Re: [PATCH 3/3] usb: phy-generic: Add ULPI VBUS support

[Chris Ruehl]

On Wednesday, December 04, 2013 05:49 PM, Heikki Krogerus wrote:
> Hi Chris,
>
> On Wed, Dec 04, 2013 at 03:16:21PM +0800, Chris Ruehl wrote:
> > On Tuesday, December 03, 2013 04:15 PM, Heikki Krogerus wrote:
> > > On Mon, Dec 02, 2013 at 03:05:19PM +0800, Chris Ruehl wrote:
> > > > @@ -154,6 +164,27 @@ int usb_phy_gen_create_phy(struct device *dev, struct usb_phy_gen_xceiv *nop,
> > > >   {
> > > >   	int err;
> > > >
> > > > +	if (nop->ulpi_vbus>   0) {
> > > > +		unsigned int flags = 0;
> > > > +
> > > > +		if (nop->ulpi_vbus&   0x1)
> > > > +			flags |= ULPI_OTG_DRVVBUS;
> > > > +		if (nop->ulpi_vbus&   0x2)
> > > > +			flags |= ULPI_OTG_DRVVBUS_EXT;
> > > > +		if (nop->ulpi_vbus&   0x4)
> > > > +			flags |= ULPI_OTG_EXTVBUSIND;
> > > > +		if (nop->ulpi_vbus&   0x8)
> > > > +			flags |= ULPI_OTG_CHRGVBUS;
> > > > +
> > > > +		nop->ulpi = otg_ulpi_create(&ulpi_viewport_access_ops, flags);
> > > > +		if (!nop->ulpi) {
> > > > +			dev_err(dev, "Failed create ULPI Phy\n");
> > > > +			return -ENOMEM;
> > > > +		}
> > > > +		dev_dbg(dev, "Create ULPI Phy\n");
> > > > +		nop->ulpi->io_priv =  nop->viewport;
> > > > +	}
> > >
> > > This is so wrong. You are registering one kind of usb phy driver from
> > > an other. Change drivers/usb/phy/ulpi.c to be a platform device. The
> > > whole flag system in it is pretty horrid. While you are at it, change
> > > that so it sets the values based on boolean flags from OF properties
> > > or platform data.
> > >
> > > NAK for the whole set.
> >
> > Heikki,
> >
> > Thanks for your comments, even not much positive to me.. any how.
> > My intention on the "horrid" path was to reduce kernel code where
> > one of_read32 vs. four of_boolean. And mentioned logic is simple.
> > But that's history.
>
> I should probable explain why I have problems with them. First of all,
> things like driving the vbus should be a function that can be called
> from upper layers. struct usb_otg has the set_vbus hook for that. You
> can call it for example from your host controller's init routine. I'm
> assuming you have a host controller since you are driving vbus.

My platform is Freescale imx27 and the host controller the ChipIdea, where I 
have already send some patches for. I uses the set_vbus it in the wrong place
nop->ulpi->otg->set_vbus(nop->ulpi->otg,true); (phy-generic:usb_gen_phy_init())

and now I start to understand where is the issue. I must tell chipidea to init 
the vbus using the platform....

> You don't need to set the ULPI_OTG_CHRGVBUS. It's used for the VBUS
> pulsing of SRP, which btw. is not anymore supported in OTG&EH2.0 spec,
> so just don't use that bit even if you want to start SRP.

OK, got it. Test it right away, yes my USB still works great even I omit the 
flag. The reason I introduced it was the fact that plat-mxc/isp1504xc.c of the 
2.6.22 with the freescale patches set this flag.

> The only of_booleans you should need are for the DRV_VBUS_EXT and
> USE_EXT_VBUS_IND. In my case I could not use even those. My controller
> provides it's own control for them, so even if I set them to my ULPI
> phy, the controller would simply override the values.
>
> Secondly, why those silly flags in the first place. Those flags are
> just bits in the registers. It would have been much easier and cleaner
> to deliver a small struct with default values for the registers
> instead.
>
> > On my way to find a solution for my board I'd look around and found using of
> > phy-ulpi.c functions in phy-tegra-usb.c and don't mind to use them too.
>
> OK, IC. I have not followed what is happening with USB in linux for a
> while.
>
> The whole otg_ulpi_create() thing, and the flags with it, were
> originally planned to be used from platform code. It's evil and it
> should have never been accepted into upstream kernel. The time it was
> introduced I was on vacation and nobody else seemed to care :(. All I
> was able to do was to protest afterwards.

Checked!


> > I accept your NAK and will work on a patch to make phy-ulpi.c
> > working as platform device.
> >
> > Last question to you. What you don't like on the patch to support
> > chip-select gpio of my patch-set.. I ask because you NAK the whole
> > set.
> > I really need the ChipSelect function to make my hardware work!
>
> OK, I did not explain my problem with that patch. I'm sorry about
> that. It also looks like I made wrong assumption with it. I thought
> that your phy (is was ISP1504 right) is just like isp1704 that I have
> worked with. On isp1704 you only have the chip_sel pin (no reset pin),
> so I thought you can not have any reason to add handler for an other
> gpio to this driver. After a quick look at isp1504 data sheet, it
> looks like you have both reset and chip_sel pins on it, which I guess
> are both connected to gpios on your platform.
Yes 1504, and my hardware guys make otg using the chipselect with gpio
and the usbh2 is fixed selected via pull down resistor.


> So I don't have a problem with that. Though I'm not sure is this
> driver the right place to handle things like these gpios, which are
> pretty phy specific, in the first place. The phy-generic was
> originally meant to be pure NOP phy driver.
May then change the meaning back to "generic" when support generic requirements
like chip-select(1704+1504) reset(1504).
If the 1504 missed a proper reset its ends up in weird errors ..

> One comment about how to handle the gpios. You should move to the new
> gpio descriptor API. The legacy gpio API is now just a wrapper on top
> of it.
Back to the Manuals.. :-) OK its on the list.


> > Chris
>
> Thanks,

I thank you!
Chris

--
GTSYS Limited RFID Technology
A01 24/F Gold King Industrial Bld
35-41 Tai Lin Pai Road, Kwai Chung, Hong Kong
Fax (852) 8167 4060 - Tel (852) 3598 9488

Disclaimer: http://www.gtsys.com.hk/email/classified.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/