added functions for reading mpr121 capacitive sensor

[Matteocaroleo]

Hi, we at Politek (the audio engineering team at Politecnico di Torino) have found the problem in the libDaisy library and propose a solution.

You can check us out at https://politek.polito.it/

Problem

In the files libDaisy/src/per/i2c.h and libDaisy/src/per/i2c.cpp to read from an I2C device the function ReceiveBlocking(...) is used.
Looking at the i2c.cpp file, at line 346, in its function definition the hal function HAL_I2C_Master_Receive (...) is used. The problem is that this hal function doesn't comply with the I2C reading protocol defined in the MPR121 datasheet, resulting in a wrong read.

Solution

We found that the hal function HAL_I2C_Mem_Read (...) implements the correct procedure to read from the MPR121, so we added a new function inside the i2c.cpp and inside the src/dev/mpr121.h files to correctly use it.
Using the function FilteredData() now returns the correct values of capacitance reading from the mpr121 device.

Closes #651

[cvpines]

Hi @Matteocaroleo, HAL_I2C_Mem_Read is already implemented via I2CHandle::ReadDataAtAddress. If you look at the source for that method, you will see that it is implemented the same way as method this PR adds.

The only difference is that I2CHandle::ReadDataAtAddress does not currently shift the address left before passing it, but #668 adds that change.

[Matteocaroleo]

You're right, so the ReadDataAtAddress() function can be used inside the mpr121 class instead of the one made to make it work, since it's the same anyway. I will do that and make another PR

[github-actions]

Test Results

150 tests  ±0   150 ✅ ±0   0s ⏱️ ±0s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit aedc1be. ± Comparison against base commit f7c63ae.

♻️ This comment has been updated with latest results.

[stephenhensley]

@Matteocaroleo thanks for the contribution!

You can modify this branch with additional commits, without having to make a separate PR.

The CI also has a few issues with the code formatting. So if you wouldn't mind cleaning those up to conform, that would be great.
Thanks!