[PATCH v2] usb: dwc3: Add support for VBUS power control

[PATCH v2] usb: dwc3: Add support for VBUS power control

[Mike Looijmans]

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.
  - resets: set of phandle and reset specifier pairs
  - snps,usb2-lpm-disable: indicate if we don't want to enable USB2 HW LPM
  - snps,usb3_lpm_capable: determines if platform is USB3 LPM capable
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index edc17155cb2b..ad341a182999 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -25,6 +25,7 @@
 #include <linux/of.h>
 #include <linux/acpi.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/regulator/consumer.h>
 #include <linux/reset.h>
 
 #include <linux/usb/ch9.h>
@@ -112,6 +113,23 @@ void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode)
 	dwc->current_dr_role = mode;
 }
 
+void dwc3_set_vbus(struct dwc3 *dwc, bool enable)
+{
+	int ret;
+
+	if (enable != dwc->vbus_reg_enabled) {
+		if (enable)
+			ret = regulator_enable(dwc->vbus_reg);
+		else
+			ret = regulator_disable(dwc->vbus_reg);
+		if (!ret)
+			dwc->vbus_reg_enabled = enable;
+	}
+
+	if (dwc->usb2_phy)
+		otg_set_vbus(dwc->usb2_phy->otg, enable);
+}
+
 static void __dwc3_set_mode(struct work_struct *work)
 {
 	struct dwc3 *dwc = work_to_dwc(work);
@@ -164,8 +182,7 @@ static void __dwc3_set_mode(struct work_struct *work)
 		if (ret) {
 			dev_err(dwc->dev, "failed to initialize host\n");
 		} else {
-			if (dwc->usb2_phy)
-				otg_set_vbus(dwc->usb2_phy->otg, true);
+			dwc3_set_vbus(dwc, true);
 			phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_HOST);
 			phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_HOST);
 		}
@@ -173,8 +190,7 @@ static void __dwc3_set_mode(struct work_struct *work)
 	case DWC3_GCTL_PRTCAP_DEVICE:
 		dwc3_event_buffers_setup(dwc);
 
-		if (dwc->usb2_phy)
-			otg_set_vbus(dwc->usb2_phy->otg, false);
+		dwc3_set_vbus(dwc, false);
 		phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_DEVICE);
 		phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_DEVICE);
 
@@ -1183,8 +1199,7 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
 	case USB_DR_MODE_PERIPHERAL:
 		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_DEVICE);
 
-		if (dwc->usb2_phy)
-			otg_set_vbus(dwc->usb2_phy->otg, false);
+		dwc3_set_vbus(dwc, false);
 		phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_DEVICE);
 		phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_DEVICE);
 
@@ -1198,8 +1213,7 @@ static int dwc3_core_init_mode(struct dwc3 *dwc)
 	case USB_DR_MODE_HOST:
 		dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_HOST);
 
-		if (dwc->usb2_phy)
-			otg_set_vbus(dwc->usb2_phy->otg, true);
+		dwc3_set_vbus(dwc, true);
 		phy_set_mode(dwc->usb2_generic_phy, PHY_MODE_USB_HOST);
 		phy_set_mode(dwc->usb3_generic_phy, PHY_MODE_USB_HOST);
 
@@ -1470,6 +1484,10 @@ static int dwc3_probe(struct platform_device *pdev)
 
 	dwc3_get_properties(dwc);
 
+	dwc->vbus_reg = devm_regulator_get_optional(dev, "vbus");
+	if (IS_ERR(dwc->vbus_reg))
+		return PTR_ERR(dwc->vbus_reg);
+
 	dwc->reset = devm_reset_control_array_get(dev, true, true);
 	if (IS_ERR(dwc->reset))
 		return PTR_ERR(dwc->reset);
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index 4c171a8e215f..cee2574d7bf4 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -1085,6 +1085,9 @@ struct dwc3 {
 
 	bool			phys_ready;
 
+	struct regulator	*vbus_reg;
+	bool			vbus_reg_enabled;
+
 	struct ulpi		*ulpi;
 	bool			ulpi_ready;
 
@@ -1397,6 +1400,7 @@ struct dwc3_gadget_ep_cmd_params {
 
 /* prototypes */
 void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode);
+void dwc3_set_vbus(struct dwc3 *dwc, bool enable);
 void dwc3_set_mode(struct dwc3 *dwc, u32 mode);
 u32 dwc3_core_fifo_space(struct dwc3_ep *dep, u8 type);
 
diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index 7db1ffc92bbd..45fdec2d128d 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -384,8 +384,7 @@ void dwc3_otg_update(struct dwc3 *dwc, bool ignore_idstatus)
 		if (ret) {
 			dev_err(dwc->dev, "failed to initialize host\n");
 		} else {
-			if (dwc->usb2_phy)
-				otg_set_vbus(dwc->usb2_phy->otg, true);
+			dwc3_set_vbus(dwc, true);
 			if (dwc->usb2_generic_phy)
 				phy_set_mode(dwc->usb2_generic_phy,
 					     PHY_MODE_USB_HOST);
@@ -398,8 +397,7 @@ void dwc3_otg_update(struct dwc3 *dwc, bool ignore_idstatus)
 		dwc3_event_buffers_setup(dwc);
 		spin_unlock_irqrestore(&dwc->lock, flags);
 
-		if (dwc->usb2_phy)
-			otg_set_vbus(dwc->usb2_phy->otg, false);
+		dwc3_set_vbus(dwc, false);
 		if (dwc->usb2_generic_phy)
 			phy_set_mode(dwc->usb2_generic_phy,
 				     PHY_MODE_USB_DEVICE);
-- 
2.17.1

Re: [PATCH v2] usb: dwc3: Add support for VBUS power control

[Rob Herring]

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

Re: [PATCH v2] usb: dwc3: Add support for VBUS power control

[Mike Looijmans]

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

Ah, now I understand. There's a vbus-supply in the connector in newer 
kernel versions than the one I have to test with. It'll have to wait 
until I've been able to upgrade the kernel version for this board.


-- 
Mike Looijmans

Re: [PATCH v2] usb: dwc3: Add support for VBUS power control

[Mike Looijmans]

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.

Or is it the intention that I write a usb-X-connector device driver 
first that handles the vbus?

-- 
Mike Looijmans

Re: [PATCH v2] usb: dwc3: Add support for VBUS power control

[Rob Herring]

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()?

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.

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

Re: [PATCH v2] usb: dwc3: Add support for VBUS power control

[Mike Looijmans]

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

Re: [PATCH v2] usb: dwc3: Add support for VBUS power control

[Mike Looijmans]

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 19:28, Mike Looijmans wrote:
> 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:
>>> 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.

Ah, I had put my "connector" child in the wrong node. If I add the 
following fragment to the dwc3 node, the vbus patch works:

     connector {
         compatible = "usb-b-connector";
         label = "micro-USB-otg";
         type = "micro";
         vbus-supply = <&reg_usb0_vbus>;
     };

The driver indeed picks up the vbus supply from a child node.

This would mean there's no change to the devicetree bindings, it's using 
already existing bindings.

>> 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