[PATCH v10 7/7] Bluetooth: hci_qca: Add support for Qualcomm Bluetooth chip wcn3990

[Balakrishna Godavarthi <bgodavar@codeaurora.org>]

Add support to set voltage/current of various regulators
to power up/down Bluetooth chip wcn3990.

Signed-off-by: Balakrishna Godavarthi <bgodavar@codeaurora.org>
---
changes in v10:
    * added support to read regulator currents from dts.
    * added support to try to connect with chip if it fails to respond to initial commands
    * updated review comments.

changes in v9:
    * moved flow control to vendor and set_baudarte functions.
    * removed parent regs.

changes in v8:
    * closing qca buffer, if qca_power_setup fails
    * chnaged ibs start timer function call location.
    * updated review comments.
  
changes in v7:
    * addressed review comments.

changes in v6:
    * Hooked up qca_power to qca_serdev.
    * renamed all the naming inconsistency functions with qca_*
    * leveraged common code of ROME for wcn3990.
    * created wrapper functions for re-usable blocks.
    * updated function of _*regulator_enable and _*regualtor_disable.  
    * removed redundant comments and functions.
    * addressed review comments.

Changes in v5:
    * updated regulator vddpa min_uV to 1304000.
      * addressed review comments.
 
Changes in v4:
    * Segregated the changes of btqca from hci_qca
    * rebased all changes on top of bluetooth-next.
    * addressed review comments.

---
 drivers/bluetooth/btqca.h   |   4 +
 drivers/bluetooth/hci_qca.c | 481 ++++++++++++++++++++++++++++++++----
 2 files changed, 439 insertions(+), 46 deletions(-)

diff --git a/drivers/bluetooth/btqca.h b/drivers/bluetooth/btqca.h
index a9c2779f3e07..9e2bbcf5c002 100644
--- a/drivers/bluetooth/btqca.h
+++ b/drivers/bluetooth/btqca.h
@@ -37,6 +37,10 @@
 #define EDL_TAG_ID_HCI			(17)
 #define EDL_TAG_ID_DEEP_SLEEP		(27)
 
+#define QCA_WCN3990_POWERON_PULSE	0xFC
+#define QCA_WCN3990_POWEROFF_PULSE	0xC0
+#define QCA_WCN3990_FORCE_BOOT_PULSE	0xC0
+
 enum qca_bardrate {
 	QCA_BAUDRATE_115200 	= 0,
 	QCA_BAUDRATE_57600,
diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index a6e7d38ef931..7ed35eb3f480 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -5,7 +5,7 @@
  *  protocol extension to H4.
  *
  *  Copyright (C) 2007 Texas Instruments, Inc.
- *  Copyright (c) 2010, 2012 The Linux Foundation. All rights reserved.
+ *  Copyright (c) 2010, 2012, 2018 The Linux Foundation. All rights reserved.
  *
  *  Acknowledgements:
  *  This file is based on hci_ll.c, which was...
@@ -31,9 +31,14 @@
 #include <linux/kernel.h>
 #include <linux/clk.h>
 #include <linux/debugfs.h>
+#include <linux/delay.h>
+#include <linux/device.h>
 #include <linux/gpio/consumer.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
 #include <linux/serdev.h>
 
 #include <net/bluetooth/bluetooth.h>
@@ -124,12 +129,46 @@ enum qca_speed_type {
 	QCA_OPER_SPEED
 };
 
+/*
+ * Voltage regulator information required for configuring the
+ * QCA Bluetooth chipset
+ */
+struct qca_vreg {
+	const char *name;
+	unsigned int min_uV;
+	unsigned int max_uV;
+	unsigned int load_uA;
+};
+
+struct qca_vreg_data {
+	enum qca_btsoc_type soc_type;
+	struct qca_vreg *vregs;
+	size_t num_vregs;
+};
+
+/*
+ * Platform data for the QCA Bluetooth power driver.
+ */
+struct qca_power {
+	struct device *dev;
+	struct qca_vreg_data *vreg_data;
+	struct regulator_bulk_data *vreg_bulk;
+	bool vregs_on;
+};
+
 struct qca_serdev {
 	struct hci_uart	 serdev_hu;
 	struct gpio_desc *bt_en;
 	struct clk	 *susclk;
+	enum qca_btsoc_type btsoc_type;
+	struct qca_power *bt_power;
+	u32 init_speed;
+	u32 oper_speed;
 };
 
