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1// SPDX-License-Identifier: (GPL-2.0-only OR MIT)2/*3 * Copyright (C) 2024 Amlogic, Inc. All rights reserved4 */5 6#include <linux/kernel.h>7#include <linux/delay.h>8#include <linux/device.h>9#include <linux/property.h>10#include <linux/of.h>11#include <linux/serdev.h>12#include <linux/clk.h>13#include <linux/firmware.h>14#include <linux/gpio/consumer.h>15#include <linux/regulator/consumer.h>16#include <net/bluetooth/bluetooth.h>17#include <net/bluetooth/hci_core.h>18#include <net/bluetooth/hci.h>19 20#include "hci_uart.h"21 22#define AML_EVT_HEAD_SIZE 423#define AML_BDADDR_DEFAULT (&(bdaddr_t) {{ 0x00, 0xff, 0x00, 0x22, 0x2d, 0xae }})24 25#define AML_FIRMWARE_OPERATION_SIZE (248)26#define AML_FIRMWARE_MAX_SIZE (512 * 1024)27 28/* TCI command */29#define AML_TCI_CMD_READ 0xFEF030#define AML_TCI_CMD_WRITE 0xFEF131#define AML_TCI_CMD_UPDATE_BAUDRATE 0xFEF232#define AML_TCI_CMD_HARDWARE_RESET 0xFEF233#define AML_TCI_CMD_DOWNLOAD_BT_FW 0xFEF334 35/* Vendor command */36#define AML_BT_HCI_VENDOR_CMD 0xFC1A37 38/* TCI operation parameter in controller chip */39#define AML_OP_UART_MODE 0x00A3012840#define AML_OP_EVT_ENABLE 0x00A7001441#define AML_OP_MEM_HARD_TRANS_EN 0x00A7000C42#define AML_OP_RF_CFG 0x00F0304043#define AML_OP_RAM_POWER_CTR 0x00F0305044#define AML_OP_HARDWARE_RST 0x00F0305845#define AML_OP_ICCM_RAM_BASE 0x0000000046#define AML_OP_DCCM_RAM_BASE 0x00D0000047 48/* UART configuration */49#define AML_UART_XMIT_EN BIT(12)50#define AML_UART_RECV_EN BIT(13)51#define AML_UART_TIMEOUT_INT_EN BIT(14)52#define AML_UART_CLK_SOURCE 4000000053 54/* Controller event */55#define AML_EVT_EN BIT(24)56 57/* RAM power control */58#define AML_RAM_POWER_ON (0)59#define AML_RAM_POWER_OFF (1)60 61/* RF configuration */62#define AML_RF_ANT_SINGLE BIT(28)63#define AML_RF_ANT_DOUBLE BIT(29)64 65/* Memory transaction */66#define AML_MM_CTR_HARD_TRAS_EN BIT(27)67 68/* Controller reset */69#define AML_CTR_CPU_RESET BIT(8)70#define AML_CTR_MAC_RESET BIT(9)71#define AML_CTR_PHY_RESET BIT(10)72 73enum {74 FW_ICCM,75 FW_DCCM76};77 78struct aml_fw_len {79 u32 iccm_len;80 u32 dccm_len;81};82 83struct aml_tci_rsp {84 u8 num_cmd_packet;85 u16 opcode;86 u8 status;87} __packed;88 89struct aml_device_data {90 int iccm_offset;91 int dccm_offset;92 bool is_coex;93};94 95struct aml_serdev {96 struct hci_uart serdev_hu;97 struct device *dev;98 struct gpio_desc *bt_en_gpio;99 struct regulator *bt_supply;100 struct clk *lpo_clk;101 const struct aml_device_data *aml_dev_data;102 const char *firmware_name;103};104 105struct aml_data {106 struct sk_buff *rx_skb;107 struct sk_buff_head txq;108};109 110static const struct h4_recv_pkt aml_recv_pkts[] = {111 { H4_RECV_ACL, .recv = hci_recv_frame },112 { H4_RECV_SCO, .recv = hci_recv_frame },113 { H4_RECV_EVENT, .recv = hci_recv_frame },114 { H4_RECV_ISO, .recv = hci_recv_frame },115};116 117/* The TCI command is a private command, which is for setting baud rate,118 * downloading firmware, initiating RAM.119 *120 * op_code | op_len | op_addr | parameter |121 * --------|-----------------------|---------|-------------|122 * 2B | 1B len(addr+param) | 4B | len(param) |123 */124static int aml_send_tci_cmd(struct hci_dev *hdev, u16 op_code, u32 op_addr,125 u32 *param, u32 param_len)126{127 struct aml_tci_rsp *rsp = NULL;128 struct sk_buff *skb = NULL;129 size_t buf_len = 0;130 u8 *buf = NULL;131 int err = 0;132 133 buf_len = sizeof(op_addr) + param_len;134 buf = kmalloc(buf_len, GFP_KERNEL);135 if (!buf)136 return -ENOMEM;137 138 memcpy(buf, &op_addr, sizeof(op_addr));139 if (param && param_len > 0)140 memcpy(buf + sizeof(op_addr), param, param_len);141 142 skb = __hci_cmd_sync_ev(hdev, op_code, buf_len, buf,143 HCI_EV_CMD_COMPLETE, HCI_INIT_TIMEOUT);144 if (IS_ERR(skb)) {145 err = PTR_ERR(skb);146 bt_dev_err(hdev, "Failed to send TCI cmd (error: %d)", err);147 goto exit;148 }149 150 rsp = skb_pull_data(skb, sizeof(struct aml_tci_rsp));151 if (!rsp)152 goto skb_free;153 154 if (rsp->opcode != op_code || rsp->status != 0x00) {155 bt_dev_err(hdev, "send TCI cmd (0x%04X), response (0x%04X):(%d)",156 op_code, rsp->opcode, rsp->status);157 err = -EINVAL;158 goto skb_free;159 }160 161skb_free:162 kfree_skb(skb);163 164exit:165 kfree(buf);166 return err;167}168 169static int aml_update_chip_baudrate(struct hci_dev *hdev, u32 baud)170{171 u32 value;172 173 value = ((AML_UART_CLK_SOURCE / baud) - 1) & 0x0FFF;174 value |= AML_UART_XMIT_EN | AML_UART_RECV_EN | AML_UART_TIMEOUT_INT_EN;175 176 return aml_send_tci_cmd(hdev, AML_TCI_CMD_UPDATE_BAUDRATE,177 AML_OP_UART_MODE, &value, sizeof(value));178}179 180static int aml_start_chip(struct hci_dev *hdev)181{182 u32 value = 0;183 int ret;184 185 value = AML_MM_CTR_HARD_TRAS_EN;186 ret = aml_send_tci_cmd(hdev, AML_TCI_CMD_WRITE,187 AML_OP_MEM_HARD_TRANS_EN,188 &value, sizeof(value));189 if (ret)190 return ret;191 192 /* controller hardware reset */193 value = AML_CTR_CPU_RESET | AML_CTR_MAC_RESET | AML_CTR_PHY_RESET;194 ret = aml_send_tci_cmd(hdev, AML_TCI_CMD_HARDWARE_RESET,195 AML_OP_HARDWARE_RST,196 &value, sizeof(value));197 return ret;198}199 200static int aml_send_firmware_segment(struct hci_dev *hdev,201 u8 fw_type,202 u8 *seg,203 u32 seg_size,204 u32 offset)205{206 u32 op_addr = 0;207 208 if (fw_type == FW_ICCM)209 op_addr = AML_OP_ICCM_RAM_BASE + offset;210 else if (fw_type == FW_DCCM)211 op_addr = AML_OP_DCCM_RAM_BASE + offset;212 213 return aml_send_tci_cmd(hdev, AML_TCI_CMD_DOWNLOAD_BT_FW,214 op_addr, (u32 *)seg, seg_size);215}216 217static int aml_send_firmware(struct hci_dev *hdev, u8 fw_type,218 u8 *fw, u32 fw_size, u32 offset)219{220 u32 seg_size = 0;221 u32 seg_off = 0;222 223 if (fw_size > AML_FIRMWARE_MAX_SIZE) {224 bt_dev_err(hdev,225 "Firmware size %d kB is larger than the maximum of 512 kB. Aborting.",226 fw_size);227 return -EINVAL;228 }229 while (fw_size > 0) {230 seg_size = (fw_size > AML_FIRMWARE_OPERATION_SIZE) ?231 AML_FIRMWARE_OPERATION_SIZE : fw_size;232 if (aml_send_firmware_segment(hdev, fw_type, (fw + seg_off),233 seg_size, offset)) {234 bt_dev_err(hdev, "Failed send firmware, type: %d, offset: 0x%x",235 fw_type, offset);236 return -EINVAL;237 }238 seg_off += seg_size;239 fw_size -= seg_size;240 offset += seg_size;241 }242 return 