[PATCH net-next v4 09/14] dpll: dpllsim: Add support to set frequency on pins

[Petr Oros <poros@redhat.com>]

Add support to set the frequency of input and output pins. The DPLL
core validates the requested value against the supported frequency
list the pin advertises, so the frequency_set callback only has to
store it. The same per type tables that validate the configured
frequency at live time serve as the supported list. The configfs
attribute is rejected with EBUSY while the device is live, so only the
netlink setter changes the frequency of a registered pin and the two
cannot race. The frequency set over netlink is kept apart from the
configured one, like the priority, so the attribute keeps showing what
was configured and every live transition starts from it.

Signed-off-by: Petr Oros <poros@redhat.com>
---
v4:
- keep the frequency set over netlink apart from the configured one,
  like the priority
- document that values set over netlink are not written back to the
  attributes
- the Reviewed-by and Acked-by of v3 are not carried over, the
  behaviour of the driver changed

v3: https://lore.kernel.org/all/20261109093523.931201-10-poros@redhat.com/
---
 Documentation/driver-api/dpllsim.rst | 10 +++++-----
 drivers/dpll/dpllsim/core.c          |  4 ++--
 drivers/dpll/dpllsim/dpll.c          | 20 ++++++++++++++++++--
 drivers/dpll/dpllsim/dpllsim.h       |  8 ++++++--
 4 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/Documentation/driver-api/dpllsim.rst b/Documentation/driver-api/dpllsim.rst
index 27cfc4b2c71518..9c717b81a9473c 100644
--- a/Documentation/driver-api/dpllsim.rst
+++ b/Documentation/driver-api/dpllsim.rst
@@ -61,11 +61,11 @@ support, when a ``mux`` pin is an output or when an output pin has a
 priority other than the default, and with ``ENOENT`` when a pin
 directory is being created or removed at the same time.
 
-Every live transition starts from the configured values. A priority set
-over netlink while the instance is live is reported back over netlink,
-it is not written to the ``prio`` attribute and is gone once the
-instance is taken down. The driver stores the priority, it does not
-select a reference by it.
+Every live transition starts from the configured values. A frequency or
+a priority set over netlink while the instance is live is reported back
+over netlink, it is not written to the ``frequency`` or ``prio``
+attribute and is gone once the instance is taken down. The driver
+stores the priority, it does not select a reference by it.
 
 Example
 =======
diff --git a/drivers/dpll/dpllsim/core.c b/drivers/dpll/dpllsim/core.c
index fca16ec0976684..caf161221fe410 100644
--- a/drivers/dpll/dpllsim/core.c
+++ b/drivers/dpll/dpllsim/core.c
@@ -110,7 +110,7 @@ static ssize_t dpllsim_pin_frequency_show(struct config_item *item, char *page)
 	struct dpllsim_pin *pin = to_dpllsim_pin(item);
 
 	guard(mutex)(&pin->dev->lock);
-	return sysfs_emit(page, "%llu\n", pin->frequency);
+	return sysfs_emit(page, "%llu\n", pin->cfg_frequency);
 }
 
 static ssize_t dpllsim_pin_frequency_store(struct config_item *item,
@@ -127,7 +127,7 @@ static ssize_t dpllsim_pin_frequency_store(struct config_item *item,
 	guard(mutex)(&pin->dev->lock);
 	if (dpllsim_dev_frozen(pin->dev))
 		return -EBUSY;
-	pin->frequency = val;
+	pin->cfg_frequency = val;
 	return count;
 }
 CONFIGFS_ATTR(dpllsim_pin_, frequency);
diff --git a/drivers/dpll/dpllsim/dpll.c b/drivers/dpll/dpllsim/dpll.c
index 9fdb5dbeba4400..0cce8fef232cd3 100644
--- a/drivers/dpll/dpllsim/dpll.c
+++ b/drivers/dpll/dpllsim/dpll.c
@@ -79,6 +79,19 @@ static int dpllsim_pin_frequency_get(const struct dpll_pin *pin,
 	return 0;
 }
 
+static int dpllsim_pin_frequency_set(const struct dpll_pin *pin,
+				     void *pin_priv,
+				     const struct dpll_device *dpll,
+				     void *dpll_priv, u64 frequency,
+				     struct netlink_ext_ack *extack)
+{
+	struct dpllsim_pin *sim_pin = pin_priv;
+
+	guard(mutex)(&sim_pin->dev->lock);
+	sim_pin->frequency = frequency;
+	return 0;
+}
+
 static int dpllsim_pin_direction_get(const struct dpll_pin *pin,
 				     void *pin_priv,
 				     const struct dpll_device *dpll,
@@ -171,6 +184,7 @@ static int dpllsim_pin_prio_set(const struct dpll_pin *pin, void *pin_priv,
 
 static const struct dpll_pin_ops dpllsim_input_pin_ops = {
 	.frequency_get = dpllsim_pin_frequency_get,
+	.frequency_set = dpllsim_pin_frequency_set,
 	.direction_get = dpllsim_pin_direction_get,
 	.state_on_dpll_get = dpllsim_pin_state_get,
 	.state_on_dpll_set = dpllsim_pin_state_set,
@@ -180,6 +194,7 @@ static const struct dpll_pin_ops dpllsim_input_pin_ops = {
 
 static const struct dpll_pin_ops dpllsim_output_pin_ops = {
 	.frequency_get = dpllsim_pin_frequency_get,
+	.frequency_set = dpllsim_pin_frequency_set,
 	.direction_get = dpllsim_pin_direction_get,
 	.state_on_dpll_get = dpllsim_pin_state_get,
 };
@@ -233,8 +248,8 @@ static bool dpllsim_pin_frequency_valid(struct dpllsim_pin *pin)
 
 	dpllsim_pin_props(pin, &prop);
 	for (i = 0; i < prop.freq_supported_num; i++)
-		if (pin->frequency >= prop.freq_supported[i].min &&
-		    pin->frequency <= prop.freq_supported[i].max)
+		if (pin->cfg_frequency >= prop.freq_supported[i].min &&
+		    pin->cfg_frequency <= prop.freq_supported[i].max)
 			return true;
 
 	return false;
@@ -258,6 +273,7 @@ static void dpllsim_pin_reset(struct dpllsim_pin *pin)
 {
 	pin->ops = dpllsim_pin_select_ops(pin);
 	pin->state = DPLL_PIN_STATE_DISCONNECTED;
+	pin->frequency = pin->cfg_frequency;
 	pin->prio = pin->cfg_prio;
 }
 
diff --git a/drivers/dpll/dpllsim/dpllsim.h b/drivers/dpll/dpllsim/dpllsim.h
index 54f4f1636f64e4..cd99227f1e4e1d 100644
--- a/drivers/dpll/dpllsim/dpllsim.h
+++ b/drivers/dpll/dpllsim/dpllsim.h
@@ -27,7 +27,7 @@ struct dpllsim_pin {
 	/* Configuration, writable only until dpllsim_dev_frozen() */
 	enum dpll_pin_type type;
 	enum dpll_pin_direction direction;
-	u64 frequency;
+	u64 cfg_frequency;
 	u32 cfg_prio;
 
 	/* Resolved at live=1 */
@@ -39,7 +39,11 @@ struct dpllsim_pin {
 
 	/* Simulated state, guarded by dev->lock */
 	enum dpll_pin_state state;
-	/* Starts from cfg_prio at live=1, changed by the netlink setter */
+	/*
+	 * Start from cfg_frequency and cfg_prio at live=1, changed by the
+	 * netlink setters
+	 */
+	u64 frequency;
 	u32 prio;
 };
 
-- 
2.56.0