dpll: add phase-adjust-gran pin attribute

Phase-adjust values are currently limited by a min-max range. Some
hardware requires, for certain pin types, that values be multiples of
a specific granularity, as in the zl3073x driver.

Add a `phase-adjust-gran` pin attribute and an appropriate field in
dpll_pin_properties. If set by the driver, use its value to validate
user-provided phase-adjust values.

Reviewed-by: Michal Schmidt <mschmidt@redhat.com>
Reviewed-by: Petr Oros <poros@redhat.com>
Tested-by: Prathosh Satish <Prathosh.Satish@microchip.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>
Link: https://patch.msgid.link/20251029153207.178448-2-ivecera@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 27 insertions, 16 deletions

diff --git a/Documentation/driver-api/dpll.rst b/Documentation/driver-api/dpll.rst
index be1fc643b645..83118c728ed9 100644
--- a/Documentation/driver-api/dpll.rst
+++ b/Documentation/driver-api/dpll.rst
@@ -198,26 +198,28 @@ be requested with the same attribute with ``DPLL_CMD_DEVICE_SET`` command.
   ================================== ======================================
 
 Device may also provide ability to adjust a signal phase on a pin.
-If pin phase adjustment is supported, minimal and maximal values that pin
-handle shall be provide to the user on ``DPLL_CMD_PIN_GET`` respond
-with ``DPLL_A_PIN_PHASE_ADJUST_MIN`` and ``DPLL_A_PIN_PHASE_ADJUST_MAX``
+If pin phase adjustment is supported, minimal and maximal values and
+granularity that pin handle shall be provided to the user on
+``DPLL_CMD_PIN_GET`` respond with ``DPLL_A_PIN_PHASE_ADJUST_MIN``,
+``DPLL_A_PIN_PHASE_ADJUST_MAX`` and ``DPLL_A_PIN_PHASE_ADJUST_GRAN``
 attributes. Configured phase adjust value is provided with
 ``DPLL_A_PIN_PHASE_ADJUST`` attribute of a pin, and value change can be
 requested with the same attribute with ``DPLL_CMD_PIN_SET`` command.
 
-  =============================== ======================================
-  ``DPLL_A_PIN_ID``               configured pin id
-  ``DPLL_A_PIN_PHASE_ADJUST_MIN`` attr minimum value of phase adjustment
-  ``DPLL_A_PIN_PHASE_ADJUST_MAX`` attr maximum value of phase adjustment
-  ``DPLL_A_PIN_PHASE_ADJUST``     attr configured value of phase
-                                  adjustment on parent dpll device
-  ``DPLL_A_PIN_PARENT_DEVICE``    nested attribute for requesting
-                                  configuration on given parent dpll
-                                  device
-    ``DPLL_A_PIN_PARENT_ID``      parent dpll device id
-    ``DPLL_A_PIN_PHASE_OFFSET``   attr measured phase difference
-                                  between a pin and parent dpll device
-  =============================== ======================================
+  ================================ ==========================================
+  ``DPLL_A_PIN_ID``                configured pin id
+  ``DPLL_A_PIN_PHASE_ADJUST_GRAN`` attr granularity of phase adjustment value
+  ``DPLL_A_PIN_PHASE_ADJUST_MIN``  attr minimum value of phase adjustment
+  ``DPLL_A_PIN_PHASE_ADJUST_MAX``  attr maximum value of phase adjustment
+  ``DPLL_A_PIN_PHASE_ADJUST``      attr configured value of phase
+                                   adjustment on parent dpll device
+  ``DPLL_A_PIN_PARENT_DEVICE``     nested attribute for requesting
+                                   configuration on given parent dpll
+                                   device
+    ``DPLL_A_PIN_PARENT_ID``       parent dpll device id
+    ``DPLL_A_PIN_PHASE_OFFSET``    attr measured phase difference
+                                   between a pin and parent dpll device
+  ================================ ==========================================
 
 All phase related values are provided in pico seconds, which represents
 time difference between signals phase. The negative value means that
@@ -384,6 +386,8 @@ according to attribute purpose.
                                        frequencies
       ``DPLL_A_PIN_ANY_FREQUENCY_MIN`` attr minimum value of frequency
       ``DPLL_A_PIN_ANY_FREQUENCY_MAX`` attr maximum value of frequency
+    ``DPLL_A_PIN_PHASE_ADJUST_GRAN``   attr granularity of phase
+                                       adjustment value
     ``DPLL_A_PIN_PHASE_ADJUST_MIN``    attr minimum value of phase
                                        adjustment
     ``DPLL_A_PIN_PHASE_ADJUST_MAX``    attr maximum value of phase
diff --git a/Documentation/netlink/specs/dpll.yaml b/Documentation/netlink/specs/dpll.yaml
index 80728f6f9bc8..78d0724d7e12 100644
--- a/Documentation/netlink/specs/dpll.yaml
+++ b/Documentation/netlink/specs/dpll.yaml
@@ -440,6 +440,12 @@ attribute-sets:
         doc: |
           Capable pin provides list of pins that can be bound to create a
           reference-sync pin pair.
+      -
+        name: phase-adjust-gran
+        type: u32
+        doc: |
+          Granularity of phase adjustment, in picoseconds. The value of
+          phase adjustment must be a multiple of this granularity.
 
   -
     name: pin-parent-device
@@ -616,6 +622,7 @@ operations:
             - capabilities
             - parent-device
             - parent-pin
+            - phase-adjust-gran
             - phase-adjust-min
             - phase-adjust-max
             - phase-adjust