-- Legacy I2C Support: CONFIG_HARD_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
- CONFIG_HARD_I2C will include the appropriate I2C driver
- for the selected CPU.
-
- This 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. See common/cmd_i2c.c for a description of the
- command line interface.
-
- CONFIG_HARD_I2C selects a hardware I2C controller.
-
- There are several other quantities that must also be
- defined when you define CONFIG_HARD_I2C.
-
- In both cases you will need to define CONFIG_SYS_I2C_SPEED
- to be the frequency (in Hz) at which you wish your i2c bus
- to run and CONFIG_SYS_I2C_SLAVE to be the address of this node (ie
- the CPU's i2c node address).
-
- Now, the u-boot i2c code for the mpc8xx
- (arch/powerpc/cpu/mpc8xx/i2c.c) sets the CPU up as a master node
- and so its address should therefore be cleared to 0 (See,
- eg, MPC823e User's Manual p.16-473). So, set
- CONFIG_SYS_I2C_SLAVE to 0.
-
- CONFIG_SYS_I2C_INIT_MPC5XXX
-
- When a board is reset during an i2c bus transfer
- chips might think that the current transfer is still
- in progress. Reset the slave devices by sending start
- commands until the slave device responds.
-
- That's all that's required for CONFIG_HARD_I2C.
-