drm/i915: Extract bxt DE PLL enable/disable from broxton_set_cdclk()

Enabling and disalbing the DE PLL are two nice self contained
operations, so let's move them into a few small helper functions.
Makes it easier to see the forest from the trees in broxton_set_cdclk().

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463172100-24715-16-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Imre Deak <imre.deak@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5777163..521ad13 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5278,6 +5278,31 @@ static int skl_cdclk_decimal(int cdclk)
        return DIV_ROUND_CLOSEST(cdclk - 1000, 500);
 }
 
+static void bxt_de_pll_disable(struct drm_i915_private *dev_priv)
+{
+       I915_WRITE(BXT_DE_PLL_ENABLE, 0);
+
+       /* Timeout 200us */
+       if (wait_for((I915_READ(BXT_DE_PLL_ENABLE) & BXT_DE_PLL_LOCK) == 0, 1))
+               DRM_ERROR("timeout waiting for DE PLL unlock\n");
+}
+
+static void bxt_de_pll_enable(struct drm_i915_private *dev_priv, u32 ratio)
+{
+       u32 val;
+
+       val = I915_READ(BXT_DE_PLL_CTL);
+       val &= ~BXT_DE_PLL_RATIO_MASK;
+       val |= ratio;
+       I915_WRITE(BXT_DE_PLL_CTL, val);
+
+       I915_WRITE(BXT_DE_PLL_ENABLE, BXT_DE_PLL_PLL_ENABLE);
+
+       /* Timeout 200us */
+       if (wait_for((I915_READ(BXT_DE_PLL_ENABLE) & BXT_DE_PLL_LOCK) != 0, 1))
+               DRM_ERROR("timeout waiting for DE PLL lock\n");
+}
+
 static void broxton_set_cdclk(struct drm_i915_private *dev_priv, int cdclk)
 {
        uint32_t divider;
@@ -5345,25 +5370,13 @@ static void broxton_set_cdclk(struct drm_i915_private *dev_priv, int cdclk)
         */
        if (cdclk == 19200 || cdclk == 624000 ||
            current_cdclk == 624000) {
-               I915_WRITE(BXT_DE_PLL_ENABLE, ~BXT_DE_PLL_PLL_ENABLE);
-               /* Timeout 200us */
-               if (wait_for(!(I915_READ(BXT_DE_PLL_ENABLE) & BXT_DE_PLL_LOCK),
-                            1))
-                       DRM_ERROR("timout waiting for DE PLL unlock\n");
+               bxt_de_pll_disable(dev_priv);
        }
 
        if (cdclk != 19200) {
                uint32_t val;
 
-               val = I915_READ(BXT_DE_PLL_CTL);
-               val &= ~BXT_DE_PLL_RATIO_MASK;
-               val |= ratio;
-               I915_WRITE(BXT_DE_PLL_CTL, val);
-
-               I915_WRITE(BXT_DE_PLL_ENABLE, BXT_DE_PLL_PLL_ENABLE);
-               /* Timeout 200us */
-               if (wait_for(I915_READ(BXT_DE_PLL_ENABLE) & BXT_DE_PLL_LOCK, 1))
-                       DRM_ERROR("timeout waiting for DE PLL lock\n");
+               bxt_de_pll_enable(dev_priv, ratio);
 
                val = divider | skl_cdclk_decimal(cdclk);
                /*