Re: [PATCH v19 0/4] Introduce usb charger framework to deal with the usb gadget power negotation

[Baolin Wang]

Hi,

On 29 March 2017 at 07:04, NeilBrown <neilb@xxxxxxxx> wrote:
> On Tue, Mar 07 2017, Baolin Wang wrote:
>
>> On 3 March 2017 at 10:23, NeilBrown <neilb@xxxxxxxx> wrote:
>>
>>>
>>> I understand your reluctance to change drivers that you cannot test.
>>> An alternative it do change all the
>>>   atomic_notifier_call_chain(.*notifier,
>>> calls that don't pass a pointer to vbus_draw to pass NULL, and to
>>> declare the passing of NULL to be deprecated (so hopefully people won't
>>> use it in new code).
>>> Then any notification callback that expects a current can just ignore
>>> calls where the pointer is NULL.
>>
>> I am afraid if it is enough to send out vbus draw information from USB
>> phy driver, for example you will miss super speed (900mA), which need
>> get the speed information from gadget driver.
>
> When the gadget driver determines that 900mA is available, it calls
> usb_phy_set_power() which calls the ->set_power() method on the usb_phy.
> The usb_phy the uses the notifier to inform all interested parties
> that 900mA is available.

That is one possible way. Now we only set vbus draw by
usb_gadget_vbus_draw() after setting config and suspend/resume usb
device. Maybe we can add one condition in usb_gadget_vbus_draw() like:

if (mA >= 500 && gadet->speed >= SUPER_SPEED)
     mA = 900;

-- 
Baolin.wang
Best Regards