RE: [PATCH v6 4/7] usb: gadget: udc: renesas_usb3: Add dual role switch support

[Biju Das <biju.das@bp.renesas.com>]

Hi Shimoda-San,

Thanks for the feedback.

> > From: Biju Das, Sent: Wednesday, May 15, 2019 9:09 PM
> > Subject: [PATCH v6 4/7] usb: gadget: udc: renesas_usb3: Add dual role
> > switch support
> 
> Now I'm confusing about the "Add dual role switch support" mean...
> Especially, this driver has already supports dual role switch support by own
> sysfs or debugfs.

Sorry for the confusion. 
What about "Enhance role switch support" ?

> > The RZ/G2E cat874 board has a type-c connector connected to hd3ss3220
> > usb type-c drp port controller. This patch adds dual role switch
> > support for the type-c connector using the usb role switch class framework.
> 
> IIUC, after this patch is applied, the hs3ss3220 type-c driver can switch the
> role by using the usb role switch class framework.

Yes, That is correct. HD3SS3220 driver detects host/device  connection events (attach/detach) and 
It calls "usb_role_switch_set_role"  to assign/switch the role.

> > Signed-off-by: Biju Das <biju.das@bp.renesas.com>
> > ---
> >  V5-->V6
> >    * Added graph api's to find the role supported by the connector.
> >  V4-->V5
> >    * Incorporated Shimoda-san's review comment
> >     (https://patchwork.kernel.org/patch/10902537/)
> >  V3-->V4
> >    * No Change
> >  V2-->V3
> >    * Incorporated Shimoda-san's review comment
> >      (https://patchwork.kernel.org/patch/10852507/)
> >    * Used renesas,usb-role-switch property for differentiating USB
> >      role switch associated with Type-C port controller driver.
> >  V1-->V2
> >    * Driver uses usb role clas for handling dual role switch and handling
> >      connect/disconnect events instead of extcon.
> > ---
> >  drivers/usb/gadget/udc/renesas_usb3.c | 121
> > ++++++++++++++++++++++++++++++++--
> >  1 file changed, 114 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/usb/gadget/udc/renesas_usb3.c
> > b/drivers/usb/gadget/udc/renesas_usb3.c
> > index 7dc2485..1d41998 100644
> > --- a/drivers/usb/gadget/udc/renesas_usb3.c
> > +++ b/drivers/usb/gadget/udc/renesas_usb3.c
> > @@ -24,6 +24,7 @@
> >  #include <linux/usb/ch9.h>
> >  #include <linux/usb/gadget.h>
> >  #include <linux/usb/of.h>
> > +#include <linux/of_graph.h>
> >  #include <linux/usb/role.h>
> >
> >  /* register definitions */
> > @@ -351,6 +352,8 @@ struct renesas_usb3 {
> >  	int disabled_count;
> >
> >  	struct usb_request *ep0_req;
> > +
> > +	enum usb_role connection_state;
> >  	u16 test_mode;
> >  	u8 ep0_buf[USB3_EP0_BUF_SIZE];
> >  	bool softconnect;
> > @@ -359,6 +362,7 @@ struct renesas_usb3 {
> >  	bool extcon_usb;		/* check vbus and set EXTCON_USB
> */
> >  	bool forced_b_device;
> >  	bool start_to_connect;
> > +	bool dual_role_sw;
> 
> I'm also confusing this name.

OK. will change it to "role_sw_by_connector"

