diff mbox series

[v1,2/4] usb: typec: Add attribute file showing the USB Modes of the partner

Message ID 20241004140440.1882311-3-heikki.krogerus@linux.intel.com
State Superseded
Headers show
Series usb: typec: USB Modes | expand

Commit Message

Heikki Krogerus Oct. 4, 2024, 2:04 p.m. UTC 
This attribute file shows the supported USB modes (USB 2.0,
USB 3.0 and USB4) of the partner, and the currently active
mode.

The active mode is determined primarily by checking the
speed of the enumerated USB device. When USB Power Delivery
is supported, the active USB mode should be always the mode
that was used with the Enter_USB Message, regardless of the
result of the USB enumeration. The port drivers can
separately assign the mode with a dedicated API.

If USB Power Delivery Identity is supplied for the partner
device, the supported modes are extracted from it.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
---
 Documentation/ABI/testing/sysfs-class-typec |  14 +++
 drivers/usb/typec/class.c                   | 123 +++++++++++++++++++-
 drivers/usb/typec/class.h                   |   2 +
 include/linux/usb/typec.h                   |   5 +
 4 files changed, 140 insertions(+), 4 deletions(-)

Comments

kernel test robot Oct. 5, 2024, 7:25 a.m. UTC | #1 
Hi Heikki,

kernel test robot noticed the following build warnings:

[auto build test WARNING on usb/usb-testing]
[also build test WARNING on usb/usb-next usb/usb-linus linus/master v6.12-rc1 next-20241004]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Heikki-Krogerus/usb-typec-Add-attribute-file-showing-the-USB-Modes-of-the-partner/20241004-230547
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
patch link:    https://lore.kernel.org/r/20241004140440.1882311-3-heikki.krogerus%40linux.intel.com
patch subject: [PATCH v1 2/4] usb: typec: Add attribute file showing the USB Modes of the partner
config: x86_64-rhel-8.3 (https://download.01.org/0day-ci/archive/20241005/202410051504.tccjB1Cp-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241005/202410051504.tccjB1Cp-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202410051504.tccjB1Cp-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/usb/typec/class.c:630: warning: Function parameter or struct member 'usb_mode' not described in 'typec_partner_set_usb_mode'
>> drivers/usb/typec/class.c:630: warning: Excess function parameter 'mode' description in 'typec_partner_set_usb_mode'


vim +630 drivers/usb/typec/class.c

   620	
   621	/**
   622	 * typec_partner_set_usb_mode - Assign active USB Mode for the partner
   623	 * @partner: USB Type-C partner
   624	 * @mode: USB Mode (USB2, USB3 or USB4)
   625	 *
   626	 * The port drivers can use this function to assign the active USB Mode to
   627	 * @partner. The USB Mode can change for example due to Data Reset.
   628	 */
   629	void typec_partner_set_usb_mode(struct typec_partner *partner, enum usb_mode usb_mode)
 > 630	{
   631		if (!partner || partner->usb_mode == usb_mode)
   632			return;
   633	
   634		partner->usb_capability |= BIT(usb_mode - 1);
   635		partner->usb_mode = usb_mode;
   636		sysfs_notify(&partner->dev.kobj, NULL, "usb_mode");
   637	}
   638	EXPORT_SYMBOL_GPL(typec_partner_set_usb_mode);
   639
Dmitry Baryshkov Oct. 6, 2024, 4:22 p.m. UTC | #2 
On Fri, Oct 04, 2024 at 05:04:37PM GMT, Heikki Krogerus wrote:
> This attribute file shows the supported USB modes (USB 2.0,
> USB 3.0 and USB4) of the partner, and the currently active
> mode.
> 
> The active mode is determined primarily by checking the
> speed of the enumerated USB device. When USB Power Delivery
> is supported, the active USB mode should be always the mode
> that was used with the Enter_USB Message, regardless of the
> result of the USB enumeration. The port drivers can
> separately assign the mode with a dedicated API.
> 
> If USB Power Delivery Identity is supplied for the partner
> device, the supported modes are extracted from it.
> 
> Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> ---
>  Documentation/ABI/testing/sysfs-class-typec |  14 +++
>  drivers/usb/typec/class.c                   | 123 +++++++++++++++++++-
>  drivers/usb/typec/class.h                   |   2 +
>  include/linux/usb/typec.h                   |   5 +
>  4 files changed, 140 insertions(+), 4 deletions(-)

I think the use of port->usbN_dev is racy and not always obviouos.
For example  on Qualcomm devices I ended up with no partner's
usb_capability and just 'usb2' in usb_mode even though the partner uses
USB3 mode. Maybe it's better to hide usb_mode completely if we can not
properly determine the actual mode?

