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// SPDX-License-Identifier: GPL-2.0-only
/*
* Texas Instruments' Bluetooth HCILL UART protocol
*
* HCILL (HCI Low Level) is a Texas Instruments' power management
* protocol extension to H4.
*
* Copyright (C) 2007 Texas Instruments, Inc.
*
* Written by Ohad Ben-Cohen <ohad@bencohen.org>
*
* Acknowledgements:
* This file is based on hci_h4.c, which was written
* by Maxim Krasnyansky and Marcel Holtmann.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#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/errno.h>
#include <linux/string.h>
#include <linux/signal.h>
#include <linux/ioctl.h>
#include <linux/of.h>
#include <linux/serdev.h>
#include <linux/skbuff.h>
#include <linux/ti_wilink_st.h>
#include <linux/clk.h>
#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <linux/gpio/consumer.h>
#include <linux/nvmem-consumer.h>
#include "hci_uart.h"
/* Vendor-specific HCI commands */
#define HCI_VS_WRITE_BD_ADDR 0xfc06
#define HCI_VS_UPDATE_UART_HCI_BAUDRATE 0xff36
/* HCILL commands */
#define HCILL_GO_TO_SLEEP_IND 0x30
#define HCILL_GO_TO_SLEEP_ACK 0x31
#define HCILL_WAKE_UP_IND 0x32
#define HCILL_WAKE_UP_ACK 0x33
/* HCILL states */
enum hcill_states_e {
HCILL_ASLEEP,
HCILL_ASLEEP_TO_AWAKE,
HCILL_AWAKE,
HCILL_AWAKE_TO_ASLEEP
};
struct ll_device {
struct hci_uart hu;
struct serdev_device *serdev;
struct gpio_desc *enable_gpio;
struct clk *ext_clk;
bdaddr_t bdaddr;
};
struct ll_struct {
struct sk_buff *rx_skb;
struct sk_buff_head txq;
spinlock_t hcill_lock; /* HCILL state lock */
unsigned long hcill_state; /* HCILL power state */
struct sk_buff_head tx_wait_q; /* HCILL wait queue */
};
/*
* Builds and sends an HCILL command packet.
* These are very simple packets with only 1 cmd byte
*/
static int send_hcill_cmd(u8 cmd, struct hci_uart *hu)
{
int err = 0;
struct sk_buff *skb = NULL;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p cmd 0x%x", hu, cmd);
/* allocate packet */
skb = bt_skb_alloc(1, GFP_ATOMIC);
if (!skb) {
BT_ERR("cannot allocate memory for HCILL packet");
err = -ENOMEM;
goto out;
}
/* prepare packet */
skb_put_u8(skb, cmd);
/* send packet */
skb_queue_tail(&ll->txq, skb);
out:
return err;
}
/* Initialize protocol */
static int ll_open(struct hci_uart *hu)
{
struct ll_struct *ll;
BT_DBG("hu %p", hu);
ll = kzalloc(sizeof(*ll), GFP_KERNEL);
if (!ll)
return -ENOMEM;
skb_queue_head_init(&ll->txq);
skb_queue_head_init(&ll->tx_wait_q);
spin_lock_init(&ll->hcill_lock);
ll->hcill_state = HCILL_AWAKE;
hu->priv = ll;
if (hu->serdev) {
struct ll_device *lldev = serdev_device_get_drvdata(hu->serdev);
if (!IS_ERR(lldev->ext_clk))
clk_prepare_enable(lldev->ext_clk);
}
return 0;
}
/* Flush protocol data */
static int ll_flush(struct hci_uart *hu)
{
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
skb_queue_purge(&ll->tx_wait_q);
skb_queue_purge(&ll->txq);
return 0;
}
/* Close protocol */
static int ll_close(struct hci_uart *hu)
{
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
skb_queue_purge(&ll->tx_wait_q);
skb_queue_purge(&ll->txq);
kfree_skb(ll->rx_skb);
if (hu->serdev) {
struct ll_device *lldev = serdev_device_get_drvdata(hu->serdev);
gpiod_set_value_cansleep(lldev->enable_gpio, 0);
clk_disable_unprepare(lldev->ext_clk);
}
hu->priv = NULL;
kfree(ll);
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.
* 2. changes internal state to HCILL_AWAKE.
* Note: assumes that hcill_lock spinlock is taken,
* shouldn't be called otherwise!
*/
static void __ll_do_awake(struct ll_struct *ll)
{
struct sk_buff *skb = NULL;
while ((skb = skb_dequeue(&ll->tx_wait_q)))
skb_queue_tail(&ll->txq, skb);
ll->hcill_state = HCILL_AWAKE;
}
/*
* Called upon a wake-up-indication from the device
*/
static void ll_device_want_to_wakeup(struct hci_uart *hu)
{
unsigned long flags;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
/* lock hcill state */
spin_lock_irqsave(&ll->hcill_lock, flags);
switch (ll->hcill_state) {
case HCILL_ASLEEP_TO_AWAKE:
/*
* This state means that both the host and the BRF chip
* have simultaneously sent a wake-up-indication packet.
* Traditionally, in this case, receiving a wake-up-indication
* was enough and an additional wake-up-ack wasn't needed.
* This has changed with the BRF6350, which does require an
* explicit wake-up-ack. Other BRF versions, which do not
* require an explicit ack here, do accept it, thus it is
* perfectly safe to always send one.
*/
BT_DBG("dual wake-up-indication");
fallthrough;
case HCILL_ASLEEP:
/* acknowledge device wake up */
if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
BT_ERR("cannot acknowledge device wake up");
goto out;
}
break;
default:
/* any other state is illegal */
BT_ERR("received HCILL_WAKE_UP_IND in state %ld",
ll->hcill_state);
break;
}
/* send pending packets and change state to HCILL_AWAKE */
__ll_do_awake(ll);
out:
spin_unlock_irqrestore(&ll->hcill_lock, flags);
/* actually send the packets */
hci_uart_tx_wakeup(hu);
}
/*
* Called upon a sleep-indication from the device
*/
static void ll_device_want_to_sleep(struct hci_uart *hu)
{
unsigned long flags;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
/* lock hcill state */
spin_lock_irqsave(&ll->hcill_lock, flags);
/* sanity check */
if (ll->hcill_state != HCILL_AWAKE)
BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld",
ll->hcill_state);
/* acknowledge device sleep */
if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
BT_ERR("cannot acknowledge device sleep");
goto out;
}
/* update state */
ll->hcill_state = HCILL_ASLEEP;
out:
spin_unlock_irqrestore(&ll->hcill_lock, flags);
/* actually send the sleep ack packet */
hci_uart_tx_wakeup(hu);
}
/*
* Called upon wake-up-acknowledgement from the device
*/
static void ll_device_woke_up(struct hci_uart *hu)
{
unsigned long flags;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p", hu);
/* lock hcill state */
spin_lock_irqsave(&ll->hcill_lock, flags);
/* sanity check */
if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
BT_ERR("received HCILL_WAKE_UP_ACK in state %ld",
ll->hcill_state);
/* send pending packets and change state to HCILL_AWAKE */
__ll_do_awake(ll);
spin_unlock_irqrestore(&ll->hcill_lock, flags);
/* actually send the packets */
hci_uart_tx_wakeup(hu);
}
/* Enqueue frame for transmittion (padding, crc, etc) */
/* may be called from two simultaneous tasklets */
static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
unsigned long flags = 0;
struct ll_struct *ll = hu->priv;
BT_DBG("hu %p skb %p", hu, skb);
/* Prepend skb with frame type */
memcpy(skb_push(skb, 1), &hci_skb_pkt_type(skb), 1);
/* lock hcill state */
spin_lock_irqsave(&ll->hcill_lock, flags);
/* act according to current state */
switch (ll->hcill_state) {
case HCILL_AWAKE:
BT_DBG("device awake, sending normally");
skb_queue_tail(&ll->txq, skb);
break;
case HCILL_ASLEEP:
BT_DBG("device asleep, waking up and queueing packet");
/* save packet for later */
skb_queue_tail(&ll->tx_wait_q, skb);
/* awake device */
if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
BT_ERR("cannot wake up device");
break;
}
ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
break;
case HCILL_ASLEEP_TO_AWAKE:
BT_DBG("device waking up, queueing packet");
/* transient state; just keep packet for later */
skb_queue_tail(&ll->tx_wait_q, skb);
break;
default:
BT_ERR("illegal hcill state: %ld (losing packet)",
ll->hcill_state);
kfree_skb(skb);
break;
}
spin_unlock_irqrestore(&ll->hcill_lock, flags);
return 0;
}
static int ll_recv_frame(struct hci_dev *hdev, struct sk_buff *skb)
{
struct hci_uart *hu = hci_get_drvdata(hdev);
struct ll_struct *ll = hu->priv;
switch (hci_skb_pkt_type(skb)) {
case HCILL_GO_TO_SLEEP_IND:
BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
ll_device_want_to_sleep(hu);
break;
case HCILL_GO_TO_SLEEP_ACK:
/* shouldn't happen */
bt_dev_err(hdev, "received HCILL_GO_TO_SLEEP_ACK in state %ld",
ll->hcill_state);
break;
case HCILL_WAKE_UP_IND:
BT_DBG("HCILL_WAKE_UP_IND packet");
ll_device_want_to_wakeup(hu);
break;
case HCILL_WAKE_UP_ACK:
BT_DBG("HCILL_WAKE_UP_ACK packet");
ll_device_woke_up(hu);
break;
}
kfree_skb(skb);
return 0;
}
#define LL_RECV_SLEEP_IND \
.type = HCILL_GO_TO_SLEEP_IND, \
.hlen = 0, \
.loff = 0, \
.lsize = 0, \
.maxlen = 0
#define LL_RECV_SLEEP_ACK \
.type = HCILL_GO_TO_SLEEP_ACK, \
.hlen = 0, \
.loff = 0, \
.lsize = 0, \
.maxlen = 0
#define LL_RECV_WAKE_IND \
.type = HCILL_WAKE_UP_IND, \
.hlen = 0, \
.loff = 0, \
.lsize = 0, \
.maxlen = 0
#define LL_RECV_WAKE_ACK \
.type = HCILL_WAKE_UP_ACK, \
.hlen = 0, \
.loff = 0, \
.lsize = 0, \
.maxlen = 0
static const struct h4_recv_pkt ll_recv_pkts[] = {
{ H4_RECV_ACL, .recv = hci_recv_frame },
{ H4_RECV_SCO, .recv = hci_recv_frame },
{ H4_RECV_EVENT, .recv = hci_recv_frame },
{ LL_RECV_SLEEP_IND, .recv = ll_recv_frame },
{ LL_RECV_SLEEP_ACK, .recv = ll_recv_frame },
{ LL_RECV_WAKE_IND, .recv = ll_recv_frame },
{ LL_RECV_WAKE_ACK, .recv = ll_recv_frame },
};
/* Recv data */
static int ll_recv(struct hci_uart *hu, const void *data, int count)
{
struct ll_struct *ll = hu->priv;
if (!test_bit(HCI_UART_REGISTERED, &hu->flags))
return -EUNATCH;
ll->rx_skb = h4_recv_buf(hu->hdev, ll->rx_skb, data, count,
ll_recv_pkts, ARRAY_SIZE(ll_recv_pkts));
if (IS_ERR(ll->rx_skb)) {
int err = PTR_ERR(ll->rx_skb);
bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);
ll->rx_skb = NULL;
return err;
}
return count;
}
static struct sk_buff *ll_dequeue(struct hci_uart *hu)
{
struct ll_struct *ll = hu->priv;
return skb_dequeue(&ll->txq);
}
#if IS_ENABLED(CONFIG_SERIAL_DEV_BUS)
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));
return PTR_ERR(skb);
}
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;
}
static int send_command_from_firmware(struct ll_device *lldev,
struct hci_command *cmd)
{
struct sk_buff *skb;
if (cmd->opcode == HCI_VS_UPDATE_UART_HCI_BAUDRATE) {
/* ignore remote change
* baud rate HCI VS command
*/
bt_dev_warn(lldev->hu.hdev,
"change remote baud rate command in firmware");
return 0;
}
if (cmd->prefix != 1)
bt_dev_dbg(lldev->hu.hdev, "command type %d", cmd->prefix);
skb = __hci_cmd_sync(lldev->hu.hdev, cmd->opcode, cmd->plen,
&cmd->speed, HCI_INIT_TIMEOUT);
if (IS_ERR(skb)) {
bt_dev_err(lldev->hu.hdev, "send command failed");
return PTR_ERR(skb);
}
kfree_skb(skb);
return 0;
}
/*
* 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 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) {
bt_dev_err(lldev->hu.hdev, "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) {
bt_dev_dbg(lldev->hu.hdev, " 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 */
bt_dev_dbg(lldev->hu.hdev, "S");
cmd = (struct hci_command *)action_ptr;
err = send_command_from_firmware(lldev, cmd);
if (err)
goto out_rel_fw;
break;
case ACTION_WAIT_EVENT: /* wait */
/* no need to wait as command was synchronous */
bt_dev_dbg(lldev->hu.hdev, "W");
break;
case ACTION_DELAY: /* sleep */
bt_dev_info(lldev->hu.hdev, "sleep command in scr");
msleep(((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_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)
{
bdaddr_t bdaddr_swapped;
struct sk_buff *skb;
/* HCI_VS_WRITE_BD_ADDR (at least on a CC2560A chip) expects the BD
* address to be MSB first, but bdaddr_t has the convention of being
* LSB first.
*/
baswap(&bdaddr_swapped, bdaddr);
skb = __hci_cmd_sync(hdev, HCI_VS_WRITE_BD_ADDR, sizeof(bdaddr_t),
&bdaddr_swapped, HCI_INIT_TIMEOUT);
if (!IS_ERR(skb))
kfree_skb(skb);
return PTR_ERR_OR_ZERO(skb);
}
static int ll_setup(struct hci_uart *hu)
{
int err, retry = 3;
struct ll_device *lldev;
struct serdev_device *serdev = hu->serdev;
u32 speed;
if (!serdev)
return 0;
lldev = serdev_device_get_drvdata(serdev);
hu->hdev->set_bdaddr = ll_set_bdaddr;
serdev_device_set_flow_control(serdev, true);
do {
/* Reset the Bluetooth device */
gpiod_set_value_cansleep(lldev->enable_gpio, 0);
msleep(5);
gpiod_set_value_cansleep(lldev->enable_gpio, 1);
mdelay(100);
err = serdev_device_wait_for_cts(serdev, true, 200);
if (err) {
bt_dev_err(hu->hdev, "Failed to get CTS");
return err;
}
err = download_firmware(lldev);
if (!err)
break;
/* Toggle BT_EN and retry */
bt_dev_err(hu->hdev, "download firmware failed, retrying...");
} while (retry--);
if (err)
return err;
/* Set BD address if one was specified at probe */
if (!bacmp(&lldev->bdaddr, BDADDR_NONE)) {
/* This means that there was an error getting the BD address
* during probe, so mark the device as having a bad address.
*/
set_bit(HCI_QUIRK_INVALID_BDADDR, &hu->hdev->quirks);
} else if (bacmp(&lldev->bdaddr, BDADDR_ANY)) {
err = ll_set_bdaddr(hu->hdev, &lldev->bdaddr);
if (err)
set_bit(HCI_QUIRK_INVALID_BDADDR, &hu->hdev->quirks);
}
/* 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) {
__le32 speed_le = cpu_to_le32(speed);
struct sk_buff *skb;
skb = __hci_cmd_sync(hu->hdev, HCI_VS_UPDATE_UART_HCI_BAUDRATE,
sizeof(speed_le), &speed_le,
HCI_INIT_TIMEOUT);
if (!IS_ERR(skb)) {
kfree_skb(skb);
serdev_device_set_baudrate(serdev, speed);
}
}
return 0;
}
static const struct hci_uart_proto llp;
static int hci_ti_probe(struct serdev_device *serdev)
{
struct hci_uart *hu;
struct ll_device *lldev;
struct nvmem_cell *bdaddr_cell;
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->enable_gpio = devm_gpiod_get_optional(&serdev->dev,
"enable",
GPIOD_OUT_LOW);
if (IS_ERR(lldev->enable_gpio))
return PTR_ERR(lldev->enable_gpio);
lldev->ext_clk = devm_clk_get(&serdev->dev, "ext_clock");
if (IS_ERR(lldev->ext_clk) && PTR_ERR(lldev->ext_clk) != -ENOENT)
return PTR_ERR(lldev->ext_clk);
of_property_read_u32(serdev->dev.of_node, "max-speed", &max_speed);
hci_uart_set_speeds(hu, 115200, max_speed);
/* optional BD address from nvram */
bdaddr_cell = nvmem_cell_get(&serdev->dev, "bd-address");
if (IS_ERR(bdaddr_cell)) {
int err = PTR_ERR(bdaddr_cell);
if (err == -EPROBE_DEFER)
return err;
/* ENOENT means there is no matching nvmem cell and ENOSYS
* means that nvmem is not enabled in the kernel configuration.
*/
if (err != -ENOENT && err != -ENOSYS) {
/* If there was some other error, give userspace a
* chance to fix the problem instead of failing to load
* the driver. Using BDADDR_NONE as a flag that is
* tested later in the setup function.
*/
dev_warn(&serdev->dev,
"Failed to get \"bd-address\" nvmem cell (%d)\n",
err);
bacpy(&lldev->bdaddr, BDADDR_NONE);
}
} else {
bdaddr_t *bdaddr;
size_t len;
bdaddr = nvmem_cell_read(bdaddr_cell, &len);
nvmem_cell_put(bdaddr_cell);
if (IS_ERR(bdaddr)) {
dev_err(&serdev->dev, "Failed to read nvmem bd-address\n");
return PTR_ERR(bdaddr);
}
if (len != sizeof(bdaddr_t)) {
dev_err(&serdev->dev, "Invalid nvmem bd-address length\n");
kfree(bdaddr);
return -EINVAL;
}
/* As per the device tree bindings, the value from nvmem is
* expected to be MSB first, but in the kernel it is expected
* that bdaddr_t is LSB first.
*/
baswap(&lldev->bdaddr, bdaddr);
kfree(bdaddr);
}
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);
hci_uart_unregister_device(&lldev->hu);
}
static const struct of_device_id hci_ti_of_match[] = {
{ .compatible = "ti,cc2560" },
{ .compatible = "ti,wl1271-st" },
{ .compatible = "ti,wl1273-st" },
{ .compatible = "ti,wl1281-st" },
{ .compatible = "ti,wl1283-st" },
{ .compatible = "ti,wl1285-st" },
{ .compatible = "ti,wl1801-st" },
{ .compatible = "ti,wl1805-st" },
{ .compatible = "ti,wl1807-st" },
{ .compatible = "ti,wl1831-st" },
{ .compatible = "ti,wl1835-st" },
{ .compatible = "ti,wl1837-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,
};
#else
#define ll_setup NULL
#endif
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,
.enqueue = ll_enqueue,
.dequeue = ll_dequeue,
.flush = ll_flush,
};
int __init ll_init(void)
{
serdev_device_driver_register(&hci_ti_drv);
return hci_uart_register_proto(&llp);
}
int __exit ll_deinit(void)
{
serdev_device_driver_unregister(&hci_ti_drv);
return hci_uart_unregister_proto(&llp);
}