drm/i915/cnl: Map VBT DDC Pin to BSpec DDC Pin.

Starting on CNL we now need to map VBT DDC Pin to
BSPec DDC Pin values. Not a direct translation anymore.

According to VBT
Block 2 (General Bytes Definition)
DDC Bus

+----------+-----------+--------------------+
| DDI Type | VBT Value | Bspec Mapped Value |
+----------+-----------+--------------------+
| DDI-B    | 0x1       | 0x1                |
| DDI-C    | 0x2       | 0x2                |
| DDI-D    | 0x3       | 0x4                |
| DDI-F    | 0x4       | 0x3                |
+----------+-----------+--------------------+

v2: Move defines to a better place.
    This is actually CNL_PCH not CNL only.
v3: Accepting Ville's suggestions: enums and array to
    to make this future proof.
v4: Protect the array access as Ville suggested.
    Also accepting all Jani's suggestions:
    	      - use already defined gmbus pin definitions.
	      - use map_ddc_pin for disambiguation.
	      - Add /* sic */ comment on inverted values
	      	so people can easily see it it nos a mistake
		we have the map 3 -> 4 and 4 -> 3 :/

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
Cc: Clinton Taylor <clinton.a.taylor@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171020172641.16029-1-rodrigo.vivi@intel.com

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_vbt_defs.h b/drivers/gpu/drm/i915/intel_vbt_defs.h
index 404569c..f225c28 100644
--- a/drivers/gpu/drm/i915/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/intel_vbt_defs.h
@@ -306,6 +306,14 @@ struct bdb_general_features {
 
 #define LEGACY_CHILD_DEVICE_CONFIG_SIZE		33
 
+/* DDC Bus DDI Type 155+ */
+enum vbt_gmbus_ddi {
+	DDC_BUS_DDI_B = 0x1,
+	DDC_BUS_DDI_C,
+	DDC_BUS_DDI_D,
+	DDC_BUS_DDI_F,
+};
+
 /*
  * The child device config, aka the display device data structure, provides a
  * description of a port and its configuration on the platform.