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Altera_Forum's avatar
Altera_Forum
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16 years ago

Problems getting GPIO Interface drivers compiled

Hey all,

So I'm making some pretty good progress on my board and learning a ton but I've hit a major road block I'm hoping you can help with...

I'm using the DE2_70_NET project for the DE2-70 board found in the demonstrations folder of the Terasic provided CD. The project has a bunch of "PIO (Parallel I/O)" components for things like switches, LEDs, buttons, and an I2C bus (connected to a Wolfson audio chip). I'm trying to get the I2C driver working in an attempt to begin talking to the audio chip.

I'm loosely following instructions found at http://www.nioswiki.com/gpio but the instructions are for a special component, a different development board, and aren't really instructions at all and are more like someone's posted posted files and a few words saying 'here you figure it out'. Not very helpful.

So without dealing with the proprietary GPIO component there, I tried adding the driver for "GPIO Interface" in the Kernel Config: Processor Type and Features --> GPIO Interface. However when I compile it keeps stopping with an error on compilation of config.c saying: 

/home/todd/nios2-linux/linux-2.6/arch/nios2/kernel/config.c: In function `nios2_gpio_init':
/home/todd/nios2-linux/linux-2.6/arch/nios2/kernel/config.c:104: error: `na_gpio_0' undeclared (first use in this function)
/home/todd/nios2-linux/linux-2.6/arch/nios2/kernel/config.c:104: error: (Each undeclared identifier is reported only once
/home/todd/nios2-linux/linux-2.6/arch/nios2/kernel/config.c:104: error: for each function it appears in.)
make: ***  Error 1
make: ***  Error 2

I even went so far as to add a SOPC builder component called 'gpio_0' and it still fails compilation.

Am I missing something?

How does one properly compile a kernel with the standard GPIO Interface enabled in the kernel config?

Do all of my GPIO pins in my design go through a single SOPC builder component like in the example: http://www.nioswiki.com/gpio ? Or can I use that same driver for each of my GPIO components?

Thanks!

Todd

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    16 years ago

    Hi Todd,

    You will need to disconnect existing ports to all the pins (LED,I2C,BUTTON etc) which you want to use with GPIO. Then you will need to add a single gpio component, named as "gpio_0". You may read the verilog code to understand this trivial core. You will need to connect all the pins(LED,I2C ..etc) to gpio_0 in the top level design. Like this,

    .bidir_port_to_and_from_the_gpio_0 ( { SCL,SDA,LED[0],sw[1],sw[0] }),

    Next, you will need to assign the port indexes in the file arch/nios2/kernel/config.c,

    eg, the above example,

    static struct i2c_gpio_platform_data i2c_gpio_0_data = {

    .sda_pin = 3, /* FIXME: gpio pin assignment */

    .scl_pin = 4, /* FIXME: gpio pin assignment */

    Hope this help.

    Cheers,

    Hippo