On 06/05/2013 09:34 PM, J, KEERTHY wrote: > Hi Stephen, > > Thanks for the quick review. > > Stephen Warren wrote at Wednesday, June 05, 2013 10:44 PM: >> On 06/04/2013 02:41 AM, J Keerthy wrote: >>> From: Graeme Gregory <gg@xxxxxxxxxxxxxxx> >>> >>> Add the various binding files for the palmas family of chips. There is >>> a top level MFD binding then a seperate binding for regulators IP >> blocks on chips. ... >> Oh, one question though: How does the regulator driver determine the >> register address of the regulator sub-device within the overall PMIC? >> Presumably if these are pluggable independent modules, that could >> change depending on which overall chip the PMIC device is plugged into. >> don't you need a reg property to specify that? > > The variants have identical register addresses. These are not pluggable > Independent modules. All the variants come with all the regulators > Listed above in general. The driver today has a statically defined > Array of all the above mentioned regulators with their addresses. > > drivers/regulator/palmas-regulator.c > > Line 38. I meant the I2C address used to communicate with the regulator registers really, and I suppose the base address of the regulator register block. In the driver, I see this is handled by the top-level Palmas driver creating a regmap object which the regulator driver used. This keeps the regulator driver completely unaware of these issues, only the top-level chip driver cares about this, which is fine. While that justification is in terms of OS-specific code, the basic argument can be applied to the HW itself (the top-level chip implies the I2C address and any register offset), so this really is a HW-driven argument, so I guess it's fine not having a reg property in the top-level regulator node. One question though: I wonder why if the HW IP blocks aren't completely independent modules that can be mixed/matched together to form new chips, there's even a need for a separate regulator node with its own compatible value. Still, I suppose it's a valid way to construct the DT either way, so it's fine. -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
