[RFC 1/2] bluetooth: hci_uart: add serdev driver support library

[RFC 1/2] bluetooth: hci_uart: add serdev driver support library

[Rob Herring]

This adds library functions for serdev based BT drivers. This is largely
copied from hci_ldisc.c and modified to use serdev calls. There's a little
bit of duplication, but I avoided intermixing this as the ldisc code should
eventually go away.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: linux-bluetooth@vger.kernel.org
---
 drivers/bluetooth/Makefile     |   2 +-
 drivers/bluetooth/hci_serdev.c | 370 +++++++++++++++++++++++++++++++++++++++++
 drivers/bluetooth/hci_uart.h   |   4 +
 3 files changed, 375 insertions(+), 1 deletion(-)
 create mode 100644 drivers/bluetooth/hci_serdev.c

diff --git a/drivers/bluetooth/Makefile b/drivers/bluetooth/Makefile
index 80627187c8b6..a69b18ac704a 100644
--- a/drivers/bluetooth/Makefile
+++ b/drivers/bluetooth/Makefile
@@ -28,7 +28,7 @@ obj-$(CONFIG_BT_QCA)		+= btqca.o
 btmrvl-y			:= btmrvl_main.o
 btmrvl-$(CONFIG_DEBUG_FS)	+= btmrvl_debugfs.o
 
