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SubjectRe: [RFC PATCHv2] usb: USB Type-C Connector Class
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On 05/25/2016 04:30 AM, Heikki Krogerus wrote:
> Hi,
>
> On Tue, May 24, 2016 at 06:42:09AM -0700, Guenter Roeck wrote:
>>> +struct typec_capability {
>>> + enum typec_data_role role;
>>> + unsigned int usb_pd:1;
>>> + struct typec_altmode *alt_modes;
>>> + unsigned int audio_accessory:1;
>>> + unsigned int debug_accessory:1;
>>> +
>>> + int (*fix_role)(struct typec_port *,
>>> + enum typec_data_role);
>>> +
>>> + int (*dr_swap)(struct typec_port *);
>>> + int (*pr_swap)(struct typec_port *);
>>> + int (*vconn_swap)(struct typec_port *);
>>> +
>>
>> The function parameter in those calls is all but useless to the caller.
>> It needs to store the typec_port returned from typec_register(), create a
>> list of ports, and then search through this list each time one of the
>> functions is called. This is quite expensive for no good reason.
>>
>> Previously, with typec_port exported, the called code could use the stored
>> caps pointer to map to its internal data structures. This is no longer
>> possible.
>
> True, the API now is in practice broken.
>
>> I think it would be useful to provide a better means for the called function
>> to identify its context. Maybe provide a pointer to the private data in
>> the registration function and use it as parameter in the callback functions ?
>
> Sounds reasonable.
>

I'll send a follow-up patch hopefully later today which fixes all the problems
I have found so far.

Guenter

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