Hi,
On Friday 19 April 2013 02:39 PM, Grant Likely wrote:
On Tue, 16 Apr 2013 15:48:07 +0530, Kishon Vijay Abraham I <kishon@xxxxxx> wrote:
On Tuesday 16 April 2013 01:20 AM, Grant Likely wrote:
On Mon, 15 Apr 2013 17:56:10 +0530, Kishon Vijay Abraham I <kishon@xxxxxx> wrote:
On Monday 15 April 2013 05:04 PM, Grant Likely wrote:
On Wed, 20 Mar 2013 14:42:00 +0530, Kishon Vijay Abraham I <kishon@xxxxxx> wrote:
We have decided not to implement the PHY layer as a separate bus layer.
The PHY provider can be part of any other bus. Making the PHY layer as a
bus will make the PHY provider to be part of multiple buses which will
lead to bad design. All we are trying to do here is keep the pool of PHY
devices under PHY class in this layer and help any controller that wants
to use the PHY to get it.
If you're using a class, then you already have your list of registered
phy devices! :-) No need to create another global list that you need to
manage.
right. We already use _class_dev_iter_ for finding the phy device.
.
.
+static struct phy *of_phy_lookup(struct device *dev, struct device_node
*node)
+{
+ struct phy *phy;
+ struct class_dev_iter iter;
+
+ class_dev_iter_init(&iter, phy_class, NULL, NULL);
+ while ((dev = class_dev_iter_next(&iter))) {
+ phy = container_of(dev, struct phy, dev);
+ if (node != phy->of_node)
+ continue;
+
+ class_dev_iter_exit(&iter);
+ return phy;
+ }
+
+ class_dev_iter_exit(&iter);
+ return ERR_PTR(-EPROBE_DEFER);
+}
.
.
however we can't get rid of the other list (phy_bind_list) where we
maintain the phy binding information. It's used for the non-dt boot case.
Why? If you're using a class, then it is always there. Why would non-DT
and DT be different in this regard? (more below)
Since there is at most a 1:N relationship between host controllers and
PHYs, there shouldn't be any need for a separate structure to describe
binding. Put the inding data into the struct phy itself. Each host
controller can have a list of phys that it is bound to.
No. Having the host controller to have a list of phys wont be a good
idea IMHO. The host controller is just an IP and the PHY to which it
will be connected can vary from board to board, platform to platform. So
ideally this binding should come from platform initialization code/dt data.
That is not what I mean. I mean the host controller instance should
contain a list of all the PHYs that are attached to it. There should not
Doesn't sound correct IMO. The host controller instance need not know
anything about the PHY instances that is connected to it. Think of it
similar to regulator, the controller wouldn't know which regulator it is
connected to, all it has to know is it just has a regulator connected to
it. It's up-to the regulator framework to give the controller the
correct regulator. It's similar here. It makes sense for me to keep a
list in the PHY framework in order for it to return the correct PHY (but
note that this list is not needed for dt boot).
With regulators and clocks it makes sense to have a global
registration place becase both implement an interconnected network
independent of the device that use them. (clocks depend on other clocks;
regulators depend on other regulators).
Phys are different. There is a 1:N relationship between host controllers
and phys, and you don't get a interconnected network of PHYs. Its a bad
idea to keep the binding data separate from the actual host controller
when there is nothing else that actually needs to use the data. It
creates a new set of data structures that need housekeeping to keep them
in sync with the actual device structures. It really is just a bad idea
and it becomes more difficult (in the non-DT case) to determine what
data is associated with a given host controller. You can't tell by
looking at the struct device.
Instead, for the non-DT case, do what we've always done for describing
connections. Put the phy reference into the host controllers
platform_data structure.
hmm... my only concern here is there is no way we can enforce the phy
reference is added in the platform_data structure.
That is what it is there for. That completely
eliminates the need to housekeep a new set of data structures.
Ok. Makes sense.
Thanks
Kishon
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