drm/i915: Introduce a gmbus power domain

Currently the gmbus code uses intel_aux_display_runtime_get/put in an
effort to make sure the hardware is powered up sufficiently for gmbus.
That function only takes the runtime PM reference which on VLV/CHV/BXT
is not enough. We need the disp2d/pipe-a well on VLV/CHV and power well
2 on BXT. So add a new power domnain for gmbus and kill off the now
unused intel_aux_display_runtime_get/put. And change
intel_hdmi_set_edid() to use the gmbus power domain too since that's all
we need there.

Also toss in a BUILD_BUG_ON() to catch problems if we run out of
bits for power domains. We're already really close to the limit...

[Patrik: Add gmbus string to debugfs output]
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Patrik Jakobsson <patrik.jakobsson@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1447084107-8521-5-git-send-email-patrik.jakobsson@linux.intel.com

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2745,6 +2745,8 @@ static const char *power_domain_str(enum intel_display_power_domain domain)
 		return "AUX_C";
 	case POWER_DOMAIN_AUX_D:
 		return "AUX_D";
+	case POWER_DOMAIN_GMBUS:
+		return "GMBUS";
 	case POWER_DOMAIN_INIT:
 		return "INIT";
 	default:

drivers/gpu/drm/i915/i915_drv.h

@@ -199,6 +199,7 @@ enum intel_display_power_domain {
 	POWER_DOMAIN_AUX_B,
 	POWER_DOMAIN_AUX_C,
 	POWER_DOMAIN_AUX_D,
+	POWER_DOMAIN_GMBUS,
 	POWER_DOMAIN_INIT,
 
 	POWER_DOMAIN_NUM,

drivers/gpu/drm/i915/intel_drv.h

@@ -1428,8 +1428,6 @@ void intel_display_power_get(struct drm_i915_private *dev_priv,
 			     enum intel_display_power_domain domain);
 void intel_display_power_put(struct drm_i915_private *dev_priv,
 			     enum intel_display_power_domain domain);
-void intel_aux_display_runtime_get(struct drm_i915_private *dev_priv);
-void intel_aux_display_runtime_put(struct drm_i915_private *dev_priv);
 void intel_runtime_pm_get(struct drm_i915_private *dev_priv);
 void intel_runtime_pm_get_noresume(struct drm_i915_private *dev_priv);
 void intel_runtime_pm_put(struct drm_i915_private *dev_priv);

drivers/gpu/drm/i915/intel_hdmi.c

@@ -1346,21 +1346,17 @@ intel_hdmi_set_edid(struct drm_connector *connector, bool force)
 {
 	struct drm_i915_private *dev_priv = to_i915(connector->dev);
 	struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
-	struct intel_encoder *intel_encoder =
-		&hdmi_to_dig_port(intel_hdmi)->base;
-	enum intel_display_power_domain power_domain;
 	struct edid *edid = NULL;
 	bool connected = false;
 
-	power_domain = intel_display_port_power_domain(intel_encoder);
-	intel_display_power_get(dev_priv, power_domain);
+	intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
 
 	if (force)
 		edid = drm_get_edid(connector,
 				    intel_gmbus_get_adapter(dev_priv,
 				    intel_hdmi->ddc_bus));
 
-	intel_display_power_put(dev_priv, power_domain);
+	intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
 
 	to_intel_connector(connector)->detect_edid = edid;
 	if (edid && edid->input & DRM_EDID_INPUT_DIGITAL) {

drivers/gpu/drm/i915/intel_i2c.c

@@ -483,7 +483,7 @@ gmbus_xfer(struct i2c_adapter *adapter,
 	int i = 0, inc, try = 0;
 	int ret = 0;
 
-	intel_aux_display_runtime_get(dev_priv);
+	intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
 	mutex_lock(&dev_priv->gmbus_mutex);
 
 	if (bus->force_bit) {
@@ -595,7 +595,9 @@ gmbus_xfer(struct i2c_adapter *adapter,
 
 out:
 	mutex_unlock(&dev_priv->gmbus_mutex);
-	intel_aux_display_runtime_put(dev_priv);
+
+	intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS);
+
 	return ret;
 }
 

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -341,6 +341,7 @@ static void hsw_set_power_well(struct drm_i915_private *dev_priv,
 	BIT(POWER_DOMAIN_AUX_C) |			\
 	BIT(POWER_DOMAIN_AUDIO) |			\
 	BIT(POWER_DOMAIN_VGA) |				\
+	BIT(POWER_DOMAIN_GMBUS) |			\
 	BIT(POWER_DOMAIN_INIT))
 #define BXT_DISPLAY_POWERWELL_1_POWER_DOMAINS (		\
 	BXT_DISPLAY_POWERWELL_2_POWER_DOMAINS |		\
@@ -1438,6 +1439,7 @@ void intel_display_power_put(struct drm_i915_private *dev_priv,
 	BIT(POWER_DOMAIN_AUX_B) |			\
 	BIT(POWER_DOMAIN_AUX_C) |			\
 	BIT(POWER_DOMAIN_AUX_D) |			\
+	BIT(POWER_DOMAIN_GMBUS) |			\
 	BIT(POWER_DOMAIN_INIT))
 #define HSW_DISPLAY_POWER_DOMAINS (				\
 	(POWER_DOMAIN_MASK & ~HSW_ALWAYS_ON_POWER_DOMAINS) |	\
@@ -1814,6 +1816,8 @@ int intel_power_domains_init(struct drm_i915_private *dev_priv)
 {
 	struct i915_power_domains *power_domains = &dev_priv->power_domains;
 
+	BUILD_BUG_ON(POWER_DOMAIN_NUM > 31);
+
 	mutex_init(&power_domains->lock);
 
 	/*
@@ -2085,36 +2089,6 @@ void intel_power_domains_suspend(struct drm_i915_private *dev_priv)
 		intel_display_power_put(dev_priv, POWER_DOMAIN_INIT);
 }
 
-/**
- * intel_aux_display_runtime_get - grab an auxiliary power domain reference
- * @dev_priv: i915 device instance
- *
- * This function grabs a power domain reference for the auxiliary power domain
- * (for access to the GMBUS and DP AUX blocks) and ensures that it and all its
- * parents are powered up. Therefore users should only grab a reference to the
- * innermost power domain they need.
- *
- * Any power domain reference obtained by this function must have a symmetric
- * call to intel_aux_display_runtime_put() to release the reference again.
- */
-void intel_aux_display_runtime_get(struct drm_i915_private *dev_priv)
-{
-	intel_runtime_pm_get(dev_priv);
-}
-
-/**
- * intel_aux_display_runtime_put - release an auxiliary power domain reference
- * @dev_priv: i915 device instance
- *
- * This function drops the auxiliary power domain reference obtained by
- * intel_aux_display_runtime_get() and might power down the corresponding
- * hardware block right away if this is the last reference.
- */
-void intel_aux_display_runtime_put(struct drm_i915_private *dev_priv)
-{
-	intel_runtime_pm_put(dev_priv);
-}
-
 /**
  * intel_runtime_pm_get - grab a runtime pm reference
  * @dev_priv: i915 device instance