drm/i915: Add correct hw/sw config check for DSI encoder

Check in vlv_crtc_clock_get if DPLL is enabled before calling dpio read.
It will not be enabled for DSI and avoid dpio read WARN dumps.

Absence of ->get_config was causing other WARN dumps as well. Update
dpll_hw_state as well correctly

v2: Address review comments by Daniel
    - Check if DPLL is enabled rather than checking pipe output type
    - set adjusted_mode->flags to 0 in compute_config rather than using
      pipe_config->quirks
    - Add helper function in intel_dsi_pll.c and use that in intel_dsi.c
    - updated dpll_hw_state correctly
    - Updated commit message and title

v3: Address review comments by Imre
    - Proper masking of P1, M1 fields while computing divisors
    - assert in case of bpp mismatch
    - guard for divide by 0 while computing pclk
    - Use ARRAY_SIZE instead of direct calculation

Signed-off-by: Shobhit Kumar <shobhit.kumar@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
index 31db33d3e5cc..fd51867fd0d3 100644
--- a/drivers/gpu/drm/i915/intel_dsi.h
+++ b/drivers/gpu/drm/i915/intel_dsi.h
@@ -132,6 +132,7 @@ static inline struct intel_dsi *enc_to_intel_dsi(struct drm_encoder *encoder)
 
 extern void vlv_enable_dsi_pll(struct intel_encoder *encoder);
 extern void vlv_disable_dsi_pll(struct intel_encoder *encoder);
+extern u32 vlv_get_dsi_pclk(struct intel_encoder *encoder, int pipe_bpp);
 
 extern struct intel_dsi_dev_ops vbt_generic_dsi_display_ops;