drm/i915/intel_i2c: refactor using intel_gmbus_get_adapter

Instead of letting other modules directly access the ->gmbus array,
introduce intel_gmbus_get_adapter() for looking up an i2c_adapter
for a given gmbus port identifier.  This will enable later refactoring
of the gmbus port list.

Note: Before requesting an adapter for a given gmbus port number, the
driver must first check its validity using i2c_intel_gmbus_is_port_valid().
If this check fails, a call to intel_gmbus_get_adapter() will WARN_ON and
return NULL.  This is relevant for parts of the driver that read a port
from VBIOS, which might be improperly initialized and contain an invalid
port.  In these cases, the driver must fall back to using a safer default
port.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/gpu/drm/i915/intel_dvo.c b/drivers/gpu/drm/i915/intel_dvo.c
index 020a7d7f744d..60ba50b956f2 100644
--- a/drivers/gpu/drm/i915/intel_dvo.c
+++ b/drivers/gpu/drm/i915/intel_dvo.c
@@ -243,7 +243,7 @@ static int intel_dvo_get_modes(struct drm_connector *connector)
          * that's not the case.
          */
         intel_ddc_get_modes(connector,
-                            &dev_priv->gmbus[GMBUS_PORT_DPC].adapter);
+                            intel_gmbus_get_adapter(dev_priv, GMBUS_PORT_DPC));
         if (!list_empty(&connector->probed_modes))
                 return 1;
 
@@ -375,7 +375,7 @@ void intel_dvo_init(struct drm_device *dev)
                  * special cases, but otherwise default to what's defined
                  * in the spec.
                  */
-                if (dvo->gpio != 0)
+                if (intel_gmbus_is_port_valid(dvo->gpio))
                         gpio = dvo->gpio;
                 else if (dvo->type == INTEL_DVO_CHIP_LVDS)
                         gpio = GMBUS_PORT_SSC;
@@ -386,7 +386,7 @@ void intel_dvo_init(struct drm_device *dev)
                  * It appears that everything is on GPIOE except for panels
                  * on i830 laptops, which are on GPIOB (DVOA).
                  */
-                i2c = &dev_priv->gmbus[gpio].adapter;
+                i2c = intel_gmbus_get_adapter(dev_priv, gpio);
 
                 intel_dvo->dev = *dvo;
                 if (!dvo->dev_ops->init(&intel_dvo->dev, i2c))