Explore devices connected via UART to find BCM2E7C Bluetooth chip

[saper]

Task

The MacBookPro13,1 has an unrecognized UART controller (Sunrise Point Intel platform)

none1@pci0:0:30:0:      class=0x118000 rev=0x21 hdr=0x00 vendor=0x8086 device=0x9d27 subvendor=0x8086 subdevice=0x7270
    vendor     = 'Intel Corporation'
    device     = 'Sunrise Point-LP Serial IO UART Controller'
    class      = dasp

ACPI tables suggest the UART is used to attach a Bluetooth chip:

            Device (URT0)  // ...

            Scope (URT0)
            {
                Device (BLTH)
                {
                    Name (_HID, EisaId ("BCM2E7C"))  // _HID: Hardware ID
                    Name (_CID, "apple-uart-blth")  // _CID: Compatible ID
                    Name (_UID, One)  // _UID: Unique ID
                    Name (_ADR, Zero)  // _ADR: Address
                    //   ....
                }
            }  

Notes

Links

• Not detecting Bluetooth host controller on Macbook8,1+Linux 5.15 leifliddy/macbook12-bluetooth-driver#18 Not detecting Bluetooth host controller on Macbook8,1+Linux 5.15
• https://bugzilla.kernel.org/show_bug.cgi?id=110901 Macbook8,1 12-inch (Early 2015) Bluetooth not working