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authorHeiko Schocher <hs@denx.de>2012-01-16 21:12:24 +0000
committerHeiko Schocher <hs@denx.de>2013-07-23 05:54:28 +0200
commit3f4978c713255c8406875fbdf23ffed1129bc44b (patch)
treec27f00ba6219d75f772167b7630bb4ebb383a271 /README
parent385c9ef5a7215b2b0c22836fee6c692dfc8559d7 (diff)
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i2c: common changes for multibus/multiadapter support
Signed-off-by: Heiko Schocher <hs@denx.de> Signed-off-by: Simon Glass <sjg@chromium.org> Cc: Henrik Nordström <henrik@henriknordstrom.net>
Diffstat (limited to 'README')
-rw-r--r--README74
1 files changed, 71 insertions, 3 deletions
diff --git a/README b/README
index bcfffc3..2fe3f08 100644
--- a/README
+++ b/README
@@ -1944,9 +1944,77 @@ CBFS (Coreboot Filesystem) support
on those systems that support this (optional)
feature, like the TQM8xxL modules.
-- I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
-
- These enable I2C serial bus commands. Defining either of
+- I2C Support: CONFIG_SYS_I2C
+
+ This enable the NEW i2c subsystem, and will allow you to use
+ i2c commands at the u-boot command line (as long as you set
+ CONFIG_CMD_I2C in CONFIG_COMMANDS) and communicate with i2c
+ based realtime clock chips or other i2c devices. See
+ common/cmd_i2c.c for a description of the command line
+ interface.
+
+ ported i2c driver to the new framework:
+
+ additional defines:
+
+ CONFIG_SYS_NUM_I2C_BUSES
+ Hold the number of i2c busses you want to use. If you
+ don't use/have i2c muxes on your i2c bus, this
+ is equal to CONFIG_SYS_NUM_I2C_ADAPTERS, and you can
+ omit this define.
+
+ CONFIG_SYS_I2C_DIRECT_BUS
+ define this, if you don't use i2c muxes on your hardware.
+ if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can
+ omit this define.
+
+ CONFIG_SYS_I2C_MAX_HOPS
+ define how many muxes are maximal consecutively connected
+ on one i2c bus. If you not use i2c muxes, omit this
+ define.
+
+ CONFIG_SYS_I2C_BUSES
+ hold a list of busses you want to use, only used if
+ CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example
+ a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and
+ CONFIG_SYS_NUM_I2C_BUSES = 9:
+
+ CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \
+ {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \
+ {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \
+ {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \
+ {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \
+ {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \
+ {1, {I2C_NULL_HOP}}, \
+ {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \
+ {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \
+ }
+
+ which defines
+ bus 0 on adapter 0 without a mux
+ bus 1 on adapter 0 without a PCA9547 on address 0x70 port 1
+ bus 2 on adapter 0 without a PCA9547 on address 0x70 port 2
+ bus 3 on adapter 0 without a PCA9547 on address 0x70 port 3
+ bus 4 on adapter 0 without a PCA9547 on address 0x70 port 4
+ bus 5 on adapter 0 without a PCA9547 on address 0x70 port 5
+ bus 6 on adapter 1 without a mux
+ bus 7 on adapter 1 without a PCA9544 on address 0x72 port 1
+ bus 8 on adapter 1 without a PCA9544 on address 0x72 port 2
+
+ If you do not have i2c muxes on your board, omit this define.
+
+- Legacy I2C Support: CONFIG_HARD_I2C | CONFIG_SOFT_I2C
+
+ NOTE: It is intended to move drivers to CONFIG_SYS_I2C which
+ provides the following compelling advantages:
+
+ - more than one i2c adapter is usable
+ - approved multibus support
+ - better i2c mux support
+
+ ** Please consider updating your I2C driver now. **
+
+ These enable legacy I2C serial bus commands. Defining either of
(but not both of) CONFIG_HARD_I2C or CONFIG_SOFT_I2C will
include the appropriate I2C driver for the selected CPU.