Re: [PATCH 1/5] dt-bindings: connector: add optional properties for Type-B

[Hans de Goede]

Hi,

On 12-03-19 04:18, Chunfeng Yun wrote:
> Hi,
> On Mon, 2019-03-11 at 09:06 +0100, Hans de Goede wrote:
> > Hi,
> >
> > On 11-03-19 06:33, Chunfeng Yun wrote:
> > > Hi,
> > >
> > > On Fri, 2019-03-08 at 13:07 +0100, Hans de Goede wrote:
> > > > Hi,
> > > >
> > > > On 08-03-19 07:13, Chunfeng Yun wrote:
> > > > > Add id-gpios, vbus-gpios, vbus-supply and pinctrl properties for
> > > > > usb-b-connector
> > > > >
> > > > > Signed-off-by: Chunfeng Yun <chunfeng.yun@xxxxxxxxxxxx>
> > > > > ---
> > > > >     .../devicetree/bindings/connector/usb-connector.txt    | 10 ++++++++++
> > > > >     1 file changed, 10 insertions(+)
> > > > >
> > > > > diff --git a/Documentation/devicetree/bindings/connector/usb-connector.txt b/Documentation/devicetree/bindings/connector/usb-connector.txt
> > > > > index a9a2f2fc44f2..7a07b0f4f973 100644
> > > > > --- a/Documentation/devicetree/bindings/connector/usb-connector.txt
> > > > > +++ b/Documentation/devicetree/bindings/connector/usb-connector.txt
> > > > > @@ -17,6 +17,16 @@ Optional properties:
> > > > >     - self-powered: Set this property if the usb device that has its own power
> > > > >       source.
> > > > >     
> > > > > +Optional properties for usb-b-connector:
> > > > > +- id-gpios: gpio for USB ID pin.
> > > >
> > > > What about boards where the ID pin is *not* connected to a GPIO,
> > > > but e.g. to a special pin on the PMIC which can also detect
> > > > an ACA adapter ? Currently this case is handled by extcon
> > > > drivers, but we have no way to set e.g. vbus-supply for the
> > > > connector. Maybe in this case the usb-connector node should
> > > > be a child of the PMIC node ?
> > > Yes, it would be, PMIC is in charger of detecting the status of ID pin
> >
> > Ok, then I think this should be documented too.
> >
> > > > And in many cases there also is a mux to switch the datalines
> > > > between the host and device(gadget) controllers, how should
> > > > that be described in this model?  See the new usb-role-switch
> > > > code under drivers/usb/roles
> > > >
> > > > In some cases the mux is controlled through a gpio, so we
> > > > may want to add a "mux-gpios" here in which case we also
> > > > need to define what 0/1 means.
> > > I'm not sure, the mux seems not belong to this connector,
> > > and may need another driver to register usb-role-switch,
> > > similar to:
> > >
> > > [v2,2/2] usb: typec: add typec switch via GPIO control
> > > https://patchwork.kernel.org/patch/10834327/
> >
> > Right the mux/role-switch will need a driver, but the "owner"
> > of the usb_connector, e.g. the PMIC or the owner of the
> > id GPIO pin needs to know which device is the role-switch so
> > that it can set the role correctly based on the id-pin.
> >
> > Your binding already contains Vbus info, allowing the owner
> > of the usb_connector to enable/disable Vbus based on the id-pin,
> > but the owner will also be responsible for setting the role-switch.
> In this patch series, I make usb_connector driver enable/disable Vbus,
> but not the parent(USB controller) of usb_connector which registers a
> usb-role-switch, which way do you think it is better?

IMHO there should not be a driver for the usb_connector child-node,
only for the parent-device of that child-node.

There are going to be too many specific setups surrounding PMICs to
be able to do a single generic driver for the connector.

Regards,

Hans