(On Qualcomm devices there is no working ACPI, so there is no USB <->
typec correlationship (yet)).
Heikki Krogerus Oct. 9, 2024, 8:34 a.m. UTC | #3 
On Sun, Oct 06, 2024 at 07:22:42PM +0300, Dmitry Baryshkov wrote:
> On Fri, Oct 04, 2024 at 05:04:37PM GMT, Heikki Krogerus wrote:
> > This attribute file shows the supported USB modes (USB 2.0,
> > USB 3.0 and USB4) of the partner, and the currently active
> > mode.
> > 
> > The active mode is determined primarily by checking the
> > speed of the enumerated USB device. When USB Power Delivery
> > is supported, the active USB mode should be always the mode
> > that was used with the Enter_USB Message, regardless of the
> > result of the USB enumeration. The port drivers can
> > separately assign the mode with a dedicated API.
> > 
> > If USB Power Delivery Identity is supplied for the partner
> > device, the supported modes are extracted from it.
> > 
> > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > ---
> >  Documentation/ABI/testing/sysfs-class-typec |  14 +++
> >  drivers/usb/typec/class.c                   | 123 +++++++++++++++++++-
> >  drivers/usb/typec/class.h                   |   2 +
> >  include/linux/usb/typec.h                   |   5 +
> >  4 files changed, 140 insertions(+), 4 deletions(-)
> 
> I think the use of port->usbN_dev is racy and not always obviouos.
> For example  on Qualcomm devices I ended up with no partner's
> usb_capability and just 'usb2' in usb_mode even though the partner uses
> USB3 mode. Maybe it's better to hide usb_mode completely if we can not
> properly determine the actual mode?
> 
> (On Qualcomm devices there is no working ACPI, so there is no USB <->
> typec correlationship (yet)).

Sure. Let's keep it hidden in that case.

thanks,
diff mbox series

Patch

diff --git a/Documentation/ABI/testing/sysfs-class-typec b/Documentation/ABI/testing/sysfs-class-typec
index 7c307f02d99e..866865ffeb66 100644
--- a/Documentation/ABI/testing/sysfs-class-typec
+++ b/Documentation/ABI/testing/sysfs-class-typec
@@ -233,6 +233,20 @@  Description:
 		directory exists, it will have an attribute file for every VDO
 		in Discover Identity command result.
 
+What:		/sys/class/typec/<port>-partner/usb_mode
+Date:		February 2024
+Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
+Description:	The USB Modes that the partner device supports. The active mode
+		is disaplayed in brackets. The active USB mode can be changed by
+		writing to this file when the port driver is able to send Data
+		Reset Message to the partner. That requires USB Power Delivery
+		contract between the partner and the port.
+
+		Valid values:
+		- usb2 (USB 2.0)
+		- usb3 (USB 3.2)
+		- usb4 (USB4)
+
 USB Type-C cable devices (eg. /sys/class/typec/port0-cable/)
 
 Note: Electronically Marked Cables will have a device also for one cable plug
diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
index 9c26d2ad40df..5d35a263a2bf 100644
--- a/drivers/usb/typec/class.c
+++ b/drivers/usb/typec/class.c
@@ -618,6 +618,74 @@  EXPORT_SYMBOL_GPL(typec_unregister_altmode);
 /* ------------------------------------------------------------------------- */
 /* Type-C Partners */
 
