dpll: add phase_offset_avg_factor_get/set callback ops

Add new callback operations for a dpll device:
- phase_offset_avg_factor_get(...) - to obtain current phase offset
  averaging factor from dpll device,
- phase_offset_avg_factor_set(...) - to set phase offset averaging factor

Obtain the factor value using the get callback and provide it to the user
if the device driver implement this callback. Execute the set callback upon
user requests, if the driver implement it.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
v2:
* do not require 'set' callback to retrieve current value
* always call 'set' callback regardless of current value
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Link: https://patch.msgid.link/20250927084912.2343597-3-ivecera@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/dpll/dpll_netlink.c

@@ -164,6 +164,27 @@ dpll_msg_add_phase_offset_monitor(struct sk_buff *msg, struct dpll_device *dpll,
 	return 0;
 }
 
+static int
+dpll_msg_add_phase_offset_avg_factor(struct sk_buff *msg,
+				     struct dpll_device *dpll,
+				     struct netlink_ext_ack *extack)
+{
+	const struct dpll_device_ops *ops = dpll_device_ops(dpll);
+	u32 factor;
+	int ret;
+
+	if (ops->phase_offset_avg_factor_get) {
+		ret = ops->phase_offset_avg_factor_get(dpll, dpll_priv(dpll),
+						       &factor, extack);
+		if (ret)
+			return ret;
+		if (nla_put_u32(msg, DPLL_A_PHASE_OFFSET_AVG_FACTOR, factor))
+			return -EMSGSIZE;
+	}
+
+	return 0;
+}
+
 static int
 dpll_msg_add_lock_status(struct sk_buff *msg, struct dpll_device *dpll,
 			 struct netlink_ext_ack *extack)
@@ -675,6 +696,9 @@ dpll_device_get_one(struct dpll_device *dpll, struct sk_buff *msg,
 	if (nla_put_u32(msg, DPLL_A_TYPE, dpll->type))
 		return -EMSGSIZE;
 	ret = dpll_msg_add_phase_offset_monitor(msg, dpll, extack);
+	if (ret)
+		return ret;
+	ret = dpll_msg_add_phase_offset_avg_factor(msg, dpll, extack);
 	if (ret)
 		return ret;
 
@@ -839,6 +863,23 @@ dpll_phase_offset_monitor_set(struct dpll_device *dpll, struct nlattr *a,
 					     extack);
 }
 
+static int
+dpll_phase_offset_avg_factor_set(struct dpll_device *dpll, struct nlattr *a,
+				 struct netlink_ext_ack *extack)
+{
+	const struct dpll_device_ops *ops = dpll_device_ops(dpll);
+	u32 factor = nla_get_u32(a);
+
+	if (!ops->phase_offset_avg_factor_set) {
+		NL_SET_ERR_MSG_ATTR(extack, a,
+				    "device not capable of changing phase offset average factor");
+		return -EOPNOTSUPP;
+	}
+
+	return ops->phase_offset_avg_factor_set(dpll, dpll_priv(dpll), factor,
+						extack);
+}
+
 static int
 dpll_pin_freq_set(struct dpll_pin *pin, struct nlattr *a,
 		  struct netlink_ext_ack *extack)
@@ -1736,14 +1777,25 @@ int dpll_nl_device_get_doit(struct sk_buff *skb, struct genl_info *info)
 static int
 dpll_set_from_nlattr(struct dpll_device *dpll, struct genl_info *info)
 {
-	int ret;
+	struct nlattr *a;
+	int rem, ret;
 
-	if (info->attrs[DPLL_A_PHASE_OFFSET_MONITOR]) {
+	nla_for_each_attr(a, genlmsg_data(info->genlhdr),
-		struct nlattr *a = info->attrs[DPLL_A_PHASE_OFFSET_MONITOR];
+			  genlmsg_len(info->genlhdr), rem) {
-
+		switch (nla_type(a)) {
-		ret = dpll_phase_offset_monitor_set(dpll, a, info->extack);
+		case DPLL_A_PHASE_OFFSET_MONITOR:
-		if (ret)
+			ret = dpll_phase_offset_monitor_set(dpll, a,
-			return ret;
+							    info->extack);
+			if (ret)
+				return ret;
+			break;
+		case DPLL_A_PHASE_OFFSET_AVG_FACTOR:
+			ret = dpll_phase_offset_avg_factor_set(dpll, a,
+							       info->extack);
+			if (ret)
+				return ret;
+			break;
+		}
 	}
 
 	return 0;

include/linux/dpll.h

@@ -38,6 +38,12 @@ struct dpll_device_ops {
 					void *dpll_priv,
 					enum dpll_feature_state *state,
 					struct netlink_ext_ack *extack);
+	int (*phase_offset_avg_factor_set)(const struct dpll_device *dpll,
+					   void *dpll_priv, u32 factor,
+					   struct netlink_ext_ack *extack);
+	int (*phase_offset_avg_factor_get)(const struct dpll_device *dpll,
+					   void *dpll_priv, u32 *factor,
+					   struct netlink_ext_ack *extack);
 };
 
 struct dpll_pin_ops {