2008-02-05 17:19:38     ADSP-SPIADC does not work for BF537 STAMP

2008-02-05 17:19:38     ADSP-SPIADC does not work for BF537 STAMP

Myrick Monroe (UNITED STATES)

Message: 50715    After two days of rebuilding kernals I am unable to see any SPI output. I used the example code provided in the documentation but nothing seems to work. I can open SPI but there is never any output for a simple write function.  I have seen this problem before without uClinux when the GPIO SPI pins are not programed for SPI.

How do I use the new driver?  Do I simply flash alpha uImage-SVN-bf537-stamp ? If this is true, do I still have to modify the board file in the kernal as explained in the documentation?  Which version does the spidev documentation refer to?

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2008-02-06 02:52:37     Re: ADSP-SPIADC does not work for BF537 STAMP

murti iki (GERMANY)

Message: 50724    Hello Myrick,

If I understood it correctly ADSP-SPIADC is absolute now (it is even removed off the wiki).  But ofcourse this doesn't explain your problem. I used the bfin_spi_adc.c driver as a module and after loading it to the kernel with insmod. I got spi output.

About the spidev documentation, I also have some doubts, if I understood it correctly, the 2007r1.1-RC3 doesn't contain the spidev driver.

Please see the post  "bfin_spi_adc.c and copy_from_user()" There Michael gives some information about this documentation and drivers.

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2008-02-06 10:06:10     Re: ADSP-SPIADC does not work for BF537 STAMP

Myrick Monroe (UNITED STATES)

Message: 50763   

Thank  you for the reply.  I didn't use your method of loading the module with insmod. I used menuconfig to select "ADSP SPI SUPPORT"  and then followed the ADSP-SPIADC documentation exactly.  Last week I could still access "How to use ADSP-SPIADC driver" documentation from here and I had no idea that it was obsolete.  I just noticed today that the file has been removed.

I am not familiar with the process you described ( I'm a hardware engineer and not a Computer Science type) . Is it done from the uClinux prompt after simply downloading the compiled bfin_spi_adc.c to the target?

Thanks again for helping me

Best Regards,

Myrick Monroe

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2008-02-06 16:00:45     Re: ADSP-SPIADC does not work for BF537 STAMP

murti iki (GERMANY)

Message: 50772    Hello,

I am also quite new in the linux arena but as far as I understand, you can either put these drivers (which also count as modules) either into the kernel permanently or at a later time as LKMs (loadable kernel module). Just get the bfin_spi_adc.c from the drivers/char  to an empty folder and then build it with make

Below code is also in the wiki

ifneq ($(KERNELRELEASE),)                                   

##################################################          

# PASS 2 do this when called by the kernel make process            

##################################################          

# produce a module from a single C file

    obj-m += spi_driver.o

  

# or  produce a module from multiple C files                  

                                                            

#   obj-$(CONFIG_MYMOD) += mymod.o                          

#  mymod-objs := mymod_main.o mymod_lib.o mymod_io.o        

                                                            

                                                            

else

                                                       

##################################################          

# PASS 1 do this when called from the user make                    

##################################################          

    KDIR        := /home/ti6rt/work/uClinux-dist-spi/linux-2.6.x

#change above line as necessary

    PWD         := $(shell pwd)                             

                                                            

default:                                                    

    $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules

          

                                                            

install:                                                    

    $(MAKE) -C $(KDIR) INSTALL_MOD_PATH=$(IDIR) \          

                    SUBDIRS=$(PWD) modules_install          

endif   

after "make" you will end up with "spi_driver.ko"    you can transfer this to the stamp board (that has already a linux running on it). Once you transfer it just type

    insmod spi_driver.ko

to see if you everything went okey type

    lsmod

now you can just call a userspace application program and test it,

The wiki document has all the information about it.  Below is what I use

#include <stdio.h>

#include <fcntl.h>

#define SAMPLES 10

int main ()

{

int fd,wr;

int i = 0;

unsigned short data_write[SAMPLES]={14,14,14,14,1,1,10,1,1,1};

unsigned short data_read[SAMPLES];

fd = open ("/dev/spi", O_RDWR);

if (fd < 0)

{

printf("Error opening dev/spi \n");

}

while(i < 3000){

wr = write(fd, data_write, SAMPLES);

// read(fd, data_read, SAMPLES);

  // zero verirse tamamdir.

   if(wr < 0)

    {

       printf("Error writing to device dev/spi \n");

       break;

    }

  i++;

}

close(fd);

return 0;

As I said, I am also new in this linux, uclinux stuff. So don't take anything I said for granted Yet this works in my case.

Ohh forgat to say, everything except the chip_select pin works. Probably I made something wrong in the in the resources section. I will look into it again and try to find the error.