Messages in this thread | | | Subject | Re: [RFT 0/3] usb: usb3503: Fix probing on Arndale board (missing phy) | From | Marek Szyprowski <> | Date | Thu, 08 Oct 2015 08:23:57 +0200 |
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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').
Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland
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