+static int qca_power_setup(struct hci_uart *hu, bool on);
+static int qca_power_shutdown(struct hci_dev *hdev);
+
 static void __serial_clock_on(struct tty_struct *tty)
 {
 	/* TODO: Some chipset requires to enable UART clock on client
@@ -407,6 +446,7 @@ static int qca_open(struct hci_uart *hu)
 {
 	struct qca_serdev *qcadev;
 	struct qca_data *qca;
+	int ret;
 
 	BT_DBG("hu %p qca_open", hu);
 
@@ -458,19 +498,32 @@ static int qca_open(struct hci_uart *hu)
 
 	hu->priv = qca;
 
-	timer_setup(&qca->wake_retrans_timer, hci_ibs_wake_retrans_timeout, 0);
-	qca->wake_retrans = IBS_WAKE_RETRANS_TIMEOUT_MS;
-
-	timer_setup(&qca->tx_idle_timer, hci_ibs_tx_idle_timeout, 0);
-	qca->tx_idle_delay = IBS_TX_IDLE_TIMEOUT_MS;
-
 	if (hu->serdev) {
 		serdev_device_open(hu->serdev);
 
 		qcadev = serdev_device_get_drvdata(hu->serdev);
-		gpiod_set_value_cansleep(qcadev->bt_en, 1);
+		if (qcadev->btsoc_type != QCA_WCN3990) {
+			gpiod_set_value_cansleep(qcadev->bt_en, 1);
+		} else {
+			hu->init_speed = qcadev->init_speed;
+			hu->oper_speed = qcadev->oper_speed;
+			ret = qca_power_setup(hu, true);
+			if (ret) {
+				destroy_workqueue(qca->workqueue);
+				kfree_skb(qca->rx_skb);
+				hu->priv = NULL;
+				kfree(qca);
+				return ret;
+			}
+		}
 	}
 
+	timer_setup(&qca->wake_retrans_timer, hci_ibs_wake_retrans_timeout, 0);
+	qca->wake_retrans = IBS_WAKE_RETRANS_TIMEOUT_MS;
+
+	timer_setup(&qca->tx_idle_timer, hci_ibs_tx_idle_timeout, 0);
+	qca->tx_idle_delay = IBS_TX_IDLE_TIMEOUT_MS;
+
 	BT_DBG("HCI_UART_QCA open, tx_idle_delay=%u, wake_retrans=%u",
 	       qca->tx_idle_delay, qca->wake_retrans);
 
@@ -554,10 +607,13 @@ static int qca_close(struct hci_uart *hu)
 	qca->hu = NULL;
 
 	if (hu->serdev) {
-		serdev_device_close(hu->serdev);
-
 		qcadev = serdev_device_get_drvdata(hu->serdev);
-		gpiod_set_value_cansleep(qcadev->bt_en, 0);
+		if (qcadev->btsoc_type == QCA_WCN3990)
+			qca_power_shutdown(hu->hdev);
+		else
+			gpiod_set_value_cansleep(qcadev->bt_en, 0);
+
+		serdev_device_close(hu->serdev);
 	}
 
 	kfree_skb(qca->rx_skb);
@@ -891,6 +947,7 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
 	struct hci_uart *hu = hci_get_drvdata(hdev);
 	struct qca_data *qca = hu->priv;
 	struct sk_buff *skb;
+	struct qca_serdev *qcadev;
 	u8 cmd[] = { 0x01, 0x48, 0xFC, 0x01, 0x00 };
 
 	if (baudrate > QCA_BAUDRATE_3200000)
@@ -904,6 +961,13 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
 		return -ENOMEM;
 	}
 
