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

[Peter Tyser]

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 at 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 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;
 
-- 
1.7.0.4