Re: [PATCH v2 1/9] drivers: base: add new class "cpu" to group cpu devices

From: Sudeep Holla
Date: Mon Jul 28 2014 - 09:37:41 EST

On 25/07/14 20:09, Stephen Boyd wrote:
On 07/25/14 09:44, Sudeep Holla wrote:
From: Sudeep Holla <sudeep.holla@xxxxxxx>

This patch creates a new class called "cpu" and assigns it to all the
cpu devices. This helps in grouping all the cpu devices and associated
child devices under the same class.

This patch also:
1. modifies the get_parent_device to return the legacy path
(/sys/devices/system/cpu/..) for the cpu class devices to support
existing sysfs ABI
2. avoids creating link in the class directory pointing to the device as
there would be per-cpu instance of these devices with the same name
3. makes sure subsystem symlink continues pointing to cpu bus instead of
cpu class for cpu devices

Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

Why can't we make a 'cache' bus that the cache devices hang off of? It
doesn't make sense to me why we would want to have cache devices living
on the cpu bus.

Yes we can group them under cache, but to support legacy sysfs path
under which various cpu related information including caches, we need
to have a workaround as in this patch.

Instead of having this fixup for each class like cache, having them
grouped under cpu is better IMO and hence I added caches to cpu class.
It also helps to move few other cpu related subsystems using raw
kobjects to the device attribute groups and corresponding APIs.


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