Add support for multiple I2C buses

Hello,

Attached is a patch providing support for multiple I2C buses at the
command level.  The second part of the patch includes an implementation
for the MPC834x CPU and MPC8349EMDS board.

/*** Note: This patch replaces ticket DNX#2006083042000018 ***/

Signed-off-by: Ben Warren <bwarren@qstreams.com>

Overview:

1. Include new 'i2c' command (based on USB implementation) using
CONFIG_I2C_CMD_TREE.

2. Allow multiple buses by defining CONFIG_I2C_MULTI_BUS.  Note that
the commands to change bus number and speed are only available under the
new 'i2c' command mentioned in the first bullet.

3. The option CFG_I2C_NOPROBES has been expanded to work in multi-bus
systems.  When CONFIG_I2C_MULTI_BUS is used, this option takes the form
of an array of bus-device pairs.  Otherwise, it is an array of uchar.

CHANGELOG:
        Added new 'i2c' master command for all I2C interaction.  This is
conditionally compiled with CONFIG_I2C_CMD_TREE.  New commands added for
setting I2C bus speed as well as changing the active bus if the board
has more than one (conditionally compiled with
CONFIG_I2C_MULTI_BUS).  Updated NOPROBE logic to handle multiple buses.
Updated README.

regards,
Ben

1 files changed, 41 insertions, 1 deletions

diff --git a/README b/README
index b78ea61..6b94f84 100644
--- a/README
+++ b/README
@@ -1207,7 +1207,12 @@ The following options need to be configured:
 		clock chips. See common/cmd_i2c.c for a description of the
 		command line interface.
 
-		CONFIG_HARD_I2C selects the CPM hardware driver for I2C.
+		CONFIG_I2C_CMD_TREE is a recommended option that places
+		all I2C commands under a single 'i2c' root command.  The
+		older 'imm', 'imd', 'iprobe' etc. commands are considered
+		deprecated and may disappear in the future.
+
+		CONFIG_HARD_I2C selects a hardware I2C controller.
 
 		CONFIG_SOFT_I2C configures u-boot to use a software (aka
 		bit-banging) driver instead of CPM or similar hardware
@@ -1312,6 +1317,31 @@ The following options need to be configured:
 		in u-boot bd_info structure based on u-boot environment
 		variable "i2cfast". (see also i2cfast)
 
+		CONFIG_I2C_MULTI_BUS
+
+		This option allows the use of multiple I2C buses, each of which
+		must have a controller.  At any point in time, only one bus is
+		active.  To switch to a different bus, use the 'i2c dev' command.
+		Note that bus numbering is zero-based.
+
+		CFG_I2C_NOPROBES
+
+		This option specifies a list of I2C devices that will be skipped
+		when the 'i2c probe' command is issued (or 'iprobe' using the legacy
+		command).  If CONFIG_I2C_MULTI_BUS is set, specify a list of bus-device
+		pairs.  Otherwise, specify a 1D array of device addresses
+
+		e.g.
+			#undef	CONFIG_I2C_MULTI_BUS
+			#define CFG_I2C_NOPROBES	{0x50,0x68}
+
+		will skip addresses 0x50 and 0x68 on a board with one I2C bus
+
+			#define	CONFIG_I2C_MULTI_BUS
+			#define CFG_I2C_MULTI_NOPROBES	{{0,0x50},{0,0x68},{1,0x54}}
+
+		will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1
+
 - SPI Support:	CONFIG_SPI
 
 		Enables SPI driver (so far only tested with
@@ -2209,6 +2239,16 @@ Low Level (hardware related) configuration options:
   CFG_POCMR2_MASK_ATTRIB: (MPC826x only)
 		Overrides the default PCI memory map in cpu/mpc8260/pci.c if set.
 
+- CONFIG_SPD_EEPROM
+		Get DDR timing information from an I2C EEPROM.  Common with pluggable
+		memory modules such as SODIMMs
+  SPD_EEPROM_ADDRESS
+		I2C address of the SPD EEPROM
+
+- CFG_SPD_BUS_NUM
+		If SPD EEPROM is on an I2C bus other than the first one, specify here.
+		Note that the value must resolve to something your driver can deal with.
+
 - CONFIG_ETHER_ON_FEC[12]
 		Define to enable FEC[12] on a 8xx series processor.