[PATCH v4 0/2] hwmon: add Altera SoC FPGA hardware monitoring support

[tze.yee.ng@altera.com]

From: Tze Yee Ng <tze.yee.ng@altera.com>

This series adds hardware monitor support for Altera SoC FPGA devices.
Temperature and voltage sensors are accessed through the Stratix 10
service layer and Secure Device Manager (SDM).

Patch 1 adds async HWMON SMC support to stratix10-svc and registers the
socfpga-hwmon platform device.

Patch 2 adds the socfpga-hwmon driver, documentation, Kconfig, and
MAINTAINERS entry.

Changes in v4:
- Address maintainer and review feedback on socfpga-hwmon (Patch 2):
  - Register devm_add_action_or_reset() before
    devm_hwmon_device_register_with_info() to fix devres teardown order
  - Remove unreferenced completion and pre-poll
    wait_for_completion_io_timeout() from async reads; poll directly
    with a retry loop after async_send()
- No functional changes in Patch 1

Changes in v3:
- Address review feedback on socfpga-hwmon (Patch 2):
  - Fix 16-bit Q8.8 temperature sign extension
  - Drop unused async callback; pass NULL to stratix10_svc_async_send()
  - Document and retain pre-poll wait (RSU pattern; firmware needs time
    before async_poll())
  - Align async poll retry behaviour with RSU
  - Use uninterruptible wait_for_completion_timeout() for sync reads
  - Handle -EINVAL and -EOPNOTSUPP when falling back to sync mode
  - Defer SVC channel cleanup via devm_add_action_or_reset()
- No functional changes in Patch 1

Changes in v2:
- Drop altr,stratix10-hwmon DT binding and intel,stratix10-svc hwmon
  child property
- Drop Stratix 10 SoCDK DTS hwmon node
- Register socfpga-hwmon from stratix10-svc (RSU-style)
- Replace DT channel parsing with hardcoded Stratix 10 and Agilex tables
- Rename driver/module to socfpga-hwmon 
  (CONFIG_SENSORS_ALTERA_SOCFPGA_HWMON)
- Add Agilex channel support
- Fix SDM value conversion (Q8.8 degrees Celsius and Q16 volts to hwmon
  millidegrees/millivolts)
- Improve sync-mode error handling via last_err

Previous version:
  https://lore.kernel.org/all/cover.1783062999.git.tze.yee.ng@altera.com/

Tze Yee Ng (2):
  firmware: stratix10-svc: add async HWMON read commands and register
    socfpga-hwmon device
  hwmon: add Altera SoC FPGA hardware monitoring driver

 Documentation/hwmon/index.rst                |   1 +
 Documentation/hwmon/socfpga-hwmon.rst        |  34 ++
 MAINTAINERS                                  |   8 +
 drivers/firmware/stratix10-svc.c             |  46 +-
 drivers/hwmon/Kconfig                        |  10 +
 drivers/hwmon/Makefile                       |   1 +
 drivers/hwmon/socfpga-hwmon.c                | 577 +++++++++++++++++++
 include/linux/firmware/intel/stratix10-smc.h |  38 ++
 8 files changed, 712 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/hwmon/socfpga-hwmon.rst
 create mode 100644 drivers/hwmon/socfpga-hwmon.c

-- 
2.43.7