[PATCH 32/51] drm/i915: Add intel_check_clock()

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

intel_check_clock() can be used to check clock validity w/o modifying
hardware state.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h      |    2 ++
 drivers/gpu/drm/i915/intel_display.c |   24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index f511fa2..53a35fd 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1600,6 +1600,8 @@ extern bool intel_fbc_enabled(struct drm_device *dev);
 extern void intel_disable_fbc(struct drm_device *dev);
 extern bool ironlake_set_drps(struct drm_device *dev, u8 val);
 extern void ironlake_init_pch_refclk(struct drm_device *dev);
+extern int intel_check_clock(struct drm_crtc *crtc,
+			     const struct drm_display_mode *adjusted_mode);
 extern void gen6_set_rps(struct drm_device *dev, u8 val);
 extern void intel_detect_pch(struct drm_device *dev);
 extern int intel_trans_dp_port_sel(struct drm_crtc *crtc);
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d6b4bfe..d4d7454 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5124,6 +5124,30 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
 	return ret;
 }
 
+int intel_check_clock(struct drm_crtc *crtc,
+		      const struct drm_display_mode *adjusted_mode)
+{
+	struct drm_device *dev = crtc->dev;
+	intel_clock_t clock, reduced_clock;
+	bool has_reduced_clock = false;
+	bool ok;
+
+	if (HAS_PCH_SPLIT(dev)) {
+		ok = ironlake_compute_clocks(crtc, adjusted_mode, &clock,
+					     &has_reduced_clock, &reduced_clock);
+	} else {
+		int num_connectors = 0;
+		bool is_dp = false;
+		int refclk;
+
+		ok = i9xx_compute_clocks(crtc, adjusted_mode, &clock,
+					 &has_reduced_clock, &reduced_clock,
+					 &refclk, &num_connectors, &is_dp);
+	}
+
+	return ok ? 0 : -EINVAL;
+}
+
 static int intel_crtc_mode_set(struct drm_crtc *crtc,
 			       struct drm_display_mode *mode,
 			       struct drm_display_mode *adjusted_mode,
-- 
1.7.8.6