0;243}244 245static int aml_download_firmware(struct hci_dev *hdev, const char *fw_name)246{247 struct hci_uart *hu = hci_get_drvdata(hdev);248 struct aml_serdev *amldev = serdev_device_get_drvdata(hu->serdev);249 const struct firmware *firmware = NULL;250 struct aml_fw_len *fw_len = NULL;251 u8 *iccm_start = NULL, *dccm_start = NULL;252 u32 iccm_len, dccm_len;253 u32 value = 0;254 int ret = 0;255 256 /* Enable firmware download event */257 value = AML_EVT_EN;258 ret = aml_send_tci_cmd(hdev, AML_TCI_CMD_WRITE,259 AML_OP_EVT_ENABLE,260 &value, sizeof(value));261 if (ret)262 goto exit;263 264 /* RAM power on */265 value = AML_RAM_POWER_ON;266 ret = aml_send_tci_cmd(hdev, AML_TCI_CMD_WRITE,267 AML_OP_RAM_POWER_CTR,268 &value, sizeof(value));269 if (ret)270 goto exit;271 272 /* Check RAM power status */273 ret = aml_send_tci_cmd(hdev, AML_TCI_CMD_READ,274 AML_OP_RAM_POWER_CTR, NULL, 0);275 if (ret)276 goto exit;277 278 ret = request_firmware(&firmware, fw_name, &hdev->dev);279 if (ret < 0) {280 bt_dev_err(hdev, "Failed to load <%s>:(%d)", fw_name, ret);281 goto exit;282 }283 284 fw_len = (struct aml_fw_len *)firmware->data;285 286 /* Download ICCM */287 iccm_start = (u8 *)(firmware->data) + sizeof(struct aml_fw_len)288 + amldev->aml_dev_data->iccm_offset;289 iccm_len = fw_len->iccm_len - amldev->aml_dev_data->iccm_offset;290 ret = aml_send_firmware(hdev, FW_ICCM, iccm_start, iccm_len,291 amldev->aml_dev_data->iccm_offset);292 if (ret) {293 bt_dev_err(hdev, "Failed to send FW_ICCM (%d)", ret);294 goto exit;295 }296 297 /* Download DCCM */298 dccm_start = (u8 *)(firmware->data) + sizeof(struct aml_fw_len) + fw_len->iccm_len;299 dccm_len = fw_len->dccm_len;300 ret = aml_send_firmware(hdev, FW_DCCM, dccm_start, dccm_len,301 amldev->aml_dev_data->dccm_offset);302 if (ret) {303 bt_dev_err(hdev, "Failed to send FW_DCCM (%d)", ret);304 goto exit;305 }306 307 /* Disable firmware download event */308 value = 0;309 ret = aml_send_tci_cmd(hdev, AML_TCI_CMD_WRITE,310 AML_OP_EVT_ENABLE,311 &value, sizeof(value));312 if (ret)313 goto exit;314 315exit:316 if (firmware)317 release_firmware(firmware);318 return ret;319}320 321static int aml_send_reset(struct hci_dev *hdev)322{323 struct sk_buff *skb;324 int err;325 326 skb = __hci_cmd_sync_ev(hdev, HCI_OP_RESET, 0, NULL,327 HCI_EV_CMD_COMPLETE, HCI_INIT_TIMEOUT);328 if (IS_ERR(skb)) {329 err = PTR_ERR(skb);330 bt_dev_err(hdev, "Failed to send hci reset cmd (%d)", err);331 return err;332 }333 334 kfree_skb(skb);335 return 0;336}337 338static int aml_dump_fw_version(struct hci_dev *hdev)339{340 struct aml_tci_rsp *rsp = NULL;341 struct sk_buff *skb;342 u8 value[6] = {0};343 u8 *fw_ver = NULL;344 int err = 0;345 346 skb = __hci_cmd_sync_ev(hdev, AML_BT_HCI_VENDOR_CMD, sizeof(value), value,347 HCI_EV_CMD_COMPLETE, HCI_INIT_TIMEOUT);348 if (IS_ERR(skb)) {349 err = PTR_ERR(skb);350 bt_dev_err(hdev, "Failed to get fw version (error: %d)", err);351 return err;352 }353 354 rsp = skb_pull_data(skb, sizeof(struct aml_tci_rsp));355 if (!rsp)356 goto exit;357 358 if (rsp->opcode != AML_BT_HCI_VENDOR_CMD || rsp->status != 0x00) {359 bt_dev_err(hdev, "dump version, error response (0x%04X):(%d)",360 rsp->opcode, rsp->status);361 err = -EINVAL;362 goto exit;363 }364 365 fw_ver = (u8 *)rsp + AML_EVT_HEAD_SIZE;366 bt_dev_info(hdev, "fw_version: date = %02x.