[PATCH v4 2/2] usb: typec: tcpm: Add support for Battery Status response message

[Amit Sunil Dhamne via B4 Relay <devnull+amitsd.google.com@kernel.org>]

From: Amit Sunil Dhamne <amitsd@google.com>

Add support for responding to a Get_Battery_Status request with a
Battery_Status message. The port partner shall request the status of a
port's battery by providing an index in the Get_Battery_Status AMS. In
case of failure to identify the battery, the port shall reply with an
appropriate message indicating so.

Support for Battery_Status message is required for sinks that contain
battery as specified in USB PD Rev3.1 v1.8
("Applicability of Data Messages" section).

Signed-off-by: Amit Sunil Dhamne <amitsd@google.com>
Reviewed-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 135 +++++++++++++++++++++++++++++++++++++++++-
 include/linux/usb/pd.h        |  29 +++++++++
 2 files changed, 161 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 7ef746a90a17..19daa17917a7 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -232,7 +232,8 @@ enum pd_msg_request {
 	PD_MSG_DATA_SINK_CAP,
 	PD_MSG_DATA_SOURCE_CAP,
 	PD_MSG_DATA_REV,
-	PD_MSG_EXT_SINK_CAP_EXT
+	PD_MSG_EXT_SINK_CAP_EXT,
+	PD_MSG_DATA_BATT_STATUS
 };
 
 enum adev_actions {
@@ -389,6 +390,14 @@ struct pd_timings {
 /* Convert microwatt to watt */
 #define UW_TO_W(pow)					((pow) / 1000000)
 
+/*
+ * As per USB PD Spec Rev 3.18 (Sec. 6.5.13.11), the number of fixed batteries
+ * that a port can be queried is restricted to 4.
+ */
+#define MAX_NUM_FIXED_BATT				4
+
+#define BATTERY_PROPERTY_UNKNOWN			0xffff
+
 /*
  * struct pd_identifier - Contains info about PD identifiers
  * @vid: Vendor ID (assigned by USB-IF)
@@ -683,6 +692,9 @@ struct tcpm_port {
 
 	struct pd_identifier pd_ident;
 	struct sink_caps_ext_data sink_caps_ext;
+	struct power_supply **fixed_batt;
+	u32 fixed_batt_cnt;
+	u32 batt_request_id;
 #ifdef CONFIG_DEBUG_FS
 	struct dentry *dentry;
 	struct mutex logbuffer_lock;	/* log buffer access lock */
@@ -1470,6 +1482,20 @@ static int tcpm_pd_send_sink_caps(struct tcpm_port *port)
 	return tcpm_pd_transmit(port, TCPC_TX_SOP, &msg);
 }
 
+static void tcpm_get_fixed_batt(struct tcpm_port *port)
+{
+	int ret;
+
+	if (!port->self_powered || port->fixed_batt_cnt > 0)
+		return;
+
+	ret = power_supply_get_system_batteries(port->dev, &port->fixed_batt);
+	if (ret < 0)
+		tcpm_log(port, "Failed to get battery array, ret=%d", ret);
+	else
+		port->fixed_batt_cnt = ret;
+}
+
 static int tcpm_pd_send_sink_cap_ext(struct tcpm_port *port)
 {
 	u16 operating_snk_watt = port->operating_snk_mw / 1000;
@@ -1482,6 +1508,8 @@ static int tcpm_pd_send_sink_cap_ext(struct tcpm_port *port)
 	if (!port->self_powered)
 		data->spr_op_pdp = operating_snk_watt;
 