> >  };
> >
> >  #define gadget_to_renesas_usb3(_gadget)	\
> <snip>
> > @@ -699,8 +703,10 @@ static void usb3_mode_config(struct renesas_usb3
> *usb3, bool host, bool a_dev)
> >  	unsigned long flags;
> >
> >  	spin_lock_irqsave(&usb3->lock, flags);
> > -	usb3_set_mode_by_role_sw(usb3, host);
> > -	usb3_vbus_out(usb3, a_dev);
> > +	if (!usb3->dual_role_sw || usb3->connection_state !=
> USB_ROLE_NONE) {
> > +		usb3_set_mode_by_role_sw(usb3, host);
> > +		usb3_vbus_out(usb3, a_dev);
> > +	}
> >  	/* for A-Peripheral or forced B-device mode */
> >  	if ((!host && a_dev) || usb3->start_to_connect)
> >  		usb3_connect(usb3);
> > @@ -716,7 +722,8 @@ static void usb3_check_id(struct renesas_usb3
> > *usb3)  {
> >  	usb3->extcon_host = usb3_is_a_device(usb3);
> >
> > -	if (usb3->extcon_host && !usb3->forced_b_device)
> > +	if ((!usb3->dual_role_sw && usb3->extcon_host && !usb3-
> >forced_b_device)
> > +	    || usb3->connection_state == USB_ROLE_HOST)
> >  		usb3_mode_config(usb3, true, true);
> >  	else
> >  		usb3_mode_config(usb3, false, false); @@ -2343,14 +2350,65
> @@
> > static enum usb_role renesas_usb3_role_switch_get(struct device *dev)
> >  	return cur_role;
> >  }
> >
> > -static int renesas_usb3_role_switch_set(struct device *dev,
> > -					enum usb_role role)
> > +static void handle_ext_role_switch_states(struct device *dev,
> > +					    enum usb_role role)
> > +{
> > +	struct renesas_usb3 *usb3 = dev_get_drvdata(dev);
> > +	struct device *host = usb3->host_dev;
> > +	enum usb_role cur_role = renesas_usb3_role_switch_get(dev);
> > +
> > +	switch (role) {
> > +	case USB_ROLE_NONE:
> > +		usb3->connection_state = USB_ROLE_NONE;
> > +		if (usb3->driver)
> > +			usb3_disconnect(usb3);
> > +		usb3_vbus_out(usb3, false);
> > +		break;
> > +	case USB_ROLE_DEVICE:
> > +		if (usb3->connection_state == USB_ROLE_NONE) {
> > +			usb3->connection_state = USB_ROLE_DEVICE;
> > +			usb3_set_mode(usb3, false);
> > +			if (usb3->driver)
> > +				usb3_connect(usb3);
> > +		} else if (cur_role == USB_ROLE_HOST)  {
> > +			device_release_driver(host);
> > +			usb3_set_mode(usb3, false);
> > +			if (usb3->driver)
> > +				usb3_connect(usb3);
> > +		}
> > +		usb3_vbus_out(usb3, false);
> > +		break;
> > +	case USB_ROLE_HOST:
> > +		if (usb3->connection_state == USB_ROLE_NONE) {
> > +			if (usb3->driver)
> > +				usb3_disconnect(usb3);
> > +
> > +			usb3->connection_state = USB_ROLE_HOST;
> > +			usb3_set_mode(usb3, true);
> > +			usb3_vbus_out(usb3, true);
> > +			if (device_attach(host) < 0)
> > +				dev_err(dev, "device_attach(host)
> failed\n");
> > +		} else if (cur_role == USB_ROLE_DEVICE) {
> > +			usb3_disconnect(usb3);
> > +			/* Must set the mode before device_attach of the
> host */
> > +			usb3_set_mode(usb3, true);
> > +			/* This device_attach() might sleep */
> > +			if (device_attach(host) < 0)
> > +				dev_err(dev, "device_attach(host)
> failed\n");
> > +		}
> > +		break;
> > +	default:
> > +		break;
> > +	}
> > +}
> > +
> > +static void handle_role_switch_states(struct device *dev,
> > +					    enum usb_role role)
> >  {
> >  	struct renesas_usb3 *usb3 = dev_get_drvdata(dev);
> >  	struct device *host = usb3->host_dev;
> >  	enum usb_role cur_role = renesas_usb3_role_switch_get(dev);
> >
> > -	pm_runtime_get_sync(dev);
> >  	if (cur_role == USB_ROLE_HOST && role == USB_ROLE_DEVICE) {
> >  		device_release_driver(host);
> >  		usb3_set_mode(usb3, false);
