[U-Boot] [PATCH RFC 0/2] usb: host: Add a wrapper layer for mutiple host support

[Simon Glass]

Hi,

On 26 June 2014 03:21, Marek Vasut <marex at denx.de> wrote:
> On Thursday, June 26, 2014 at 06:46:11 AM, Vivek Gautam wrote:
>> Hi Simon, Marek,
>>
>>
>> On Thu, Jun 26, 2014 at 10:04 AM, Vivek Gautam <gautam.vivek at samsung.com>
>> wrote:
>>
>> sorry for spamming, the earlier message got sent by mistake.
>>
>> > On Thu, Jun 26, 2014 at 8:00 AM, Simon Glass <sjg at chromium.org> wrote:
>> >> Hi Marek,
>> >>
>> >> On 25 June 2014 02:33, Marek Vasut <marex at denx.de> wrote:
>> >>> On Wednesday, June 25, 2014 at 08:27:39 AM, Simon Glass wrote:
>> >>> [...]
>> >>>
>> >>>> > > > model. Instead, I'd love to see a mean to instantiate each *HCI
>> >>>> > > > controller and have a USB core which would track those
>> >>>> > > > instances. The USB core would then be able to call whatever
>> >>>> > > > generic ops on those instances as needed. Does that make sense
>> >>>> > > > please ?
>> >>>> > >
>> >>>> > > True, i understand your point here. I think the second approach i
>> >>>> > > was talking of, goes in this direction.
>> >>>> > > I think i could not put it well in words there.
>> >>>> > >
>> >>>> > > I will prepare an RFC patch for that, and post it as soon as its
>> >>>> > > ready, so that you can have
>> >>>> > > a look.
>> >>>> >
>> >>>> > Ah, this would be so very appreciated! Thank you!
>> >>>>
>> >>>> Should we consider just going straight for driver model?
>> >>>
>> >>> I was thinking about that, but I'm worried it might break USB support
>> >>> on some platforms. Also, the size of U-Boot will grow on many
>> >>> platforms, right?
>> >>>
>> >>> What do you think ?
>> >>
>> >> If you add CONFIG_DM_USB as an option, you can then pull in either
>> >> usb-uclass.c or the old usb code. Since USB is often tied to a board
>> >> then you can move just that board (or group of boards) to dm.
>> >>
>> >> I am keeping a working tree in u-boot-dm.git which does this for
>> >> serial, SPI, SPI flash and GPIO. It seems to work fairly well as a
>> >> technique for keeping both things in the tree in the interim..
>>
>> Ok, so i am having a look at the u-boot-dm tree, and also going through the
>> documentation for driver-model.
>> The driver-model looks a promising choice at the moment keeping in mind
>> that later we would need to move to it anyways.
>>
>> I will try understanding the things and raise a flag in case something
>> is not clear.
>
> Even better, if I don't have to do this myself :) I'm really glad to see how
> many people put effort into the USB and how things are coming together nicely.
> Thank you guys!

Please note I have updated the 'working' branch. A parent device (such
as a SPI bus or USB bus) can now have private data for each of its
children. This was useful for SPI and may be useful for USB.

Regards,
Simon