/* Trivial i2c driver for reading "2-byte eeproms".
* On 'open' the read-pointer is reset to 0, subsequent
* read operations slurp data from there...
*/
/*
* Authorship
* ----------
* This software was created by
* Till Straumann <strauman@slac.stanford.edu>, 2005,
* Stanford Linear Accelerator Center, Stanford University.
*
* Acknowledgement of sponsorship
* ------------------------------
* This software was produced by
* the Stanford Linear Accelerator Center, Stanford University,
* under Contract DE-AC03-76SFO0515 with the Department of Energy.
*
* Government disclaimer of liability
* ----------------------------------
* Neither the United States nor the United States Department of Energy,
* nor any of their employees, makes any warranty, express or implied, or
* assumes any legal liability or responsibility for the accuracy,
* completeness, or usefulness of any data, apparatus, product, or process
* disclosed, or represents that its use would not infringe privately owned
* rights.
*
* Stanford disclaimer of liability
* --------------------------------
* Stanford University makes no representations or warranties, express or
* implied, nor assumes any liability for the use of this software.
*
* Stanford disclaimer of copyright
* --------------------------------
* Stanford University, owner of the copyright, hereby disclaims its
* copyright and all other rights in this software. Hence, anyone may
* freely use it for any purpose without restriction.
*
* Maintenance of notices
* ----------------------
* In the interest of clarity regarding the origin and status of this
* SLAC software, this and all the preceding Stanford University notices
* are to remain affixed to any copy or derivative of this software made
* or distributed by the recipient and are to be affixed to any copy of
* software made or distributed by the recipient that contains a copy or
* derivative of this software.
*
* ------------------ SLAC Software Notices, Set 4 OTT.002a, 2004 FEB 03
*/
#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) (((uint32_t)(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;
unsigned char *buf = (unsigned char *)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,
(unsigned char *)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;