+	tcpm_get_fixed_batt(port);
+
 	/*
 	 * SPR Sink Minimum PDP indicates the minimum power required to operate
 	 * a sink device in its lowest level of functionality without requiring
@@ -1507,6 +1535,7 @@ static int tcpm_pd_send_sink_cap_ext(struct tcpm_port *port)
 	skedb.load_step = data->load_step;
 	skedb.load_char = cpu_to_le16(data->load_char);
 	skedb.compliance = data->compliance;
+	skedb.batt_info = min(port->fixed_batt_cnt, MAX_NUM_FIXED_BATT);
 	skedb.modes = data->modes;
 	skedb.spr_min_pdp = data->spr_min_pdp;
 	skedb.spr_op_pdp = data->spr_op_pdp;
@@ -1525,6 +1554,88 @@ static int tcpm_pd_send_sink_cap_ext(struct tcpm_port *port)
 					   port->message_id,
 					   data_obj_cnt,
 					   1 /* Denotes if ext header */));
+
+	return tcpm_pd_transmit(port, TCPC_TX_SOP, &msg);
+}
+
+static int tcpm_pd_send_batt_status(struct tcpm_port *port)
+{
+	u16 present_charge = BATTERY_PROPERTY_UNKNOWN;
+	bool batt_present = false, invalid_ref = true;
+	u32 batt_id = port->batt_request_id;
+	union power_supply_propval val;
+	struct power_supply *batt;
+	u8 charging_status = 0;
+	struct pd_message msg;
+	int ret, charge_now;
+	u64 energy_now;
+	u32 bsdo;
+
+	tcpm_get_fixed_batt(port);
+	memset(&msg, 0, sizeof(msg));
+
+	if (batt_id >= port->fixed_batt_cnt || batt_id >= MAX_NUM_FIXED_BATT)
+		goto send_status;
+
+	invalid_ref = false;
+	batt = port->fixed_batt[batt_id];
+	ret = power_supply_get_property(batt, POWER_SUPPLY_PROP_PRESENT, &val);
+	if (ret)
+		tcpm_log(port,
+			 "Failed to fetch power_supply_prop_present ret %d",
+			 ret);
+	else
+		batt_present = val.intval > 0;
+
+	ret = power_supply_get_property(batt, POWER_SUPPLY_PROP_CHARGE_NOW,
+					&val);
+	if (!ret) {
+		charge_now = val.intval;
+
+		ret = power_supply_get_property(batt,
+						POWER_SUPPLY_PROP_VOLTAGE_AVG,
+						&val);
+		if (!ret) {
+			energy_now = ((u64)charge_now * val.intval) / 1000000;
+
+			/*
+			 * Battery Present Charge is reported in
+			 * increments of 0.1WH.
+			 */
+			present_charge = (u16)UW_TO_W(energy_now * 10);
+		}
+	}
+
+	ret = power_supply_get_property(batt, POWER_SUPPLY_PROP_STATUS, &val);
+	if (!ret) {
+		switch (val.intval) {
+		case POWER_SUPPLY_STATUS_CHARGING:
+			charging_status = BSDO_BATTERY_INFO_CHARGING;
+			break;
+		case POWER_SUPPLY_STATUS_DISCHARGING:
+			charging_status = BSDO_BATTERY_INFO_DISCHARGING;
+			break;
+		case POWER_SUPPLY_STATUS_NOT_CHARGING:
+		case POWER_SUPPLY_STATUS_FULL:
+			charging_status = BSDO_BATTERY_INFO_IDLE;
+			break;
+		default:
+			charging_status = BSDO_BATTERY_INFO_RSVD;
+			break;
+		}
+	}
+
+send_status:
+
+	bsdo = BSDO(present_charge, charging_status, batt_present, invalid_ref);
+	msg.payload[0] = cpu_to_le32(bsdo);
+	msg.header = PD_HEADER_LE(PD_DATA_BATT_STATUS,
+				  port->pwr_role,
+				  port->data_role,
+				  port->negotiated_rev,
+				  port->message_id,
+				  1);
+
 	return tcpm_pd_transmit(port, TCPC_TX_SOP, &msg);
 }
 
@@ -3886,6 +3997,7 @@ static void tcpm_pd_ext_msg_request(struct tcpm_port *port,
 {
 	enum pd_ext_msg_type type = pd_header_type_le(msg->header);
 	unsigned int data_size = pd_ext_header_data_size_le(msg->ext_msg.header);
+	const struct pd_chunked_ext_message_data *ext_msg = &msg->ext_msg;
 
 	/* stopping VDM state machine if interrupted by other Messages */
 	if (tcpm_vdm_ams(port)) {
@@ -3894,7 +4006,7 @@ static void tcpm_pd_ext_msg_request(struct tcpm_port *port,
 		mod_vdm_delayed_work(port, 0);
 	}
 