%02x, number = 0x%02x%02x",367 *(fw_ver + 1), *fw_ver, *(fw_ver + 3), *(fw_ver + 2));368 369exit:370 kfree_skb(skb);371 return err;372}373 374static int aml_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)375{376 struct aml_tci_rsp *rsp = NULL;377 struct sk_buff *skb;378 int err = 0;379 380 bt_dev_info(hdev, "set bdaddr (%pM)", bdaddr);381 skb = __hci_cmd_sync_ev(hdev, AML_BT_HCI_VENDOR_CMD,382 sizeof(bdaddr_t), bdaddr,383 HCI_EV_CMD_COMPLETE, HCI_INIT_TIMEOUT);384 if (IS_ERR(skb)) {385 err = PTR_ERR(skb);386 bt_dev_err(hdev, "Failed to set bdaddr (error: %d)", err);387 return err;388 }389 390 rsp = skb_pull_data(skb, sizeof(struct aml_tci_rsp));391 if (!rsp)392 goto exit;393 394 if (rsp->opcode != AML_BT_HCI_VENDOR_CMD || rsp->status != 0x00) {395 bt_dev_err(hdev, "error response (0x%x):(%d)", rsp->opcode, rsp->status);396 err = -EINVAL;397 goto exit;398 }399 400exit:401 kfree_skb(skb);402 return err;403}404 405static int aml_check_bdaddr(struct hci_dev *hdev)406{407 struct hci_rp_read_bd_addr *paddr;408 struct sk_buff *skb;409 int err;410 411 if (bacmp(&hdev->public_addr, BDADDR_ANY))412 return 0;413 414 skb = __hci_cmd_sync(hdev, HCI_OP_READ_BD_ADDR, 0, NULL,415 HCI_INIT_TIMEOUT);416 if (IS_ERR(skb)) {417 err = PTR_ERR(skb);418 bt_dev_err(hdev, "Failed to read bdaddr (error: %d)", err);419 return err;420 }421 422 paddr = skb_pull_data(skb, sizeof(struct hci_rp_read_bd_addr));423 if (!paddr)424 goto exit;425 426 if (!bacmp(&paddr->bdaddr, AML_BDADDR_DEFAULT)) {427 bt_dev_info(hdev, "amlbt using default bdaddr (%pM)", &paddr->bdaddr);428 set_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks);429 }430 431exit:432 kfree_skb(skb);433 return 0;434}435 436static int aml_config_rf(struct hci_dev *hdev, bool is_coex)437{438 u32 value = AML_RF_ANT_DOUBLE;439 440 /* Use a single antenna when co-existing with wifi */441 if (is_coex)442 value = AML_RF_ANT_SINGLE;443 444 return aml_send_tci_cmd(hdev, AML_TCI_CMD_WRITE,445 AML_OP_RF_CFG,446 &value, sizeof(value));447}448 449static int aml_parse_dt(struct aml_serdev *amldev)450{451 struct device *pdev = amldev->dev;452 453 amldev->bt_en_gpio = devm_gpiod_get(pdev, "enable",454 GPIOD_OUT_LOW);455 if (IS_ERR(amldev->bt_en_gpio)) {456 dev_err(pdev, "Failed to acquire enable gpios");457 return PTR_ERR(amldev->bt_en_gpio);458 }459 460 if (device_property_read_string(pdev, "firmware-name",461 &amldev->firmware_name)) {462 dev_err(pdev, "Failed to acquire firmware path");463 return -ENODEV;464 }465 466 amldev->bt_supply = devm_regulator_get(pdev, "vddio");467 if (IS_ERR(amldev->bt_supply)) {468 dev_err(pdev, "Failed to acquire regulator");469 return PTR_ERR(amldev->bt_supply);470 }471 472 amldev->lpo_clk = devm_clk_get(pdev, NULL);473 if (IS_ERR(amldev->lpo_clk)) {474 dev_err(pdev, "Failed to acquire clock source");475 return PTR_ERR(amldev->lpo_clk);476 }477 478 return 0;479}480 481static int aml_power_on(struct aml_serdev *amldev)482{483 