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From: Felipe Balbi on 26 Jan 2010 14:00
On Tue, Jan 26, 2010 at 04:21:28PM +0100, ext David Brownell wrote:
>On Tuesday 26 January 2010, Felipe Balbi wrote:
>> >
>> >Thing is, supplying current is a bit more involved. �If the
>> >board can't supply 300 mA, the USB configuration selection
>> >mechanism has to know that, so it never selects peripheral
>> >configurations which require that much current.
>>
>> but that's done already by the usb core, no ? It rules out configuration
>> based on the hub->power_budget (can't remember if the field is that
>> exact name).
>
>Yes, it handles that ... but where does the power budget
>come from? That's what I meant by "more involved".

we set it from board-files (on ARM, at least). It's a board
characteristic, no ?

>As in, the host/supplying side of the power equation can't
>be event driven like the peripheral/consuming side can.
>
>And that's another reason I think it's best to fully solve
>the common (peripheral, recharge-that-batter) case first.

fair enough.

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balbi
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From: Felipe Balbi on 26 Jan 2010 14:20
Hi,

On Tue, Jan 26, 2010 at 08:09:34PM +0100, Balbi Felipe (Nokia-D/Helsinki) wrote:
>well, if you have access to twl5031 docs you'd understand what I'm
>talking about, the charger detection involves at least 3 blocks on
>twl5031 plus musb to enable/disable pullups. The sequence is pretty much
>as below:

there's more which I forgot:

>1. vbus irq
>2. usb_gadget_disconnect()
>3. disable usb ldos

3.1 put transceiver in non-drivig mode

>4. switch usb3v1 supply from vbat to vbus (to let charger detection work
>on low bat)
>5. enable usb3v1 *only*
>6. call the notifier chain
>7. BCC module kicks charger detection
>8. disable usb3v1
>9. switch usb3v1 supply back to vbat

9.1 put transceiver back to normal mode

>10. enable usb ldos
>11. usb_gadget_connect() (necessary since we might be connected to
>charging port)

now it should be all fine.

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balbi
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