Messages in this thread | | | Subject | Re: [PATCH v2] usb: dwc3: Add support for VBUS power control | From | Mike Looijmans <> | Date | Wed, 17 Jun 2020 19:28:23 +0200 |
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Met vriendelijke groet / kind regards,
Mike Looijmans System Expert
TOPIC Embedded Products B.V. Materiaalweg 4, 5681 RJ Best The Netherlands
T: +31 (0) 499 33 69 69 E: mike.looijmans@topicproducts.com W: www.topicproducts.com
Please consider the environment before printing this e-mail On 17-06-2020 18:13, Rob Herring wrote: > On Wed, Jun 17, 2020 at 8:38 AM Mike Looijmans <mike.looijmans@topic.nl> wrote: >> >> Met vriendelijke groet / kind regards, >> >> Mike Looijmans >> System Expert >> >> >> TOPIC Embedded Products B.V. >> Materiaalweg 4, 5681 RJ Best >> The Netherlands >> >> T: +31 (0) 499 33 69 69 >> E: mike.looijmans@topicproducts.com >> W: www.topicproducts.com >> >> Please consider the environment before printing this e-mail >> On 10-06-2020 22:22, Rob Herring wrote: >>> On Wed, Jun 03, 2020 at 02:09:15PM +0200, Mike Looijmans wrote: >>>> Support VBUS power control using regulator framework. Enables the regulator >>>> while the port is in host mode. >>>> >>>> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl> >>>> --- >>>> v2: Add missing devm_regulator_get call which got lost during rebase >>>> >>>> .../devicetree/bindings/usb/dwc3.txt | 1 + >>>> drivers/usb/dwc3/core.c | 34 ++++++++++++++----- >>>> drivers/usb/dwc3/core.h | 4 +++ >>>> drivers/usb/dwc3/drd.c | 6 ++-- >>>> 4 files changed, 33 insertions(+), 12 deletions(-) >>>> >>>> diff --git a/Documentation/devicetree/bindings/usb/dwc3.txt b/Documentation/devicetree/bindings/usb/dwc3.txt >>>> index 9946ff9ba735..56bc3f238e2d 100644 >>>> --- a/Documentation/devicetree/bindings/usb/dwc3.txt >>>> +++ b/Documentation/devicetree/bindings/usb/dwc3.txt >>>> @@ -37,6 +37,7 @@ Optional properties: >>>> - phys: from the *Generic PHY* bindings >>>> - phy-names: from the *Generic PHY* bindings; supported names are "usb2-phy" >>>> or "usb3-phy". >>>> + - vbus-supply: Regulator handle that provides the VBUS power. >>> Does the DWC3 block require Vbus to power itself? Doubtful. This >>> belongs in a usb-connector node. If the DWC3 driver wants to get the >>> Vbus supply, it can fetch it from that node. >>> >>> Rob >> Okay, I've been digging into that. But there's no actual driver that >> binds to a "usb-b-connector" compatible, so how do we get to the >> vbus-supply from there? >> >> [devm_]regulator_get only accepts a device as argument, and will not >> look into child nodes. The only way to get at the vbus of a child node >> (or a node linked through a port) would be to hand-code the equivalent >> of of_regulator_get(), which will not be acceptable. > Doesn't it look into child nodes calling of_get_child_regulator()? Looking at the code in regulator/core.c, yeah, it should. I'll have to add some debugging lines and look into why it didn't work in my test. > You're right that it wouldn't work if graph is used. The connector has > to be either a child of a controller for the connector or the USB > controller. I'd expect you'd have the former for Type-C, but for > "usb-b-connector" the parent is more likely just the USB controller. For my current case, using a direct child would be fine, there's nothing else connected. But I expect that we'll produce a board with some USB-C connector some day yeah. > > In any case, having a struct device shouldn't be a requirement and > most subsystems expose a get function only needing the DT node. > >> Or is it the intention that I write a usb-X-connector device driver >> first that handles the vbus? > That's a kernel implementation detail that is independent of the > binding, but yes we'll probably need a driver or library helper > functions eventually. Note that it is possible to have a struct device > without a driver. > > Rob
-- Mike Looijmans
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