From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kx5hJ-0005mw-Rw for barebox@lists.infradead.org; Wed, 06 Jan 2021 10:05:46 +0000 Date: Wed, 6 Jan 2021 11:05:43 +0100 Message-ID: <20210106100543.GO19063@pengutronix.de> References: <20201221003251.83042-1-ahmad@a3f.at> <20201221003251.83042-2-ahmad@a3f.at> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201221003251.83042-2-ahmad@a3f.at> From: Sascha Hauer List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH 1/2] fixup! usb: dwc2: Add support for optional usb phy To: Ahmad Fatoum Cc: barebox@lists.infradead.org, mgr@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 -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox