Compiler/CC2541: CC2541 not connecting with iOS

Do I need to edit something in hal_adc.c file and the 3.7v battery is fully charged

I remember I had checked your schematic and I am pretty sure your 3.7v battery is not connected directly to P0.7. Please use multi-meter to check your P0.7 voltage first.

I checked with multi-meter. At P0_7 I'm getting 3.72v 

Can you attach your schematics?

Battery and Device Schmeatics pdf.

4861.SZ17052601 503040-600mAh 电池规格书 加板加线）2020.07.31.pdfMJ-03-M.pdf

I did just now. The device and battery schematics 

Your schematics shows that your P0.7 connects to BT_V and the voltage is divided by 10K/10K resistors from BAT. This doesn't look like it would be 3.7V.

I connected multimeter at battery points and the voltage I got is 3.7v. How I can re-verify it ?

Maybe try to disconnect R3 from your PCB and use power supply to give voltage to P0.7 to test/verify ADC reading first.

that I can't do as I don't have extra PCBA but Voltage at R3 is 0.925v and at R6 is 0v

If Voltage at R3 is 0.925v and at R6 is 0v, how is it possible P0.7 is 3.7V?

okay that was my mistake. Battery Voltage is 3.7v and at P0_7 I'm getting 3.4v

How can it be 3.4V and Voltage at R3 is 0.925v and at R6 is 0v?

I genuinely don't know and that's why I'm confused and not getting the correct values. Even at he 3.4v, the battery is notifying 100% battery percentage. 

Since you call HalAdcSetReference(HAL_ADC_REF_125V) to set reference voltage to 1.25V and it is 3.4V at P0.7, the ADC reading will be full and it's normal to see 100%.

So, what Do I need to change ? Internal Reference Voltage ?

You should adjust resistors to divided battery voltage down to between 0V to 1.25V for ADC reading.