Physical SPI interface to Linux device tree mapping

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Last Post 14 Nov 2016 10:22 AM by Adam Ford

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Anton Bakulev

New Member
Posts:13

10 Nov 2016 04:52 AM
I have a SDK-DM3730-30-256512R with Torpedo Launcher 3 Baseboard and SOMDM3730-20-2780AGCR and a propriate module with SPI interface. This SPI interface is connected to MCSPI1_CLK, MCSPI1_SIMO, MCSPI1_SOMI and MCSPI1_CS1 pins on Baseboard LogicPD_Linux_BSP_2.4-4 runs on Baseboard. And there is such devices in /dev directory: /dev/spidev1.0 /dev/spidev1.1 /dev/spidev1.2 /dev/spidev1.3 /dev/spidev3.0 /dev/spidev3.1 Question is: What device from /dev shoud I use to manage my propriate module by SPI interface?

Adam Ford

Advanced Member
Posts:794

11 Nov 2016 06:30 AM	Accepted Answer
The devices are presented by bus and chipselect. SPIDEV1 represents SPI1 the the .0, .1, .2, etc. represent chipselect 0, 1, 2, etc. For SPI1, CS1, I would expect it to be on /dev/spidev1.1 adam

Anton Bakulev

New Member
Posts:13

14 Nov 2016 09:49 AM
Adam, thank you for valuable reply! Could you explain me one more question? According to Torpedo Launcher 3 Baseboard schematics there is following SPI interfaces on it: SPI1 CS0 CS1 CS2 CS3 SPI2 CS0 CS1 SPI3 CS0 CS1 SPI4 CS0 For SPI1 CS0 CS1 CS2 CS3 and SPI3 CS0 CS1 there is appropriate sipdevs in /dev, but there is no no appropriate spidevs in /dev for SPI2 CS0 CS1 and SPI4 CS0. Why?

Adam Ford

Advanced Member
Posts:794

14 Nov 2016 10:22 AM
Only certain SPI interfaces were opened. If you go into the menuconfig for the linux, there are some configuration options for enabling different SPI chip selects. Location: │ │ -> System Type │ │ -> TI OMAP2/3/4 Specific Features │ │ -> OMAP3LOGIC setup │ │ -> OMAP3LOGIC SPI Config