> > @@ -2361,6 +2419,20 @@ static int renesas_usb3_role_switch_set(struct
> device *dev,
> >  		if (device_attach(host) < 0)
> >  			dev_err(dev, "device_attach(host) failed\n");
> >  	}
> > +}
> > +
> > +static int renesas_usb3_role_switch_set(struct device *dev,
> > +					enum usb_role role)
> > +{
> > +	struct renesas_usb3 *usb3 = dev_get_drvdata(dev);
> > +
> > +	pm_runtime_get_sync(dev);
> > +
> > +	if (usb3->dual_role_sw)
> > +		handle_ext_role_switch_states(dev, role);
> > +	else
> > +		handle_role_switch_states(dev, role);
> > +
> >  	pm_runtime_put(dev);
> >
> >  	return 0;
> > @@ -2650,12 +2722,41 @@ static const unsigned int renesas_usb3_cable[]
> = {
> >  	EXTCON_NONE,
> >  };
> >
> > -static const struct usb_role_switch_desc
> > renesas_usb3_role_switch_desc = {
> > +static struct usb_role_switch_desc renesas_usb3_role_switch_desc = {
> >  	.set = renesas_usb3_role_switch_set,
> >  	.get = renesas_usb3_role_switch_get,
> >  	.allow_userspace_control = true,
> >  };
> >
> > +static bool is_usb_dual_role_switch(struct device *dev) {
> > +	struct device_node *np = dev->of_node;
> > +	struct device_node *parent;
> > +	struct device_node *child;
> > +	bool ret = false;
> > +	const char *role_type = NULL;
> > +
> > +	child = of_graph_get_endpoint_by_regs(np, -1, -1);
> > +	if (!child)
> > +		return ret;
> > +
> > +	parent = of_graph_get_remote_port_parent(child);
> > +	of_node_put(child);
> > +	child = of_get_child_by_name(parent, "connector");
> > +	of_node_put(parent);
> > +	if (!child)
> > +		return ret;
> > +
> > +	if (of_device_is_compatible(child, "usb-c-connector")) {
> > +		of_property_read_string(child, "data-role", &role_type);
> > +		if (role_type && (!strncmp(role_type, "dual",
> strlen("dual"))))
> > +			ret = true;
> > +	}
> > +
> > +	of_node_put(child);
> > +	return ret;
> > +}
> > +
> >  static int renesas_usb3_probe(struct platform_device *pdev)  {
> >  	struct renesas_usb3 *usb3;
> > @@ -2741,6 +2842,12 @@ static int renesas_usb3_probe(struct
> platform_device *pdev)
> >  	if (ret < 0)
> >  		goto err_dev_create;
> >
> > +	if (device_property_read_bool(&pdev->dev, "usb-role-switch") &&
> > +	    is_usb_dual_role_switch(&pdev->dev)) {
> 
> I think either one of the conditions is enough. (Only "usb-role-switch"
> checking is enough, IIUC).

OK, Will remove the other check.

> JFYI, according to the binding document [1], this "usb-role-switch" means:
> ---
> + - usb-role-switch: boolean, indicates that the device is capable of assigning
> +			the USB data role (USB host or USB device) for a
> given
> +			USB connector, such as Type-C, Type-B(micro).
> +			see connector/usb-connector.txt.
> ---
> 
> So, R-Car Gen3 / Salvator-XS cannot have this property because the board
> has Type-A connector.
> 
> [1] https://patchwork.kernel.org/patch/10934835/

I have updated the  binding patch to cover this[1]
[1]. https://patchwork.kernel.org/patch/10944631/
Are you ok with this binding patch?

> > +		usb3->dual_role_sw = true;
> 
> So, "role_sw_by_connector" matches with my image.
> What do you think?

OK, will use " role_sw_by_connector"

Regards,
Biju
 
> > +		renesas_usb3_role_switch_desc.fwnode =
> dev_fwnode(&pdev->dev);
> > +	}
> > +
> >  	INIT_WORK(&usb3->role_work, renesas_usb3_role_work);
> >  	usb3->role_sw = usb_role_switch_register(&pdev->dev,
> >  					&renesas_usb3_role_switch_desc);
> > --
> > 2.7.4