-hci_uart-y				:= hci_ldisc.o
+hci_uart-y				:= hci_ldisc.o hci_serdev.o
 hci_uart-$(CONFIG_BT_HCIUART_H4)	+= hci_h4.o
 hci_uart-$(CONFIG_BT_HCIUART_BCSP)	+= hci_bcsp.o
 hci_uart-$(CONFIG_BT_HCIUART_LL)	+= hci_ll.o
diff --git a/drivers/bluetooth/hci_serdev.c b/drivers/bluetooth/hci_serdev.c
new file mode 100644
index 000000000000..b2f7293a3162
--- /dev/null
+++ b/drivers/bluetooth/hci_serdev.c
@@ -0,0 +1,370 @@
+/*
+ *
+ *  Bluetooth HCI serdev driver lib
+ *
+ *  Copyright (C) 2017  Linaro, Ltd., Rob Herring <robh@kernel.org>
+ *
+ *  Based on hci_ldisc.c:
+ *
+ *  Copyright (C) 2000-2001  Qualcomm Incorporated
+ *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
+ *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
+ *
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/serdev.h>
+#include <linux/skbuff.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "hci_uart.h"
+
+struct serdev_device_ops hci_serdev_client_ops;
+
+static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
+{
+	struct hci_dev *hdev = hu->hdev;
+
+	/* Update HCI stat counters */
+	switch (pkt_type) {
+	case HCI_COMMAND_PKT:
+		hdev->stat.cmd_tx++;
+		break;
+
+	case HCI_ACLDATA_PKT:
+		hdev->stat.acl_tx++;
+		break;
+
+	case HCI_SCODATA_PKT:
+		hdev->stat.sco_tx++;
+		break;
+	}
+}
+
+static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
+{
+	struct sk_buff *skb = hu->tx_skb;
+
+	if (!skb)
+		skb = hu->proto->dequeue(hu);
+	else
+		hu->tx_skb = NULL;
+
+	return skb;
+}
+
+static void hci_uart_write_work(struct work_struct *work)
+{
+	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
+	struct serdev_device *serdev = hu->serdev;
+	struct hci_dev *hdev = hu->hdev;
+	struct sk_buff *skb;
+
+	/* REVISIT: should we cope with bad skbs or ->write() returning
+	 * and error value ?
+	 */
+
+restart:
+	clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
+
+	while ((skb = hci_uart_dequeue(hu))) {
+		int len;
+
+		len = serdev_device_write_buf(serdev, skb->data, skb->len);
+		hdev->stat.byte_tx += len;
+
+		skb_pull(skb, len);
+		if (skb->len) {
+			hu->tx_skb = skb;
+			break;
+		}
+
+		hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
+		kfree_skb(skb);
+	}
+
+	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
+		goto restart;
+
+	clear_bit(HCI_UART_SENDING, &hu->tx_state);
+}
+
+/* ------- Interface to HCI layer ------ */
+/* Initialize device */
+static int hci_uart_open(struct hci_dev *hdev)
+{
+	struct hci_uart *hu  = hci_get_drvdata(hdev);
+
+	BT_DBG("%s %p", hdev->name, hdev);
+
+	serdev_device_set_client_ops(hu->serdev, &hci_serdev_client_ops);
+
+	return serdev_device_open(hu->serdev);
+}
+
+/* Reset device */
+static int hci_uart_flush(struct hci_dev *hdev)
+{
+	struct hci_uart *hu  = hci_get_drvdata(hdev);
+
+	BT_DBG("hdev %p serdev %p", hdev, hu->serdev);
+
+	if (hu->tx_skb) {
+		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
+	}
+
+	/* Flush any pending characters in the driver and discipline. */
+	serdev_device_write_flush(hu->serdev);
+
+	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
+		hu->proto->flush(hu);
+
+	return 0;
+}
+
+/* Close device */
+static int hci_uart_close(struct hci_dev *hdev)
+{
+	struct hci_uart *hu  = hci_get_drvdata(hdev);
+
+	BT_DBG("hdev %p", hdev);
+
+	hci_uart_flush(hdev);
+	hdev->flush = NULL;
+
+	serdev_device_close(hu->serdev);
+
+	return 0;
+}
+
+/* Send frames from HCI layer */
+static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	struct hci_uart *hu = hci_get_drvdata(hdev);
+
+	BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
+	       skb->len);
+
+	hu->proto->enqueue(hu, skb);
+
+	hci_uart_tx_wakeup(hu);
+
+	return 0;
+}
+
+static int hci_uart_setup(struct hci_dev *hdev)
+{
+	struct hci_uart *hu = hci_get_drvdata(hdev);
+	struct hci_rp_read_local_version *ver;
+	struct sk_buff *skb;
+	unsigned int speed;
+	int err;
+
+	/* Init speed if any */
+	if (hu->init_speed)
+		speed = hu->init_speed;
+	else if (hu->proto->init_speed)
+		speed = hu->proto->init_speed;
+	else
+		speed = 0;
+
+	if (speed)
+		serdev_device_set_baudrate(hu->serdev, speed);
+
+	/* Operational speed if any */
+	if (hu->oper_speed)
+		speed = hu->oper_speed;
+	else if (hu->proto->oper_speed)
+		speed = hu->proto->oper_speed;
+	else
+		speed = 0;
+
+	if (hu->proto->set_baudrate && speed) {