+/**
+ * typec_partner_set_usb_mode - Assign active USB Mode for the partner
+ * @partner: USB Type-C partner
+ * @mode: USB Mode (USB2, USB3 or USB4)
+ *
+ * The port drivers can use this function to assign the active USB Mode to
+ * @partner. The USB Mode can change for example due to Data Reset.
+ */
+void typec_partner_set_usb_mode(struct typec_partner *partner, enum usb_mode usb_mode)
+{
+	if (!partner || partner->usb_mode == usb_mode)
+		return;
+
+	partner->usb_capability |= BIT(usb_mode - 1);
+	partner->usb_mode = usb_mode;
+	sysfs_notify(&partner->dev.kobj, NULL, "usb_mode");
+}
+EXPORT_SYMBOL_GPL(typec_partner_set_usb_mode);
+
+static ssize_t
+usb_mode_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct typec_partner *partner = to_typec_partner(dev);
+	int len = 0;
+	int i;
+
+	for (i = USB_MODE_USB2; i < USB_MODE_USB4 + 1; i++) {
+		if (!(BIT(i - 1) & partner->usb_capability))
+			continue;
+
+		if (i == partner->usb_mode)
+			len += sysfs_emit_at(buf, len, "[%s] ", usb_modes[i]);
+		else
+			len += sysfs_emit_at(buf, len, "%s ", usb_modes[i]);
+	}
+
+	buf[len - 1] = '\n';
+	return len;
+}
+
+static ssize_t usb_mode_store(struct device *dev, struct device_attribute *attr,
+			      const char *buf, size_t size)
+{
+	struct typec_partner *partner = to_typec_partner(dev);
+	struct typec_port *port = to_typec_port(dev->parent);
+	int mode;
+	int ret;
+
+	if (!port->ops || !port->ops->data_reset)
+		return -EOPNOTSUPP;
+
+	mode = sysfs_match_string(usb_modes, buf);
+	if (mode < 0)
+		return mode;
+
+	if (mode == partner->usb_mode)
+		return size;
+
+	ret = port->ops->data_reset(port, mode);
+	if (ret)
+		return ret;
+
+	typec_partner_set_usb_mode(partner, mode);
+
+	return size;
+}
+static DEVICE_ATTR_RW(usb_mode);
+
 static ssize_t accessory_mode_show(struct device *dev,
 				   struct device_attribute *attr,
 				   char *buf)
@@ -664,6 +732,7 @@  static struct attribute *typec_partner_attrs[] = {
 	&dev_attr_supports_usb_power_delivery.attr,
 	&dev_attr_number_of_alternate_modes.attr,
 	&dev_attr_type.attr,
+	&dev_attr_usb_mode.attr,
 	&dev_attr_usb_power_delivery_revision.attr,
 	NULL
 };
@@ -671,6 +740,14 @@  static struct attribute *typec_partner_attrs[] = {
 static umode_t typec_partner_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
 {
 	struct typec_partner *partner = to_typec_partner(kobj_to_dev(kobj));
+	struct typec_port *port = to_typec_port(partner->dev.parent);
+
+	if (attr == &dev_attr_usb_mode.attr) {
+		if (!partner->usb_capability)
+			return 0;
+		if (!port->ops || !port->ops->data_reset)
+			return 0444;
+	}
 
 	if (attr == &dev_attr_number_of_alternate_modes.attr) {
 		if (partner->num_altmodes < 0)
@@ -744,10 +821,33 @@  static void typec_partner_unlink_device(struct typec_partner *partner, struct de
  */
 int typec_partner_set_identity(struct typec_partner *partner)
 {
-	if (!partner->identity)
+	u8 usb_capability = partner->usb_capability;
+	struct device *dev = &partner->dev;
+	struct usb_pd_identity *id;
+
+	id = get_pd_identity(dev);
+	if (!id)
 		return -EINVAL;
 
-	typec_report_identity(&partner->dev);
+	if (to_typec_port(dev->parent)->data_role == TYPEC_HOST)  {
+		u32 devcap = PD_VDO_UFP_DEVCAP(id->vdo[0]);
+
+		if (devcap & (DEV_USB2_CAPABLE | DEV_USB2_BILLBOARD))
+			usb_capability |= USB_CAPABILITY_USB2;
+		if (devcap & DEV_USB3_CAPABLE)
+			usb_capability |= USB_CAPABILITY_USB3;
+		if (devcap & DEV_USB4_CAPABLE)
+			usb_capability |= USB_CAPABILITY_USB4;
+	} else {
+		usb_capability = PD_VDO_DFP_HOSTCAP(id->vdo[0]);
+	}
+
+	if (partner->usb_capability != usb_capability) {
+		partner->usb_capability = usb_capability;
+		sysfs_notify(&dev->kobj, NULL, "usb_mode");
+	}
+
+	typec_report_identity(dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(typec_partner_set_identity);
@@ -917,6 +1017,7 @@  struct typec_partner *typec_register_partner(struct typec_port *port,
 	partner->usb_pd = desc->usb_pd;
 	partner->accessory = desc->accessory;
 	partner->num_altmodes = -1;
+	partner->usb_capability = desc->usb_capability;
 	partner->pd_revision = desc->pd_revision;
 	partner->svdm_version = port->cap->svdm_version;
 	partner->attach = desc->attach;
@@ -936,6 +1037,15 @@  struct typec_partner *typec_register_partner(struct typec_port *port,
 	partner->dev.type = &typec_partner_dev_type;
 	dev_set_name(&partner->dev, "%s-partner", dev_name(&port->dev));
 
