[PATCH net-next v3 0/3] dpll: add frequency monitoring feature

[Ivan Vecera <ivecera@redhat.com>]

This series adds support for monitoring the measured input frequency
of DPLL input pins via the DPLL netlink interface.

Some DPLL devices can measure the actual frequency being received on
input pins. The approach mirrors the existing phase-offset-monitor
feature: a device-level attribute (DPLL_A_FREQUENCY_MONITOR) enables
or disables monitoring, and a per-pin attribute
(DPLL_A_PIN_MEASURED_FREQUENCY) exposes the measured frequency in
millihertz (mHz) when monitoring is enabled.

Patch 1 adds the new attributes to the DPLL netlink spec (dpll.yaml),
the DPLL_PIN_MEASURED_FREQUENCY_DIVIDER constant, regenerates the
auto-generated UAPI header and netlink policy, and updates
Documentation/driver-api/dpll.rst.

Patch 2 adds the callback operations (freq_monitor_get/set for
devices, measured_freq_get for pins) and the corresponding netlink
GET/SET handlers in the DPLL core. The core only invokes
measured_freq_get when the frequency monitor is enabled on the parent
device. The freq_monitor_get callback is required when measured_freq_get
is provided.

Patch 3 implements the feature in the ZL3073x driver by extracting
a common measurement latch helper from the existing FFO update path,
adding a frequency measurement function, and wiring up the new
callbacks.

Changes v2 -> v3:
- Improved frequency-monitor doc wording (Jakub)
- Changed measured-frequency to mHz with divider constant (Jakub)
- Made freq_monitor_get required when measured_freq_get is present (Jakub)

Changes v1 -> v2:
- Renamed actual-frequency to measured-frequency (Vadim)

Signed-off-by: Ivan Vecera <ivecera@redhat.com>

Ivan Vecera (3):
  dpll: add frequency monitoring to netlink spec
  dpll: add frequency monitoring callback ops
  dpll: zl3073x: implement frequency monitoring

 Documentation/driver-api/dpll.rst     |  20 ++++++
 Documentation/netlink/specs/dpll.yaml |  35 +++++++++
 drivers/dpll/dpll_netlink.c           |  92 ++++++++++++++++++++++++
 drivers/dpll/dpll_nl.c                |   5 +-
 drivers/dpll/zl3073x/core.c           |  88 +++++++++++++++++++----
 drivers/dpll/zl3073x/dpll.c           | 100 ++++++++++++++++++++++++--
 drivers/dpll/zl3073x/dpll.h           |   2 +
 drivers/dpll/zl3073x/ref.h            |  14 ++++
 include/linux/dpll.h                  |  10 +++
 include/uapi/linux/dpll.h             |   5 +-
 10 files changed, 351 insertions(+), 20 deletions(-)

-- 
2.52.0