+	/* Disabling hardware flow control is mandatory while
+	 * sending change baudrate request to wcn3990 SoC.
+	 */
+	qcadev = serdev_device_get_drvdata(hu->serdev);
+	if (qcadev->btsoc_type == QCA_WCN3990)
+		hci_uart_set_flow_control(hu, true);
+
 	/* Assign commands to change baudrate and packet type. */
 	skb_put_data(skb, cmd, sizeof(cmd));
 	hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
@@ -919,6 +983,9 @@ static int qca_set_baudrate(struct hci_dev *hdev, uint8_t baudrate)
 	schedule_timeout(msecs_to_jiffies(BAUDRATE_SETTLE_TIMEOUT_MS));
 	set_current_state(TASK_RUNNING);
 
+	if (qcadev->btsoc_type == QCA_WCN3990)
+		hci_uart_set_flow_control(hu, false);
+
 	return 0;
 }
 
@@ -930,6 +997,43 @@ static inline void host_set_baudrate(struct hci_uart *hu, unsigned int speed)
 		hci_uart_set_baudrate(hu, speed);
 }
 
+static int qca_send_vendor_pulse(struct hci_dev *hdev, u8 cmd)
+{
+	struct hci_uart *hu = hci_get_drvdata(hdev);
+	struct qca_data *qca = hu->priv;
+	struct sk_buff *skb;
+
+	/* These vendor pulses are single byte command which are sent
+	 * at required baudrate to WCN3990. on WCN3990, we have an external
+	 * circuit at Tx pin which decodes the pulse sent at specific baudrate.
+	 * For example, as WCN3990 supports RF COEX frequency for both Wi-Fi/BT
+	 * and also, we use the same power inputs to turn ON and OFF for
+	 * Wi-Fi/BT. Powering up the power sources will not enable BT, until
+	 * we send a POWER ON pulse at 115200. This algorithm will help to
+	 * save power. Disabling hardware flow control is mandatory while
+	 * sending vendor pulses to SoC.
+	 */
+	bt_dev_dbg(hdev, "sending vendor pulse %02x to SoC", cmd);
+
+	skb = bt_skb_alloc(sizeof(cmd), GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
+	hci_uart_set_flow_control(hu, true);
+
+	skb_put_u8(skb, cmd);
+	hci_skb_pkt_type(skb) = HCI_COMMAND_PKT;
+
+	skb_queue_tail(&qca->txq, skb);
+	hci_uart_tx_wakeup(hu);
+
+	/* Wait for 100 uS for SoC to settle down */
+	usleep_range(100, 200);
+	hci_uart_set_flow_control(hu, false);
+
+	return 0;
+}
+
 static unsigned int qca_get_speed(struct hci_uart *hu,
 				  enum qca_speed_type speed_type)
 {
@@ -952,9 +1056,18 @@ static unsigned int qca_get_speed(struct hci_uart *hu,
 
 static int qca_check_speeds(struct hci_uart *hu)
 {
-	if (!qca_get_speed(hu, QCA_INIT_SPEED) ||
-	    !qca_get_speed(hu, QCA_OPER_SPEED))
-		return -EINVAL;
+	struct qca_serdev *qcadev;
+
+	qcadev = serdev_device_get_drvdata(hu->serdev);
+	if (qcadev->btsoc_type == QCA_WCN3990) {
+		if (!qca_get_speed(hu, QCA_INIT_SPEED) &&
+		    !qca_get_speed(hu, QCA_OPER_SPEED))
+			return -EINVAL;
+	} else {
+		if (!qca_get_speed(hu, QCA_INIT_SPEED) ||
+		    !qca_get_speed(hu, QCA_OPER_SPEED))
+			return -EINVAL;
+	}
 
 	return 0;
 }
@@ -985,15 +1098,78 @@ static int qca_set_speed(struct hci_uart *hu, enum qca_speed_type speed_type)
 	return 0;
 }
 
