[ts-7000] gpio kernel drivers....

["Yan Seiner" <>]

I've started down the rocky path of writing a module for GPIO
irq-driven access....

This is the first time I've tried to write a kernel module, and I'm a
bit stuck...

The following code should spit out the 4 registers of a TSDIO24 card
every time you read major device 253...  (You have to compile and load
the module: arm-linux-gcc -D__KERNEL__ -DMODULE
-I/usr/local/src/linux24/include -O -Wall   -c -o gpio.o gpio.c )

And in fact it does spit out 4 bytes, which occasionally change in
value.  But alas they don't have any connection to what should be in
the registers....

I can't find any docs on ioremap, readb, or readw...  So I am flying
blind.  If anyone has a bit of time and knows something about kernel
2.4 modules, I would appreciate some advice....

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <asm-arm/io.h>

#define TSDIO24region 0x11e00104
#define TSDIO24length 4
#define TSDIO24ctrl 0x11e00104
#define TSDIO24regA 0x11e00105
#define TSDIO24regB 0x11e00106
#define TSDIO24regC 0x11e00107

// device numbers
// major - 253
// minor:
//      0 - ctrl
//      1 - regA
//      2 - regB
//      3 - regC

#define TSDIO24major 253

static char *mem_virt_addr;

static ssize_t tsdio24_write(struct file *file, const char *buf,
size_t length, loff_t *ppos)
{
   printk("<1>in write\n");
   return 0;
}
 
static ssize_t tsdio24_read(struct file *file, char *buf, size_t
length, loff_t *ppos)
{
   printk("0x%02x %02x %02x %02x\n",
        readb(mem_virt_addr),
        readb(mem_virt_addr+1),
        readb(mem_virt_addr+2),
        readb(mem_virt_addr+3));
   return 0;
}

static struct file_operations tsdio24_fops = {
 write:  tsdio24_write,
 read:  tsdio24_read
 };
 
int init_TSgpio(void)
{
        int result;
        
        printk("<1>Hello world.\n");
        
        if (check_mem_region(TSDIO24region, TSDIO24length)) 
        { 
                printk("TSgpio: memory already in use\n");
                return -EBUSY; 
        }
        request_mem_region(TSDIO24region, TSDIO24length, "TSDIO24gpio");
        
        if( (result = register_chrdev(TSDIO24major, "TSDIO24",
&tsdio24_fops)) < 0) 
        {
                printk(KERN_WARNING "tsdio24: can't get major 
%d\n",TSDIO24major);
                return result;
        }
        mem_virt_addr = ioremap(TSDIO24region, TSDIO24length); 
        return 0;
}

void exit_TSgpio(void)
{
        iounmap(mem_virt_addr);
        unregister_chrdev(TSDIO24major,"TSDIO24");
        release_mem_region(TSDIO24region, TSDIO24length);
        printk("<1>Goodbye, cruel world.\n");
}


module_init(init_TSgpio);
module_exit(exit_TSgpio);






 
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