Re: [PATCH 1/2] fixup! usb: dwc2: Add support for optional usb phy

[Sascha Hauer <sha@pengutronix.de>]

On Mon, Dec 21, 2020 at 01:32:50AM +0100, Ahmad Fatoum wrote:
> Linux doesn't seem to enforce a fixed order between phy_init and
> phy_power_on. The Linux dwc2 driver does power_on and then phy_init,
> which is the inverse of what barebox is currently doing.
> 
> The PHYs normally used with dwc2 are written with this in mind.
> For example, our stm32-usbphyc driver fails to disable:
> 
>   ERROR: stm32-usbphyc 5a006000.usbphyc@5a006000.of: PLL not reset
>   ERROR: phy1: phy exit failed --> -5
> 
> Because Linux does exit -> power_off, but barebox does power_off ->
> exit.
> 
> Issue was raised upstream:
> https://lore.kernel.org/lkml/6cd01e79-fdc0-3bd4-32b5-a85142533f8a@pengutronix.de/T/#t
> 
> Until this is settled, swap the order to follow what Linux does.
> This is suboptimal, because it means controller drivers have different
> order of the operations and that you can't combine arbitrary PHYs and
> controllers, but it seems unlikely we will support combinations that
> aren't supported by Linux in the first place anyway.

This is valuable information and I don't want it to be lost, so instead
of applying this as a fixup I rewrote the subject to:

usb: dwc2: swap order of phy_init and phy_power_on to what Linux does

and applied it as a separate patch.

Sascha

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