+static int qca_wcn3990_init(struct hci_uart *hu, u32 *soc_ver)
+{
+	struct hci_dev *hdev = hu->hdev;
+	int i, ret = 1;
+
+	/* WCN3990 is a discrete Bluetooth chip connected to APPS processor.
+	 * sometimes we will face communication synchronization issues,
+	 * like reading version command timeouts. In which HCI_SETUP fails,
+	 * to overcome these issues, we try to communicate by performing an
+	 * COLD power OFF and ON.
+	 */
+	for (i = 1; i <= 10 && ret; i++) {
+		/* This helper will turn ON chip if it is powered off.
+		 * if the chip is already powered ON, function call will
+		 * return zero.
+		 */
+		ret = qca_power_setup(hu, true);
+		if (ret)
+			goto regs_off;
+
+		/* Forcefully enable wcn3990 to enter in to boot mode. */
+		host_set_baudrate(hu, 2400);
+		ret = qca_send_vendor_pulse(hdev, QCA_WCN3990_FORCE_BOOT_PULSE);
+		if (ret)
+			goto regs_off;
+
+		qca_set_speed(hu, QCA_INIT_SPEED);
+		ret = qca_send_vendor_pulse(hdev, QCA_WCN3990_POWERON_PULSE);
+		if (ret)
+			goto regs_off;
+
+		/* Wait for 100 ms for SoC to boot */
+		msleep(100);
+
+		/* Now the device is in ready state to communicate with host.
+		 * To sync HOST with device we need to reopen port.
+		 * Without this, we will have RTS and CTS synchronization
+		 * issues.
+		 */
+		serdev_device_close(hu->serdev);
+		ret = serdev_device_open(hu->serdev);
+		if (ret) {
+			bt_dev_err(hu->hdev, "failed to open port");
+			break;
+		}
+
+		hci_uart_set_flow_control(hu, false);
+		ret = qca_read_soc_version(hdev, soc_ver);
+		if (ret < 0 || soc_ver == 0)
+			bt_dev_err(hdev, "Failed to get version:%d", ret);
+
+		if (!ret)
+			break;
+
+regs_off:
+		bt_dev_err(hdev, "retrying to establish communication: %d", i);
+		qca_power_shutdown(hdev);
+	}
+
+	return ret;
+}
+
 static int qca_setup(struct hci_uart *hu)
 {
 	struct hci_dev *hdev = hu->hdev;
 	struct qca_data *qca = hu->priv;
 	unsigned int speed, qca_baudrate = QCA_BAUDRATE_115200;
+	struct qca_serdev *qcadev;
 	int ret;
 	int soc_ver = 0;
 
-	bt_dev_info(hdev, "ROME setup");
+	qcadev = serdev_device_get_drvdata(hu->serdev);
 
 	ret = qca_check_speeds(hu);
 	if (ret)
@@ -1002,8 +1178,15 @@ static int qca_setup(struct hci_uart *hu)
 	/* Patch downloading has to be done without IBS mode */
 	clear_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
 
-	/* Setup initial baudrate */
-	qca_set_speed(hu, QCA_INIT_SPEED);
+	if (qcadev->btsoc_type == QCA_WCN3990) {
+		bt_dev_info(hdev, "setting up wcn3990");
+		ret = qca_wcn3990_init(hu, &soc_ver);
+		if (ret)
+			return ret;
+	} else {
+		bt_dev_info(hdev, "ROME setup");
+		qca_set_speed(hu, QCA_INIT_SPEED);
+	}
 
 	/* Setup user speed if needed */
 	speed = qca_get_speed(hu, QCA_OPER_SPEED);
@@ -1015,15 +1198,16 @@ static int qca_setup(struct hci_uart *hu)
 		qca_baudrate = qca_get_baudrate_value(speed);
 	}
 
