Fixed readLedStatus to return current LED status rather than transition status

[Gadgetoid]

Working from https://cdn-shop.adafruit.com/datasheets/CAP1188.pdf, page 43 gives an overview of the LED Status register - currently used in this library to get the current status of LEDs - and describes it as "The LED Status Registers indicate when an LED has completed its configured behavior"

IE: if you set up an LED to transition/fade slowly between on/off states then this register will indicate when that transition has completed.

I have corrected readLedStatus() to read the REG_LED_CONTROL register which will correctly reflect the current desired state of the LED, although it will not always represent the actual state of the LED since it may be transitioning.

I have preserved the original transition status functionality in readLedTransitionStatus() and better documented its expected behaviour.

This was tested on a Pimoroni Drum HAT/Cap1188- however this required another tweak to pass a custom i2c address which I will submit in a separate PR.

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[Gadgetoid]

I signed it!

[googlebot]

CLAs look good, thanks!

[proppy]

I wonder if it's possible to add tests that break with the previous/buggy behavior? Or if it's not necessary because this is mostly due to a miss-interpretation of the datasheet. /cc @jdkoren

[Gadgetoid]

I don't believe a test would be necessary since this is unlikely to be regressed, but one could be implemented like so as long as a hardware device is connected and LED linking and fading is disabled:

setLedStatus(0, true);
setLedStatus(1, true);
check if getLedStatus() & 0b00000011 == 0b00000011

Under certain circumstances it's still possible for the LED_STATUS register to match the contents of the LED_CONTROL register, even though they are both describing different things.

[mangini]

Hey, @sarahmwittman , can you please review this CL?