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. However, on Exynos5420, "ONLY" 'sclk_usbphy300' can be used for USB2.0 pico phy. (so, '301' CANNOT support USB2.0 pico phy.) Best regards, Jingoo Han -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
