On 10/03/2012 02:24 AM, Alex Courbot wrote: > On 09/14/2012 12:24 AM, Stephen Warren wrote: >> On 09/13/2012 01:29 AM, Mark Brown wrote: >>> On Thu, Sep 13, 2012 at 04:26:34PM +0900, Alex Courbot wrote: >>>> On Thursday 13 September 2012 15:19:30 Mark Brown wrote: >>>>>> On Thursday 13 September 2012 14:25:53 Mark Brown wrote: >>>>>>> It would be sensible to make sure that the framework is done in >>>>>>> such a >>>>>>> way that drivers can use it - there will be drivers (perhaps not >>>>>>> display >>>>>>> ones) that have a known power sequence and which could benefit >>>>>>> from the >>>>>>> ability to use library code to implement it based on the user simply >>>>>>> supplying named resources. >>> >>>>>> Not sure I understand what you mean, but things should be working >>>>>> this way >>>>>> already - regulators and PWMs are acquired by name using the standard >>>>>> regulator_get() and pwm_get() functions. GPIOs do not, AFAIK, have >>>>>> a way >>>>>> to be referenced by name so their number is used instead. >>> >>>>> Right, but the sequencing for enabling them is currently open coded in >>>>> each driver. >>> >>>> Mmm then I'm afraid I don't see what you wanted to say initially - >>>> could you >>>> elaborate? >>> >>> The driver knows the power sequence. Having to type the same sequence >>> into the DT or platform data for each board using the device wouuld be >>> retarded so we need the drivers to be able to give the sequence to the >>> library if they're going to be able to reuse it (which is a lot of what >>> Tomi is talking about). >> >> I believe that's trivial to implement. The relevant function is: >> >> struct power_seq_set *devm_power_seq_set_build(struct device *dev, >> struct platform_power_seq_set *pseq); >> >> It's up to the driver whether pseq comes from platform data or is >> hard-coded into the driver (or not provided at all, for the DT case). >> So, the only change needed to convert a "hard-coded" driver to this API >> is to convert the current custom data structure (or code) that describes >> the sequence into a struct platform_power_seq_set. > > If we go this way (which looks good IMO!), then maybe we should abandon > that "platform" denomination and merge platform_power_seq* structures > with the currently private power_seq*, and also replace the "building" > step with a resources acquisition one. Calling these structures > "platform" implies they are for platform data while they can be used to > perform more flexible things as Mark mentioned. That all seems reasonable. > Also making the resolved > resource visible would allow drivers to "patch" generic sequences with > the proper GPIO numbers at runtime. That doesn't sound like a great idea to me, but we can simply avoid doing this even though it's technically possible. > We would also avoid a few memory > copies and both design and usage would be simplified, at the cost of > having more things exposed. How does that sound? Sounds fine to me at least. -- 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
