u-boot/post/drivers/i2c.c
Peter Tyser 9d921f19b3 post/i2c: Add ability to ignore I2C devices
Add the ability to not report an I2C POST error for a set of given I2C
addresses on bootup.  This is useful for cases when a device may or may
not be present, and neither case is considered an error.  For example:

- Some form factors such as XMC and Compact PCI Express have an I2C
  EEPROM whose address changes based on geographical address.  Eg
  installed in one slot its EEPROM address is, 0x50, in another its
  0x51, etc.  This allows multiple devices to have their EEPROMs present
  on the same I2C bus.  Thus the I2C devices present for an XMC or
  CPCIe card depend on if and where other cards are installed in the
  same system.

- Some cards have optional I2C devices.  Eg one hardware build
  configuration has different I2C devices than another and software
  can't determine if the optional device should be present or not.

- Some cards have optional daughtercards with I2C devices on them.

- I2C EEPROMs address range depends on their size.  Its possible to
  support differently size EEPROMs by only probing the EEPROM's base
  address and ignoring the other addresses that are impacted by its
  size.

A new CONFIG_SYS_POST_I2C_IGNORES define has been added which specifies
a list of I2C addresses for the I2C POST to ignore.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
Acked-by: Heiko Schocher <hs@denx.de>
Acked-by: Wolfgang Denk <wd@denx.de>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2010-10-22 02:19:14 -05:00

110 lines
2.8 KiB
C

/*
* (C) Copyright 2002
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* I2C test
*
* For verifying the I2C bus, a full I2C bus scanning is performed.
*
* #ifdef CONFIG_SYS_POST_I2C_ADDRS
* The test is considered as passed if all the devices and only the devices
* in the list are found.
* #ifdef CONFIG_SYS_POST_I2C_IGNORES
* Ignore devices listed in CONFIG_SYS_POST_I2C_IGNORES. These devices
* are optional or not vital to board functionality.
* #endif
* #else [ ! CONFIG_SYS_POST_I2C_ADDRS ]
* The test is considered as passed if any I2C device is found.
* #endif
*/
#include <common.h>
#include <post.h>
#include <i2c.h>
#if CONFIG_POST & CONFIG_SYS_POST_I2C
static int i2c_ignore_device(unsigned int chip)
{
#ifdef CONFIG_SYS_POST_I2C_IGNORES
const unsigned char i2c_ignore_list[] = CONFIG_SYS_POST_I2C_IGNORES;
int i;
for (i = 0; i < sizeof(i2c_ignore_list); i++)
if (i2c_ignore_list[i] == chip)
return 1;
#endif
return 0;
}
int i2c_post_test (int flags)
{
unsigned int i;
#ifndef CONFIG_SYS_POST_I2C_ADDRS
/* Start at address 1, address 0 is the general call address */
for (i = 1; i < 128; i++)
if (i2c_ignore_device(i))
continue;
if (i2c_probe (i) == 0)
return 0;
/* No devices found */
return -1;
#else
unsigned int ret = 0;
int j;
const unsigned char i2c_addr_list[] = CONFIG_SYS_POST_I2C_ADDRS;
/* Start at address 1, address 0 is the general call address */
for (i = 1; i < 128; i++) {
if (i2c_ignore_device(i))
continue;
if (i2c_probe(i) != 0)
continue;
for (j = 0; j < sizeof(i2c_addr_list); ++j) {
if (i == i2c_addr_list[j]) {
i2c_addr_list[j] = 0xff;
break;
}
}
if (j == sizeof(i2c_addr_list)) {
ret = -1;
post_log("I2C: addr %02x not expected\n", i);
}
}
for (i = 0; i < sizeof(i2c_addr_list); ++i) {
if (i2c_addr_list[i] == 0xff)
continue;
post_log("I2C: addr %02x did not respond\n", i2c_addr_list[i]);
ret = -1;
}
return ret;
#endif
}
#endif /* CONFIG_POST & CONFIG_SYS_POST_I2C */