Felipe Balbi <balbi@xxxxxx> writes:
> On Sun, Nov 09, 2014 at 03:58:14PM +0100, Robert Jarzmik wrote:
>> + if (!enabled) {
>> + ret = regulator_enable(vbus_draw);
>> + if (ret < 0)
>> + return;
>> + nop->vbus_draw_enabled = 1;
>
> do you really need this flag here ? How about:
>
> if (regulator_is_enabled(vbus_draw))
> foo();
Good question, I copy-pasted that code from gpio-vbus...
Philipp, do you have an insight here ?
>> + if (vbus) {
>> + status = USB_EVENT_VBUS;
>> + nop->phy.state = OTG_STATE_B_PERIPHERAL;
>> + nop->phy.last_event = status;
>> + usb_gadget_vbus_connect(otg->gadget);
>> +
>> + /* drawing a "unit load" is *always* OK, except for OTG */
>> + nop_set_vbus_draw(nop, 100);
>
> right, we need to take into considering the Battery Charging
> specification here, though. We might need to setup a timer for the
> amount of time we can draw 100mA before device enumerates. If the times
> expires we're only allowed to draw 8mA or 2mA, or something like that.
>
> The time gets cancelled as soon as we get enumerated.
>
> Another possibility would be to move this policy into userland, then
> kernel only provides the interfaces.
Ah ok.
Do you know exactly what the spec is telling in here ?
Is it something such as :
- upon vbus insertion, a UDC can draw 100mA during ??? ms
- if during ??? ms, the device is enumerated, it can continue drawing 100mA
- if not, it should not draw more than 8mA after ??? ms
Is this right ? I can add a timer I think, if the spec if that simple. Now if
there are a lot of special cases then maybe it could be dropped to userland.
Cheers.
--
Robert
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