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 Acked-by: Heiko Schocher hs@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 0cbbf77..3508177 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; const unsigned char i2c_addr_list[] = 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) continue;