2022-02-01 20:50:23

by Andrey Smirnov

[permalink] [raw]
Subject: [PATCH] usb: dwc3: Prioritize extcon over USB role switching API

It is necessary that:

ROLE_SWITCH && device_property_read_bool(dwc->dev, "usb-role-switch")

is true in order for dwc3_get_dr_mode() to _not_ force us from OTG to
PERIPHERAL mode here:

if (mode == USB_DR_MODE_OTG &&
(!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
!device_property_read_bool(dwc->dev, "usb-role-switch")) &&
!DWC3_VER_IS_PRIOR(DWC3, 330A))
mode = USB_DR_MODE_PERIPHERAL;

and dwc3_drd_init() to be called later in dwc3_core_init_mode(). So,
to avoid always ignoring extcon device returned by dwc3_get_extcon()
change dwc3_drd_init() to check and use it first, before checking if
dwc3_setup_role_switch() should be called.

Cc: Felipe Balbi <[email protected]>
Cc: Thinh Nguyen <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Andrey Smirnov <[email protected]>
---

Hopefully I didn't miss something important making this patch
unnecessary. Don't know if this is a good solution or not, part of me
thinks than maybe changing the aforementioned code in
dwc3_get_dr_mode() to account for extcon wopuld be
simpler/better. Happy to rework this.

drivers/usb/dwc3/drd.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index e2b68bb770d1..835bd0be87d5 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -579,12 +579,7 @@ int dwc3_drd_init(struct dwc3 *dwc)
if (IS_ERR(dwc->edev))
return PTR_ERR(dwc->edev);

- if (ROLE_SWITCH &&
- device_property_read_bool(dwc->dev, "usb-role-switch")) {
- ret = dwc3_setup_role_switch(dwc);
- if (ret < 0)
- return ret;
- } else if (dwc->edev) {
+ if (dwc->edev) {
dwc->edev_nb.notifier_call = dwc3_drd_notifier;
ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
&dwc->edev_nb);
@@ -594,6 +589,11 @@ int dwc3_drd_init(struct dwc3 *dwc)
}

dwc3_drd_update(dwc);
+ } else if (ROLE_SWITCH &&
+ device_property_read_bool(dwc->dev, "usb-role-switch")) {
+ ret = dwc3_setup_role_switch(dwc);
+ if (ret < 0)
+ return ret;
} else {
dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);
dwc->current_dr_role = DWC3_GCTL_PRTCAP_OTG;
--
2.25.1


2022-02-03 07:25:01

by Thinh Nguyen

[permalink] [raw]
Subject: Re: [PATCH] usb: dwc3: Prioritize extcon over USB role switching API

Andrey Smirnov wrote:
> It is necessary that:
>
> ROLE_SWITCH && device_property_read_bool(dwc->dev, "usb-role-switch")
>
> is true in order for dwc3_get_dr_mode() to _not_ force us from OTG to
> PERIPHERAL mode here:
>
> if (mode == USB_DR_MODE_OTG &&
> (!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
> !device_property_read_bool(dwc->dev, "usb-role-switch")) &&
> !DWC3_VER_IS_PRIOR(DWC3, 330A))
> mode = USB_DR_MODE_PERIPHERAL;
>
> and dwc3_drd_init() to be called later in dwc3_core_init_mode(). So,
> to avoid always ignoring extcon device returned by dwc3_get_extcon()
> change dwc3_drd_init() to check and use it first, before checking if
> dwc3_setup_role_switch() should be called.
>
> Cc: Felipe Balbi <[email protected]>
> Cc: Thinh Nguyen <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Andrey Smirnov <[email protected]>
> ---
>
> Hopefully I didn't miss something important making this patch
> unnecessary. Don't know if this is a good solution or not, part of me
> thinks than maybe changing the aforementioned code in
> dwc3_get_dr_mode() to account for extcon wopuld be
> simpler/better. Happy to rework this.

The driver either use extcon or usb-role-switch. It doesn't make sense to
enable usb-role-switch for extcon just so the driver doesn't default
the dr_mode to peripheral.

