[U-Boot] [PATCH 12/17] post/i2c: Don't probe address 0

Peter Tyser
2010-09-29T19:05:51Z

According to the I2C specification device address 0 is the "general call
address", ie a broadcast address. The I2C specification states that the
format of a general call uses at least 2 bytes, which U-Boot's probing
routine does not adhere to.

Not probing device address 0 will prevent possible issues with devices
that accept general calls. Additionally, this change shouldn't reduce
POST coverage since each I2C device should still be accessed via its
own, unique address.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
CC: hs at denx.de
---
post/drivers/i2c.c | 6 ++++--
1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/post/drivers/i2c.c b/post/drivers/i2c.c
index 635438d..2dd128e 100644
--- a/post/drivers/i2c.c
+++ b/post/drivers/i2c.c
@@ -44,7 +44,8 @@ int i2c_post_test (int flags)
{
unsigned int i;
#ifndef I2C_ADDR_LIST
- for (i = 0; i < 128; i++)
+ /* Start at address 1, address 0 is the general call address */
+ for (i = 1; i < 128; i++)
if (i2c_probe (i) == 0)
return 0;

@@ -55,7 +56,8 @@ int i2c_post_test (int flags)
int j;
unsigned char i2c_addr_list[] = I2C_ADDR_LIST;

- for (i = 0; i < 128; i++) {
+ /* Start@address 1, address 0 is the general call address */
+ for (i = 1; i < 128; i++) {
if (i2c_probe(i) != 0)
continue;

--
1.7.0.4