Hello, On 10/08/2015 08:23 AM, Marek Szyprowski wrote: > Hello, > > On 2015-10-08 08:02, Krzysztof Kozlowski wrote: >> On 07.10.2015 23:26, Marek Szyprowski wrote: >>> Hello, >>> >>> On 2015-10-07 02:30, Krzysztof Kozlowski wrote: >>>> Introduction >>>> ============ >>>> This patchset tries to fix probing of usb3503 on Arndale board >>>> if the Samsung PHY driver is probed later (or built as a module). >>>> >>>> *The patchset was not tested on Arndale board.* >>>> I don't have that board. Please test it and say if the usb3503 >>>> deferred probe >>>> works fine and the issue is solved. >>>> >>>> The patchset was tested on Odroid U3 board (which is different!) >>>> in a simulated environment. It is not sufficient testing. >>>> >>>> >>>> Difference >>>> ========== >>>> The usb3503 device driver can be used as a I2C device (on Odroid U3) >>>> or as a platform device connected through phy (on Arndale). In the second >>>> case the necessary phy reference has to be obtained and enabled. >>>> >>>> For some details please look also at thread [0][1]. >>>> >>>> [0] >>>> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/348524.html >>>> >>>> [1] >>>> http://lists.infradead.org/pipermail/linux-arm-kernel/2015-June/348875.html >>>> >>>> >>> I'm not sure that this is the correct approach. usb3503 chip is simply >>> connected >>> to Exynos USB2 phy, so it visible on the USB bus. The real driver that >>> controls USB2 >>> PHY is Exynos EHCI driver and USB3503 should not mess around it. >> The ehci node (usb@12110000) has one port configured and it takes one >> PHY reference (phy of id 1 - USB host). I can't see driver taking >> reference to HSIC0 or HSIC1 phys... Since I cannot diagnose the error I >> don't know what is really expected here. > > It looks that EHCI in Exynos 5250 and 5420 still use old phy bindings. For > the reference, see Exynos4 dts and exynos4412-odroidu3.dts to check how to enable > more than one USB port (Odroid U3 has both HSIC ports enabled). > >> >>> In my opinion all that is needed in case of Arndale board is forcing >>> reset of >>> usb3503 chip after successful EHCI and USB2 PHY initialization (for some >>> reason >>> initialization of usb3503 chip must be done after usb host initialization). >>> However I have no idea which driver should trigger this reset. Right now >>> I didn't >>> find any good solution for additional control for devices which are on >>> autoprobed >>> bus like usb. >> The reset is done at the end of usb3503's probe. The question "why >> usb3503 has to be initialized after EHCI and USB PHY" is still valid... > > I remember that I saw some code to reset HSIC device after phy power on in case > of HSIC-connected modem chip, so maybe this is somehow common for HSIC chips > (which are some special case of 'embedded usb'). > I also don't have an Arndale board and haven't followed the thread to closely but I just wanted to mention that the ChromiumOS 3.8 tree has a workaround to reset the HSIC phys: https://chromium.googlesource.com/chromiumos/third_party/kernel/+/81685c447954a29d1098268776582457258dd98f%5E%21/ and later a "supports-hsicphy-reset" DT property was added to force the reset per board instead of unconditionally: https://chromium.googlesource.com/chromiumos/third_party/kernel/+/a4d1c1a223ffa1ed38a4257d0378ca70c6667be0%5E%21/ Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America -- 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
