Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754400AbaDVDfg (ORCPT ); Mon, 21 Apr 2014 23:35:36 -0400 Received: from mail-qc0-f170.google.com ([209.85.216.170]:35200 "EHLO mail-qc0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754192AbaDVDfJ (ORCPT ); Mon, 21 Apr 2014 23:35:09 -0400 MIME-Version: 1.0 In-Reply-To: <001101cf5dd1$2e04d390$8a0e7ab0$%han@samsung.com> References: <1396967803-28868-1-git-send-email-gautam.vivek@samsung.com> <1396967803-28868-2-git-send-email-gautam.vivek@samsung.com> <534529B2.2020107@samsung.com> <53454C11.7060607@samsung.com> <534E892B.6090409@samsung.com> <001101cf5dd1$2e04d390$8a0e7ab0$%han@samsung.com> Date: Tue, 22 Apr 2014 09:05:07 +0530 X-Google-Sender-Auth: wF1dxK3SNKtkQXXXbiZ208Y-_EQ Message-ID: Subject: Re: [PATCH V4 1/5] phy: Add new Exynos5 USB 3.0 PHY driver From: Vivek Gautam To: Jingoo Han Cc: Tomasz Figa , Linux USB Mailing List , "linux-samsung-soc@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , linux-doc@vger.kernel.org, kishon , Greg KH , Felipe Balbi , Kukjin Kim , Kamil Debski , Sylwester Nawrocki Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jingoo, On Tue, Apr 22, 2014 at 7:48 AM, Jingoo Han wrote: > On Wednesday, April 16, 2014 11:49 PM, Vivek Gautam wrote: >> On Wed, Apr 16, 2014 at 7:14 PM, Tomasz Figa wrote: >> > On 15.04.2014 08:09, Vivek Gautam wrote: >> >> On Thu, Apr 10, 2014 at 5:09 PM, Vivek Gautam wrote: >> >>> On Wed, Apr 9, 2014 at 7:03 PM, Tomasz Figa wrote: >> >>>> On 09.04.2014 13:49, Vivek Gautam wrote: >> >>> >> >>> So, USB30_SCLK_100M is the SCLK that we are talking in the driver. I >> >>> don't see any reference to XXTI in the USB 3.0 DRD controller chapter >> >>> (in both Exynos5250 and 5420) >> >>> In addition to this there's one more point to be noticed here. >> >>> On Exynos5420 system, the sclk_usbphy300 (which is the sclk_usbphy30 >> >>> for USB DRD channel 0), is also the PICO phy clock, i.e. USB 2.0 phy >> >>> clock. >> >>> So we should add a similar clk_get() for this clock in the >> >>> phy-exynos5250-usb2 driver too, to support Exynos5420. >> >> >> >> >> >> Is something clear from the above block diagram ? (although the >> >> diagram looks weird - space and tabs problem :-( ) >> >> Basically there's the clock USB30_SCLK_100M which is going into the >> >> USB 3.0 DRD PHY controller. >> >> And this is the only sclk mentioned in the block diagram for USB 3.0 >> >> DRD controller in Exynos5420. >> >> Same is not there in the block diagram in Exynos5250 UM. >> > >> > >> > From what I can see in the documentation, there are 4 USB 3.0 related clocks >> > generated in CMU: >> > >> > - sclk_usbphy300, >> > - sclk_usbphy301, >> > - sclk_usbdrd300, >> > - sclk_usbdrd301, >> > >> > They are all rated to max. 24 MHz and the recommended operating frequency is >> > 24 MHz, so it looks exactly like USB PHY reference, which is usually a 24 >> > MHz clock. >> > >> > To me, this looks like on Exynos5420 a separate special clock path is used >> > instead of xusbxti as reference of USB 3.0 PHY and so the sclk should be >> > simply passed as the "ref" clock. >> >> Ok, i will clear on this with the hardware engineer also once. >> May be Jingoo can help me with this. >> >> Jingoo, >> Can you please enquire about the clock path of usbphy30 reference >> clocks on Exynos5420. >> As mentioned by Tomasz above, we have sclk_usbphy300 and >> sclk_usbphy301 as the reference clocks for USB3.0 DRD phy. *Also* >> sclk_usbphy300 is used for Pico phy (which is the USb 2.0 phy used by >> ehci/ohci controller on Exynos5420). >> It will be of great help. > > Hi Vevek, Tomasz > > Long time no see. > > I asked USB S/W engineer and USB H/W engineer. > > There are two USB3.0 on Exynos5420; thus there are two sclks > such as 'sclk_usbphy300 and sclk_usbphy301'. > > As Tomasz mentioned, 'sclk_usbphy300 and sclk_usbphy301' can > be used instead of 'xusbxti' as reference of USB 3.0 PHY. Thank you so much for getting this information. I can re-spin the patch. :-) > > However, on Exynos5420, "ONLY" 'sclk_usbphy300' can be used > for USB2.0 pico phy. (so, '301' CANNOT support USB2.0 pico phy.) True, for USB 2.0 pico phy, only sclk_usbphy300 can be used. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/