[PATCH v3 0/2] AMD Promontory 21 xHCI temperature hwmon support

[Jihong Min <hurryman2212@gmail.com>]

Hi,

This series adds hwmon support for the temperature sensor exposed by AMD
Promontory 21 (PROM21) xHCI controllers.

Patch 1 adds a small generic auxiliary-device registration path to xhci-pci
for selected xHCI PCI controllers.

Patch 2 adds the PROM21 hwmon driver. The driver binds through the
auxiliary bus, reads the PROM21 xHCI temperature value through the
controller MMIO BAR, and exposes it through hwmon.

Changes in v3:
- Use pci_match_id() with a plain struct pci_device_id table and
  PCI_DEVICE_DATA() for the auxiliary device name.
- Remove conditional compilation blocks from xhci-pci.c and guard the
  auxiliary add/remove call sites with IS_ENABLED().
- Use the full AMD Promontory 21 name in commit messages, Kconfig help
  text, and documentation.
- Document the PROM21 chipset IP relationship to AMD 6xx/8xx series
  chipsets.
- Change the default hwmon read behavior to not wake the xHCI PCI device.
  Return -EPERM when the device is suspended, matching the amdgpu
  precedent, and keep pm as an opt-in module parameter for runtime PM
  state changes during device memory access.
- Keep Documentation/hwmon/index.rst sorted.
- Small refactoring: remove the duplicate PROM21 PCI ID check from the
  hwmon driver and use the hwmon device name as the auxiliary device
  suffix.

v2:
https://lore.kernel.org/r/cover.1778099627.git.hurryman2212@gmail.com

v1:
https://lore.kernel.org/r/20260506032939.92351-1-hurryman2212@gmail.com

Jihong Min (2):
  usb: xhci-pci: add generic auxiliary device interface
  hwmon: add AMD Promontory 21 xHCI temperature sensor support

 Documentation/hwmon/index.rst        |   1 +
 Documentation/hwmon/prom21-hwmon.rst |  86 ++++++++
 drivers/hwmon/Kconfig                |  11 +
 drivers/hwmon/Makefile               |   1 +
 drivers/hwmon/prom21-hwmon.c         | 293 +++++++++++++++++++++++++++
 drivers/usb/host/Kconfig             |  10 +
 drivers/usb/host/xhci-pci.c          |  83 ++++++++
 7 files changed, 485 insertions(+)
 create mode 100644 Documentation/hwmon/prom21-hwmon.rst
 create mode 100644 drivers/hwmon/prom21-hwmon.c

-- 
2.53.0