Currently, userspace can retrieve the DPLL working mode but cannot
configure it. This prevents changing the device operation, such as
switching from manual to automatic mode and vice versa.

Add a new callback .mode_set() to struct dpll_device_ops. Extend
the netlink policy and device-set command handling to process
the DPLL_A_MODE attribute.  Update the netlink YAML specification
to include the mode attribute in the device-set operation.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
v2:
* fixed bitmap size in dpll_mode_set()
---
 Documentation/netlink/specs/dpll.yaml |  1 +
 drivers/dpll/dpll_netlink.c           | 44 +++++++++++++++++++++++++++
 drivers/dpll/dpll_nl.c                |  1 +
 include/linux/dpll.h                  |  2 ++
 4 files changed, 48 insertions(+)

diff --git a/Documentation/netlink/specs/dpll.yaml b/Documentation/netlink/specs/dpll.yaml
index 78d0724d7e12c..b55afa77eac4b 100644
--- a/Documentation/netlink/specs/dpll.yaml
+++ b/Documentation/netlink/specs/dpll.yaml
@@ -550,6 +550,7 @@ operations:
         request:
           attributes:
             - id
+            - mode
             - phase-offset-monitor
             - phase-offset-avg-factor
     -
diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index d6a0e272d7038..7a72d5d0d7093 100644
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c
@@ -853,6 +853,45 @@ int dpll_pin_change_ntf(struct dpll_pin *pin)
 }
 EXPORT_SYMBOL_GPL(dpll_pin_change_ntf);
 
+static int
+dpll_mode_set(struct dpll_device *dpll, struct nlattr *a,
+	      struct netlink_ext_ack *extack)
+{
+	const struct dpll_device_ops *ops = dpll_device_ops(dpll);
+	enum dpll_mode mode = nla_get_u32(a), old_mode;
+	DECLARE_BITMAP(modes, DPLL_MODE_MAX + 1) = { 0 };
+	int ret;
+
+	if (!(ops->mode_set && ops->supported_modes_get)) {
+		NL_SET_ERR_MSG_ATTR(extack, a,
+				    "dpll device does not support mode switch");
+		return -EOPNOTSUPP;
+	}
+
+	ret = ops->mode_get(dpll, dpll_priv(dpll), &old_mode, extack);
+	if (ret) {
+		NL_SET_ERR_MSG(extack, "unable to get current mode");
+		return ret;
+	}
+
+	if (mode == old_mode)
+		return 0;
+
+	ret = ops->supported_modes_get(dpll, dpll_priv(dpll), modes, extack);
+	if (ret) {
+		NL_SET_ERR_MSG(extack, "unable to get supported modes");
+		return ret;
+	}
+
+	if (!test_bit(mode, modes)) {
+		NL_SET_ERR_MSG(extack,
+			       "dpll device does not support requested mode");
+		return -EINVAL;
+	}
+
+	return ops->mode_set(dpll, dpll_priv(dpll), mode, extack);
+}
+
 static int
 dpll_phase_offset_monitor_set(struct dpll_device *dpll, struct nlattr *a,
 			      struct netlink_ext_ack *extack)
@@ -1808,6 +1847,11 @@ dpll_set_from_nlattr(struct dpll_device *dpll, struct genl_info *info)
 	nla_for_each_attr(a, genlmsg_data(info->genlhdr),
 			  genlmsg_len(info->genlhdr), rem) {
 		switch (nla_type(a)) {
+		case DPLL_A_MODE:
+			ret = dpll_mode_set(dpll, a, info->extack);
+			if (ret)
+				return ret;
+			break;
 		case DPLL_A_PHASE_OFFSET_MONITOR:
 			ret = dpll_phase_offset_monitor_set(dpll, a,
 							    info->extack);
diff --git a/drivers/dpll/dpll_nl.c b/drivers/dpll/dpll_nl.c
index 36d11ff195df4..a2b22d4921142 100644
--- a/drivers/dpll/dpll_nl.c
+++ b/drivers/dpll/dpll_nl.c
@@ -45,6 +45,7 @@ static const struct nla_policy dpll_device_get_nl_policy[DPLL_A_ID + 1] = {
 /* DPLL_CMD_DEVICE_SET - do */
 static const struct nla_policy dpll_device_set_nl_policy[DPLL_A_PHASE_OFFSET_AVG_FACTOR + 1] = {
 	[DPLL_A_ID] = { .type = NLA_U32, },
+	[DPLL_A_MODE] = NLA_POLICY_RANGE(NLA_U32, 1, 2),
 	[DPLL_A_PHASE_OFFSET_MONITOR] = NLA_POLICY_MAX(NLA_U32, 1),
 	[DPLL_A_PHASE_OFFSET_AVG_FACTOR] = { .type = NLA_U32, },
 };
diff --git a/include/linux/dpll.h b/include/linux/dpll.h
index 912a2ca3e0ee7..c6d0248fa5273 100644
--- a/include/linux/dpll.h
+++ b/include/linux/dpll.h
@@ -20,6 +20,8 @@ struct dpll_pin_esync;
 struct dpll_device_ops {
 	int (*mode_get)(const struct dpll_device *dpll, void *dpll_priv,
 			enum dpll_mode *mode, struct netlink_ext_ack *extack);
+	int (*mode_set)(const struct dpll_device *dpll, void *dpll_priv,
+			enum dpll_mode mode, struct netlink_ext_ack *extack);
 	int (*supported_modes_get)(const struct dpll_device *dpll,
 				   void *dpll_priv, unsigned long *modes,
 				   struct netlink_ext_ack *extack);
-- 
2.52.0