On 06/23/2015 05:56 AM, Roger Quadros wrote:
+ Kukjin, Stephen,
for board specific USB question.
On Tue, 23 Jun 2015 16:35:49 +0800
Li Jun <b47624@xxxxxxxxxxxxx> wrote:
On Tue, Jun 23, 2015 at 10:43:28AM +0300, Roger Quadros wrote:
If the dr_mode was "otg" for such case and we want OTG disabled then it is really the DT fault.
It's ID pin detect for dual role switch as many current OTG controllers have.
not DT fault, its dt only has a dr_mode = "otg".
We don't need to tackle this case. Just fix up the DT to dr_mode = "peripheral" if
OTG behaviour is not needed.
OTG behaviour is not needed, so we need disable HNP/SRP/ADP. but dr_mode =
"otg" as it already works fine with ID pin detect.
Do you know which platform has plain non-otg dual-role working as of today
with dr_mode set to "otg"?
I don't know.
The dt property dr_mode is already there, and currently there are some platforms
as its user, so I assume those platforms either are non-otg dual-role, or real OTG
with HNP supported, I guess most are the former cases; chipidea is the later case.
For TI platforms none of them have it working currently.
So for Ti platforms, some enables non-otg dual-role function but do not use
dr_mode = "otg"?
for TI we have only musb based and dwc3 based platforms. MUSB based are OTG.
dwc3 doesn't support dual-role or OTG yet so we use either "peripheral" or "Host"
For those only have non-otg dual-role platforms, no matter using dr_mode or not,
we need keep it's real OTG disabled for legacy users after it's controller
driver adds real OTG later.
I wouldn't even bother about platforms expecting dual-role behaviour
with dr_mode not set to "otg". That is just plain wrong and can't be supported.
These are the dts files having dr_mode == "otg".
I've sorted them as per Soc vendor and USB controller
...
Nvidia
------
arm/boot/dts/tegra20-seaboard.dts: dr_mode = "otg";
compatible = "nvidia,tegra20-ehci", "usb-ehci";
arm/boot/dts/tegra30-colibri-eval-v3.dts: dr_mode = "otg";
compatible = "nvidia,tegra30-ehci", "usb-ehci";
I couldn't find gadget side implementation for this.
Stephen, any comments on whether this board supports true OTG operation or just dual-role operation?
Sorry for the slow reply; I was on vacation.
I'm not sure what the difference is?
I won't be able to answer for the Colibri board since I'm not familiar
with the HW. I have the schematics for Seaboard, so I should be able to
answer once I understand the question:-)
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