From fd8d03bd8b1dbba81f70a892541813faab097285 Mon Sep 17 00:00:00 2001
From: Kamil Piszczek <Kamil.Piszczek@nordicsemi.no>
Date: Mon, 6 Jul 2020 10:01:04 -0400
Subject: [PATCH] bluetooth: conn: add api for getting tx power level

Added a new Bluetooth API that can be used to read the current and
maximum transmit power level of the radio. The reading operation is
performed over HCI.

Signed-off-by: Kamil Piszczek <Kamil.Piszczek@nordicsemi.no>
---
 include/bluetooth/conn.h     | 24 ++++++++++++++++
 subsys/bluetooth/host/conn.c | 54 ++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+)

diff --git a/include/bluetooth/conn.h b/include/bluetooth/conn.h
index df2e5653a5f..1a1c2e2fed9 100644
--- a/include/bluetooth/conn.h
+++ b/include/bluetooth/conn.h
@@ -370,6 +370,19 @@ struct bt_conn_remote_info {
 	};
 };
 
+/** LE Transmit Power Level Structure */
+struct bt_conn_le_tx_power {
+
+	/** Input: 1M, 2M, Coded S2 or Coded S8 */
+	uint8_t phy;
+
+	/** Output: current transmit power level */
+	int8_t current_level;
+
+	/** Output: maximum transmit power level */
+	int8_t max_level;
+};
+
 /** @brief Get connection info
  *
  *  @param conn Connection object.
@@ -397,6 +410,17 @@ int bt_conn_get_info(const struct bt_conn *conn, struct bt_conn_info *info);
 int bt_conn_get_remote_info(struct bt_conn *conn,
 			    struct bt_conn_remote_info *remote_info);
 
+/** @brief Get connection transmit power level.
+ *
+ *  @param conn           Connection object.
+ *  @param tx_power_level Transmit power level descriptor.
+ *
+ *  @return Zero on success or (negative) error code on failure.
+ *  @return -ENOBUFS HCI command buffer is not available.
+ */
+int bt_conn_le_get_tx_power_level(struct bt_conn *conn,
+				  struct bt_conn_le_tx_power *tx_power_level);
+
 /** @brief Update the connection parameters.
  *
  *  If the local device is in the peripheral role then updating the connection
diff --git a/subsys/bluetooth/host/conn.c b/subsys/bluetooth/host/conn.c
index 034daa82730..0d2b4d6262c 100644
--- a/subsys/bluetooth/host/conn.c
+++ b/subsys/bluetooth/host/conn.c
@@ -1974,6 +1974,60 @@ int bt_conn_get_remote_info(struct bt_conn *conn,
 	}
 }
 
+/* Read Transmit Power Level HCI command */
+static int bt_conn_get_tx_power_level(struct bt_conn *conn, uint8_t type,
+				      int8_t *tx_power_level)
+{
+	int err;
+	struct bt_hci_rp_read_tx_power_level *rp;
+	struct net_buf *rsp;
+	struct bt_hci_cp_read_tx_power_level *cp;
+	struct net_buf *buf;
+
+	buf = bt_hci_cmd_create(BT_HCI_OP_READ_TX_POWER_LEVEL, sizeof(*cp));
+	if (!buf) {
+		return -ENOBUFS;
+	}
+
+	cp = net_buf_add(buf, sizeof(*cp));
+	cp->type = type;
+	cp->handle = sys_cpu_to_le16(conn->handle);
+
+	err = bt_hci_cmd_send_sync(BT_HCI_OP_READ_TX_POWER_LEVEL, buf, &rsp);
+	if (err) {
+		return err;
+	}
+
+	rp = (void *) rsp->data;
+	*tx_power_level = rp->tx_power_level;
+	net_buf_unref(rsp);
+
+	return 0;
+}
+
+int bt_conn_le_get_tx_power_level(struct bt_conn *conn,
+				  struct bt_conn_le_tx_power *tx_power_level)
+{
+	int err;
+
+	if (tx_power_level->phy != 0) {
+		/* Extend the implementation when LE Enhanced Read Transmit
+		 * Power Level HCI command is available for use.
+		 */
+		return -ENOTSUP;
+	}
+
+	err = bt_conn_get_tx_power_level(conn, BT_TX_POWER_LEVEL_CURRENT,
+					 &tx_power_level->current_level);
+	if (err) {
+		return err;
+	}
+
+	err = bt_conn_get_tx_power_level(conn, BT_TX_POWER_LEVEL_MAX,
+					 &tx_power_level->max_level);
+	return err;
+}
+
 static int conn_disconnect(struct bt_conn *conn, uint8_t reason)
 {
 	int err;