I have trying to get my dm6446 running SDK2.0 to output on the SPI bus.
I was grateful to Josh Hintze who posted a driver on this forum a few
years ago (thank god for archives!), however I can't seem to get it to
work.

 

When I send a write command to the driver it sends the SPI_CLK, SPI_D0
and SPI_EN0 pins high but doesn't change their voltage. How do I get the
clock to start cycling and data to come out?

 

The driver is practically the same as the one given in
http://linux.omap.com/pipermail/davinci-linux-open-source/2008-March/005
587.html

 

And my user code is just a simple prog:

 

int main(Int argc, String argv[]) {

  int fd_spi;

  unsigned char *input_data;

  input_data = (unsigned char *)malloc(2);

  input_data[0] = 0xAA;

  input_data[1] = 0x2C;

 

  fd_spi = open("/dev/dv_spi", O_RDWR);

  if (fd_spi < 0) {

      printf("Failed to open /dev/dv_spi (%s)\n", strerror(errno));

      return -1;

  }

  write (fd_spi, input_data, 2);

  close(fd_spi);

  return (0);

}

 

What am I doing wrong? I just want to get some fast way of clocking out
my data on an IO line. I initially tried extending
davinci_spi_platform.c (in lsp/../arch/arm/mach-davinci) and including
the module in the kernel, but I couldn't work out how to access the
functions from user space.

 

Does anyone know a simple(ish) method of getting SPI to work on my
dm6446?

 

Thanks,

 

Alex

 

Alex Tarter

Systems Engineer

Ultra Electronics

Communication & Integrated Systems

Tel: +44 (0)20 8813 4527

www.ultra-electronics.com

 

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