On Sun, Jul 21, 2013 at 01:07:48AM +0200, Andrea Adami wrote: > The ADS7846 driver _requires_ the use of a voltage regulator > or if not present, CONFIG_REGULATOR_DUMMY should be used for proper operation. > This was made mandatory by the following commit: No, CONFIG_REGULATOR_DUMMY should *never* be used in production. > The ADS7846 in spitz machines is not connected to > any power regulator so it needs CONFIG_REGULATOR_DUMMY enabled. I don't think that's the case, it would be a very unusual piece of silicon that was able to operate without power. It may be that it's not using a software controllable regulator but there will be one or more power supplies. Judging by your problem here it seems like there is actually a software controllable regulator though... > However, enabling CONFIG_REGULATOR and CONFIG_REGULATOR_DUMMY > will break pxamci driver and cause the following error output: This is why you should never use CONFIG_REGULATOR_DUMMY in production, it's just a crutch to help things boot during development. > Regulator support in pxamci_init_ocr() is not > written with the existence of the dummy regulator driver in > mind. It does not check the return value of mmc_regulator_get_ocrmask() > and it will only fall back to platform data if no regulator was found. No regulator driver should be written with CONFIG_REGULATOR_DUMMY in mind. My guess here is that your custom callbacks for this board should be being replaced by a regulator, for example the fixed voltage regulator if there's only one voltage supported.
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