+		err = hu->proto->set_baudrate(hu, speed);
+		if (!err)
+			serdev_device_set_baudrate(hu->serdev, speed);
+	}
+
+	if (hu->proto->setup)
+		return hu->proto->setup(hu);
+
+	if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
+		return 0;
+
+	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
+			     HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		BT_ERR("%s: Reading local version information failed (%ld)",
+		       hdev->name, PTR_ERR(skb));
+		return 0;
+	}
+
+	if (skb->len != sizeof(*ver)) {
+		BT_ERR("%s: Event length mismatch for version information",
+		       hdev->name);
+		goto done;
+	}
+
+done:
+	kfree_skb(skb);
+	return 0;
+}
+
+/* hci_uart_write_wakeup()
+ *
+ *    Callback for transmit wakeup. Called when low level
+ *    device driver can accept more send data.
+ *
+ * Arguments:        tty    pointer to associated tty instance data
+ * Return Value:    None
+ */
+static void hci_uart_write_wakeup(struct serdev_device *serdev)
+{
+	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
+
+	BT_DBG("");
+
+	if (!hu)
+		return;
+
+	if (serdev != hu->serdev)
+		return;
+
+	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
+		hci_uart_tx_wakeup(hu);
+}
+
+/* hci_uart_receive_buf()
+ *
+ *     Called by tty low level driver when receive data is
+ *     available.
+ *
+ * Arguments:  tty          pointer to tty isntance data
+ *             data         pointer to received data
+ *             flags        pointer to flags for data
+ *             count        count of received data in bytes
+ *
+ * Return Value:    None
+ */
+static int hci_uart_receive_buf(struct serdev_device *serdev, const u8 *data,
+				   size_t count)
+{
+	struct hci_uart *hu = serdev_device_get_drvdata(serdev);
+
+	if (!hu || serdev != hu->serdev)
+		return 0;
+
+	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
+		return 0;
+
+	/* It does not need a lock here as it is already protected by a mutex in
+	 * tty caller
+	 */
+	hu->proto->recv(hu, data, count);
+
+	if (hu->hdev)
+		hu->hdev->stat.byte_rx += count;
+
+	return count;
+}
+
+struct serdev_device_ops hci_serdev_client_ops = {
+	.receive_buf = hci_uart_receive_buf,
+	.write_wakeup = hci_uart_write_wakeup,
+};
+
+int hci_uart_register_device(struct hci_uart *hu, const struct hci_uart_proto *p)
+{
+	int err;
+	struct hci_dev *hdev;
+
+	BT_DBG("");
+
+	err = p->open(hu);
+	if (err)
+		return err;
+
+	hu->proto = p;
+	set_bit(HCI_UART_PROTO_READY, &hu->flags);
+
+	/* Initialize and register HCI device */
+	hdev = hci_alloc_dev();
+	if (!hdev) {
+		BT_ERR("Can't allocate HCI device");
+		err = -ENOMEM;
+		goto err_alloc;
+	}
+
+	hu->hdev = hdev;
+
+	hdev->bus = HCI_UART;
+	hci_set_drvdata(hdev, hu);
+
+	INIT_WORK(&hu->write_work, hci_uart_write_work);
+
+	/* Only when vendor specific setup callback is provided, consider
+	 * the manufacturer information valid. This avoids filling in the
+	 * value for Ericsson when nothing is specified.
+	 */
+	if (hu->proto->setup)
+		hdev->manufacturer = hu->proto->manufacturer;
+
+	hdev->open  = hci_uart_open;
+	hdev->close = hci_uart_close;
+	hdev->flush = hci_uart_flush;
+	hdev->send  = hci_uart_send_frame;
+	hdev->setup = hci_uart_setup;
+	SET_HCIDEV_DEV(hdev, &hu->serdev->dev);
+
+	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
+		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
+
+	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
+		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
+
+	if (!test_bit(HCI_UART_RESET_ON_INIT, &hu->hdev_flags))
+		set_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
+
+	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
+		hdev->dev_type = HCI_AMP;
+	else
+		hdev->dev_type = HCI_PRIMARY;
+
+	if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
+		return 0;
+
+	if (hci_register_dev(hdev) < 0) {
+		BT_ERR("Can't register HCI device");
+		err = -ENODEV;
+		goto err_register;
+	}
+
+	set_bit(HCI_UART_REGISTERED, &hu->flags);
+
+	return 0;
+
+err_register:
+	hci_free_dev(hdev);
+err_alloc:
+	clear_bit(HCI_UART_PROTO_READY, &hu->flags);
+	p->close(hu);
+	return err;
+}
diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
index cb7f4b4aeca0..4796a29d575f 100644
--- a/drivers/bluetooth/hci_uart.h
+++ b/drivers/bluetooth/hci_uart.h
@@ -58,6 +58,7 @@
 #define HCI_UART_VND_DETECT	5
 
