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spi-config

spi board configuration without having to recompile the kernel

NOTE: it is no longer recommended to use spi-config with the newer kernels that have device-tree enabled.

For an example how to configure via device-tree overlays please look at: raspberrypi/linux#848

this includes:

  • clocks
  • interrupts
  • gpio directions
  • spi registrations

Compiling

make
make install

Usage:

loading the module:

modprobe spi-config devices=<devicedev1>,<devicedev2>,...,<devicedev16>

and a <devicedev> is defined as a list of : separated key=value pairs

possible keys are:

  • bus = the bus number
  • cs = the chip select
  • modalias = the driver to assign/use
  • irq = the irq to assign
  • irqgpio = the GPIO pin of the irq
  • mode = the SPI mode
  • pd = platform data length to allocate
  • pdx- = sets the hex values at byte-offset of the platform data (hex string - 2 chars per byte!!!)
  • pds64- = sets the s64-value at byte-offset of the platform data
  • pdu64- = sets the u64-value at byte-offset of the platform data
  • pds32- = sets the s32-value at byte-offset of the platform data
  • pdu32- = sets the u32-value at byte-offset of the platform data
  • pds16- = sets the u16-value at byte-offset of the platform data
  • pdu16- = sets the s16-value at byte-offset of the platform data
  • pds8- = sets the u8-value at byte-offset of the platform data
  • pdu8- = sets the u8-value at byte-offset of the platform data
  • pdp- = sets a pointer to platform_data+ at byte-offset of the platform data
  • force_release = forces a release of a spi device if it has NOT been configured by this module this action taints the kernel!!! Also this is defined without a =.

and can typically get prefixed with 0x for hex and 0 for octal.

So the following:

modprobe spi-config devices=\
bus=0:cs=0:modalias=mcp2515:speed=10000000:gpioirq=25:pd=20:pdu32-0=16000000:pdu32-4=0x2002,\
bus=0:cs=1:modalias=mcp2515:speed=6000000:gpioirq=22:pd=0x14:pdu32-0=20000000:pdu32-4=0x02

will configure:

  • on SPI0.0 a mcp251x device with max_speed of 10MHz with IRQ on GPIO25 and platform data that reflects: 16MHz crystal and Interrupt flags with IRQF_TRIGGER_FALLING|IRQF_ONESHOT
  • on SPI0.1 a mcp251x device with max_speed of 6MHz with IRQ on GPIO22 and platform data that reflects: 20MHz crystal and Interrupt flags with IRQF_TRIGGER_FALLING