On Thu, Feb 9, 2017 at 1:19 PM, Roger Quadros <rogerq@xxxxxx> wrote: > Vivek, > > On 09/02/17 08:42, Vivek Gautam wrote: >> Hi Roger, >> >> On Mon, Jan 23, 2017 at 4:49 PM, Roger Quadros <rogerq@xxxxxx> wrote: >>> Hi, >>> >>> We rely on the OTG controller block to provide us with >>> VBUS and ID line status via an interrupt. >>> >>> This is then used to switch the controller between host, peripheral >>> and idle roles based on the following table. >>> >>> ID VBUS dual-role state >>> -- ---- --------------- >>> 0 x A_HOST - Host controller active >>> 1 0 B_IDLE - Both Host and Gadget controllers inactive >>> 1 1 B_PERIPHERAL - Gadget controller active >>> >> >> Thanks for this series. >> Sorry, i was held up with something else so couldn't take a look at it. >> I will integrate this with my work, and add some basic extcon >> support to enable passing vbus and id events to dwc3 layer to test >> this out on msm platforms. > > I already have this done for one of our platforms to workaround > a limitation with the OTG IP block on it. > I can post it today and you can give your comments. Okay, cool. Thanks. I will wait. Regards Vivek > > cheers, > -roger >> >> >> Regards >> Vivek >> >>> Couple of things to clarify: >>> - There is a small window where we can potentially miss an >>> event related to OTG. I've added a comment in the code where this >>> could happen. How can we prevent this? Is it better to just leave >>> the OTG events unmasked (but keep otg_irq on ARM GIC disabled) >>> so that any new events can be captured by the OTG event register >>> and interrupt re-triggered if it has not been serviced by the >>> previous interrupt. >>> - I'm running the entire dual-role state change logic inside >>> the threaded interrupt handler with dwc->lock (spinlock) held >>> but IRQs enabled. OTG events are very rare i.e. manual intervention >>> so I don't see this as a problem. Just wanted to double check. >>> - Some SoC's (e.g. Qualcomm MSM) do not have the OTG controller block >>> but do have both host and peripheral controllers and so can operate >>> in dual role mode. Current series does not address this case. >>> We can get dual-role to work with such SoCs if core.c can get >>> information about ID and VBUS somehow (private interface >>> from parent or directly read extcon?). >>> >>> cheers, >>> -roger >>> >>> Roger Quadros (8): >>> usb: otg-fsm: Prevent build warning "VDBG" redefined >>> usb: dwc3-omap: Fix missing break in dwc3_omap_set_mailbox() >>> usb: dwc3: use BIT() macro where possible >>> usb: dwc3: core.h: add some register definitions >>> usb: dwc3: add dual-role support >>> ARM: dts: dra7x-evm: Enable dual-role mode for USB1 >>> ARM: dts: am43xx: Enable dual-role mode for USB1 >>> ARM: dts: am57xx-idk: Enable dual-role mode for USB2 >>> >>> arch/arm/boot/dts/am437x-gp-evm.dts | 2 +- >>> arch/arm/boot/dts/am437x-sk-evm.dts | 2 +- >>> arch/arm/boot/dts/am43x-epos-evm.dts | 2 +- >>> arch/arm/boot/dts/am57xx-idk-common.dtsi | 2 +- >>> arch/arm/boot/dts/dra7-evm.dts | 2 +- >>> arch/arm/boot/dts/dra72-evm-common.dtsi | 2 +- >>> drivers/usb/common/usb-otg-fsm.c | 7 + >>> drivers/usb/dwc3/core.c | 583 ++++++++++++++++++++++++++++++- >>> drivers/usb/dwc3/core.h | 312 ++++++++++++----- >>> drivers/usb/dwc3/dwc3-omap.c | 49 +-- >>> drivers/usb/dwc3/gadget.c | 18 +- >>> drivers/usb/dwc3/gadget.h | 20 +- >>> drivers/usb/phy/phy-fsl-usb.c | 7 + >>> include/linux/usb/otg-fsm.h | 15 - >>> 14 files changed, 848 insertions(+), 175 deletions(-) >>> >>> -- >>> 2.7.4 >>> >> > > -- > cheers, > -roger -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- 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
