Re: [PATCH v8 0/4] Introduce usb charger framework to deal with the usb gadget power negotation

Baolin Wang
2016-03-31T08:24:55Z

On 31 March 2016 at 16:15, Felipe Balbi <balbi@kernel.org> wrote:
>
> Hi Baolin,
>
> Baolin Wang <baolin.wang@linaro.org> writes:
>>>> >> Make sense. In our company's solution, charger detection can be done
>>>> >> by hardware from PMIC at first, then it will not affect the DP/DM
>>>> >> line when gadget starts to enumeration.
>>>> >
>>>> > I see, charger type detection is done automatically by PMIC when VBUS
>>>> > is detected in your case, you just assume the process is complete
>>>> > before SW do gadget connect. To make the framework common, you may do
>>>> one time charger type check when vbus is on, and save it to avoid repeat
>>>> charger type check.
>>>>
>>>> OK. I'll add one judgement to check if the charger type is set in
>>>> 'usb_charger_detect_type()' function.
>>>
>>> Just adding a judgement isn't enough here, your framework should make sure
>>> usb_charger_detect_type() is called before gadget connect, with that, the
>>> existing caller place just gets the charger type from the saved value.
>>> The real charger type detection done by usb_charger_detect_type() can
>>> be called only when vbus is on.
>>> e.g. maybe in usb_udc_vbus_handler() before usb_udc_connect_control().
>>
>> Yeah, Like Felipe suggested, I think we need to introduce one
>> 'charger_detect()' method to do the SW charger type detection at the
>> right gadget state. Thanks for your comments.
>
> Just to be clear, we add ->charger_detect() when we know of a platform
> which needs to manually detect the charger type. Until then, we ignore
> that situation. It might be a good idea, however, do document this in
> comments on your structure definition stating that if we need to detect
> charger type, a new method should be added ;-)

Make sense. Thanks.

>
> cheers
>
> --
> balbi

--
Baolin.wang
Best Regards