-	/* Get QCA version information */
-	ret = qca_read_soc_version(hdev, &soc_ver);
-	if (ret)
-		return ret;
+	if (qcadev->btsoc_type != QCA_WCN3990) {
+		/* Get QCA version information */
+		ret = qca_read_soc_version(hdev, &soc_ver);
+		if (ret)
+			return ret;
+	}
 
 	bt_dev_info(hdev, "QCA controller version 0x%08x", soc_ver);
-
 	/* Setup patch / NVM configurations */
-	ret = qca_uart_setup(hdev, qca_baudrate, QCA_ROME, soc_ver);
+	ret = qca_uart_setup(hdev, qca_baudrate, qcadev->btsoc_type, soc_ver);
 	if (!ret) {
 		set_bit(STATE_IN_BAND_SLEEP_ENABLED, &qca->flags);
 		qca_debugfs_init(hdev);
@@ -1059,9 +1243,174 @@ static struct hci_uart_proto qca_proto = {
 	.dequeue	= qca_dequeue,
 };
 
+static const struct qca_vreg_data qca_soc_data = {
+	.soc_type = QCA_WCN3990,
+	.vregs = (struct qca_vreg []) {
+		{ "vddio",   1800000, 1800000,  15000  },
+		{ "vddxo",   1800000, 1800000,  80000  },
+		{ "vddrf",   1304000, 1304000,  300000 },
+		{ "vddch0",  3000000, 3312000,  450000 },
+	},
+	.num_vregs = 4,
+};
+
+static int qca_power_shutdown(struct hci_dev *hdev)
+{
+	struct hci_uart *hu = hci_get_drvdata(hdev);
+
+	host_set_baudrate(hu, 2400);
+	qca_send_vendor_pulse(hdev, QCA_WCN3990_POWEROFF_PULSE);
+	return qca_power_setup(hu, false);
+}
+
+static int qca_enable_regulator(struct qca_vreg vregs,
+				struct regulator *regulator)
+{
+	int ret;
+
+	ret = regulator_set_voltage(regulator, vregs.min_uV,
+				    vregs.max_uV);
+	if (ret)
+		return ret;
+
+	if (vregs.load_uA)
+		ret = regulator_set_load(regulator,
+					 vregs.load_uA);
+
+	if (ret)
+		return ret;
+
+	return regulator_enable(regulator);
+
+}
+
+static void qca_disable_regulator(struct qca_vreg vregs,
+				  struct regulator *regulator)
+{
+	regulator_disable(regulator);
+	regulator_set_voltage(regulator, 0, vregs.max_uV);
+	if (vregs.load_uA)
+		regulator_set_load(regulator, 0);
+
+}
+
+static int qca_power_setup(struct hci_uart *hu, bool on)
+{
+	struct qca_vreg *vregs;
+	struct regulator_bulk_data *vreg_bulk;
+	struct qca_serdev *qcadev;
+	int i, num_vregs, ret = 0;
+
+	qcadev = serdev_device_get_drvdata(hu->serdev);
+	if (!qcadev || !qcadev->bt_power || !qcadev->bt_power->vreg_data ||
+	    !qcadev->bt_power->vreg_bulk)
+		return -EINVAL;
+
+	vregs = qcadev->bt_power->vreg_data->vregs;
+	vreg_bulk = qcadev->bt_power->vreg_bulk;
+	num_vregs = qcadev->bt_power->vreg_data->num_vregs;
+	BT_DBG("on: %d", on);
+	if (on  && !qcadev->bt_power->vregs_on) {
+		for (i = 0; i < num_vregs; i++) {
+			ret = qca_enable_regulator(vregs[i],
+						   vreg_bulk[i].consumer);
+			if (ret)
+				break;
+		}
+
+		if (ret) {
+			BT_ERR("failed to enable regulator:%s", vregs[i].name);
+			/* turn off regulators which are enabled */
+			for (i = i - 1; i >= 0; i--)
+				qca_disable_regulator(vregs[i],
+						      vreg_bulk[i].consumer);
+		} else {
+			qcadev->bt_power->vregs_on = true;
+		}
+	} else if (!on && qcadev->bt_power->vregs_on) {
+		/* turn off regulator in reverse order */
+		i = qcadev->bt_power->vreg_data->num_vregs - 1;
+		for ( ; i >= 0; i--)
+			qca_disable_regulator(vregs[i], vreg_bulk[i].consumer);
+
+		qcadev->bt_power->vregs_on = false;
+	}
+
+	return ret;
+}
+
