Add Aux input, temperature reads, fix battery voltage read, fixes

[dvosully]

This PR adds the following capabilities:

• Read the Aux Input pin
• Read the temperature using the TEMP0 register (one point mode)
• Read the temperature using the TEMP1 register (two point mode)
• Enable PENIRQ pin option. (Note: Can't use this in the driver to check for touch, but can enable the output from the chip)
• Enable Vref ON option. (Leaves the Vref permanently on to reduce transactions when reading battery/aux/temperature

It also fixes the following issues:

• The battery voltage value wasn't being right-shifted by 3 so was 8 times too large.
• Vref is approx 2.507V, not 2.500V (you need to look at the internal Vref vs temperature graph in the datasheet to find that, between 5C and 40C it's above 2.507V, and still above 2.505V between -25C and 65C, which is basically the normal range)
• Fixes co-ordinate averaging.
  • The bug:
  • If the screen press is released while the averaging loop is being run, some co-ordinates with value 0 get introduced into the average.
  • This means that instead of the averaged coordinate value being the press location, it is 'torn' between the press location and the corner of the screen (coordinate 0,0)
  • Because this happens on a press release, it results in a 'click' action in a completely different location than the press.
  • This is more likely to occur the more frequently the touch panel is sampled
  • The fix:
  • Sanity check every input coordinate pair while looping
  • Count how many coordinate pairs were valid
  • Check there were sufficient valid coordinate pairs (at least 1, and >= 50%)
  • Average only the valid coordinate pairs

Tested on IDF v5.2.1 with a TSC2048 (the TI chip which the XPT2046 cloned)

[dvosully]

I have added the check for the PENIRQ active to xpt2046_read_data. If the input is high (no touch) then it returns no touch immediately, instead of querying the Z pressure registers.

It builds and runs normally when CONFIG_XPT2046_INTERRUPT_MODE is enabled and int_gpio_num is set to GPIO_NUM_NC, but I can't test its operation when connected as the PENIRQ is not connected on my board.

[atanisoft]

I can't test its operation when connected as the PENIRQ is not connected on my board.

I'll see if I can test it out, I've got a touch based board (also using the TI part) to see if I can trigger it.