[MinnowBoard] SPI questions

Kevin Shelton kmshelton at gmail.com
Fri Jan 23 20:02:33 UTC 2015

Hello, I am trying to poke around and understand how to add support for a
new lure.

I saw the thread 'Adding an SPI device to the Minnowboard' from late 2013
and 'SPI support on minnowboard v1' from Aug 2014.

Darren Hart notes:
Ultimately we want to do things like this without board files by using the
_DSD mechanisms introduced by the ACPI 5.1 specification last week

I just wanted to confirm the ACPI mechanism is not the recommended way yet,
and that using low-speed-spidev.c as a template is still the way to go.

Additional q:
How do you tell the SPI controller that you have an active-high instead of
the usual active-low device?  Is it correct to do a bitwise or with
SPI_CS_HIGH (0x4) with your SPI_MODE in your spi_board_info struct, like:
.mode = SPI_MODE_0 | SPI_CS_HIGH
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