[U-Boot] [PATCH 13/17] post/i2c: Add ability to ignore I2C devices

Peter Tyser
2010-09-29T19:05:52Z

Add the ability to not report an I2C POST error for a set of given I2C
addresses on bootup. This is useful for the following cases:

- 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.

- 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 I2C_ADDR_IGNORE_LIST 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>
CC: hs at denx.de
---
post/drivers/i2c.c | 16 ++++++++++++++++
1 files changed, 16 insertions(+), 0 deletions(-)

diff --git a/post/drivers/i2c.c b/post/drivers/i2c.c
index 2dd128e..9e1fd50 100644
--- a/post/drivers/i2c.c
+++ b/post/drivers/i2c.c
@@ -40,6 +40,20 @@

#if CONFIG_POST & CONFIG_SYS_POST_I2C

+static int i2c_ignore_device(unsigned int chip)
+{
+#ifdef I2C_ADDR_IGNORE_LIST
+ unsigned char i2c_ignore_list[] = I2C_ADDR_IGNORE_LIST;
+ 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;
@@ -58,6 +72,8 @@ int i2c_post_test (int flags)

/* Start@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;

--
1.7.0.4