, FEM, LED, ME)

GBC

Category: (Hardware, Software/stack, Firmware/bootloader, Documentation)

Firmware/OCWare
Describe the solution you'd like
One option was to use ADC if we have nT2P pin connected to EC ADC port but that's not the case here. Approach I can think of is to monitor the PD power good signal and if this signal goes low enable edge triggered interrupt for nT2P GPIO pin for a while and check if MCU is receiving multiple interrupts if so we can conclude it's connected to LTEPOE++ device otherwise if no interrupts are received we read the GPIO pin and decide if it's type 13 W or 25.5W based on the state.

Is your feature request related to a problem? Please describe.
nT2P GPIO pin (referenced in code as GPIO PORT J Pin 0 / PJ0 ) will start toggling as soon as it find the source as LTEPOE++ device. The frequency at which this pin is toggling is 840 Hz. So approximately at each tick period, it's changing its state. It would be really difficult from TIVA to read the nT2P pin every 1/840 sec without preemption of the task.