[v2,0/6] add USB Type-B GPIO based role switch driver

Because the USB Connector is introduced and the requirement of
usb-connector.txt binding, the old way using extcon to support
USB Dual-Role switch is now deprecated, meanwhile there is no
available common driver when use Type-B connector.
This patch series introduce a Type-B connector driver and try
to replace the function provided by extcon-usb-gpio driver.
The main purpose of the patches is also to solve the Type-B
connector problem encountered in [1].

[1]: https://patchwork.kernel.org/patch/10819377/

v2 changes:
 1. make binding clear, and add a extra compatible suggested by Hans

Chunfeng Yun (6):
  dt-bindings: connector: add optional properties for Type-B
  dt-bindings: usb: add binding for Type-B dual role switch by GPIO
  dt-bindings: usb: mtu3: add properties about USB Role Switch
  usb: roles: add API to get usb_role_switch by node
  usb: roles: add driver of USB Type-B role switch by GPIO
  usb: mtu3: register a USB Role Switch for dual role mode

 .../bindings/connector/usb-connector.txt      |   9 +
 .../devicetree/bindings/usb/mediatek,mtu3.txt |  10 +-
 .../bindings/usb/typeb-switch-gpio.txt        |  26 ++
 drivers/usb/mtu3/mtu3.h                       |   5 +
 drivers/usb/mtu3/mtu3_dr.c                    |  50 ++-
 drivers/usb/mtu3/mtu3_plat.c                  |   3 +-
 drivers/usb/roles/Kconfig                     |  14 +
 drivers/usb/roles/Makefile                    |   1 +
 drivers/usb/roles/class.c                     |  30 ++
 drivers/usb/roles/typeb-switch-gpio.c         | 285 ++++++++++++++++++
 include/linux/usb/role.h                      |   1 +
 11 files changed, 428 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/usb/typeb-switch-gpio.txt
 create mode 100644 drivers/usb/roles/typeb-switch-gpio.c

On Fri, Mar 15, 2019 at 03:38:31PM +0800, Chunfeng Yun wrote:
> Add usb_role_switch_get_by_node() to make easier to get
> usb_role_switch by node which register it.
> It's useful when there is not device_connection registered
> between two drivers and only knows the node which register
> usb_role_switch.
> 
> Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> ---
>  drivers/usb/roles/class.c | 30 ++++++++++++++++++++++++++++++
>  include/linux/usb/role.h  |  1 +
>  2 files changed, 31 insertions(+)
> 
> diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> index 99116af07f1d..284b19856dc4 100644
> --- a/drivers/usb/roles/class.c
> +++ b/drivers/usb/roles/class.c
> @@ -11,6 +11,7 @@
>  #include <linux/device.h>
>  #include <linux/module.h>
>  #include <linux/mutex.h>
> +#include <linux/of.h>
>  #include <linux/slab.h>
>  
>  static struct class *role_class;
> @@ -121,6 +122,35 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev)
>  }
>  EXPORT_SYMBOL_GPL(usb_role_switch_get);
>  
> +static int __switch_match_node(struct device *dev, const void *node)
> +{
> +	return dev->parent->of_node == (const struct device_node *)node;
> +}

Andy already pointed out that you need to use fwnodes.

Rule of thumb: You always use fwnodes. Only if there is something that
can't be done with fwnodes you use DT or ACPI nodes directly.

In this case there is absolutely nothing that would prevent you from
using fwnodes.


thanks,

On Fri, Mar 15, 2019 at 10:18:35AM +0200, Heikki Krogerus wrote:
> Andy already pointed out that you need to use fwnodes.
> 
> Rule of thumb: You always use fwnodes. Only if there is something that
> can't be done with fwnodes you use DT or ACPI nodes directly.
> 
> In this case there is absolutely nothing that would prevent you from
> using fwnodes.

...

