Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751569AbdFEI5G (ORCPT ); Mon, 5 Jun 2017 04:57:06 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:34550 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751352AbdFEI5E (ORCPT ); Mon, 5 Jun 2017 04:57:04 -0400 Message-ID: <1496653020.31741.2.camel@collabora.co.uk> Subject: Re: [RFC] usb-phy-generic: Add support to SMSC USB3315 From: Fabien Lahoudere To: Stephen Boyd Cc: Peter Chen , Peter Senna Tschudin , Felipe Balbi , Greg Kroah-Hartman , "open list:USB PHY LAYER" , open list Date: Mon, 05 Jun 2017 10:57:00 +0200 In-Reply-To: <20170602220010.GQ20170@codeaurora.org> References: <20170419061413.20961-1-peter.senna@collabora.com> <20170420085046.GA11378@b29397-desktop> <1495563396.12055.93.camel@collabora.co.uk> <20170523210022.GN20170@codeaurora.org> <1495708587.12055.97.camel@collabora.co.uk> <1495789230.12055.104.camel@collabora.co.uk> <20170602220010.GQ20170@codeaurora.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3441 Lines: 82 On Fri, 2017-06-02 at 15:00 -0700, Stephen Boyd wrote: > On 05/26, Fabien Lahoudere wrote: > > Hello > > > > I modify ci_hrdc_imx_probe to bypass "data->phy = devm_usb_get_phy_by_phandle(&pdev->dev, > > "fsl,usbphy", 0);". Everything works as expected and call ci_ulpi_init. > > > > The problem is that in ci_ulpi_init, before calling "ci->ulpi = ulpi_register_interface(ci->dev, > > &ci->ulpi_ops);" (to initialize our phy), "hw_phymode_configure(ci);" is called which is the > > original function that make our system to hang. > > > > Our phy is not initialised before calling ulpi_register_interface so I don't understand how the > > phy > > can reply if it is not out of reset state. > > I haven't see any problem in hw_phymode_configure(). What's the > value of ci->platdata->phy_mode? USBPHY_INTERFACE_MODE_ULPI? If > you phy needs to be taken out of reset to reply to the ulpi reads > of the vendor/product ids, then it sounds like you have a similar > situation to what I had. I needed to turn on some regulators to > get those reads to work, otherwise they would fail, but knowing > what needed to be turned on basically meant I needed to probe the > ulpi driver so probing the ids wasn't going to be useful. So on > my device the reads for the ids go through, but they get all > zeroes back, which is actually ok because there aren't any bits > set on my devices anyway. After the reads see 0, we fallback to > DT matching, which avoids the "bring it out of reset/power it on" > sorts of problems entirely. > Yes the phy mode is configured to USBPHY_INTERFACE_MODE_ULPI. Indeed, this phy need to be out of reset to work. For example everything works fine if I call  "_ci_usb_phy_init(ci);" before calling "hw_phymode_configure(ci);" This function only init reset GPIO and clock. For information, the original patch I have to fix the issue: diff --git a/drivers/usb/chipidea/core.c b/drivers/usb/chipidea/core.c index 79ad8e9..21aaff1 100644 --- a/drivers/usb/chipidea/core.c +++ b/drivers/usb/chipidea/core.c @@ -391,6 +391,7 @@ static int ci_usb_phy_init(struct ci_hdrc *ci)   case USBPHY_INTERFACE_MODE_UTMI:   case USBPHY_INTERFACE_MODE_UTMIW:   case USBPHY_INTERFACE_MODE_HSIC: + case USBPHY_INTERFACE_MODE_ULPI:   ret = _ci_usb_phy_init(ci);   if (!ret)   hw_wait_phy_stable(); @@ -398,7 +399,6 @@ static int ci_usb_phy_init(struct ci_hdrc *ci)   return ret;   hw_phymode_configure(ci);   break; - case USBPHY_INTERFACE_MODE_ULPI:   case USBPHY_INTERFACE_MODE_SERIAL:   hw_phymode_configure(ci);   ret = _ci_usb_phy_init(ci); --  So if some ULPI phys need to be initialised before calling "hw_phymode_configure", is it acceptable if I separate "case USBPHY_INTERFACE_MODE_ULPI:" and add a DT binding ("init_phy_first") to define the order to call both functions? Something like: case USBPHY_INTERFACE_MODE_ULPI: if (ci->platdata->init_phy_first) { ret = _ci_usb_phy_init(ci);                 if (!ret)                         hw_wait_phy_stable();                 else                         return ret; } hw_phymode_configure(ci); if (!ci->platdata->init_phy_first) { ret = _ci_usb_phy_init(ci);                 if (ret)                         return ret; } break; This approach will not modify current behaviour but allow to initialize phy first on demand.