[U-Boot] [PATCH 2/4 v3] musb: Add Phy programming for usingexternal Vbus

Gupta, Ajay Kumar
2011-07-05T11:15:56Z

Hello,
>> MUSB PHY on OMAP3EVM Rev>= E uses external Vbus supply to support
>> 500mA of power.We need to program MUSB PHY to use external Vbus
>> for this purpose.
>>
>> Adding 'extvbus' member in musb_config structure which should be set
>> by all the boards where MUSB interface is using external Vbus supply.
>
>Ajay,
>
>How does the DRVVBUS bit behave on the OMAP3 EVM board on issuing the
>'usb reset' command (with musb_cfg.extvbus being set)?
OMAP3EVM doesn't use TPS PHY but it has ISP1507 PHY and uses external Vbus
And so it needs extvbus programming (musb_cfg.extvbus =1)in OTG_CTRL
register. As for as I know it is not needed for boards using usb PHY on TPS
device.

> This post has a
>few more details, but in short it seems that DRVVBUS is automatically
>set by the TPS chip when doing the bus reset:

Looks like TPS sets the extvbus and so musb_cfg.extvbus doesn't have
Any effect.

Ajay
>
> http://lists.denx.de/pipermail/u-boot/2011-June/095221.html
>
>(And indeed, on a board with *no* external vbus, setting
>musb_cfg.extvbus and reading from a memory stick works just fine.)
>
>I checked the u-boot in the current DVSDK (4.02.00.06) and the git repo
>for u-boot-ti and they all have the same construct.
>
>Thanks,
>Orjan
>
>--
>Orjan Friberg
>FlatFrog Laboratories AB