 struct hci_uart;
+struct serdev_device;
 
 struct hci_uart_proto {
 	unsigned int id;
@@ -77,6 +78,7 @@ struct hci_uart_proto {
 
 struct hci_uart {
 	struct tty_struct	*tty;
+	struct serdev_device	*serdev;
 	struct hci_dev		*hdev;
 	unsigned long		flags;
 	unsigned long		hdev_flags;
@@ -105,6 +107,8 @@ struct hci_uart {
 
 int hci_uart_register_proto(const struct hci_uart_proto *p);
 int hci_uart_unregister_proto(const struct hci_uart_proto *p);
+int hci_uart_register_device(struct hci_uart *hu, const struct hci_uart_proto *p);
+
 int hci_uart_tx_wakeup(struct hci_uart *hu);
 int hci_uart_init_ready(struct hci_uart *hu);
 void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed);
-- 
2.10.1

[RFC 2/2] bluetooth: hci_uart: add LL protocol serdev driver support

[Rob Herring]

Turns out that the LL protocol and the TI-ST are the same thing AFAICT.
The TI-ST adds firmware loading, GPIO control, and shared access for
NFC, FM radio, etc. For now, we're only implementing what is needed for
BT. This mirrors other drivers like BCM and Intel, but uses the new
serdev bus.

The firmware loading is greatly simplified by using existing
infrastructure to send commands. It may be a bit slower than the
original code using synchronous functions, but the real bottleneck is
likely doing firmware load at 115.2kbps.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: linux-bluetooth@vger.kernel.org
---
 drivers/bluetooth/hci_ll.c | 248 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 247 insertions(+), 1 deletion(-)

diff --git a/drivers/bluetooth/hci_ll.c b/drivers/bluetooth/hci_ll.c
index 02692fe30279..716c610fa54a 100644
--- a/drivers/bluetooth/hci_ll.c
+++ b/drivers/bluetooth/hci_ll.c
@@ -34,20 +34,23 @@
 #include <linux/sched.h>
 #include <linux/types.h>
 #include <linux/fcntl.h>
+#include <linux/firmware.h>
 #include <linux/interrupt.h>
 #include <linux/ptrace.h>
 #include <linux/poll.h>
 
 #include <linux/slab.h>
-#include <linux/tty.h>
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/signal.h>
 #include <linux/ioctl.h>
+#include <linux/serdev.h>
 #include <linux/skbuff.h>
+#include <linux/ti_wilink_st.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
+#include <linux/gpio/consumer.h>
 
 #include "hci_uart.h"
 
@@ -76,6 +79,12 @@ struct hcill_cmd {
 	u8 cmd;
 } __packed;
 
+struct ll_device {
+	struct hci_uart hu;
+	struct serdev_device *serdev;
+	struct gpio_desc *nshutdown;
+};
+
 struct ll_struct {
 	unsigned long rx_state;
 	unsigned long rx_count;
@@ -164,6 +173,11 @@ static int ll_close(struct hci_uart *hu)
 
 	kfree_skb(ll->rx_skb);
 
+	if (hu->serdev) {
+		struct ll_device *lldev = serdev_device_get_drvdata(hu->serdev);
+		gpiod_set_value_cansleep(lldev->nshutdown, 1);
+	}
+
 	hu->priv = NULL;
 
 	kfree(ll);
@@ -171,6 +185,184 @@ static int ll_close(struct hci_uart *hu)
 	return 0;
 }
 
