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SubjectRe: [PATCH v2 4/4] usb: dwc3: Workaround for super-speed host on dra7 in dual-role mode
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On 02/24/2017 06:27 AM, Peter Chen wrote:
> On Thu, Feb 23, 2017 at 02:04:50PM +0530, Vivek Gautam wrote:
>>
>> On 02/16/2017 06:36 PM, Roger Quadros wrote:
>>> dra7 OTG core limits the host controller to USB2.0 (high-speed) mode
>>> when we're operating in dual-role.
>>>
>>> We work around that by bypassing the OTG core and reading the
>>> extcon framework directly for ID/VBUS events.
>>>
>>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>>> ---
>>> Documentation/devicetree/bindings/usb/dwc3.txt | 2 +
>>> drivers/usb/dwc3/core.c | 169 ++++++++++++++++++++++++-
>>> drivers/usb/dwc3/core.h | 5 +
>>> 3 files changed, 170 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt
>>> index e3e6983..9955c0d 100644
>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt
>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt
>>> @@ -53,6 +53,8 @@ Optional properties:
>>> - snps,quirk-frame-length-adjustment: Value for GFLADJ_30MHZ field of GFLADJ
>>> register for post-silicon frame length adjustment when the
>>> fladj_30mhz_sdbnd signal is invalid or incorrect.
>>> + - extcon: phandle to the USB connector extcon device. If present, extcon
>>> + device will be used to get USB cable events instead of OTG controller.
>>> - <DEPRECATED> tx-fifo-resize: determines if the FIFO *has* to be reallocated.
>>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>>> index 619fa7c..b02d911 100644
>>> --- a/drivers/usb/dwc3/core.c
>>> +++ b/drivers/usb/dwc3/core.c
>> [snip]
>>
>>> @@ -1587,6 +1727,14 @@ static int dwc3_probe(struct platform_device *pdev)
>>> dwc3_get_properties(dwc);
>>> + if (dev->of_node) {
>>> + if (of_property_read_bool(dev->of_node, "extcon"))
>>> + dwc->edev = extcon_get_edev_by_phandle(dev, 0);
>> Don't we want separate edev's for vbus and id ?
>> One can have separate pins connected to them and in that case
>> we can't get the events out of one pin only.
>>
> Current extcon-usb-gpio driver supports id and vbus at the same time,
> that means there are two optional gpios under one extcon node.
>

Right, and we would want to leverage that by providing couple
of phandles for vbus and id, and requesting the two in driver.


Regards
Vivek

--
The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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