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, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 99eb7cad62a8..018fb7222f60 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6161,6 +6161,10 @@ static void vlv_crtc_clock_get(struct intel_crtc *crtc,
 	u32 mdiv;
 	int refclk = 100000;
 
+	/* In case of MIPI DPLL will not even be used */
+	if (!(pipe_config->dpll_hw_state.dpll & DPLL_VCO_ENABLE))
+		return;
+
 	mutex_lock(&dev_priv->dpio_lock);
 	mdiv = vlv_dpio_read(dev_priv, pipe, VLV_PLL_DW3(pipe));
 	mutex_unlock(&dev_priv->dpio_lock);