usb: typec: pd: Add higher capability sysfs for sink PDO

28th bit of fixed supply sink PDO represents higher capability.
When this bit is set, the sink device needs more than vsafe5V
(eg: 12 V) to provide full functionality. This patch adds
this higher capability sysfs interface for sink PDO.
28th bit of fixed supply source PDO represents usb_suspend_supported
attribute. This usb_suspend_supported sysfs is already exposed for
source PDOs. This patch adds 'source-capabilities' in
usb_suspend_supported sysfs documentation for additional clarity.

Signed-off-by: Saranya Gopal <saranya.gopal@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20230214114543.205103-2-saranya.gopal@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: saranyagopal1

Documentation/ABI/testing/sysfs-class-usb_power_delivery

@@ -69,7 +69,7 @@ Description:
 		This file contains boolean value that tells does the device
 		support both source and sink power roles.
 
-What:		/sys/class/usb_power_delivery/.../<capability>/1:fixed_supply/usb_suspend_supported
+What:		/sys/class/usb_power_delivery/.../source-capabilities/1:fixed_supply/usb_suspend_supported
 Date:		May 2022
 Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>
 Description:
@@ -78,6 +78,15 @@ Description:
 		will follow the USB 2.0 and USB 3.2 rules for suspend and
 		resume.
 
+What:		/sys/class/usb_power_delivery/.../sink-capabilities/1:fixed_supply/higher_capability
+Date:		February 2023
+Contact:	Saranya Gopal <saranya.gopal@linux.intel.com>
+Description:
+		This file shows the value of the Higher capability bit in
+		vsafe5V Fixed Supply Object. If the bit is set, then the sink
+		needs more than vsafe5V(eg. 12 V) to provide full functionality.
+		Valid values: 0, 1
+
 What:		/sys/class/usb_power_delivery/.../<capability>/1:fixed_supply/unconstrained_power
 Date:		May 2022
 Contact:	Heikki Krogerus <heikki.krogerus@linux.intel.com>

drivers/usb/typec/pd.c

@@ -48,6 +48,13 @@ usb_suspend_supported_show(struct device *dev, struct device_attribute *attr, ch
 }
 static DEVICE_ATTR_RO(usb_suspend_supported);
 
+static ssize_t
+higher_capability_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	return sysfs_emit(buf, "%u\n", !!(to_pdo(dev)->pdo & PDO_FIXED_HIGHER_CAP));
+}
+static DEVICE_ATTR_RO(higher_capability);
+
 static ssize_t
 unconstrained_power_show(struct device *dev, struct device_attribute *attr, char *buf)
 {
@@ -161,6 +168,7 @@ static struct device_type source_fixed_supply_type = {
 
 static struct attribute *sink_fixed_supply_attrs[] = {
 	&dev_attr_dual_role_power.attr,
+	&dev_attr_higher_capability.attr,
 	&dev_attr_unconstrained_power.attr,
 	&dev_attr_usb_communication_capable.attr,
 	&dev_attr_dual_role_data.attr,