STRUCT BCM_DEVICE(9)

💖 struct bcm_device — device driver resources 💖

okay so this is a page from the Kernel API Manual, section 9, and it's literally all about struct bcm_device bestie — one big gorgeous bundle of every resource a Bluetooth-over-UART driver could ever need. grab a snack, we're going member by member 🍓

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✨ NAME ✨

struct bcm_device — device driver resources. that's it, that's the whole vibe. it's the resource container, the little suitcase the driver carries around 💅

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🦋 SYNOPSIS 🦋

here's the whole struct, no cap, copied exactly:

struct bcm_device {
    struct hci_uart         serdev_hu;
    struct list_head        list;
    struct device           *dev;
    const char              *name;
    struct gpio_desc        *device_wakeup;
    struct gpio_desc        *shutdown;
    struct gpio_desc        *reset;
    int (*set_device_wakeup)(struct bcm_device *, bool);
    int (*set_shutdown)(struct bcm_device *, bool);
  #ifdef CONFIG_ACPI;
    acpi_handle btlp, btpu, btpd;
    int gpio_count;
    int gpio_int_idx;
  #endif;
    struct clk              *txco_clk;
    struct clk              *lpo_clk;
    struct regulator_bulk_data supplies[BCM_NUM_SUPPLIES];
    bool res_enabled;
    u32 init_speed;
    u32 oper_speed;
    int irq;
    bool irq_active_low;
    bool irq_acquired;
  #ifdef CONFIG_PM;
    struct hci_uart         *hu;
    bool is_suspended;
  #endif;
    bool no_early_set_baudrate;
    bool drive_rts_on_open;
    bool no_uart_clock_set;
    bool use_autobaud_mode;
    u8 pcm_int_params[5];
    u32 max_autobaud_speed;
   };

notice the #ifdef blocks? those fields only show up when CONFIG_ACPI or CONFIG_PM are on — conditional queen behavior 👑

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🌸 Members 🌸

this is the part where each field gets its moment. every single one, in order, no skipping. let's go 🫶

• serdev_hu — the HCI UART controller struct. main character energy fr.
• list — the bcm_device_list node. it's how this device links up with its friends 💖
• dev — the physical UART slave.
• name — the device name that gets logged by the bt_dev_*() functions. it's giving name tag at a party.
• device_wakeup — the BT_WAKE pin. assert = the Bluetooth device must wake up or remain awake; deassert = it may sleep when the sleep criteria are met. so basically a "u up?" pin 😭
• shutdown — the BT_REG_ON pin, which powers the Bluetooth device's internal regulators up or down. iconic power move.
• reset — the BT_RST_N pin. active low, resets the Bluetooth logic core. the factory-reset button of pins 💅
• set_device_wakeup — callback to toggle the BT_WAKE pin, either by poking at device_wakeup directly or by calling btlp.
• set_shutdown — callback to toggle the BT_REG_ON pin, either by poking at shutdown directly or by calling btpu/btpd.
• btlp — the Apple ACPI method that toggles the BT_WAKE pin ("Bluetooth Low Power"). so fancy ✨
• btpu — the Apple ACPI method that drives the BT_REG_ON pin high ("Bluetooth Power Up"). up up up 🎈
• btpd — the Apple ACPI method that drives the BT_REG_ON pin low ("Bluetooth Power Down"). nap time 😴
• gpio_count — internal counter for the GPIO resources tied to the ACPI device.
• gpio_int_idx — the index in _CRS for the GpioInt resource. lowkey niche but we respect it.
• txco_clk — the external reference frequency clock the Bluetooth device uses.
• lpo_clk — the external LPO clock the Bluetooth device uses. two clocks, double the slay 🕰️
• supplies — the VBAT and VDDIO supplies the Bluetooth device uses. yes bestie, it eats.
• res_enabled — whether the clocks and supplies are prepared and enabled. both. not one, both 🔥
• init_speed — the default baudrate of the Bluetooth device. the host UART starts out at this baudrate so it can configure the Bluetooth device for oper_speed. it's giving starter speed.
• oper_speed — the preferred baudrate of the Bluetooth device. set to 0 if init_speed is already the preferred baudrate. no point glamming twice 💄
• irq — the interrupt triggered by the HOST_WAKE_BT pin.
• irq_active_low — whether irq is active low.
• irq_acquired — a flag showing whether the IRQ handler has been assigned. like a little "taken ✅" sticker.
• hu — pointer to the HCI UART controller struct, used to disable flow control during runtime suspend and system sleep. (only around when CONFIG_PM is on, iykyk 🧚)
• is_suspended — whether flow control is currently disabled.
• no_early_set_baudrate — don't set_baudrate before setup. literally just don't 🚫
• drive_rts_on_open — drive the RTS signal on ->open when the platform requires it.
• no_uart_clock_set — the UART clock set command for >3Mbps mode is unavailable. sad but true 💀
• use_autobaud_mode — start the Bluetooth device in autobaud mode.
• pcm_int_params — keep the initial PCM configuration. preserve the lore 🙈
• max_autobaud_speed — the max baudrate the device supports in autobaud mode. fastest girlie in the room ⭐

ngl this struct is long but every single field pulls its weight. no filler, no dead weight, just resource management excellence 👑

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/bluetooth/hci_bcm.c
• struct bcm_device_data(9)

go read hci_bcm.c bestie, it's where all this actually lives 🐛

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that's the whole page!! this one lives under ./drivers/bluetooth and it's dated October 2026 — so yes, we're reading the future, and it's giving kernel API excellence 💜 periodt.