Perhaps, this is what you're looking for? (code is not tested)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index bffd719b8b52..a52331ea7a0d 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -86,7 +86,7 @@ static int dwc3_get_dr_mode(struct dwc3 *dwc)
* mode. If the controller supports DRD but the dr_mode is not
* specified or set to OTG, then set the mode to peripheral.
*/
- if (mode == USB_DR_MODE_OTG &&
+ if (mode == USB_DR_MODE_OTG && !dwc->edev &&
(!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
!device_property_read_bool(dwc->dev, "usb-role-switch")) &&
!DWC3_VER_IS_PRIOR(DWC3, 330A))
@@ -1715,6 +1715,13 @@ static int dwc3_probe(struct platform_device *pdev)
goto err2;
}

+ dwc->edev = dwc3_get_extcon(dwc);
+ if (IS_ERR(dwc->edev)) {
+ ret = PTR_ERR(dwc->edev);
+ dev_err(dwc->dev, "failed to get extcon %d\n", ret);
+ goto err3;
+ }
+
ret = dwc3_get_dr_mode(dwc);
if (ret)
goto err3;
diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
index 63089c7fb530..d02fcfdc74db 100644
--- a/drivers/usb/dwc3/drd.c
+++ b/drivers/usb/dwc3/drd.c
@@ -585,16 +585,7 @@ int dwc3_drd_init(struct dwc3 *dwc)
{
int ret, irq;

- dwc->edev = dwc3_get_extcon(dwc);
- if (IS_ERR(dwc->edev))
- return PTR_ERR(dwc->edev);
-
- if (ROLE_SWITCH &&
- device_property_read_bool(dwc->dev, "usb-role-switch")) {
- ret = dwc3_setup_role_switch(dwc);
- if (ret < 0)
- return ret;
- } else if (dwc->edev) {
+ if (dwc->edev) {
dwc->edev_nb.notifier_call = dwc3_drd_notifier;
ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
&dwc->edev_nb);
@@ -604,6 +595,11 @@ int dwc3_drd_init(struct dwc3 *dwc)
}

dwc3_drd_update(dwc);
+ } else if (ROLE_SWITCH &&
+ device_property_read_bool(dwc->dev, "usb-role-switch")) {
+ ret = dwc3_setup_role_switch(dwc);
+ if (ret < 0)
+ return ret;
} else {
dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);


2022-02-03 12:42:19

by Andrey Smirnov

[permalink] [raw]
Subject: Re: [PATCH] usb: dwc3: Prioritize extcon over USB role switching API

On Wed, Feb 2, 2022 at 6:54 PM Thinh Nguyen <[email protected]> wrote:
>
> Andrey Smirnov wrote:
> > It is necessary that:
> >
> > ROLE_SWITCH && device_property_read_bool(dwc->dev, "usb-role-switch")
> >
> > is true in order for dwc3_get_dr_mode() to _not_ force us from OTG to
> > PERIPHERAL mode here:
> >
> > if (mode == USB_DR_MODE_OTG &&
> > (!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
> > !device_property_read_bool(dwc->dev, "usb-role-switch")) &&
> > !DWC3_VER_IS_PRIOR(DWC3, 330A))
> > mode = USB_DR_MODE_PERIPHERAL;
> >
> > and dwc3_drd_init() to be called later in dwc3_core_init_mode(). So,
> > to avoid always ignoring extcon device returned by dwc3_get_extcon()
> > change dwc3_drd_init() to check and use it first, before checking if
> > dwc3_setup_role_switch() should be called.
> >
> > Cc: Felipe Balbi <[email protected]>
> > Cc: Thinh Nguyen <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Andrey Smirnov <[email protected]>
> > ---
> >
> > Hopefully I didn't miss something important making this patch
> > unnecessary. Don't know if this is a good solution or not, part of me
> > thinks than maybe changing the aforementioned code in
> > dwc3_get_dr_mode() to account for extcon wopuld be
> > simpler/better. Happy to rework this.
>
> The driver either use extcon or usb-role-switch. It doesn't make sense to
> enable usb-role-switch for extcon just so the driver doesn't default
> the dr_mode to peripheral.
>
> Perhaps, this is what you're looking for? (code is not tested)
>

Yeah that kind of what I meant by "maybe changing the aforementioned code in
dwc3_get_dr_mode() to account for extcon wopuld be
simpler/better." OK let me rework the patch to do that.

> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
> index bffd719b8b52..a52331ea7a0d 100644
> --- a/drivers/usb/dwc3/core.c
> +++ b/drivers/usb/dwc3/core.c
> @@ -86,7 +86,7 @@ static int dwc3_get_dr_mode(struct dwc3 *dwc)
> * mode. If the controller supports DRD but the dr_mode is not
> * specified or set to OTG, then set the mode to peripheral.
> */
> - if (mode == USB_DR_MODE_OTG &&
> + if (mode == USB_DR_MODE_OTG && !dwc->edev &&
> (!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
> !device_property_read_bool(dwc->dev, "usb-role-switch")) &&
> !DWC3_VER_IS_PRIOR(DWC3, 330A))
> @@ -1715,6 +1715,13 @@ static int dwc3_probe(struct platform_device *pdev)
> goto err2;
> }
>
> + dwc->edev = dwc3_get_extcon(dwc);
> + if (IS_ERR(dwc->edev)) {
> + ret = PTR_ERR(dwc->edev);
> + dev_err(dwc->dev, "failed to get extcon %d\n", ret);
> + goto err3;
> + }
> +
> ret = dwc3_get_dr_mode(dwc);
> if (ret)
> goto err3;
> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
> index 63089c7fb530..d02fcfdc74db 100644
> --- a/drivers/usb/dwc3/drd.c
> +++ b/drivers/usb/dwc3/drd.c
> @@ -585,16 +585,7 @@ int dwc3_drd_init(struct dwc3 *dwc)
> {
> int ret, irq;
>
> - dwc->edev = dwc3_get_extcon(dwc);
> - if (IS_ERR(dwc->edev))
> - return PTR_ERR(dwc->edev);
> -
> - if (ROLE_SWITCH &&
> - device_property_read_bool(dwc->dev, "usb-role-switch")) {
> - ret = dwc3_setup_role_switch(dwc);
> - if (ret < 0)
> - return ret;
> - } else if (dwc->edev) {

We probably don't even need to move this around. If "usb-role-switch"
isn't going to be set then that "if" could go first and not interfere.

> + if (dwc->edev) {
> dwc->edev_nb.notifier_call = dwc3_drd_notifier;
> ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
> &dwc->edev_nb);
> @@ -604,6 +595,11 @@ int dwc3_drd_init(struct dwc3 *dwc)
> }
>
> dwc3_drd_update(dwc);
> + } else if (ROLE_SWITCH &&
> + device_property_read_bool(dwc->dev, "usb-role-switch")) {
> + ret = dwc3_setup_role_switch(dwc);
> + if (ret < 0)
> + return ret;
> } else {
> dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);
>
>

2022-02-03 14:47:35

by Thinh Nguyen

[permalink] [raw]
Subject: Re: [PATCH] usb: dwc3: Prioritize extcon over USB role switching API

