I will expose my problem. I have a device, a microchip PIC with I2C through the SSP library.
The I2C works correctly with the firmware version #893. However, it will not work with any newer version up to today, since #894.
Other I2C devices work.
So my question is:
Could I know what the changes to I2C at #894 version?
I have already looked into the code at:
https://github.com/raspberrypi/firmware ... f9604c2b26
I read the change log and I couldn't see anything in the code about I2C. However, the binary kernel drivers: i2c/i2c-dev.ko and i2c/busses/i2c-bcm2708.ko changed in that version.
I am reviewing the PIC implementation at the same time, but I would also like to know the origin of the I2C lack of detection, since version #894.
Thanks in advance,
EDIT: by using piscope
, I have seen the following flow when i2cdetect'ing for the address (0x15):
https://drive.google.com/open?id=1pgwgt ... 7XaW0cITZw
with firmware #894.
As you can see, it looks like bit 9 (ACK) has been ACK'ed (first line: SDA low) but i2cdetects returns "--" for the specified address.