+	if (port->usb2_dev) {
+		partner->usb_capability |= USB_CAPABILITY_USB2;
+		partner->usb_mode = USB_MODE_USB2;
+	}
+	if (port->usb3_dev) {
+		partner->usb_capability |= USB_CAPABILITY_USB2 | USB_CAPABILITY_USB3;
+		partner->usb_mode = USB_MODE_USB3;
+	}
+
 	ret = device_register(&partner->dev);
 	if (ret) {
 		dev_err(&port->dev, "failed to register partner (%d)\n", ret);
@@ -1935,13 +2045,18 @@  static void typec_partner_attach(struct typec_connector *con, struct device *dev
 	struct typec_port *port = container_of(con, struct typec_port, con);
 	struct typec_partner *partner = typec_get_partner(port);
 	struct usb_device *udev = to_usb_device(dev);
+	enum usb_mode usb_mode;
 
-	if (udev->speed < USB_SPEED_SUPER)
+	if (udev->speed < USB_SPEED_SUPER) {
+		usb_mode = USB_MODE_USB2;
 		port->usb2_dev = dev;
-	else
+	} else {
+		usb_mode = USB_MODE_USB3;
 		port->usb3_dev = dev;
+	}
 
 	if (partner) {
+		typec_partner_set_usb_mode(partner, usb_mode);
 		typec_partner_link_device(partner, dev);
 		put_device(&partner->dev);
 	}
diff --git a/drivers/usb/typec/class.h b/drivers/usb/typec/class.h
index 85bc50aa54f7..b3076a24ad2e 100644
--- a/drivers/usb/typec/class.h
+++ b/drivers/usb/typec/class.h
@@ -35,6 +35,8 @@  struct typec_partner {
 	int				num_altmodes;
 	u16				pd_revision; /* 0300H = "3.0" */
 	enum usb_pd_svdm_ver		svdm_version;
+	enum usb_mode			usb_mode;
+	u8				usb_capability;
 
 	struct usb_power_delivery	*pd;
 
diff --git a/include/linux/usb/typec.h b/include/linux/usb/typec.h
index d8999472212d..c35221b0e164 100644
--- a/include/linux/usb/typec.h
+++ b/include/linux/usb/typec.h
@@ -220,6 +220,7 @@  struct typec_cable_desc {
  * @accessory: Audio, Debug or none.
  * @identity: Discover Identity command data
  * @pd_revision: USB Power Delivery Specification Revision if supported
+ * @usb_capability: Supported USB Modes
  * @attach: Notification about attached USB device
  * @deattach: Notification about removed USB device
  *
@@ -237,6 +238,7 @@  struct typec_partner_desc {
 	enum typec_accessory	accessory;
 	struct usb_pd_identity	*identity;
 	u16			pd_revision; /* 0300H = "3.0" */
+	u8			usb_capability;
 
 	void (*attach)(struct typec_partner *partner, struct device *dev);
 	void (*deattach)(struct typec_partner *partner, struct device *dev);
@@ -252,6 +254,7 @@  struct typec_partner_desc {
  * @pd_get: Get available USB Power Delivery Capabilities.
  * @pd_set: Set USB Power Delivery Capabilities.
  * @usb_mode_set: Set the USB Mode to be used with Enter_USB message
+ * @data_reset: Set new USB mode by using the Data Reset message
  */
 struct typec_operations {
 	int (*try_role)(struct typec_port *port, int role);
@@ -263,6 +266,7 @@  struct typec_operations {
 	struct usb_power_delivery **(*pd_get)(struct typec_port *port);
 	int (*pd_set)(struct typec_port *port, struct usb_power_delivery *pd);
 	int (*usb_mode_set)(struct typec_port *port, enum usb_mode mode);
+	int (*data_reset)(struct typec_port *port, enum usb_mode mode);
 };
 
 enum usb_pd_svdm_ver {
@@ -365,6 +369,7 @@  int typec_port_set_usb_power_delivery(struct typec_port *port, struct usb_power_
 int typec_partner_set_usb_power_delivery(struct typec_partner *partner,
 					 struct usb_power_delivery *pd);
 
+void typec_partner_set_usb_mode(struct typec_partner *partner, enum usb_mode usb_mode);
 void typec_port_set_usb_mode(struct typec_port *port, enum usb_mode mode);
 
 /**