Messages in this thread | | | Date | Thu, 2 Aug 2012 17:27:44 +0900 | From | Alex Courbot <> | Subject | Re: [RFC][PATCH v3 1/3] runtime interpreted power sequences |
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On Thu 02 Aug 2012 05:21:57 PM JST, Thierry Reding wrote: > * PGP Signed by an unknown key > > On Thu, Aug 02, 2012 at 05:00:13PM +0900, Alex Courbot wrote: >> On 07/31/2012 07:45 AM, Stephen Warren wrote: >>> Oh I see. That's a little confusing. Why not just reference the relevant >>> resources directly in each step; something more like: >>> >>> gpio@1 { >>> action = "enable-gpio"; >>> gpio = <&gpio 1 0>; >>> }; >>> >>> I guess that might make parsing/building a little harder, since you'd >>> have to detect when you'd already done gpio_request() on a given GPIO >>> and not repeat it or something like that, but to me this makes the DT a >>> lot easier to comprehend. >> >> I tried to move towards having the phandles directly in the >> sequences themselves - that reminded me why I did not do that in the >> first place. Let's say we have a sequence like this (reg property >> omitted on purpose): >> >> power-on-sequence { >> step@0 { >> regulator = <&backlight_reg>; >> enable; >> }; >> step@1 { >> delay = <10000>; >> }; >> step@2 { >> pwm = <&pwm 2 5000000>; >> enable; >> }; >> step@3 { >> gpio = <&gpio 28 0>; >> enable; >> }; >> }; >> >> The problem is, how do we turn these phandles into the resource of >> interest. The type of the resource can be infered by the name of the >> property. The hard part is resolving the resource from the phandle - >> it seems like the API just does not allow to do this. GPIO has >> of_get_named_gpio, but AFAIK there are no equivalent for regulator >> consumer and PWM: the only way to use the DT with them is through >> get_regulator and get_pwm which work at the device level. >> >> Or is there a way that I overlooked? > > No, you are right. Perhaps we should add exported functions that do the > equivalent of of_pwm_request() or the regulator_dev_lookup() and > of_get_regulator() pair.
How would that be looked with respect to "good DT practices"? I can somehow understand the wish to restrain DT access to these functions that integrate well with current workflows. Aren't we going to be frowned upon if we make more low-level functions public?
Alex.
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