-	if (!(le16_to_cpu(msg->ext_msg.header) & PD_EXT_HDR_CHUNKED)) {
+	if (!(le16_to_cpu(ext_msg->header) & PD_EXT_HDR_CHUNKED)) {
 		tcpm_pd_handle_msg(port, PD_MSG_CTRL_NOT_SUPP, NONE_AMS);
 		tcpm_log(port, "Unchunked extended messages unsupported");
 		return;
@@ -3919,9 +4031,17 @@ static void tcpm_pd_ext_msg_request(struct tcpm_port *port,
 					     NONE_AMS, 0);
 		}
 		break;
+	case PD_EXT_GET_BATT_STATUS:
+		if (data_size >= 1) {
+			port->batt_request_id = ext_msg->data[0];
+			tcpm_pd_handle_msg(port, PD_MSG_DATA_BATT_STATUS,
+					   GETTING_BATTERY_STATUS);
+		} else {
+			tcpm_set_state(port, SOFT_RESET_SEND, 0);
+		}
+		break;
 	case PD_EXT_SOURCE_CAP_EXT:
 	case PD_EXT_GET_BATT_CAP:
-	case PD_EXT_GET_BATT_STATUS:
 	case PD_EXT_BATT_CAP:
 	case PD_EXT_GET_MANUFACTURER_INFO:
 	case PD_EXT_MANUFACTURER_INFO:
@@ -4132,6 +4252,14 @@ static bool tcpm_send_queued_message(struct tcpm_port *port)
 					 ret);
 			tcpm_ams_finish(port);
 			break;
+		case PD_MSG_DATA_BATT_STATUS:
+			ret = tcpm_pd_send_batt_status(port);
+			if (ret)
+				tcpm_log(port,
+					 "Failed to send battery status ret=%d",
+					 ret);
+			tcpm_ams_finish(port);
+			break;
 		default:
 			break;
 		}
@@ -8633,6 +8761,7 @@ void tcpm_unregister_port(struct tcpm_port *port)
 	hrtimer_cancel(&port->vdm_state_machine_timer);
 	hrtimer_cancel(&port->state_machine_timer);
 
+	power_supply_put_system_batteries(port->fixed_batt, port->fixed_batt_cnt);
 	tcpm_reset_port(port);
 
 	tcpm_port_unregister_pd(port);
diff --git a/include/linux/usb/pd.h b/include/linux/usb/pd.h
index 337a5485af7c..afb9c2c65588 100644
--- a/include/linux/usb/pd.h
+++ b/include/linux/usb/pd.h
@@ -724,4 +724,33 @@ void usb_power_delivery_unlink_device(struct usb_power_delivery *pd, struct devi
 
 #endif /* CONFIG_TYPEC */
 
+/* Battery Status Data Object */
+#define BSDO_PRESENT_CAPACITY				GENMASK(31, 16)
+#define BSDO_CHG_STATUS					GENMASK(11, 10)
+#define BSDO_BATTERY_PRESENT				BIT(9)
+#define BSDO_INVALID_BATTERY_REFERENCE			BIT(8)
+
+/*
+ * Battery Charge Status: Battery Charging Status Values as defined in
+ * "USB PD Spec Rev3.1 Ver1.8", "Table 6-46 Battery Status Data Object (BSDO)".
+ */
+#define BSDO_BATTERY_INFO_CHARGING			0x0
+#define BSDO_BATTERY_INFO_DISCHARGING			0x1
+#define BSDO_BATTERY_INFO_IDLE				0x2
+#define BSDO_BATTERY_INFO_RSVD				0x3
+
+/**
+ * BSDO() - Pack data into Battery Status Data Object format.
+ * @batt_charge: Battery's present state of charge in 0.1WH increment.
+ * @chg_status: Battery charge status.
+ * @batt_present: Indicates that battery is present/attached when set else absent when unset.
+ * @invalid_ref: Indicates that an invalid battery reference was made in the Get_Battery_Status
+ *		 request.
+ */
+#define BSDO(batt_charge, chg_status, batt_present, invalid_ref)	\
+	((FIELD_PREP(BSDO_PRESENT_CAPACITY, batt_charge)) |		\
+	 (FIELD_PREP(BSDO_CHG_STATUS, chg_status)) |			\
+	 ((batt_present) ? BSDO_BATTERY_PRESENT : 0) |			\
+	 ((invalid_ref) ? BSDO_INVALID_BATTERY_REFERENCE : 0))
+
 #endif /* __LINUX_USB_PD_H */

-- 
2.55.0.rc0.799.gd6f94ed593-goog