+static void qca_regulator_get_current(struct device *dev,
+				      struct qca_vreg *vregs)
+{
+	char prop_name[32]; /* 32 is max size of property name */
+
+	/* We have different platforms where the load value is controlled
+	 * via PMIC controllers. In such cases load required to power ON
+	 * Bluetooth chips are defined in the PMIC. We have option to set
+	 * operation mode like high or low power modes.
+	 * We do have some platforms where driver need to enable the load for
+	 * WCN3990. Based on the current property value defined for the
+	 * regulators, driver will decide the regulator output load.
+	 * If the current property for the regulator is defined in the dts
+	 * we will read from dts tree, else from the default load values.
+	 */
+	snprintf(prop_name, 32, "%s-current", vregs->name);
+	BT_DBG("Looking up %s from device tree\n", prop_name);
+
+	if (device_property_read_bool(dev, prop_name))
+		device_property_read_u32(dev, prop_name, &vregs->load_uA);
+
+	BT_DBG("current %duA selected for regulator %s", vregs->load_uA,
+		vregs->name);
+}
+
+static int qca_init_regulators(struct qca_power *qca,
+				const struct qca_vreg_data *data)
+{
+	int i, num_vregs;
+	int load_uA;
+
+	num_vregs = data->num_vregs;
+	qca->vreg_bulk = devm_kzalloc(qca->dev, num_vregs *
+				      sizeof(struct regulator_bulk_data),
+				      GFP_KERNEL);
+	if (!qca->vreg_bulk)
+		return -ENOMEM;
+
+	qca->vreg_data = devm_kzalloc(qca->dev, sizeof(struct qca_vreg_data),
+				      GFP_KERNEL);
+	if (!qca->vreg_data)
+		return -ENOMEM;
+
+	qca->vreg_data->num_vregs = data->num_vregs;
+	qca->vreg_data->soc_type = data->soc_type;
+
+	qca->vreg_data->vregs = devm_kzalloc(qca->dev, num_vregs *
+				      sizeof(struct qca_vreg_data),
+				      GFP_KERNEL);
+
+	if (!qca->vreg_data->vregs)
+		return -ENOMEM;
+
+	for (i = 0; i < num_vregs; i++) {
+		/* copy regulator name, min voltage, max voltage */
+		qca->vreg_data->vregs[i].name = data->vregs[i].name;
+		qca->vreg_data->vregs[i].min_uV = data->vregs[i].min_uV;
+		qca->vreg_data->vregs[i].max_uV = data->vregs[i].max_uV;
+		load_uA = data->vregs[i].load_uA;
+		qca->vreg_data->vregs[i].load_uA = load_uA;
+		qca_regulator_get_current(qca->dev, &qca->vreg_data->vregs[i]);
+
+		qca->vreg_bulk[i].supply = qca->vreg_data->vregs[i].name;
+	}
+
+	return devm_regulator_bulk_get(qca->dev, num_vregs, qca->vreg_bulk);
+}
+
 static int qca_serdev_probe(struct serdev_device *serdev)
 {
 	struct qca_serdev *qcadev;
+	const struct qca_vreg_data *data;
 	int err;
 
 	qcadev = devm_kzalloc(&serdev->dev, sizeof(*qcadev), GFP_KERNEL);
@@ -1069,47 +1418,87 @@ static int qca_serdev_probe(struct serdev_device *serdev)
 		return -ENOMEM;
 
 	qcadev->serdev_hu.serdev = serdev;
+	data = of_device_get_match_data(&serdev->dev);
 	serdev_device_set_drvdata(serdev, qcadev);
+	if (data && data->soc_type == QCA_WCN3990) {
+		qcadev->btsoc_type = QCA_WCN3990;
+		qcadev->bt_power = devm_kzalloc(&serdev->dev,
+						sizeof(struct qca_power),
+						GFP_KERNEL);
+		if (!qcadev->bt_power)
+			return -ENOMEM;
+
+		qcadev->bt_power->dev = &serdev->dev;
+		err = qca_init_regulators(qcadev->bt_power, data);
+		if (err) {
+			BT_ERR("Failed to init regulators:%d", err);
+			goto out;
+		}
 
