Peter, On Wed, Feb 16, 2011 at 03:13:07AM -0500, Peter Korsgaard wrote: > >>>>> "Guenter" == Guenter Roeck <guenter.roeck@xxxxxxxxxxxx> writes: > > Guenter> Hi all, > > Guenter> I am trying to use the new GPIO based I2C > Guenter> multiplexer. Unfortunately, I have an initialization problem > Guenter> with it. > > Guenter> Some time after registering the multiplexer as platform driver, its > Guenter> probe function is called. Unfortunately, that does not happen in sync > Guenter> with I2C adapter initialization. The GPIO mux probe function is called > Guenter> before the parent's (ie the multiplexed I2C adapter) probe function is > Guenter> called. As a result, the GPIO mux driver does not find its parent i2c > Guenter> adapter, and the probe function aborts with an error. > > Guenter> Any idea how I I can fix the problem, ie how I can ensure that > Guenter> the GPIO mux probe function is only called after its parent > Guenter> I2C adapter is initialized ? > > What i2c bus controller are you using? Are you registering it's platform > data very late (E.G. after you register the platform data for gpiomux)? > It is part of an mfd device. The same device also hosts the multiplexer pin. The bus drivers and the multiplexer driver are instantiated from the mfd core driver, so I can control the order. > If you do register the platform data in the correct order, things SHOULD The I2C bus driver is registered before the GPIO driver. > work correctly as busses are listed in drivers/i2c/Makefile before > muxes, but alternatively you could play with the init order (E.G. use > subsys_initcall instead of module_init in the bus driver, see > b8680784875 for an example). > I tried that, but it does not help. Here is a log: [ 16.027528] spanky_i2c spanky_i2c.12: probe 12 [ 16.130652] spanky_i2c spanky_i2c.13: probe 13 [ 16.131095] spanky-i2cmux spanky-i2cmux.72: Parent adapter (54) not found ^^^ This is the (renamed) gpio mux driver [ 16.284040] spanky_i2c spanky_i2c.14: probe 14 [ 16.292194] spanky_i2c spanky_i2c.15: probe 15 [ 16.300029] spanky_i2c spanky_i2c.18: probe 18 [ 16.394173] spanky_i2c spanky_i2c.19: probe 19 [ 16.537542] spanky_i2c spanky_i2c.20: probe 20 [ 16.544743] spanky_i2c spanky_i2c.21: probe 21 [ 16.552497] spanky_i2c spanky_i2c.24: probe 24 [ 16.657112] spanky_i2c spanky_i2c.25: probe 25 [ 16.806678] spanky_i2c spanky_i2c.26: probe 26 [ 16.815207] spanky_i2c spanky_i2c.27: probe 27 [ 17.396906] spanky_i2c spanky_i2c.30: probe 30 [ 17.500035] spanky_i2c spanky_i2c.31: probe 31 [ 17.652316] spanky_i2c spanky_i2c.32: probe 32 [ 17.659550] spanky_i2c spanky_i2c.33: probe 33 [ 18.137137] spanky_i2c spanky_i2c.36: probe 36 [ 18.239038] spanky_i2c spanky_i2c.37: probe 37 [ 18.390166] spanky_i2c spanky_i2c.38: probe 38 [ 18.400315] spanky_i2c spanky_i2c.39: probe 39 [ 18.857240] spanky_i2c spanky_i2c.42: probe 42 [ 18.961723] spanky_i2c spanky_i2c.43: probe 43 [ 19.117111] spanky_i2c spanky_i2c.44: probe 44 [ 19.125823] spanky_i2c spanky_i2c.45: probe 45 [ 19.746365] spanky_i2c spanky_i2c.54: probe 54 ^^^ this is where the i2c bus driver is registered [ 19.758068] spanky_i2c spanky_i2c.55: probe 55 [ 19.768026] spanky_i2c spanky_i2c.55: Registering I2C device pca9541 at 0x74 [ 19.768378] spanky_i2c spanky_i2c.55: Registering I2C device pca9541 at 0x75 [ 19.768729] spanky_i2c spanky_i2c.56: probe 56 [ 19.778987] spanky_i2c spanky_i2c.57: probe 57 [ 19.789395] spanky_i2c spanky_i2c.57: Registering I2C device pca9541 at 0x70 [ 19.789741] spanky_i2c spanky_i2c.58: probe 58 As you can see, I have a somewhat special situation, with a large number of I2C bus driver instances. It would work if there was only one instance, but that does not help me. I thought about registering the GPIO driver as I2C device as suggested in the other response, but that would be a bit kludgy and I would prefer to avoid it if I can. Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
