On 12/10/15 20:19, Tony Lindgren wrote: > * Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx> [151012 11:22]: >> On 12/10/15 18:45, Tony Lindgren wrote: >>> * Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx> [151012 10:38]: >>>> The AM3715 OHCI controller will not function without the EHCI >>>> unit's 120m fclk being enabled. If all the ports in the system >>>> are set to OHCI then the 120m_fclk will not get enabled and no >>>> devices are detected. >>>> >>>> Add a new (optional) property to signal the system must enable >>>> the 120m_fck for OHCI so that if no EHCI ports are signalled >>>> then the 120m_fclk should be enabled. >>>> >>>> We have found no information about why this is necessary, but >>>> it is suspected the EHCI controller does not complete the initial >>>> reset sequence and therefore does not hand control of the USB >>>> port back. >>>> >>>> Signed-off-by: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx> >>>> --- >>>> Documentation/devicetree/bindings/usb/omap-usb.txt | 3 +++ >>>> drivers/mfd/omap-usb-host.c | 4 ++++ >>>> 2 files changed, 7 insertions(+) >>>> >>>> diff --git a/Documentation/devicetree/bindings/usb/omap-usb.txt b/Documentation/devicetree/bindings/usb/omap-usb.txt >>>> index 38d9bb8..fb5fea5 100644 >>>> --- a/Documentation/devicetree/bindings/usb/omap-usb.txt >>>> +++ b/Documentation/devicetree/bindings/usb/omap-usb.txt >>>> @@ -23,6 +23,9 @@ OMAP MUSB GLUE >>>> Optional properties: >>>> - ctrl-module : phandle of the control module this glue uses to write to >>>> mailbox >>>> + - ti,ohci-needs-120m-fck : bool, enable the 120m ehci clock even if just >>>> + using ohci. Needed for AM3517 in OHCI only mode. >>>> + >>>> >>>> SOC specific device node entry >>>> usb_otg_hs: usb_otg_hs@4a0ab000 { >>>> diff --git a/drivers/mfd/omap-usb-host.c b/drivers/mfd/omap-usb-host.c >>>> index 1d924d1..13880cf 100644 >>>> --- a/drivers/mfd/omap-usb-host.c >>>> +++ b/drivers/mfd/omap-usb-host.c >>>> @@ -680,6 +680,10 @@ static int usbhs_omap_probe(struct platform_device *pdev) >>>> need_logic_fck |= true; >>>> } >>>> >>>> + /* The AM3517 requries the 120m-fck active to allow the OHCI to work */ >>>> + if (of_property_read_bool(dev->of_node, "ti,ohci-needs-120m-fck")) >>>> + need_logic_fck |= true; >>>> + >>>> if (need_logic_fck) { >>>> omap->ehci_logic_fck = devm_clk_get(dev, >>>> "usbhost_120m_fck"); >>> >>> Hmm why not just use the standard device tree clocks property and then do >>> clk_get_rate() on the clock? >> >> I don't see that helps enabling the clock. The code decideds if >> no EHCI ports in use that it doesn't need to enable the EHCI fclk. > > Right, you need to do clk_prepare_enable() in it first? :) No, if that was the case the driver would never work for the EHCI case. The issue is: 1) All ports on the system are set to OHCI 2) The omap-usb-host.c does not touch usbhost_120m_fck if no EHCI ports 3) The OHCI fails to detect any devices due to point 2. -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html