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Diffstat (limited to 'README')
| -rw-r--r-- | README | 47 |
1 files changed, 0 insertions, 47 deletions
@@ -2225,53 +2225,6 @@ CBFS (Coreboot Filesystem) support If not defined, then U-Boot uses predefined value for specified DTT device. - CONFIG_I2C_MUX - - Define this option if you have I2C devices reached over 1 .. n - I2C Muxes like the pca9544a. This option addes a new I2C - Command "i2c bus [muxtype:muxaddr:muxchannel]" which adds a - new I2C Bus to the existing I2C Busses. If you select the - new Bus with "i2c dev", u-bbot sends first the commandos for - the muxes to activate this new "bus". - - CONFIG_I2C_MULTI_BUS must be also defined, to use this - feature! - - Example: - Adding a new I2C Bus reached over 2 pca9544a muxes - The First mux with address 70 and channel 6 - The Second mux with address 71 and channel 4 - - => i2c bus pca9544a:70:6:pca9544a:71:4 - - Use the "i2c bus" command without parameter, to get a list - of I2C Busses with muxes: - - => i2c bus - Busses reached over muxes: - Bus ID: 2 - reached over Mux(es): - pca9544a@70 ch: 4 - Bus ID: 3 - reached over Mux(es): - pca9544a@70 ch: 6 - pca9544a@71 ch: 4 - => - - If you now switch to the new I2C Bus 3 with "i2c dev 3" - u-boot first sends the command to the mux@70 to enable - channel 6, and then the command to the mux@71 to enable - the channel 4. - - After that, you can use the "normal" i2c commands as - usual to communicate with your I2C devices behind - the 2 muxes. - - This option is actually implemented for the bitbanging - algorithm in common/soft_i2c.c and for the Hardware I2C - Bus on the MPC8260. But it should be not so difficult - to add this option to other architectures. - CONFIG_SOFT_I2C_READ_REPEATED_START defining this will force the i2c_read() function in |