Andrey Smirnov wrote:
> On Wed, Feb 2, 2022 at 6:54 PM Thinh Nguyen <[email protected]> wrote:
>>
>> Andrey Smirnov wrote:
>>> It is necessary that:
>>>
>>> ROLE_SWITCH && device_property_read_bool(dwc->dev, "usb-role-switch")
>>>
>>> is true in order for dwc3_get_dr_mode() to _not_ force us from OTG to
>>> PERIPHERAL mode here:
>>>
>>> if (mode == USB_DR_MODE_OTG &&
>>> (!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
>>> !device_property_read_bool(dwc->dev, "usb-role-switch")) &&
>>> !DWC3_VER_IS_PRIOR(DWC3, 330A))
>>> mode = USB_DR_MODE_PERIPHERAL;
>>>
>>> and dwc3_drd_init() to be called later in dwc3_core_init_mode(). So,
>>> to avoid always ignoring extcon device returned by dwc3_get_extcon()
>>> change dwc3_drd_init() to check and use it first, before checking if
>>> dwc3_setup_role_switch() should be called.
>>>
>>> Cc: Felipe Balbi <[email protected]>
>>> Cc: Thinh Nguyen <[email protected]>
>>> Cc: [email protected]
>>> Cc: [email protected]
>>> Signed-off-by: Andrey Smirnov <[email protected]>
>>> ---
>>>
>>> Hopefully I didn't miss something important making this patch
>>> unnecessary. Don't know if this is a good solution or not, part of me
>>> thinks than maybe changing the aforementioned code in
>>> dwc3_get_dr_mode() to account for extcon wopuld be
>>> simpler/better. Happy to rework this.
>>
>> The driver either use extcon or usb-role-switch. It doesn't make sense to
>> enable usb-role-switch for extcon just so the driver doesn't default
>> the dr_mode to peripheral.
>>
>> Perhaps, this is what you're looking for? (code is not tested)
>>
>
> Yeah that kind of what I meant by "maybe changing the aforementioned code in
> dwc3_get_dr_mode() to account for extcon wopuld be
> simpler/better." OK let me rework the patch to do that.
>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index bffd719b8b52..a52331ea7a0d 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -86,7 +86,7 @@ static int dwc3_get_dr_mode(struct dwc3 *dwc)
>> * mode. If the controller supports DRD but the dr_mode is not
>> * specified or set to OTG, then set the mode to peripheral.
>> */
>> - if (mode == USB_DR_MODE_OTG &&
>> + if (mode == USB_DR_MODE_OTG && !dwc->edev &&
>> (!IS_ENABLED(CONFIG_USB_ROLE_SWITCH) ||
>> !device_property_read_bool(dwc->dev, "usb-role-switch")) &&
>> !DWC3_VER_IS_PRIOR(DWC3, 330A))
>> @@ -1715,6 +1715,13 @@ static int dwc3_probe(struct platform_device *pdev)
>> goto err2;
>> }
>>
>> + dwc->edev = dwc3_get_extcon(dwc);
>> + if (IS_ERR(dwc->edev)) {
>> + ret = PTR_ERR(dwc->edev);
>> + dev_err(dwc->dev, "failed to get extcon %d\n", ret);
>> + goto err3;
>> + }
>> +
>> ret = dwc3_get_dr_mode(dwc);
>> if (ret)
>> goto err3;
>> diff --git a/drivers/usb/dwc3/drd.c b/drivers/usb/dwc3/drd.c
>> index 63089c7fb530..d02fcfdc74db 100644
>> --- a/drivers/usb/dwc3/drd.c
>> +++ b/drivers/usb/dwc3/drd.c
>> @@ -585,16 +585,7 @@ int dwc3_drd_init(struct dwc3 *dwc)
>> {
>> int ret, irq;
>>
>> - dwc->edev = dwc3_get_extcon(dwc);
>> - if (IS_ERR(dwc->edev))
>> - return PTR_ERR(dwc->edev);
>> -
>> - if (ROLE_SWITCH &&
>> - device_property_read_bool(dwc->dev, "usb-role-switch")) {
>> - ret = dwc3_setup_role_switch(dwc);
>> - if (ret < 0)
>> - return ret;
>> - } else if (dwc->edev) {
>
> We probably don't even need to move this around. If "usb-role-switch"
> isn't going to be set then that "if" could go first and not interfere.
>

Yeah, this is unnecessary.

>> + if (dwc->edev) {
>> dwc->edev_nb.notifier_call = dwc3_drd_notifier;
>> ret = extcon_register_notifier(dwc->edev, EXTCON_USB_HOST,
>> &dwc->edev_nb);
>> @@ -604,6 +595,11 @@ int dwc3_drd_init(struct dwc3 *dwc)
>> }
>>
>> dwc3_drd_update(dwc);
>> + } else if (ROLE_SWITCH &&
>> + device_property_read_bool(dwc->dev, "usb-role-switch")) {
>> + ret = dwc3_setup_role_switch(dwc);
>> + if (ret < 0)
>> + return ret;
>> } else {
>> dwc3_set_prtcap(dwc, DWC3_GCTL_PRTCAP_OTG);
>>
>>

Thanks,
Thinh