-	qcadev->bt_en = devm_gpiod_get(&serdev->dev, "enable",
-				       GPIOD_OUT_LOW);
-	if (IS_ERR(qcadev->bt_en)) {
-		dev_err(&serdev->dev, "failed to acquire enable gpio\n");
-		return PTR_ERR(qcadev->bt_en);
-	}
+		qcadev->bt_power->vregs_on = false;
 
-	qcadev->susclk = devm_clk_get(&serdev->dev, NULL);
-	if (IS_ERR(qcadev->susclk)) {
-		dev_err(&serdev->dev, "failed to acquire clk\n");
-		return PTR_ERR(qcadev->susclk);
-	}
+		/* Read max speed supported by wcn3990 from dts
+		 * tree. if max-speed property is not enabled in
+		 * dts, QCA driver will use default operating speed
+		 * from proto structure.
+		 */
+		device_property_read_u32(&serdev->dev, "max-speed",
+					 &qcadev->oper_speed);
+		if (!qcadev->oper_speed)
+			BT_INFO("UART will pick default operating speed");
+
+		err = hci_uart_register_device(&qcadev->serdev_hu, &qca_proto);
+		if (err) {
+			BT_ERR("wcn3990 serdev registration failed");
+			goto out;
+		}
+	} else {
+		qcadev->btsoc_type = QCA_ROME;
+		qcadev->bt_en = devm_gpiod_get(&serdev->dev, "enable",
+					       GPIOD_OUT_LOW);
+		if (IS_ERR(qcadev->bt_en)) {
+			dev_err(&serdev->dev, "failed to acquire enable gpio\n");
+			return PTR_ERR(qcadev->bt_en);
+		}
 
-	err = clk_set_rate(qcadev->susclk, SUSCLK_RATE_32KHZ);
-	if (err)
-		return err;
+		qcadev->susclk = devm_clk_get(&serdev->dev, NULL);
+		if (IS_ERR(qcadev->susclk)) {
+			dev_err(&serdev->dev, "failed to acquire clk\n");
+			return PTR_ERR(qcadev->susclk);
+		}
 
-	err = clk_prepare_enable(qcadev->susclk);
-	if (err)
-		return err;
+		err = clk_set_rate(qcadev->susclk, SUSCLK_RATE_32KHZ);
+		if (err)
+			return err;
 
-	err = hci_uart_register_device(&qcadev->serdev_hu, &qca_proto);
-	if (err)
-		clk_disable_unprepare(qcadev->susclk);
+		err = clk_prepare_enable(qcadev->susclk);
+		if (err)
+			return err;
+
+		err = hci_uart_register_device(&qcadev->serdev_hu, &qca_proto);
+		if (err)
+			clk_disable_unprepare(qcadev->susclk);
+	}
+
+out:	return err;
 
-	return err;
 }
 
 static void qca_serdev_remove(struct serdev_device *serdev)
 {
 	struct qca_serdev *qcadev = serdev_device_get_drvdata(serdev);
 
-	hci_uart_unregister_device(&qcadev->serdev_hu);
+	if (qcadev->btsoc_type == QCA_WCN3990)
+		qca_power_shutdown(qcadev->serdev_hu.hdev);
+	else
+		clk_disable_unprepare(qcadev->susclk);
 
-	clk_disable_unprepare(qcadev->susclk);
+	hci_uart_unregister_device(&qcadev->serdev_hu);
 }
 
 static const struct of_device_id qca_bluetooth_of_match[] = {
 	{ .compatible = "qcom,qca6174-bt" },
+	{ .compatible = "qcom,wcn3990-bt", .data = &qca_soc_data},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, qca_bluetooth_of_match);
-- 
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