+static int read_local_version(struct hci_dev *hdev)
+{
+	int err = 0;
+	unsigned short version = 0;
+	struct sk_buff *skb;
+	struct hci_rp_read_local_version *ver;
+
+	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL, HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		bt_dev_err(hdev, "Reading TI version information failed (%ld)",
+			   PTR_ERR(skb));
+		err = PTR_ERR(skb);
+		goto out;
+	}
+	if (skb->len != sizeof(*ver)) {
+		err = -EILSEQ;
+		goto out;
+	}
+
+	ver = (struct hci_rp_read_local_version *)skb->data;
+	if (le16_to_cpu(ver->manufacturer) != 13) {
+		err = -ENODEV;
+		goto out;
+	}
+
+	version = le16_to_cpu(ver->lmp_subver);
+
+out:
+	if (err) bt_dev_err(hdev, "Failed to read TI version info: %d", err);
+	kfree_skb(skb);
+	return err ? err : version;
+}
+
+/**
+ * download_firmware -
+ *	internal function which parses through the .bts firmware
+ *	script file intreprets SEND, DELAY actions only as of now
+ */
+static int download_firmware(struct ll_device *lldev)
+{
+	unsigned short chip, min_ver, maj_ver;
+	int version, err, len;
+	unsigned char *ptr, *action_ptr;
+	unsigned char bts_scr_name[40];	/* 40 char long bts scr name? */
+	const struct firmware *fw;
+	struct sk_buff *skb;
+	struct hci_command *cmd;
+
+	version = read_local_version(lldev->hu.hdev);
+	if (version < 0)
+		return version;
+
+	chip = (version & 0x7C00) >> 10;
+	min_ver = (version & 0x007F);
+	maj_ver = (version & 0x0380) >> 7;
+	if (version & 0x8000)
+		maj_ver |= 0x0008;
+
+	snprintf(bts_scr_name, sizeof(bts_scr_name),
+		 "ti-connectivity/TIInit_%d.%d.%d.bts",
+		 chip, maj_ver, min_ver);
+
+	err = request_firmware(&fw, bts_scr_name, &lldev->serdev->dev);
+	if (err || !fw->data || !fw->size) {
+		pr_err(" request_firmware failed(errno %d) for %s", err,
+			   bts_scr_name);
+		return -EINVAL;
+	}
+	ptr = (void *)fw->data;
+	len = fw->size;
+	/* bts_header to remove out magic number and
+	 * version
+	 */
+	ptr += sizeof(struct bts_header);
+	len -= sizeof(struct bts_header);
+
+	while (len > 0 && ptr) {
+		pr_debug(" action size %d, type %d ",
+			   ((struct bts_action *)ptr)->size,
+			   ((struct bts_action *)ptr)->type);
+
+		action_ptr = &(((struct bts_action *)ptr)->data[0]);
+
+		switch (((struct bts_action *)ptr)->type) {
+		case ACTION_SEND_COMMAND:	/* action send */
+			pr_debug("S");
+			cmd = (struct hci_command *)action_ptr;
+			if (cmd->opcode == 0xff36) {
+				/* ignore remote change
+				 * baud rate HCI VS command */
+				pr_warn("change remote baud"
+				    " rate command in firmware");
+				break;
+			}
+			if (cmd->prefix != 1)
+				printk("command type %d\n", cmd->prefix);
+
+			skb = __hci_cmd_sync(lldev->hu.hdev, cmd->opcode, cmd->plen, &cmd->speed, HCI_INIT_TIMEOUT);
+			if (IS_ERR(skb)) {
+				printk("send command failed\n");
+				goto out_rel_fw;
+			}
+			kfree_skb(skb);
+			break;
+		case ACTION_WAIT_EVENT:  /* wait */
+			/* no need to wait as command was synchronous */
+			pr_debug("W");
+			break;
+		case ACTION_DELAY:	/* sleep */
+			pr_info("sleep command in scr");
+			mdelay(((struct bts_action_delay *)action_ptr)->msec);
+			break;
+		}
+		len -= (sizeof(struct bts_action) +
+			((struct bts_action *)ptr)->size);
