[RFC PATCH 2/3] power: supply: Add support for PDOs props

[Prashant Malani]

Add support for reporting Source and Sink Capabilities
Power Data Object (PDO) property. These are reported by USB
Power Delivery (PD) capable power sources.

Signed-off-by: Prashant Malani <pmalani@xxxxxxxxxxxx>
---
 Documentation/ABI/testing/sysfs-class-power | 30 +++++++++++++++++++++
 drivers/power/supply/power_supply_sysfs.c   | 18 ++++++++++++-
 include/linux/power_supply.h                |  5 ++++
 3 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-class-power b/Documentation/ABI/testing/sysfs-class-power
index ca830c6cd809..90d4198e6dfb 100644
--- a/Documentation/ABI/testing/sysfs-class-power
+++ b/Documentation/ABI/testing/sysfs-class-power
@@ -562,6 +562,36 @@ Description:
 			      "Unknown", "SDP", "DCP", "CDP", "ACA", "C", "PD",
 			      "PD_DRP", "PD_PPS", "BrickID"
 
+What:		/sys/class/power_supply/<supply_name>/source_cap_pdos
+Date:		September 2021
+Contact:	linux-pm@xxxxxxxxxxxxxxx
+Description:
+		Reports the Source Capabilities Power Data Objects (PDO) reported by the USB
+		PD-capable power source. 13 PDOs are listed. PDOs 1-7 represent the Source Caps
+		for devices which only support Standard Power Range (SPR), whereas PDOs 8-13
+		are for Extended Power Range (EPR) capable sources.
+		NOTE: The EPR Source Caps message is a superset of the Source Cap message, so on
+		SPR-only sources, PDOs 8-13 will be 0.
+
+		Access: Read-Only
+
+		Valid values: Represented as a list of 13 32-bit PDO objects in hexadecimal format.
+
+What:		/sys/class/power_supply/<supply_name>/sink_cap_pdos
+Date:		September 2021
+Contact:	linux-pm@xxxxxxxxxxxxxxx
+Description:
+		Reports the Sink Capabilities Power Data Objects (PDO) reported by the USB
+		PD-capable power source. 13 PDOs are listed. PDOs 1-7 represent the Sink Caps
+		for devices which only support Standard Power Range (SPR), whereas PDOs 8-13
+		are for Extended Power Range (EPR) capable sinks.
+		NOTE: The EPR Sink Caps message is a superset of the Sink Cap message, so on
+		SPR-only sinks, PDOs 8-13 will be 0.
+
+		Access: Read-Only
+
+		Valid values: Represented as a list of 13 32-bit PDO objects in hexadecimal format.
+
 **Device Specific Properties**
 
 What:		/sys/class/power/ds2760-battery.*/charge_now
diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
index c3d7cbcd4fad..9d17d3376949 100644
--- a/drivers/power/supply/power_supply_sysfs.c
+++ b/drivers/power/supply/power_supply_sysfs.c
@@ -211,6 +211,9 @@ static struct power_supply_attr power_supply_attrs[] = {
 	POWER_SUPPLY_ATTR(MODEL_NAME),
 	POWER_SUPPLY_ATTR(MANUFACTURER),
 	POWER_SUPPLY_ATTR(SERIAL_NUMBER),
+	/* Array properties */
+	POWER_SUPPLY_ATTR(SINK_CAP_PDOS),
+	POWER_SUPPLY_ATTR(SOURCE_CAP_PDOS),
 };
 
 static struct attribute *
@@ -267,7 +270,11 @@ static ssize_t power_supply_show_property(struct device *dev,
 	struct power_supply *psy = dev_get_drvdata(dev);
 	struct power_supply_attr *ps_attr = to_ps_attr(attr);
 	enum power_supply_property psp = dev_attr_psp(attr);
-	union power_supply_propval value;
+	union power_supply_propval value = {
+		.pdos = {0}
+	};
+	size_t count;
+	int i;
 
 	if (psp == POWER_SUPPLY_PROP_TYPE) {
 		value.intval = psy->desc->type;
@@ -299,6 +306,15 @@ static ssize_t power_supply_show_property(struct device *dev,
 	case POWER_SUPPLY_PROP_MODEL_NAME ... POWER_SUPPLY_PROP_SERIAL_NUMBER:
 		ret = sprintf(buf, "%s\n", value.strval);
 		break;
+	case POWER_SUPPLY_PROP_SINK_CAP_PDOS:
+	case POWER_SUPPLY_PROP_SOURCE_CAP_PDOS:
+		ret = 0;
+		for (i = 0; i < PDO_MAX_OBJECTS; i++) {
+			count = sprintf(buf, "0x%08x\n", value.pdos[i]);
+			buf += count;
+			ret += count;
+		}
+		break;
 	default:
 		ret = sprintf(buf, "%d\n", value.intval);
 	}
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
index 9ca1f120a211..a53c8fa4c1c9 100644
--- a/include/linux/power_supply.h
+++ b/include/linux/power_supply.h
@@ -17,6 +17,7 @@
 #include <linux/leds.h>
 #include <linux/spinlock.h>
 #include <linux/notifier.h>
+#include <linux/usb/pd.h>
 
 /*
  * All voltages, currents, charges, energies, time and temperatures in uV,
@@ -171,6 +172,9 @@ enum power_supply_property {
 	POWER_SUPPLY_PROP_MODEL_NAME,
 	POWER_SUPPLY_PROP_MANUFACTURER,
 	POWER_SUPPLY_PROP_SERIAL_NUMBER,
+	/* Array properties */
+	POWER_SUPPLY_PROP_SINK_CAP_PDOS,
+	POWER_SUPPLY_PROP_SOURCE_CAP_PDOS,
 };
 
 enum power_supply_type {
@@ -209,6 +213,7 @@ enum power_supply_notifier_events {
 union power_supply_propval {
 	int intval;
 	const char *strval;
+	u32 pdos[PDO_MAX_OBJECTS];
 };
 
 struct device_node;
-- 
2.33.0.153.gba50c8fa24-goog