On 05/21/2014 10:10 AM, Arnd Bergmann wrote:
On Wednesday 21 May 2014 09:15:34 Daniel Lezcano wrote:
On 05/15/2014 10:40 PM, Kukjin Kim wrote:
[ ... ]
Exynos cpuidle is not a device on the SoC, so I don't think there is
any
way to represent it in DT. The only thing I could see this is matching
root node with a central SoC driver that instantiates specific
subdevices, such as cpufreq and cpuidle, but I don't see any available
infrastructure for this.
There is a RFC for defining generic idle states [1].
The idea behind using the platform driver framework is to unify the code
across the different drivers and separate the PM / cpuidle code.
By this way, we can move the different drivers to drivers/cpuidle and
store them in a single place. That make easier the tracking, the review
and the maintenance.
Yes, that would be great. I only looked briefly at the series now, doesn't
that require the use of psci?
No, because PSCI is for some specific platform (eg. calxeda), all the
other drivers are legacy and manually handling the PM via some low level
callbacks. This is why all drivers were implemented all over the place
making so difficult to maintain them. Little by little, we split the PM
callbacks from the idle algorithm so reducing the platform dependency
with the generic code.
The PSCI implements such PM callbacks in the firmware directly and are
accessed through an API. PSCI is, let's say some kindof nextgen cpuidle.
It is similar than mwait on Intel. But if a new platform does not have
such firmware, then the cpuidle driver will have the legacy format.
That's not a bad idea of course, but it
doesn't solve the problem I raised here.
I am ok to by using platform_device_register_resndata() but I would
prefer to do that a bit later by converting the other drivers too. That
will be easier if we have them grouped in a single directory (this is
what does this patchset at the end).
As there are some more work based on this patchset and the link error
could be fixed as an independent patch, I would recommend to
re-integrate it in the tree as asked by Bartlomiej.
In general, it would be nice to have everything done properly, but I'd
consider Daniel's series as a huge improvement already and a nice
intermediate step towards further clean-up.
So based on the comments quoted above, instead of stalling the
development, I'd suggest to accept this series and then move forward.
I'm fine.
Arnd, how about you?
- Kukjin
Arnd ?
Sorry for the delay.
No problem.
Yes, let's do it this way once more, but please
come up with something better for the future that doesn't tie the
cpuidle method to the root compatible string as this does.
ok.
Thanks
-- Daniel
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