[PATCH 05/21] drm: Minimally initialise drm_dp_aux

Chris Wilson chris at chris-wilson.co.uk
Mon May 30 22:39:13 UTC 2016


When trying to split up the initialisation phase and the registration
phase, one immediate problem encountered is trying to use our own i2c
devices before registration with userspace. drm_dp_aux in particular
only offers an interface for setting up the device after we have exposed
the connector via sysfs. In order to break the chicken-and-egg problem,
export drm_dp_aux_init() to minimally prepare the i2c device for
internal use before drm_connector_register().

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Rafael Antognolli <rafael.antognolli at intel.com>
Cc: dri-devel at lists.freedesktop.org
---
 drivers/gpu/drm/drm_dp_helper.c | 18 +++++++++++++-----
 include/drm/drm_dp_helper.h     |  1 +
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
index eeaf5a7c3aa7..e1900d386685 100644
--- a/drivers/gpu/drm/drm_dp_helper.c
+++ b/drivers/gpu/drm/drm_dp_helper.c
@@ -774,6 +774,17 @@ static const struct i2c_algorithm drm_dp_i2c_algo = {
 	.master_xfer = drm_dp_i2c_xfer,
 };
 
+void drm_dp_aux_init(struct drm_dp_aux *aux)
+{
+	mutex_init(&aux->hw_mutex);
+	rt_mutex_init(&aux->ddc.bus_lock);
+
+	aux->ddc.algo = &drm_dp_i2c_algo;
+	aux->ddc.algo_data = aux;
+	aux->ddc.retries = 3;
+}
+EXPORT_SYMBOL(drm_dp_aux_init);
+
 /**
  * drm_dp_aux_register() - initialise and register aux channel
  * @aux: DisplayPort AUX channel
@@ -784,11 +795,8 @@ int drm_dp_aux_register(struct drm_dp_aux *aux)
 {
 	int ret;
 
-	mutex_init(&aux->hw_mutex);
-
-	aux->ddc.algo = &drm_dp_i2c_algo;
-	aux->ddc.algo_data = aux;
-	aux->ddc.retries = 3;
+	if (!aux->ddc.algo)
+		drm_dp_aux_init(aux);
 
 	aux->ddc.class = I2C_CLASS_DDC;
 	aux->ddc.owner = THIS_MODULE;
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h
index 5a848e734422..4d85cf2874af 100644
--- a/include/drm/drm_dp_helper.h
+++ b/include/drm/drm_dp_helper.h
@@ -805,6 +805,7 @@ int drm_dp_link_power_up(struct drm_dp_aux *aux, struct drm_dp_link *link);
 int drm_dp_link_power_down(struct drm_dp_aux *aux, struct drm_dp_link *link);
 int drm_dp_link_configure(struct drm_dp_aux *aux, struct drm_dp_link *link);
 
+void drm_dp_aux_init(struct drm_dp_aux *aux);
 int drm_dp_aux_register(struct drm_dp_aux *aux);
 void drm_dp_aux_unregister(struct drm_dp_aux *aux);
 
-- 
2.8.1



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