> +/**
> + * usb_role_switch_get_by_node - Find USB role switch by it's parent node
> + * @node: The node that register USB role switch
> + *
> + * Finds and returns role switch registered by @node. The reference count
> + * for the found switch is incremented.
> + */
> +struct usb_role_switch *usb_role_switch_get_by_node(struct device_node *node)

This is my proposal for function prototype:

struct usb_role_switch *
fwnode_usb_role_switch_get(struct fwnode_handle *fwnode);


thanks,

Hi,
On Fri, 2019-03-15 at 10:18 +0200, Heikki Krogerus wrote:
> On Fri, Mar 15, 2019 at 03:38:31PM +0800, Chunfeng Yun wrote:
> > Add usb_role_switch_get_by_node() to make easier to get
> > usb_role_switch by node which register it.
> > It's useful when there is not device_connection registered
> > between two drivers and only knows the node which register
> > usb_role_switch.
> > 
> > Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
> > ---
> >  drivers/usb/roles/class.c | 30 ++++++++++++++++++++++++++++++
> >  include/linux/usb/role.h  |  1 +
> >  2 files changed, 31 insertions(+)
> > 
> > diff --git a/drivers/usb/roles/class.c b/drivers/usb/roles/class.c
> > index 99116af07f1d..284b19856dc4 100644
> > --- a/drivers/usb/roles/class.c
> > +++ b/drivers/usb/roles/class.c
> > @@ -11,6 +11,7 @@
> >  #include <linux/device.h>
> >  #include <linux/module.h>
> >  #include <linux/mutex.h>
> > +#include <linux/of.h>
> >  #include <linux/slab.h>
> >  
> >  static struct class *role_class;
> > @@ -121,6 +122,35 @@ struct usb_role_switch *usb_role_switch_get(struct device *dev)
> >  }
> >  EXPORT_SYMBOL_GPL(usb_role_switch_get);
> >  
> > +static int __switch_match_node(struct device *dev, const void *node)
> > +{
> > +	return dev->parent->of_node == (const struct device_node *)node;
> > +}
> 
> Andy already pointed out that you need to use fwnodes.
> 
> Rule of thumb: You always use fwnodes. Only if there is something that
> can't be done with fwnodes you use DT or ACPI nodes directly.
> 
> In this case there is absolutely nothing that would prevent you from
> using fwnodes.
> 
Got it, will fix it in next version.

BTW:

I encounter a build error when CONFIG_USB_ROLE_SWITCH is not enabled,

drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_role_sw_register':
./drivers/usb/mtu3/mtu3_dr.c:460: undefined reference to
`usb_role_switch_register'
drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_otg_switch_exit':
./drivers/usb/mtu3/mtu3_dr.c:491: undefined reference to
`usb_role_switch_unregister'

the following patch has fixed the issue, but seems not get into kernel,
[v3,08/12] usb: roles: Add usb role switch notifier.
https://patchwork.kernel.org/patch/10836525/

What should I do if I add a new API? Thanks

> 
> thanks,
>

Hi,
On Fri, 2019-03-15 at 11:11 +0200, Heikki Krogerus wrote:
> On Fri, Mar 15, 2019 at 10:18:35AM +0200, Heikki Krogerus wrote:
> > Andy already pointed out that you need to use fwnodes.
> > 
> > Rule of thumb: You always use fwnodes. Only if there is something that
> > can't be done with fwnodes you use DT or ACPI nodes directly.
> > 
> > In this case there is absolutely nothing that would prevent you from
> > using fwnodes.
> 
> ...
> 
> > +/**
> > + * usb_role_switch_get_by_node - Find USB role switch by it's parent node
> > + * @node: The node that register USB role switch
> > + *
> > + * Finds and returns role switch registered by @node. The reference count
> > + * for the found switch is incremented.
> > + */
> > +struct usb_role_switch *usb_role_switch_get_by_node(struct device_node *node)
> 
> This is my proposal for function prototype:
> 
> struct usb_role_switch *
> fwnode_usb_role_switch_get(struct fwnode_handle *fwnode);
Ok, thanks again
> 
> 
> thanks,
>

Hi,
On Fri, 2019-03-15 at 11:26 +0200, Heikki Krogerus wrote:
> Hi Chunfeng,
> 
> On Fri, Mar 15, 2019 at 05:13:24PM +0800, Chunfeng Yun wrote:
> > I encounter a build error when CONFIG_USB_ROLE_SWITCH is not enabled,
> > 
> > drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_role_sw_register':
> > ./drivers/usb/mtu3/mtu3_dr.c:460: undefined reference to
> > `usb_role_switch_register'
> > drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_otg_switch_exit':
> > ./drivers/usb/mtu3/mtu3_dr.c:491: undefined reference to
> > `usb_role_switch_unregister'
> 
> So you need to add dependency on USB_ROLE_SWITCH, right?
Yes

