Messages in this thread | | | Date | Wed, 31 Oct 2012 16:47:15 -0600 | From | Stephen Warren <> | Subject | Re: [RFC PATCH] dt: describe base reset signal binding |
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On 10/31/2012 04:32 AM, Mike Turquette wrote: > Quoting Stephen Warren (2012-10-30 11:02:05) >> On 10/29/2012 12:32 PM, Mike Turquette wrote: >>> Quoting Stephen Warren (2012-10-23 14:45:56) >>>> What do people think of this? Does it sound like a good idea to go ahead >>>> with a reset subsystem? Should we simply add a new API to the common clock >>>> subsystem instead (and assume that reset and clock domains match 1:1). >>>> Should this be implemented as part of the generic power management domains; >>>> see include/linux/pm_domain.h instead? >>>> >>> >>> Hi Stephen, >>> >>> I'm not sure a "reset subsystem" is necessary, but I also do not like >>> using clocks as the keys for IP reset. >> >> I'm not sure what you're suggesting as an alternative to a reset >> subsystem (or API if you want something that sounds smaller!) :-) > > My point was that I do not know if a new subsystem is necessary or not. > Your suggestion to "simply add a new API to the common clock subsystem" > is an example of an alternative to a whole new subsystem. However I > instinctively feel that the clock api is not the right place for > reseting devices.
driver/base/power is about the only related place I can think of given a quick look. However, in a similar way to clocks, I don't think there's necessarily a 1:1 relationship between power domains and reset domains either, so driver/base/power doesn't feel like a good fit in just the same way that drivers/clk doesn't.
I wonder if a drivers/base/reset/ or drivers/base/reset.c would be appropriate?
>>> I think it is more common to map IPs to struct device, no? >> >> It is indeed probably common that there's a 1:1 mapping between IP >> blocks and struct device. However, I'm sure there are plenty of >> counter-examples; IP blocks with multiple reset domains (hence struct >> devices that encompass multiple reset domains, or reset domains that >> encompass multiple struct devices), just as there are many examples of >> non-1:1 mappings between struct device and struct clk. > > In OMAP code we handle IP resets through the hwmod code and I prefer > that IP-centric approach to associating IP resets with a clock node. > Perhaps the hwmod approach could serve as inspiration for a new generic > way to reset modules.
OK, I'm not even slightly familiar with the hwmod code, but I keep hearing about it, so I'll go take a quick look.
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