drm: Pass the drm_dp_aux->hw_mutex to i2c for its locking

Rather than have both drm_dp_aux lock within its transfer, and i2c to lock around the transfer, use the same lock by filling in the locking callbacks that i2c wants to use. We require our own hw_mutex as we bypass i2c_transfer for drm_dp_dpcd_access(). Signed-off-by: Chris Wilson <[email protected]> Cc: Dave Airlie <[email protected]> Cc: Rafael Antognolli <[email protected]> Cc: Ville Syrjälä <[email protected]> Cc: [email protected] Signed-off-by: Daniel Vetter <[email protected]> Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]
olifre · Jun 17, 2016 · 0c2f6f1 · 0c2f6f1
1 parent 1cee2a2
commit 0c2f6f1
Showing 1 changed file with 24 additions and 4 deletions.
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
@@ -708,8 +708,6 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 
 	memset(&msg, 0, sizeof(msg));
 
-	mutex_lock(&aux->hw_mutex);
-
 	for (i = 0; i < num; i++) {
 		msg.address = msgs[i].addr;
 		drm_dp_i2c_msg_set_request(&msg, &msgs[i]);
@@ -764,8 +762,6 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
 	msg.size = 0;
 	(void)drm_dp_i2c_do_msg(aux, &msg);
 
-	mutex_unlock(&aux->hw_mutex);
-
 	return err;
 }
 
@@ -774,6 +770,26 @@ static const struct i2c_algorithm drm_dp_i2c_algo = {
 	.master_xfer = drm_dp_i2c_xfer,
 };
 
+static struct drm_dp_aux *i2c_to_aux(struct i2c_adapter *i2c)
+{
+	return container_of(i2c, struct drm_dp_aux, ddc);
+}
+
+static void lock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+	mutex_lock(&i2c_to_aux(i2c)->hw_mutex);
+}
+
+static int trylock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+	return mutex_trylock(&i2c_to_aux(i2c)->hw_mutex);
+}
+
+static void unlock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+	mutex_unlock(&i2c_to_aux(i2c)->hw_mutex);
+}
+
 /**
  * drm_dp_aux_register() - initialise and register aux channel
  * @aux: DisplayPort AUX channel
@@ -790,6 +806,10 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
 	aux->ddc.algo_data = aux;
 	aux->ddc.retries = 3;
 
+	aux->ddc.lock_bus = lock_bus;
+	aux->ddc.trylock_bus = trylock_bus;
+	aux->ddc.unlock_bus = unlock_bus;
+
 	aux->ddc.class = I2C_CLASS_DDC;
 	aux->ddc.owner = THIS_MODULE;
 	aux->ddc.dev.parent = aux->dev;