Re: [PATCH 2/2] extcon: usbc-tusb320: add usb_role_switch support

[Alvin Šipraga]

On Fri, Mar 17, 2023 at 01:13:51PM +0200, Heikki Krogerus wrote:
> On Fri, Mar 17, 2023 at 11:42:28AM +0100, Alvin Šipraga wrote:
> > From: Alvin Šipraga <alsi@xxxxxxxxxxxxxxx>
> > 
> > The connector child node of the TUSB320 device might be linked with a
> > USB OTG controller with USB role switch capability. Add driver support
> > for detecting a usb_role_switch and setting its state in the typec
> > interrupt handler. This follows similar practice in other drivers in the
> > typec subsystem, which this extcon driver can opt-in to.
> 
> I'm sorry to be a bit picky here, but I must ask that you don't use
> the term USB OTG. It is too confusing - OTG may refer to USB device
> controller, USB host controller, or dual-role capable USB controller,
> depending on the case, so we need to be specific.
> 
> The OTG spec itself is in any case obsolete - USB Type-C and USB PD
> specs define their own way of handling the roles, and they are not
> compatible with the USB OTG specification(s).

Sure thing, I will reword the commit. Gives me an excuse to label it v3
as well. Thanks!

Kind regards,
Alvin

> 
> thanks,
> 
> > Signed-off-by: Alvin Šipraga <alsi@xxxxxxxxxxxxxxx>
> > ---
> > v2: remove unused variable as reported by kernel test robot
> > ---
> >  drivers/extcon/extcon-usbc-tusb320.c | 21 +++++++++++++++++++++
> >  1 file changed, 21 insertions(+)
> > 
> > diff --git a/drivers/extcon/extcon-usbc-tusb320.c b/drivers/extcon/extcon-usbc-tusb320.c
> > index 882d1f48495e..cc2d0ac7c5f6 100644
> > --- a/drivers/extcon/extcon-usbc-tusb320.c
> > +++ b/drivers/extcon/extcon-usbc-tusb320.c
> > @@ -16,6 +16,7 @@
> >  #include <linux/regmap.h>
> >  #include <linux/usb/typec.h>
> >  #include <linux/usb/typec_altmode.h>
> > +#include <linux/usb/role.h>
> >  
> >  #define TUSB320_REG8				0x8
> >  #define TUSB320_REG8_CURRENT_MODE_ADVERTISE	GENMASK(7, 6)
> > @@ -80,6 +81,7 @@ struct tusb320_priv {
> >  	enum typec_port_type port_type;
> >  	enum typec_pwr_opmode pwr_opmode;
> >  	struct fwnode_handle *connector_fwnode;
> > +	struct usb_role_switch *role_sw;
> >  };
> >  
> >  static const char * const tusb_attached_states[] = {
> > @@ -278,6 +280,7 @@ static void tusb320_typec_irq_handler(struct tusb320_priv *priv, u8 reg9)
> >  	struct typec_port *port = priv->port;
> >  	struct device *dev = priv->dev;
> >  	int typec_mode;
> > +	enum usb_role usb_role;
> >  	enum typec_role pwr_role;
> >  	enum typec_data_role data_role;
> >  	u8 state, mode, accessory;
> > @@ -300,11 +303,13 @@ static void tusb320_typec_irq_handler(struct tusb320_priv *priv, u8 reg9)
> >  	switch (state) {
> >  	case TUSB320_ATTACHED_STATE_DFP:
> >  		typec_mode = TYPEC_MODE_USB2;
> > +		usb_role = USB_ROLE_HOST;
> >  		pwr_role = TYPEC_SOURCE;
> >  		data_role = TYPEC_HOST;
> >  		break;
> >  	case TUSB320_ATTACHED_STATE_UFP:
> >  		typec_mode = TYPEC_MODE_USB2;
> > +		usb_role = USB_ROLE_DEVICE;
> >  		pwr_role = TYPEC_SINK;
> >  		data_role = TYPEC_DEVICE;
> >  		break;
> > @@ -316,6 +321,7 @@ static void tusb320_typec_irq_handler(struct tusb320_priv *priv, u8 reg9)
> >  		if (accessory == TUSB320_REG8_ACCESSORY_CONNECTED_AUDIO ||
> >  		    accessory == TUSB320_REG8_ACCESSORY_CONNECTED_ACHRG) {
> >  			typec_mode = TYPEC_MODE_AUDIO;
> > +			usb_role = USB_ROLE_NONE;
> >  			pwr_role = TYPEC_SINK;
> >  			data_role = TYPEC_DEVICE;
> >  			break;
> > @@ -323,12 +329,14 @@ static void tusb320_typec_irq_handler(struct tusb320_priv *priv, u8 reg9)
> >  			   TUSB320_REG8_ACCESSORY_CONNECTED_DBGDFP) {
> >  			typec_mode = TYPEC_MODE_DEBUG;
> >  			pwr_role = TYPEC_SOURCE;
> > +			usb_role = USB_ROLE_HOST;
> >  			data_role = TYPEC_HOST;
> >  			break;
> >  		} else if (accessory ==
> >  			   TUSB320_REG8_ACCESSORY_CONNECTED_DBGUFP) {
> >  			typec_mode = TYPEC_MODE_DEBUG;
> >  			pwr_role = TYPEC_SINK;
> > +			usb_role = USB_ROLE_DEVICE;
> >  			data_role = TYPEC_DEVICE;
> >  			break;
> >  		}
> > @@ -339,6 +347,7 @@ static void tusb320_typec_irq_handler(struct tusb320_priv *priv, u8 reg9)
> >  		fallthrough;
> >  	default:
> >  		typec_mode = TYPEC_MODE_USB2;
> > +		usb_role = USB_ROLE_NONE;
> >  		pwr_role = TYPEC_SINK;
> >  		data_role = TYPEC_DEVICE;
> >  		break;
> > @@ -348,6 +357,7 @@ static void tusb320_typec_irq_handler(struct tusb320_priv *priv, u8 reg9)
> >  	typec_set_pwr_role(port, pwr_role);
> >  	typec_set_data_role(port, data_role);
> >  	typec_set_mode(port, typec_mode);
> > +	usb_role_switch_set_role(priv->role_sw, usb_role);
> >  
> >  	mode = FIELD_GET(TUSB320_REG8_CURRENT_MODE_DETECT, reg8);
> >  	if (mode == TUSB320_REG8_CURRENT_MODE_DETECT_DEF)
> > @@ -472,10 +482,20 @@ static int tusb320_typec_probe(struct i2c_client *client,
> >  		goto err_put;
> >  	}
> >  
> > +	/* Find any optional USB role switch that needs reporting to */
> > +	priv->role_sw = fwnode_usb_role_switch_get(connector);
> > +	if (IS_ERR(priv->role_sw)) {
> > +		ret = PTR_ERR(priv->role_sw);
> > +		goto err_unreg;
> > +	}
> > +
> >  	priv->connector_fwnode = connector;
> >  
> >  	return 0;
> >  
> > +err_unreg:
> > +	typec_unregister_port(priv->port);
> > +
> >  err_put:
> >  	fwnode_handle_put(connector);
> >  
> > @@ -484,6 +504,7 @@ static int tusb320_typec_probe(struct i2c_client *client,
> >  
> >  static void tusb320_typec_remove(struct tusb320_priv *priv)
> >  {
> > +	usb_role_switch_put(priv->role_sw);
> >  	typec_unregister_port(priv->port);
> >  	fwnode_handle_put(priv->connector_fwnode);
> >  }
> > -- 
> > 2.39.2
> 
> -- 
> heikki