Messages in this thread | | | Date | Mon, 15 Jul 2013 13:16:32 -0400 | From | Eduardo Valentin <> | Subject | Re: [RFC PATCH 2/4] thermal: introduce device tree parser |
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On 15-07-2013 13:03, R, Durgadoss wrote: >> -----Original Message----- >> From: linux-pm-owner@vger.kernel.org [mailto:linux-pm- >> owner@vger.kernel.org] On Behalf Of Eduardo Valentin >> Sent: Monday, July 15, 2013 5:25 PM >> To: Wei Ni >> Cc: Eduardo Valentin; linux-pm@vger.kernel.org; R, Durgadoss; >> amit.daniel@samsung.com; Zhang, Rui; linux-kernel@vger.kernel.org >> Subject: Re: [RFC PATCH 2/4] thermal: introduce device tree parser >> >> On 10-07-2013 02:48, Wei Ni wrote: >>> On 07/09/2013 10:00 PM, Eduardo Valentin wrote: >>>> In order to be able to build thermal policies >>>> based on generic sensors, like I2C device, that >>>> can be places in different points on different boards, >>>> there is a need to have a way to feed board dependent >>>> data into the thermal framework. >>>> >>>> This patch introduces a thermal data parser for device >>>> tree. The parsed data is used to build thermal zones >>>> and thermal binding parameters. The output data >>>> can then be used to deploy thermal policies. >>>> >>>> This patch adds also documentation regarding this >>>> API and how to define define tree nodes to use >>>> this infrastructure. >>> >>> It looks good, with this infrastructure, we can add generic sensor >>> driver into the thermal fw easily. >>> >>> >>>> + >>>> +Below is an example: >>>> +thermal_zone { >>>> + type = "CPU"; >>>> + mask = <0x03>; /* trips writability */ >>>> + passive_delay = <250>; /* milliseconds */ >>>> + polling_delay = <1000>; /* milliseconds */ >>>> + governor = "step_wise"; >>>> + trips { >>>> + alert@100000{ >>>> + temperature = <100000>; /* milliCelsius */ >>>> + hysteresis = <0>; /* milliCelsius */ >>>> + type = <1>; >>> >>> how about to use the trip type name directly, such as named as >>> "passive-trip;", I think it's more readable. for example: >>> trip0 { >>> .... >>> passive-trip; >>> } >>> trip1 { >>> .... >>> active-trip; >>> } >>> >>>> + }; >>>> + crit@125000{ >>>> + temperature = <125000>; /* milliCelsius */ >>>> + hysteresis = <0>; /* milliCelsius */ >>>> + type = <3>; >>>> + }; >>>> + }; >>>> + bind_params { >>>> + action@0{ >>>> + cooling_device = "thermal-cpufreq"; >>>> + weight = <100>; /* percentage */ >>>> + mask = <0x01>; >>>> + }; >>>> + }; >>>> +}; >>> >>> as we know, thermal_zone_bind_cooling_device() will set the upper/lower >>> in the thermal_instance. In the default .bind function, it just set to >>> THERMAL_NO_LIMIT, but for some platform, it need to set these >>> upper/lower values for different cooling device and trips, how to pass >>> these values in DT? how about to set: >>> action@0 { >>> ... >>> mask = <0x03>; //or you can remove this property; >> >> Well, this has been added accordingly to current API needs. >> >>> trip0 = <&alert 1 2>; //1 is lower value, 2 is upper value; >>> trip1 = <&crit 3 4>; >> >> I suppose the first item in you 3-tuple is the trip point. >> >>> } >> >> Yeah, I also noticed that I was missing the upper and lower limits. But >> unfortunately this is a limitation on the thermal FW API too! >> >> If one passes a bind params, the structure which represents platform >> info, then it won't be able to pass the upper and lower limits. But by >> passing a .bind callback, then you have the opportunity to match it >> using these two values. >> >> I believe we would need to change the data structures and the API to >> support upper and lower limits via platform representation. We could >> simply use the .bind callback of the dt thermal zone, but I believe that >> would abusing the API, assuming that .match is for platform binding. >> Durga, what do you think? > > okay, I see.. Two approaches I could think of: > 1. Introduce two arrays (size = number of trips in the tz) named > upper/lower_limits[size] in the 'thermal_bind_params' structure. > This way we don't need any API change. We can slightly change the > implementation inside '__bind' function in thermal_core.c to get this > working. > > 2. Pass 3 more parameters in the .match function: > .match(tz, cdev, trip, &lower, &upper). The platform layer > then determines whether there is a match; and if so, > provides sane values for lower and upper variables. > > At this point of time, I think I prefer method 1 ;) > Let me know your thoughts. >
Yeah, I agree that (1) is likely to scale. I will cook something with it for next version.
> Thanks, > Durga >> >> >>> >>> >>> Thanks. >>> Wei. >>> >>> >>> >> >> >> -- >> You have got to be excited about what you are doing. (L. Lamport) >> >> Eduardo Valentin > > >
-- You have got to be excited about what you are doing. (L. Lamport)
Eduardo Valentin
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