On 04/02/2013 02:37 AM, Kishon Vijay Abraham I wrote:
> Hi,
>
> On Thursday 28 March 2013 09:15 PM, Stephen Warren wrote:
>> On 03/27/2013 11:43 PM, Kishon Vijay Abraham I wrote:
>>> The PHY framework provides a set of APIs for the PHY drivers to
>>> create/destroy a PHY and APIs for the PHY users to obtain a reference
>>> to the
>>
>>> diff --git a/Documentation/devicetree/bindings/phy/phy-bindings.txt
>>> +PHY subsystem refer Documentation/phy.txt
>>> +
>>> +PHY device node
>>> +===============
>>> +
>>> +Optional Properties:
>>> +#phy-cells: Number of cells in a PHY specifier; The meaning of all those
>>> + cells is defined by the binding for the phy node. However
>>> + in-order to return the correct PHY, the PHY susbsystem
>>> + requires the first cell always refers to the port.
>>
>> Why impose that restriction? Other DT bindings do not.
>>
>> This is typically implemented by having each provider driver implement a
>> .of_xlate() operation, which parses all of the specifier cells, and
>> returns the ID of the object it represents. This allows bindings to use
>> whatever arbitrary representation they want.
>
> Do you mean something like this
>
> struct phy *of_phy_get(struct device *dev, int index)
> {
> struct phy *phy = NULL;
> struct phy_bind *phy_map = NULL;
> struct of_phandle_args args;
> struct device_node *node;
>
> if (!dev->of_node) {
> dev_dbg(dev, "device does not have a device node entry\n");
> return ERR_PTR(-EINVAL);
> }
>
> ret = of_parse_phandle_with_args(dev->of_node, "phys", "#phy-cells",
> index, &args);
> if (ret) {
> dev_dbg(dev, "failed to get phy in %s node\n",
> dev->of_node->full_name);
> return ERR_PTR(-ENODEV);
> }
Looks good.
> //Here we have to get a reference to the phy in order to call of_xlate
> which seems a little hacky to me. I'm not sure how else can we call the
> provider driver :-(
> phy = of_phy_lookup(dev, node);
> if (IS_ERR(phy) || !try_module_get(phy->ops->owner)) {
> phy = ERR_PTR(-EPROBE_DEFER);
> goto err0;
> }
I think the concept of a "PHY provider" and a "PHY instance" are different.
of_xlate should be called on a "PHY provider", and return a "PHY
instance". Hence, above you want to only look up a "PHY provider", so
there's no hackiness involved.
> //here we are checking if the phy has additional specifiers and if so
> call of_xlate using the phy we just obtained. The provider driver should
> check the args and return the appropriate *phy in this case.
> if (args.args_count > 0) {
It's probably simplest to always call of_xlate; that way, you're always
calling it on a "PHY provider" and getting back a "PHY instance". For
providers that only provide 1 instance, the implementation should be
simple:-)
> phy = phy->of_xlate(&args);
> if (IS_ERR(phy))
> goto err0;
> }
>
> phy_map = phy_bind(dev_name(dev), index, dev_name(&phy->dev));
> if (!IS_ERR(phy_map)) {
> phy_map->phy = phy;
> phy_map->auto_bind = true;
> }
>
> get_device(&phy->dev);
>
> err0:
> of_node_put(node);
>
> return phy;
> }
> EXPORT_SYMBOL_GPL(of_phy_get);
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