[ECOS] device driver enquirey

[Yi Tang]

Hi,

I still don't understand the routine for ecos to find the specific I/O 
functions simply using handlers and cyg_io_xxx functions.

Some examples use the cyg_io_lookup fuctions to pass the device info to 
"handle", like this:
    err = cyg_io_lookup( "/dev/serial", &handle );

but where the device info of this lookup function comes from. Through the 
definition of DEVTAB_ENTRY?

Following is my test driver for a gpio, I use cyg_io_lookup function to get 
the correct "handle", but Cyg_ErrNo returns -2, no entitiy found. Hope you 
can instruct me if anything wrong in my code.

Thanks a lot

Regards,
Tony

--------------------------------------------------------------
#include <stdio.h>
#include <cyg/io/devtab.h>
#include <cyg/io/io.h>
#include <cyg/hal/drv_api.h>
#include "gpio.h"

static int mask;
int *gpio_reg = (int *) GPIO_ADDR;
cyg_devio_table_t cyg_io_gpio_devio;

Cyg_ErrNo gpio_write(cyg_io_handle_t handle, const void *buf, cyg_uint32 
*len);
Cyg_ErrNo gpio_read(cyg_io_handle_t handle, void *buf, cyg_uint32 *len);
cyg_bool gpio_select(cyg_io_handle_t handle, cyg_uint32 imask, CYG_ADDRWORD 
info);
Cyg_ErrNo gpio_get_config(cyg_io_handle_t handle, cyg_uint32 key, void *buf, 
cyg_uint32 *len);
Cyg_ErrNo gpio_set_config(cyg_io_handle_t handle, cyg_uint32 key, const void 
*buf, cyg_uint32 *len);

DEVTAB_ENTRY(gpio_entry,
             "/dev/gpio",
             0,                     // Does not depend on a lower level 
interface
             &cyg_io_gpio_devio,
             0,
             0,                     // No initialization/lookup needed
    0);

DEVIO_TABLE(cyg_io_gpio_devio,
            gpio_write,
            gpio_read,
            gpio_select,
            gpio_get_config,
            gpio_set_config
    );

static Cyg_ErrNo gpio_write(cyg_io_handle_t handle, const void *buf, 
cyg_uint32 *len)
{
 gpio_reg[GPIO_OUT/4] = *(cyg_uint32*)buf & mask;
 return(ENOERR);
}

static Cyg_ErrNo gpio_read(cyg_io_handle_t handle, void *buf, cyg_uint32 
*len)
{
 cyg_uint32 *tmp;
 *tmp = gpio_reg[GPIO_OUT/4] & mask;
 buf = tmp;
 return(ENOERR);
}

/* software mask for GPIO , if set '0', the bit is enalbed for I/O, if set 
'1', it's masked for I/O, default is 0, all I/O enabled */
static cyg_bool gpio_select(cyg_io_handle_t handle, cyg_uint32 which, 
CYG_ADDRWORD info)
{
 mask = - which;
 return(ENOERR);
}

static Cyg_ErrNo gpio_get_config(cyg_io_handle_t handle, cyg_uint32 key, 
void *buf, cyg_uint32 *len)
{
 switch (key) {
  case GPIO_DIR_INFO:
   *(cyg_uint32*)buf = gpio_reg[GPIO_DIR/4];
   break;
  case GPIO_IMASK_INFO:
   *(cyg_uint32*)buf = gpio_reg[GPIO_IMASK/4];
   break;
  case GPIO_POLAR_INFO:
   *(cyg_uint32*)buf = gpio_reg[GPIO_POLAR/4];
   break;
  case GPIO_EDGE_INFO:
   *(cyg_uint32*)buf = gpio_reg[GPIO_EDGE/4];
   break;
  default:
   return(ENOENT);
 }
 return (ENOERR);
}


static Cyg_ErrNo gpio_set_config(cyg_io_handle_t handle, cyg_uint32 key, 
const void *buf, cyg_uint32 *len)
{
 switch (key) {
  case GPIO_DIR_INFO:
   gpio_reg[GPIO_DIR/4] = *(cyg_uint32*)buf;
   break;
  case GPIO_IMASK_INFO:
   gpio_reg[GPIO_IMASK/4] = *(cyg_uint32*)buf;
   break;
  case GPIO_POLAR_INFO:
   gpio_reg[GPIO_POLAR/4] = *(cyg_uint32*)buf;
   break;
  case GPIO_EDGE_INFO:
   gpio_reg[GPIO_EDGE/4] = *(cyg_uint32*)buf;
   break;
  default:
   return(ENOENT);
 }
 return (ENOERR);
}
/* EOF of gpio.c */



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