drm/i915: initialize backlight max from VBT
Normally we determine the backlight PWM modulation frequency (which we
also use as backlight max value) from the backlight registers at module
load time, expecting the registers have been initialized by the BIOS. If
this is not the case, we fail.
The VBT contains the backlight modulation frequency in Hz. Add platform
specific functions to convert the frequency in Hz to backlight PWM
modulation frequency, and use them to initialize the backlight when the
registers are not initialized by the BIOS.
v2: Fix SPT and VLV. Thanks to Clint for the VLV code.
Cc: Clint Taylor <clinton.a.taylor@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Clint Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 5811eeb..65b5682 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4648,6 +4648,7 @@
#define CBR1_VLV (VLV_DISPLAY_BASE + 0x70400)
#define CBR_PND_DEADLINE_DISABLE (1<<31)
+#define CBR_PWM_CLOCK_MUX_SELECT (1<<30)
/* FIFO watermark sizes etc */
#define G4X_FIFO_LINE_SIZE 64
@@ -6325,9 +6326,11 @@
#define FDI_PHASE_SYNC_OVR(pipe) (1<<(FDIA_PHASE_SYNC_SHIFT_OVR - ((pipe) * 2)))
#define FDI_PHASE_SYNC_EN(pipe) (1<<(FDIA_PHASE_SYNC_SHIFT_EN - ((pipe) * 2)))
#define FDI_BC_BIFURCATION_SELECT (1 << 12)
+#define SPT_PWM_GRANULARITY (1<<0)
#define SOUTH_CHICKEN2 0xc2004
#define FDI_MPHY_IOSFSB_RESET_STATUS (1<<13)
#define FDI_MPHY_IOSFSB_RESET_CTL (1<<12)
+#define LPT_PWM_GRANULARITY (1<<5)
#define DPLS_EDP_PPS_FIX_DIS (1<<0)
#define _FDI_RXA_CHICKEN 0xc200c