drm/i915: Explain usage of power well IDs vs bit groups

v2: Add explanation of the fixed power well bits (Imre)

Signed-off-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447682467-6237-2-git-send-email-patrik.jakobsson@linux.intel.com

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 89018bab5ebd89137151b9e1513fe7000fa7c58c..082408ee578961ca2c80d7be6dc1cdee33e6a634 100644 (file)
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -609,6 +609,7 @@
 
 /* See the PUNIT HAS v0.8 for the below bits */
 enum punit_power_well {
+       /* These numbers are fixed and must match the position of the pw bits */
        PUNIT_POWER_WELL_RENDER                 = 0,
        PUNIT_POWER_WELL_MEDIA                  = 1,
        PUNIT_POWER_WELL_DISP2D                 = 3,
@@ -621,10 +622,12 @@ enum punit_power_well {
        PUNIT_POWER_WELL_DPIO_RX1               = 11,
        PUNIT_POWER_WELL_DPIO_CMN_D             = 12,
 
+       /* Not actual bit groups. Used as IDs for lookup_power_well() */
        PUNIT_POWER_WELL_ALWAYS_ON,
 };
 
 enum skl_disp_power_wells {
+       /* These numbers are fixed and must match the position of the pw bits */
        SKL_DISP_PW_MISC_IO,
        SKL_DISP_PW_DDI_A_E,
        SKL_DISP_PW_DDI_B,
@@ -633,6 +636,7 @@ enum skl_disp_power_wells {
        SKL_DISP_PW_1 = 14,
        SKL_DISP_PW_2,
 
+       /* Not actual bit groups. Used as IDs for lookup_power_well() */
        SKL_DISP_PW_ALWAYS_ON,
 };