diff options
| author | Heiko Schocher <hs@denx.de> | 2008-10-15 09:39:47 +0200 |
|---|---|---|
| committer | Wolfgang Denk <wd@denx.de> | 2008-10-18 21:54:02 +0200 |
| commit | 67b23a322848d828a5e45c0567b72762bfde7abf (patch) | |
| tree | 8dc26375504482eaa0e9600a6a52a6bb047dccf3 /README | |
| parent | c24853644ddd2dd2e4246b5854a93e6254a14092 (diff) | |
I2C: adding new "i2c bus" Command to the I2C Subsystem.
With this Command it is possible to add new I2C Busses,
which are behind 1 .. n I2C Muxes. Details see README.
Signed-off-by: Heiko Schocher <hs@denx.de>
Diffstat (limited to 'README')
| -rw-r--r-- | README | 47 |
1 files changed, 47 insertions, 0 deletions
@@ -1429,6 +1429,53 @@ The following options need to be configured: Define this option if you want to use Freescale's I2C driver in drivers/i2c/fsl_i2c.c. + 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 sends First the Commando to the mux@70 to enable + channel 6, and then the Commando 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. + - SPI Support: CONFIG_SPI |