drm/i915: add some framework for backlight bl_power support

Make backlight class sysfs bl_power a sub-state of backlight enabled, if
a backlight power connector callback is defined. It's up to the
connector callback to handle the sub-state, typically in a way that
respects panel power sequencing.

v2: Post the version that does not oops. *facepalm*.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed_by: Clinton Taylor <Clinton.A.Taylor@intel.com>
Tested_by: Clinton Taylor <Clinton.A.Taylor@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

2 files changed, 28 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 2466b2bc9099..a35d8a22bf87 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -179,6 +179,8 @@ struct intel_panel {
                 bool active_low_pwm;
                 struct backlight_device *device;
         } backlight;
+
+        void (*backlight_power)(struct intel_connector *, bool enable);
 };
 
 struct intel_connector {
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 59b028f0b1e8..af5435634929 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -751,6 +751,8 @@ void intel_panel_disable_backlight(struct intel_connector *connector)
 
         spin_lock_irqsave(&dev_priv->backlight_lock, flags);
 
+        if (panel->backlight.device)
+                panel->backlight.device->props.power = FB_BLANK_POWERDOWN;
         panel->backlight.enabled = false;
         dev_priv->display.disable_backlight(connector);
 
@@ -957,6 +959,8 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
 
         dev_priv->display.enable_backlight(connector);
         panel->backlight.enabled = true;
+        if (panel->backlight.device)
+                panel->backlight.device->props.power = FB_BLANK_UNBLANK;
 
         spin_unlock_irqrestore(&dev_priv->backlight_lock, flags);
 }
@@ -965,6 +969,7 @@ void intel_panel_enable_backlight(struct intel_connector *connector)
 static int intel_backlight_device_update_status(struct backlight_device *bd)
 {
         struct intel_connector *connector = bl_get_data(bd);
+        struct intel_panel *panel = &connector->panel;
         struct drm_device *dev = connector->base.dev;
 
         drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
@@ -972,6 +977,22 @@ static int intel_backlight_device_update_status(struct backlight_device *bd)
                       bd->props.brightness, bd->props.max_brightness);
         intel_panel_set_backlight(connector, bd->props.brightness,
                                   bd->props.max_brightness);
+
+        /*
+         * Allow flipping bl_power as a sub-state of enabled. Sadly the
+         * backlight class device does not make it easy to to differentiate
+         * between callbacks for brightness and bl_power, so our backlight_power
+         * callback needs to take this into account.
+         */
+        if (panel->backlight.enabled) {
+                if (panel->backlight_power) {
+                        bool enable = bd->props.power == FB_BLANK_UNBLANK;
+                        panel->backlight_power(connector, enable);
+                }
+        } else {
+                bd->props.power = FB_BLANK_POWERDOWN;
+        }
+
         drm_modeset_unlock(&dev->mode_config.connection_mutex);
         return 0;
 }
@@ -1023,6 +1044,11 @@ static int intel_backlight_device_register(struct intel_connector *connector)
                                             panel->backlight.level,
                                             props.max_brightness);
 
+        if (panel->backlight.enabled)
+                props.power = FB_BLANK_UNBLANK;
+        else
+                props.power = FB_BLANK_POWERDOWN;
+
         /*
          * Note: using the same name independent of the connector prevents
          * registration of multiple backlight devices in the driver.