libraries/Wire: Add support for target mode.

[iabdalkader]

Test sketch:

#include <Wire.h>

void onRequest() {
  Wire.write("HelloWorld!");
}

void onReceive(int howMany) {
  while (Wire.available()) {
    char c = Wire.read();
    Serial.print(c);
  }
  
  if (howMany) {
    Serial.println("");
  }
}

void setup() {
  Serial.begin(115200);
  Wire.begin(8);
  Wire.onRequest(onRequest);
  Wire.onReceive(onReceive);
}

void loop() {
  delay(1000);
}

---

Retested master mode with VL53L1X and target mode with bus pirate:

[pennam]

@iabdalkader I've tested this PR on a Nano 33 BLE sense Rev2 and I2C controller mode is not working anymore.

I've used this example.

With the released core i get this output:

15:12:48.431 -> Pressure = 100.55 kPa
15:12:48.431 -> Temperature = 28.37 C
15:12:48.431 -> 
15:12:49.428 -> Pressure = 100.54 kPa
15:12:49.428 -> Temperature = 28.35 C

using this PR instead i get this:

Failed to initialize pressure sensor!

I think it would be better to split this commit an put the "Fix buffer overflows, bad return values etc.." in a separate commit /PR because i suspect something in those changes has break I2C controller mode.

[iabdalkader]

I think it would be better to split this commit an put the "Fix buffer overflows, bad return values etc.."

That's not possible, the changes are required for Target mode.

[pennam]

The issue is now requestFrom is returning 0 on success and it should return the number of bytes returned from the peripheral.

vl5xl1x library works because is not checking the return value but other libraries do it

[iabdalkader]

it should return the number of bytes returned from the peripheral.

Except that doesn't specify what to return if it fails to read. Also, the return is unsigned so we can't return -1. I fixed it anyway, but now it's not possible to know if it failed or the buffer is just full.

[pennam]

I guess 0 is the only option we have to point out an error, considering a request of 0 bytes an edge case.

[pennam]

I2CSCanner 👍
LPS22HB ReadPressure 👍
I2CMasterReader/I2CSlaveWriter 👍
I2CMasterWriter/I2CSlaveReceiver 👍