[PATCH 7/8] i3c: master: Export i3c_master_enec_disec_locked()

[Adrian Hunter]

The existing i3c_master_enec_locked() wrapper always treats a NACKed
ENEC CCC as a failure (M2 error).  However, broadcasting ENEC to enable
Hot-Join is legitimately useful even when no I3C devices are currently
present on the bus, in which case the broadcast will be NACKed and
should not be reported as an error.

The underlying helper i3c_master_enec_disec_locked() already accepts a
suppress_m2 flag that lets callers ignore such NACKs.  Expose it so that
a subsequent patch enabling Hot-Join events can issue ENEC with M2
suppression.

Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
---
 drivers/i3c/master.c       | 27 ++++++++++++++++++++++++---
 include/linux/i3c/master.h |  2 ++
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c
index 1eb157c8091d..db46cc12c7db 100644
--- a/drivers/i3c/master.c
+++ b/drivers/i3c/master.c
@@ -1121,9 +1121,29 @@ int i3c_master_entdaa_locked(struct i3c_master_controller *master)
 }
 EXPORT_SYMBOL_GPL(i3c_master_entdaa_locked);
 
-static int i3c_master_enec_disec_locked(struct i3c_master_controller *master,
-					u8 addr, bool enable, u8 evts,
-					bool suppress_m2)
+/**
+ * i3c_master_enec_disec_locked() - send an ENEC or DISEC CCC command
+ * @master: master used to send frames on the bus
+ * @addr: a valid I3C slave address or %I3C_BROADCAST_ADDR
+ * @enable: true to send ENEC, false to send DISEC
+ * @evts: events to enable or disable
+ * @suppress_m2: if true, treat an M2 (NACK) error from the CCC as success
+ *
+ * Send an ENEC or DISEC CCC command to enable or disable some or all events
+ * coming from a specific slave, or all devices if @addr is
+ * %I3C_BROADCAST_ADDR.
+ *
+ * When @suppress_m2 is true, a NACK of the broadcast (which can happen when
+ * no devices are present on the bus) is not reported as an error. This is
+ * useful for callers that want to configure event reporting unconditionally,
+ * regardless of whether any devices are currently on the bus.
+ *
+ * This function must be called with the bus lock held in write mode.
+ *
+ * Return: 0 in case of success, or a negative error code otherwise.
+ */
+int i3c_master_enec_disec_locked(struct i3c_master_controller *master, u8 addr,
+				 bool enable, u8 evts, bool suppress_m2)
 {
 	struct i3c_ccc_events *events;
 	struct i3c_ccc_cmd_dest dest;
@@ -1148,6 +1168,7 @@ static int i3c_master_enec_disec_locked(struct i3c_master_controller *master,
 
 	return ret;
 }
+EXPORT_SYMBOL_GPL(i3c_master_enec_disec_locked);
 
 /**
  * i3c_master_disec_locked() - send a DISEC CCC command
diff --git a/include/linux/i3c/master.h b/include/linux/i3c/master.h
index 8cdd7be505d3..e2c831fb5354 100644
--- a/include/linux/i3c/master.h
+++ b/include/linux/i3c/master.h
@@ -607,6 +607,8 @@ int i3c_master_disec_locked(struct i3c_master_controller *master, u8 addr,
 			    u8 evts);
 int i3c_master_enec_locked(struct i3c_master_controller *master, u8 addr,
 			   u8 evts);
+int i3c_master_enec_disec_locked(struct i3c_master_controller *master, u8 addr,
+				 bool enable, u8 evts, bool suppress_m2);
 int i3c_master_entdaa_locked(struct i3c_master_controller *master);
 int i3c_master_defslvs_locked(struct i3c_master_controller *master);
 
-- 
2.51.0