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/* $Id$ */
/* Trivial i2c driver for reading "2-byte eeproms".
* On 'open' the read-pointer is reset to 0, subsequent
* read operations slurp data from there...
*/
/* Author: Till Straumann, 2005 */
#include <rtems.h>
#include <rtems/libi2c.h>
#include <libchip/i2c-2b-eeprom.h>
#include <rtems/libio.h>
#define EEPROM_PG_SZ 32
#define ALGN(x) (((unsigned32)(x) + EEPROM_PG_SZ) & ~(EEPROM_PG_SZ-1))
static rtems_status_code
send_file_ptr (rtems_device_minor_number minor, unsigned pos, int tout)
{
int sc;
unsigned char bytes[2];
bytes[0] = (pos >> 8) & 0xff;
bytes[1] = (pos) & 0xff;
/* poll addressing the next page; if 'tout' is <=0 we only try once
* and return the status. If 'tout' is positive, we try 'tout' times
* and return RTEMS_TIMEOUT if it didnt work
*/
while ((sc = rtems_libi2c_start_write_bytes (minor, bytes, 2)) < 0) {
if (--tout <= 0)
return tout ? -sc : RTEMS_TIMEOUT;
rtems_task_wake_after (1);
}
return RTEMS_SUCCESSFUL;
}
static rtems_status_code
i2c_2b_eeprom_write (rtems_device_major_number major,
rtems_device_minor_number minor, void *arg)
{
rtems_libio_rw_args_t *rwargs = arg;
unsigned off = rwargs->offset;
int cnt = rwargs->count;
char *buf = rwargs->buffer;
int sc;
unsigned end;
int l;
if (cnt <= 0)
return RTEMS_SUCCESSFUL;
if ((sc = send_file_ptr (minor, off, 0)))
return sc;
do {
/* write up to next page boundary */
end = ALGN (off);
l = end - off;
if (l > cnt)
l = cnt;
sc = rtems_libi2c_write_bytes (minor, buf, l);
if (sc < 0)
return -sc;
sc = rtems_libi2c_send_stop (minor);
if (sc)
return sc;
rwargs->bytes_moved += l;
buf += l;
cnt -= l;
off += l;
/* poll addressing the next page */
if ((sc = send_file_ptr (minor, off, 100)))
return sc;
} while (cnt > 0);
return rtems_libi2c_send_stop (minor);
}
static rtems_status_code
i2c_2b_eeprom_read (rtems_device_major_number major,
rtems_device_minor_number minor, void *arg)
{
int sc;
rtems_libio_rw_args_t *rwargs = arg;
if (RTEMS_SUCCESSFUL != (sc = send_file_ptr (minor, rwargs->offset, 0)))
return -sc;
sc = rtems_libi2c_start_read_bytes (minor, rwargs->buffer, rwargs->count);
if (sc < 0) {
rwargs->bytes_moved = 0;
return -sc;
}
rwargs->bytes_moved = sc;
return rtems_libi2c_send_stop (minor);
}
static rtems_driver_address_table myops = {
read_entry: i2c_2b_eeprom_read,
write_entry: i2c_2b_eeprom_write,
};
static rtems_libi2c_drv_t my_drv_tbl = {
ops: &myops,
size: sizeof (my_drv_tbl),
};
/* provide a second table for R/O access */
static rtems_driver_address_table my_ro_ops = {
read_entry: i2c_2b_eeprom_read,
};
static rtems_libi2c_drv_t my_ro_drv_tbl = {
ops: &my_ro_ops,
size: sizeof (my_ro_drv_tbl),
};
rtems_libi2c_drv_t *i2c_2b_eeprom_driver_descriptor = &my_drv_tbl;
rtems_libi2c_drv_t *i2c_2b_eeprom_ro_driver_descriptor = &my_ro_drv_tbl;
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