From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755534Ab3ILL0j (ORCPT ); Thu, 12 Sep 2013 07:26:39 -0400 Received: from mail-bk0-f43.google.com ([209.85.214.43]:64527 "EHLO mail-bk0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753645Ab3ILL0h (ORCPT ); Thu, 12 Sep 2013 07:26:37 -0400 MIME-Version: 1.0 In-Reply-To: <52319FC4.8040703@ti.com> References: <1378136591-7463-1-git-send-email-kishon@ti.com> <1378136591-7463-2-git-send-email-kishon@ti.com> <52319912.8030203@ti.com> <52319FC4.8040703@ti.com> Date: Thu, 12 Sep 2013 16:56:34 +0530 Message-ID: Subject: Re: [PATCH 1/7] usb: dwc3: get "usb_phy" only if the platform indicates the presence of PHY From: Vivek Gautam To: Roger Quadros Cc: Kishon Vijay Abraham I , Felipe Balbi , Benoit Cousson , Tony Lindgren , Rob Herring , Pawel Moll , Mark Rutland , Russell King - ARM Linux , Grant Likely , Sylwester Nawrocki , Kumar Gala , Stephen Warren , Ian Campbell , Rob Landley , george.cherian@ti.com, Greg KH , linux-doc@vger.kernel.org, linux-omap@vger.kernel.org, "devicetree@vger.kernel.org" , Linux USB Mailing List , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Thu, Sep 12, 2013 at 4:34 PM, Roger Quadros wrote: > Hi, > > On 09/12/2013 01:47 PM, Vivek Gautam wrote: >> On Thu, Sep 12, 2013 at 4:06 PM, Roger Quadros wrote: >>> Hi Kishon, >>> >>> On 09/02/2013 06:43 PM, Kishon Vijay Abraham I wrote: >>>> There can be systems which does not have a external usb_phy, so get >>>> usb_phy only if usb-phy property is added in the case of dt boot or if >>>> platform_data indicates the presence of PHY. Also remove checking if >>>> return value is -ENXIO since it's now changed to always enable usb_phy layer. >>>> >>>> Signed-off-by: Kishon Vijay Abraham I >>>> --- >>>> drivers/usb/dwc3/Kconfig | 1 + >>>> drivers/usb/dwc3/core.c | 60 +++++++++++++++++--------------------- >>>> drivers/usb/dwc3/platform_data.h | 1 + >>>> 3 files changed, 28 insertions(+), 34 deletions(-) >>>> >>>> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig >>>> index f969ea2..cfc16dd 100644 >>>> --- a/drivers/usb/dwc3/Kconfig >>>> +++ b/drivers/usb/dwc3/Kconfig >>>> @@ -2,6 +2,7 @@ config USB_DWC3 >>>> tristate "DesignWare USB3 DRD Core Support" >>>> depends on (USB || USB_GADGET) && GENERIC_HARDIRQS && HAS_DMA >>>> depends on EXTCON >>>> + select USB_PHY >>>> select USB_XHCI_PLATFORM if USB_SUPPORT && USB_XHCI_HCD >>>> help >>>> Say Y or M here if your system has a Dual Role SuperSpeed >>>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c >>>> index 474162e..428c29e 100644 >>>> --- a/drivers/usb/dwc3/core.c >>>> +++ b/drivers/usb/dwc3/core.c >>>> @@ -387,16 +387,38 @@ static int dwc3_probe(struct platform_device *pdev) >>>> if (node) { >>>> dwc->maximum_speed = of_usb_get_maximum_speed(node); >>>> >>>> - dwc->usb2_phy = devm_usb_get_phy_by_phandle(dev, "usb-phy", 0); >>>> - dwc->usb3_phy = devm_usb_get_phy_by_phandle(dev, "usb-phy", 1); >>>> + if (of_property_read_bool(node, "usb-phy")) { >>>> + dwc->usb2_phy = devm_usb_get_phy_by_phandle(dev, >>>> + "usb-phy", 0); >>>> + if (IS_ERR(dwc->usb2_phy)) >>>> + return PTR_ERR(dwc->usb2_phy); >>>> + dwc->usb3_phy = devm_usb_get_phy_by_phandle(dev, >>>> + "usb-phy", 1); >>>> + if (IS_ERR(dwc->usb3_phy)) >>>> + return PTR_ERR(dwc->usb3_phy); >>> >>> Some DWC3 instances use only usb2_phy. e.g. on DRA7 the 2nd dwc3 instance doesn't use usb3_phy. >>> This needs to be a valid case and driver shouldn't error out. >> >> So, i think adding flexibility to DWC3 to have either >> usb2-phy/usb3-phy or both of them seems to be valid point. >> Any suggestions ? >> > > For high speed operation we need only usb2_phy but for super speed we need both usb2_phy > and usb3_phy. > > Why would a dwc3 controller use only usb3_phy? A USB3.0 interface has to be compatible with > USB2.0 as well, no? True and for that reason we need both UTMI+ interface as well as PIPE3 interface, right ? But as also mentioned in the thread: https://lkml.org/lkml/2013/9/12/181, on Samsung exynos5 architecturally same block is managing UTMI+ and PIPE3 interfaces, which is handled by phy-samsung-usb3 driver and denoted by "usb3_phy: usbphy@12100000" node in "arch/arm/boot/dts/exynos5250.dtsi". So on exynos5250, DWC3 really needs just usb3-phy, which is compatible for USB 2.0 as well. > > cheers, > -roger > -- Best Regards Vivek