+		ptr += sizeof(struct bts_action) +
+			((struct bts_action *)ptr)->size;
+	}
+
+out_rel_fw:
+	/* fw download complete */
+	release_firmware(fw);
+	return err;
+}
+
+static int ll_setup(struct hci_uart *hu)
+{
+	int err, retry = 3;
+	struct ll_device *lldev;
+	u32 speed;
+
+	if (!hu->serdev)
+		return 0;
+
+	lldev = serdev_device_get_drvdata(hu->serdev);
+
+	serdev_device_set_flow_control(hu->serdev, true);
+
+	do {
+		/* Configure BT nShutdown to HIGH state */
+		gpiod_set_value_cansleep(lldev->nshutdown, 1);
+		msleep(5);	/* FIXME: a proper toggle */
+		gpiod_set_value_cansleep(lldev->nshutdown, 0);
+		msleep(100);
+
+		err = download_firmware(lldev);
+		if (err != 0) {
+			/* ldisc installed but fw download failed,
+			 * flush uart & power cycle BT_EN */
+			pr_err("download firmware failed");
+			continue;
+		} else {	/* on success don't retry */
+			break;
+		}
+	} while (retry--);
+
+	if (err)
+		return err;
+
+	/* Operational speed if any */
+	if (hu->oper_speed)
+		speed = hu->oper_speed;
+	else if (hu->proto->oper_speed)
+		speed = hu->proto->oper_speed;
+	else
+		speed = 0;
+
+	if (speed) {
+		struct sk_buff *skb = __hci_cmd_sync(hu->hdev, 0xff36, sizeof(speed), &speed, HCI_INIT_TIMEOUT);
+		if (!IS_ERR(skb)) {
+			kfree_skb(skb);
+			serdev_device_set_baudrate(hu->serdev, speed);
+		}
+	}
+
+	return 0;
+}
+
 /*
  * internal function, which does common work of the device wake up process:
  * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
@@ -508,6 +700,7 @@ static struct sk_buff *ll_dequeue(struct hci_uart *hu)
 static const struct hci_uart_proto llp = {
 	.id		= HCI_UART_LL,
 	.name		= "LL",
+	.setup		= ll_setup,
 	.open		= ll_open,
 	.close		= ll_close,
 	.recv		= ll_recv,
@@ -525,3 +718,56 @@ int __exit ll_deinit(void)
 {
 	return hci_uart_unregister_proto(&llp);
 }
+
+static int hci_ti_probe(struct serdev_device *serdev)
+{
+	struct hci_uart *hu;
+	struct ll_device *lldev;
+	u32 max_speed = 3000000;
+
+	lldev = devm_kzalloc(&serdev->dev, sizeof(struct ll_device), GFP_KERNEL);
+	if (!lldev)
+		return -ENOMEM;
+	hu = &lldev->hu;
+
+	serdev_device_set_drvdata(serdev, lldev);
+	lldev->serdev = hu->serdev = serdev;
+
+	lldev->nshutdown = devm_gpiod_get(&serdev->dev, "shutdown", GPIOD_OUT_HIGH);
+	if (IS_ERR(lldev->nshutdown))
+		return PTR_ERR(lldev->nshutdown);
+
+	of_property_read_u32(serdev->dev.of_node, "max-speed", &max_speed);
+	hci_uart_set_speeds(hu, 115200, max_speed);
+
+	return hci_uart_register_device(hu, &llp);
+}
+
+static void hci_ti_remove(struct serdev_device *serdev)
+{
+	struct ll_device *lldev = serdev_device_get_drvdata(serdev);
+	struct hci_uart *hu = &lldev->hu;
+	struct hci_dev *hdev = hu->hdev;
+
+	cancel_work_sync(&hu->write_work);
+
+	hci_unregister_dev(hdev);
+	hci_free_dev(hdev);
+	hu->proto->close(hu);
+}
+
+static const struct of_device_id hci_ti_of_match[] = {
+	{ .compatible = "ti,wl1835-st" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, hci_ti_of_match);
+
+static struct serdev_device_driver hci_ti_drv = {
+	.driver		= {
+		.name	= "hci-ti",
+		.of_match_table = of_match_ptr(hci_ti_of_match),
+	},
+	.probe	= hci_ti_probe,
+	.remove	= hci_ti_remove,
+};
+module_serdev_device_driver(hci_ti_drv);
-- 
2.10.1