drm/msm/dp: Allow attaching a drm_panel

eDP panels might need some power sequencing and backlight management,
so make it possible to associate a drm_panel with a DP instance and
prepare and enable the panel accordingly.

Link: https://lore.kernel.org/linux-arm-msm/20210726231351.655302-1-bjorn.andersson@linaro.org/
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>

drivers/gpu/drm/msm/dp/dp_display.c

@@ -10,6 +10,7 @@
 #include <linux/component.h>
 #include <linux/of_irq.h>
 #include <linux/delay.h>
+#include <drm/drm_panel.h>
 
 #include "msm_drv.h"
 #include "msm_kms.h"
@@ -253,6 +254,7 @@ static int dp_display_bind(struct device *dev, struct device *master,
 	}
 
 	dp->aux->drm_dev = drm;
+	dp->dp_display.drm_panel = dp->parser->drm_panel;
 	rc = dp_aux_register(dp->aux, drm);
 	if (rc) {
 		DRM_ERROR("DRM DP AUX register failed\n");
@@ -867,8 +869,10 @@ static int dp_display_set_mode(struct msm_dp *dp_display,
 	return 0;
 }
 
-static int dp_display_prepare(struct msm_dp *dp)
+static int dp_display_prepare(struct msm_dp *dp_display)
 {
+	drm_panel_prepare(dp_display->drm_panel);
+
 	return 0;
 }
 
@@ -886,6 +890,8 @@ static int dp_display_enable(struct dp_display_private *dp, u32 data)
 	if (!rc)
 		dp_display->power_on = true;
 
+	drm_panel_enable(dp_display->drm_panel);
+
 	return rc;
 }
 
@@ -915,6 +921,8 @@ static int dp_display_disable(struct dp_display_private *dp, u32 data)
 	if (!dp_display->power_on)
 		return 0;
 
+	drm_panel_disable(dp_display->drm_panel);
+
 	/* wait only if audio was enabled */
 	if (dp_display->audio_enabled) {
 		/* signal the disconnect event */
@@ -939,8 +947,10 @@ static int dp_display_disable(struct dp_display_private *dp, u32 data)
 	return 0;
 }
 
-static int dp_display_unprepare(struct msm_dp *dp)
+static int dp_display_unprepare(struct msm_dp *dp_display)
 {
+	drm_panel_unprepare(dp_display->drm_panel);
+
 	return 0;
 }
 

drivers/gpu/drm/msm/dp/dp_display.h

@@ -15,6 +15,7 @@ struct msm_dp {
 	struct device *codec_dev;
 	struct drm_connector *connector;
 	struct drm_encoder *encoder;
+	struct drm_panel *drm_panel;
 	bool is_connected;
 	bool audio_enabled;
 	bool power_on;

drivers/gpu/drm/msm/dp/dp_parser.c

@@ -6,6 +6,7 @@
 #include <linux/of_gpio.h>
 #include <linux/phy/phy.h>
 
+#include <drm/drm_of.h>
 #include <drm/drm_print.h>
 
 #include "dp_parser.h"
@@ -276,6 +277,20 @@ static int dp_parser_clock(struct dp_parser *parser)
 	return 0;
 }
 
+static int dp_parser_find_panel(struct dp_parser *parser)
+{
+	struct device_node *np = parser->pdev->dev.of_node;
+	int rc;
+
+	rc = drm_of_find_panel_or_bridge(np, 2, 0, &parser->drm_panel, NULL);
+	if (rc == -ENODEV)
+		rc = 0;
+	else if (rc)
+		DRM_ERROR("failed to acquire DRM panel: %d\n", rc);
+
+	return rc;
+}
+
 static int dp_parser_parse(struct dp_parser *parser)
 {
 	int rc = 0;
@@ -297,6 +312,10 @@ static int dp_parser_parse(struct dp_parser *parser)
 	if (rc)
 		return rc;
 
+	rc = dp_parser_find_panel(parser);
+	if (rc)
+		return rc;
+
 	/* Map the corresponding regulator information according to
 	 * version. Currently, since we only have one supported platform,
 	 * mapping the regulator directly.

drivers/gpu/drm/msm/dp/dp_parser.h

@@ -122,6 +122,7 @@ struct dp_parser {
 	struct dp_display_data disp_data;
 	const struct dp_regulator_cfg *regulator_cfg;
 	u32 max_dp_lanes;
+	struct drm_panel *drm_panel;
 
 	int (*parse)(struct dp_parser *parser);
 };