I'm looking for some help on setting up SPI low-speed connector, I'm running Android build #95 that was installed from an SD card. I did go through many posts about SPI, but still pretty much confused about how to enable it on Android. And yes, I have read - https://www.96boards.org/forums/topic/how-to-enable-spi-and-access-it-in-debian-os/ and https://developer.qualcomm.com/qfile/28819/lm80-p0436-5_peripherals_programming_guide.pdf
So, my questions are:
1) Is it really required to compile the kernel just to enable SPI communication? I was able to find "spi0" under "spi_master".
/sys/class/spi_master # ls
Shouldn't that be enough for initiating communication? Does it mean that the SPI master is already registered?
2) According to the docs I'm also required to register a slave device, however, I cannot find where are the below files located in the android file system that is mounted.
3) I read somewhere that when the device tree changes there is no need to recompile the kernel, is that the case here when only SPI salve need to be registered?