power: supply: Add 'usb_type' property and supporting code

This commit adds the 'usb_type' property to represent USB supplies
which can report a number of different types based on a connection
event.

Examples of this already exist in drivers whereby the existing 'type'
property is updated, based on an event, to represent what was
connected (e.g. USB, USB_DCP, USB_ACA, ...). Current implementations
however don't show all supported connectable types, so this knowledge
has to be exlicitly known for each driver that supports this.

The 'usb_type' property is intended to fill this void and show users
all possible USB types supported by a driver. The property, when read,
shows all available types for the driver, and the one currently chosen
is highlighted/bracketed. It is expected that the 'type' property
would then just show the top-level type 'USB', and this would be
static.

Currently the 'usb_type' enum contains all of the USB variant types
that exist for the 'type' enum at this time, and in addition has
SDP and PPS types. The mirroring is intentional so as to not impact
existing usage of the 'type' property.

Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 52 insertions, 1 deletions

diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c
index a7984af1dc66..ecd68c2053c5 100644
--- a/drivers/power/supply/power_supply_core.c
+++ b/drivers/power/supply/power_supply_core.c
@@ -843,7 +843,7 @@ __power_supply_register(struct device *parent,
 {
 	struct device *dev;
 	struct power_supply *psy;
-	int rc;
+	int i, rc;
 
 	if (!parent)
 		pr_warn("%s: Expected proper parent device for '%s'\n",
@@ -852,6 +852,12 @@ __power_supply_register(struct device *parent,
 	if (!desc || !desc->name || !desc->properties || !desc->num_properties)
 		return ERR_PTR(-EINVAL);
 
+	for (i = 0; i < desc->num_properties; ++i) {
+		if ((desc->properties[i] == POWER_SUPPLY_PROP_USB_TYPE) &&
+		    (!desc->usb_types || !desc->num_usb_types))
+			return ERR_PTR(-EINVAL);
+	}
+
 	psy = kzalloc(sizeof(*psy), GFP_KERNEL);
 	if (!psy)
 		return ERR_PTR(-ENOMEM);
diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index 5204f115970f..1350068c401a 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -46,6 +46,11 @@ static const char * const power_supply_type_text[] = {
 	"USB_PD", "USB_PD_DRP", "BrickID"
 };
 
+static const char * const power_supply_usb_type_text[] = {
+	"Unknown", "SDP", "DCP", "CDP", "ACA", "C",
+	"PD", "PD_DRP", "PD_PPS", "BrickID"
+};
+
 static const char * const power_supply_status_text[] = {
 	"Unknown", "Charging", "Discharging", "Not charging", "Full"
 };
@@ -73,6 +78,41 @@ static const char * const power_supply_scope_text[] = {
 	"Unknown", "System", "Device"
 };
 
+static ssize_t power_supply_show_usb_type(struct device *dev,
+					  enum power_supply_usb_type *usb_types,
+					  ssize_t num_usb_types,
+					  union power_supply_propval *value,
+					  char *buf)
+{
+	enum power_supply_usb_type usb_type;
+	ssize_t count = 0;
+	bool match = false;
+	int i;
+
+	for (i = 0; i < num_usb_types; ++i) {
+		usb_type = usb_types[i];
+
+		if (value->intval == usb_type) {
+			count += sprintf(buf + count, "[%s] ",
+					 power_supply_usb_type_text[usb_type]);
+			match = true;
+		} else {
+			count += sprintf(buf + count, "%s ",
+					 power_supply_usb_type_text[usb_type]);
+		}
+	}
+
+	if (!match) {
+		dev_warn(dev, "driver reporting unsupported connected type\n");
+		return -EINVAL;
+	}
+
+	if (count)
+		buf[count - 1] = '\n';
+
+	return count;
+}
+
 static ssize_t power_supply_show_property(struct device *dev,
 					  struct device_attribute *attr,
 					  char *buf) {
@@ -115,6 +155,10 @@ static ssize_t power_supply_show_property(struct device *dev,
 	else if (off == POWER_SUPPLY_PROP_TYPE)
 		return sprintf(buf, "%s\n",
 			       power_supply_type_text[value.intval]);
+	else if (off == POWER_SUPPLY_PROP_USB_TYPE)
+		return power_supply_show_usb_type(dev, psy->desc->usb_types,
+						  psy->desc->num_usb_types,
+						  &value, buf);
 	else if (off == POWER_SUPPLY_PROP_SCOPE)
 		return sprintf(buf, "%s\n",
 			       power_supply_scope_text[value.intval]);
@@ -241,6 +285,7 @@ static struct device_attribute power_supply_attrs[] = {
 	POWER_SUPPLY_ATTR(time_to_full_now),
 	POWER_SUPPLY_ATTR(time_to_full_avg),
 	POWER_SUPPLY_ATTR(type),
+	POWER_SUPPLY_ATTR(usb_type),
 	POWER_SUPPLY_ATTR(scope),
 	POWER_SUPPLY_ATTR(precharge_current),
 	POWER_SUPPLY_ATTR(charge_term_current),