Hi Jingoo, On Tue, Apr 22, 2014 at 7:48 AM, Jingoo Han <jg1.han@xxxxxxxxxxx> wrote: > On Wednesday, April 16, 2014 11:49 PM, Vivek Gautam wrote: >> On Wed, Apr 16, 2014 at 7:14 PM, Tomasz Figa <t.figa@xxxxxxxxxxx> 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 <t.figa@xxxxxxxxxxx> 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-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
