Add support for multiple I2C buses

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

diff --git a/README b/README
index f83d7745d3ddd9af984a95a8225351edf77778fe..6b94f8482c5c55816a9d878c006d1d64f641aa0b 100644 (file)
--- a/README
+++ b/README
@@ -461,6 +461,11 @@ The following options need to be configured:
                Board code has addition modification that it wants to make
                to the flat device tree before handing it off to the kernel
 
+               CONFIG_OF_BOOT_CPU
+
+               This define fills in the correct boot cpu in the boot
+               param header, the default value is zero if undefined.
+
 - Serial Ports:
                CFG_PL010_SERIAL
 
@@ -1202,7 +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
@@ -1307,6 +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
@@ -1461,10 +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
@@ -2200,6 +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.
 
@@ -3069,6 +3118,55 @@ format!) to the "bootm" command:
 
        bash#
 
+Boot Linux and pass a flat device tree:
+-----------
+
+First, U-Boot must be compiled with the appropriate defines. See the section
+titled "Linux Kernel Interface" above for a more in depth explanation. The
+following is an example of how to start a kernel and pass an updated
+flat device tree:
+
+=> print oftaddr
+oftaddr=0x300000
+=> print oft
+oft=oftrees/mpc8540ads.dtb
+=> tftp $oftaddr $oft
+Speed: 1000, full duplex
+Using TSEC0 device
+TFTP from server 192.168.1.1; our IP address is 192.168.1.101
+Filename 'oftrees/mpc8540ads.dtb'.
+Load address: 0x300000
+Loading: #
+done
+Bytes transferred = 4106 (100a hex)
+=> tftp $loadaddr $bootfile
+Speed: 1000, full duplex
+Using TSEC0 device
+TFTP from server 192.168.1.1; our IP address is 192.168.1.2
+Filename 'uImage'.
+Load address: 0x200000
+Loading:############
+done
+Bytes transferred = 1029407 (fb51f hex)
+=> print loadaddr
+loadaddr=200000
+=> print oftaddr
+oftaddr=0x300000
+=> bootm $loadaddr - $oftaddr
+## Booting image at 00200000 ...
+   Image Name:   Linux-2.6.17-dirty
+   Image Type:   PowerPC Linux Kernel Image (gzip compressed)
+   Data Size:    1029343 Bytes = 1005.2 kB
+   Load Address: 00000000
+   Entry Point:  00000000
+   Verifying Checksum ... OK
+   Uncompressing Kernel Image ... OK
+Booting using flat device tree at 0x300000
+Using MPC85xx ADS machine description
+Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb
+[snip]
+
+
 More About U-Boot Image Types:
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