Add support for multiple I2C buses

[people/ms/u-boot.git] / README

diff --git a/README b/README
index 8d876e435e2f3d4c81c8a9b7016d001490ff858d..6b94f8482c5c55816a9d878c006d1d64f641aa0b 100644 (file)
--- 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
@@ -1466,10 +1496,14 @@ The following options need to be configured:
                default value of 5 is used.
 
 - Command Interpreter:
-               CFG_AUTO_COMPLETE
+               CONFIG_AUTO_COMPLETE
 
                Enable auto completion of commands using TAB.
 
+                Note that this feature has NOT been implemented yet
+                for the "hush" shell.
+
+
                CFG_HUSH_PARSER
 
                Define this variable to enable the "hush" shell (from
@@ -2205,6 +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.