> 
> --- a/drivers/usb/mtu3/Kconfig
> +++ b/drivers/usb/mtu3/Kconfig
> @@ -43,6 +43,7 @@ config USB_MTU3_DUAL_ROLE
>         bool "Dual Role mode"
>         depends on ((USB=y || USB=USB_MTU3) && (USB_GADGET=y || USB_GADGET=USB_MTU3))
>         depends on (EXTCON=y || EXTCON=USB_MTU3)
> +       depends on USB_ROLE_SWITCH
>         help
>           This is the default mode of working of MTU3 controller where
>           both host and gadget features are enabled.
> 
> > the following patch has fixed the issue, but seems not get into kernel,
> > [v3,08/12] usb: roles: Add usb role switch notifier.
> > https://patchwork.kernel.org/patch/10836525/
> 
> I don't understand how that fixes the problem? That patch will in any
> case be targeting v5.2. We are in the middle of merge window, so
> nothing is happening until v5.1-rc1 is tagged.
It provides some dummy inline functions when USB_ROLE_SWITCH is not
enabled, this will avoid build error

> 
> 
> thanks,
>

On Fri, Mar 15, 2019 at 05:32:59PM +0800, Chunfeng Yun wrote:
> Hi,
> On Fri, 2019-03-15 at 11:26 +0200, Heikki Krogerus wrote:
> > Hi Chunfeng,
> > 
> > On Fri, Mar 15, 2019 at 05:13:24PM +0800, Chunfeng Yun wrote:
> > > I encounter a build error when CONFIG_USB_ROLE_SWITCH is not enabled,
> > > 
> > > drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_role_sw_register':
> > > ./drivers/usb/mtu3/mtu3_dr.c:460: undefined reference to
> > > `usb_role_switch_register'
> > > drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_otg_switch_exit':
> > > ./drivers/usb/mtu3/mtu3_dr.c:491: undefined reference to
> > > `usb_role_switch_unregister'
> > 
> > So you need to add dependency on USB_ROLE_SWITCH, right?
> Yes
> 
> > 
> > --- a/drivers/usb/mtu3/Kconfig
> > +++ b/drivers/usb/mtu3/Kconfig
> > @@ -43,6 +43,7 @@ config USB_MTU3_DUAL_ROLE
> >         bool "Dual Role mode"
> >         depends on ((USB=y || USB=USB_MTU3) && (USB_GADGET=y || USB_GADGET=USB_MTU3))
> >         depends on (EXTCON=y || EXTCON=USB_MTU3)
> > +       depends on USB_ROLE_SWITCH
> >         help
> >           This is the default mode of working of MTU3 controller where
> >           both host and gadget features are enabled.
> > 
> > > the following patch has fixed the issue, but seems not get into kernel,
> > > [v3,08/12] usb: roles: Add usb role switch notifier.
> > > https://patchwork.kernel.org/patch/10836525/
> > 
> > I don't understand how that fixes the problem? That patch will in any
> > case be targeting v5.2. We are in the middle of merge window, so
> > nothing is happening until v5.1-rc1 is tagged.
> It provides some dummy inline functions when USB_ROLE_SWITCH is not
> enabled, this will avoid build error

Ah, true. Those should brobable be introduced in their own patch.


thanks,

On Fri, Mar 15, 2019 at 05:13:24PM +0800, Chunfeng Yun wrote:
> I encounter a build error when CONFIG_USB_ROLE_SWITCH is not enabled,
> 
> drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_role_sw_register':
> ./drivers/usb/mtu3/mtu3_dr.c:460: undefined reference to
> `usb_role_switch_register'
> drivers/usb/mtu3/mtu3_dr.o: In function `ssusb_otg_switch_exit':
> ./drivers/usb/mtu3/mtu3_dr.c:491: undefined reference to
> `usb_role_switch_unregister'
> 
> the following patch has fixed the issue, but seems not get into kernel,
> [v3,08/12] usb: roles: Add usb role switch notifier.
> https://patchwork.kernel.org/patch/10836525/
> 
> What should I do if I add a new API? Thanks

So if you are asking should you supply dummy functions for the new API,
then I would just say that if you do so, you need to prepare these
patches on top of that series from Yu Chen. In general I'm not sure we
need dummy functions with this API.

Hans, comments?


thanks,