int err;484 485 err = regulator_enable(amldev->bt_supply);486 if (err) {487 dev_err(amldev->dev, "Failed to enable regulator: (%d)", err);488 return err;489 }490 491 err = clk_prepare_enable(amldev->lpo_clk);492 if (err) {493 dev_err(amldev->dev, "Failed to enable lpo clock: (%d)", err);494 return err;495 }496 497 gpiod_set_value_cansleep(amldev->bt_en_gpio, 1);498 499 /* Wait 20ms for bluetooth controller power on */500 msleep(20);501 return 0;502}503 504static int aml_power_off(struct aml_serdev *amldev)505{506 gpiod_set_value_cansleep(amldev->bt_en_gpio, 0);507 508 clk_disable_unprepare(amldev->lpo_clk);509 510 regulator_disable(amldev->bt_supply);511 512 return 0;513}514 515static int aml_set_baudrate(struct hci_uart *hu, unsigned int speed)516{517 /* update controller baudrate */518 if (aml_update_chip_baudrate(hu->hdev, speed) != 0) {519 bt_dev_err(hu->hdev, "Failed to update baud rate");520 return -EINVAL;521 }522 523 /* update local baudrate */524 serdev_device_set_baudrate(hu->serdev, speed);525 526 return 0;527}528 529/* Initialize protocol */530static int aml_open(struct hci_uart *hu)531{532 struct aml_serdev *amldev = serdev_device_get_drvdata(hu->serdev);533 struct aml_data *aml_data;534 int err;535 536 err = aml_parse_dt(amldev);537 if (err)538 return err;539 540 if (!hci_uart_has_flow_control(hu)) {541 bt_dev_err(hu->hdev, "no flow control");542 return -EOPNOTSUPP;543 }544 545 aml_data = kzalloc(sizeof(*aml_data), GFP_KERNEL);546 if (!aml_data)547 return -ENOMEM;548 549 skb_queue_head_init(&aml_data->txq);550 551 hu->priv = aml_data;552 553 return 0;554}555 556static int aml_close(struct hci_uart *hu)557{558 struct aml_serdev *amldev = serdev_device_get_drvdata(hu->serdev);559 struct aml_data *aml_data = hu->priv;560 561 skb_queue_purge(&aml_data->txq);562 kfree_skb(aml_data->rx_skb);563 kfree(aml_data);564 565 hu->priv = NULL;566 567 return aml_power_off(amldev);568}569 570static int aml_flush(struct hci_uart *hu)571{572 struct aml_data *aml_data = hu->priv;573 574 skb_queue_purge(&aml_data->txq);575 576 return 0;577}578 579static int aml_setup(struct hci_uart *hu)580{581 struct aml_serdev *amldev = serdev_device_get_drvdata(hu->serdev);582 struct hci_dev *hdev = amldev->serdev_hu.hdev;583 int err;584 585 /* Setup bdaddr */586 hdev->set_bdaddr = aml_set_bdaddr;587 588 err = aml_power_on(amldev);589 if (err)590 return err;591 592 err = aml_set_baudrate(hu, amldev->serdev_hu.proto->oper_speed);593 if (err)594 return err;595 596 err = aml_download_firmware(hdev, amldev->firmware_name);597 if (err)598 return err;599 600 err = aml_config_rf(hdev, amldev->aml_dev_data->is_coex);601 if (err)602 return err;603 604 err = aml_start_chip(hdev);605 if (err)606 return err;607 608 /* Wait 60ms for controller startup */609 msleep(60);610 611 err = aml_dump_fw_version(hdev);612 if (err)613 return err;614 615 err = aml_send_reset(hdev);616 if (err)617 return err;618 619 err = aml_check_bdaddr(hdev);620 if (err)621 return err;622 623 return 0;624}625 626static int aml_enqueue(struct hci_uart *hu, struct sk_buff *skb)627{628 struct aml_data *aml_data = hu->priv;629 630 skb_queue_tail(&aml_data->txq, skb);631 632 return 0;633}634 635static struct sk_buff *aml_dequeue(struct hci_uart *hu)636{637 struct aml_data *aml_data = hu->priv;638 struct sk_buff *skb;639 640 skb = skb_dequeue(&aml_data->txq);641 642 /* Prepend skb with frame type */643 if (skb)644 memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);645 646 return skb;647}648 649static int aml_recv(struct hci_uart *hu, const void *data, int count)650{651 struct aml_data *aml_data = hu->priv;652 int err;653 654 aml_data->rx_skb = h4_recv_buf(hu->hdev, aml_data->rx_skb, data, count,655 aml_recv_pkts,656 ARRAY_SIZE(aml_recv_pkts));657 if (IS_ERR(aml_data->rx_skb)) {658 err = PTR_ERR(aml_data->rx_skb);659 bt_dev_err(hu->hdev, "Frame reassembly failed (%d)", err);660 aml_data->rx_skb = NULL;661 return err;662 }663 664 return count;665}666 667static const struct hci_uart_proto aml_hci_proto = {668 .id = HCI_UART_AML,669 .name = "AML",670 .init_speed = 115200,671 .oper_speed = 4000000,672 .open = aml_open,673 .close = aml_close,674 .setup = aml_setup,675 .flush = aml_flush,676 .recv = aml_recv,677 .enqueue = aml_enqueue,678 .dequeue = aml_dequeue,679};680 681static void aml_device_driver_shutdown(struct device *dev)682{683 struct aml_serdev *amldev = dev_get_drvdata(dev);684 685 aml_power_off(amldev);686}687 688static int aml_serdev_probe(struct serdev_device *serdev)689{690 struct aml_serdev *amldev;691 int err;692 693 amldev = devm_kzalloc(&serdev->dev, sizeof(*amldev), GFP_KERNEL);694 if (!amldev)695 return -ENOMEM;696 697 amldev->serdev_hu.serdev = serdev;698 amldev->dev = &serdev->dev;699 serdev_device_set_drvdata(serdev, amldev);700 701 err = hci_uart_register_device(&amldev->serdev_hu, &aml_hci_proto);702 if (err)703 return dev_err_probe(amldev->dev, err,704 "Failed to register hci uart device");705 706 amldev->aml_dev_data = device_get_match_data(&serdev->dev);707 708 return 0;709}710 711static void aml_serdev_remove(struct serdev_device *serdev)712{713 struct aml_serdev *amldev = serdev_device_get_drvdata(serdev);714 715 hci_uart_unregister_device(&amldev->serdev_hu);716}717 718static const struct aml_device_data data_w155s2 = {719 .iccm_offset = 256 * 1024,720};721 722static const struct aml_device_data data_w265s2 = {723 .iccm_offset = 384 * 1024,724};725 726static const struct of_device_id aml_bluetooth_of_match[] = {727 { .compatible = "amlogic,w155s2-bt", .data = &data_w155s2 },728 { .compatible = "amlogic,w265s2-bt", .data = &data_w265s2 },729 { /* sentinel */ },730};731MODULE_DEVICE_TABLE(of, aml_bluetooth_of_match);732 733static struct serdev_device_driver aml_serdev_driver = {734 .probe = aml_serdev_probe,735 .remove = aml_serdev_remove,736 .driver = {737 .name = "hci_uart_aml",738 .of_match_table = aml_bluetooth_of_match,739 .shutdown = aml_device_driver_shutdown,740 },741};742 743int __init aml_init(void)744{745 serdev_device_driver_register(&aml_serdev_driver);746 747 return hci_uart_register_proto(&aml_hci_proto);748}749 750int __exit aml_deinit(void)751{752 serdev_device_driver_unregister(&aml_serdev_driver);753 754 return hci_uart_unregister_proto(&aml_hci_proto);755}756