XPT2046 Touch driver

[spearson78]

No description provided.

[sago35]

Thank you for your contribution.
Please add Examples.

[sago35]

I would like you to implement the following interface.

drivers/touch/point.go

Lines 4 to 6 in 90a13a6

	type Pointer interface {
	ReadTouchPoint() Point
	}

[spearson78]

I've added an example and migrated to the ReadTouchPoint interface.

I removed the internal scaling to display size to be consistent with the fourwire implementation however I currently return 12 bit values. Should I scale them to 16 bit to match fourwire?

[sago35]

Thanks for the update.
For the most part I think it is very nice.

Please add it to README.md.
Also, please add smoketest to the Makefile.

[spearson78]

I've added a default value of 10 for precision if the user sets it to 0 and I now scale the values to 16 bits
I moved the precision to a new Config struct. Should I move the entire pin config to the Configure method?
I updated the Readme and make smoke-test targets.

I'd like to say thank you for guiding me through the requirements for contributions to this project. This is my first commit to tinygo and its been very enjoyable so far :)

[sago35]

It seems that there are few cases where the config struct contains pin information.
I think the current source code is fine.

[sago35]

Looks good to me.

I'm a little concerned because I think tz is probably 24-bit-range.
However, this is probably not a problem for z.

[sago35]

Thank you for your contribution.
Now marging.