Hi Peter,
Thank you for your reply.
Yes, I think I can change CS0 line as GPIO manually. But it is not expected method for me.
My problem is,
when I use mraa_spi_init(1) to get spi bus context, I saw CS1 was driven as expected during mraa_spi_transfer_buf etc.
But when I use mraa_spi_init(0) to access other chip I connected CS0, CS0 was not driven during mraa_spi_transfer_buf.
But SCK/MOSI lines were driven. I feel it looks strange. ( I used oscilloscope to check lines )
I can not find /dev/spidev5.0, so I think mraa_spi_init(0) should be failed.
I saw mraa source code, mraa_spi is just wrapped spidev access.
Arduino breakout uses CS0 line for ADC.
So I think I have to detach(unbind?) CS0 driver from ADC, and re-attach CS0 driver to spidev.
I would like to know how to do this. May be I have to re-build kernel with modification, or may be I can unbind/bind from command line.
Regards,
w2r