1 files changed, 96 insertions, 46 deletions

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index be312b5c04dd..21939d4352cf 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -27,6 +27,7 @@
 #include <linux/module.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 
 #include <video/display_timing.h>
@@ -175,6 +176,8 @@ struct panel_simple {
 	bool enabled;
 	bool no_hpd;
 
+	bool prepared;
+
 	ktime_t prepared_time;
 	ktime_t unprepared_time;
 
@@ -186,6 +189,8 @@ struct panel_simple {
 	struct gpio_desc *enable_gpio;
 	struct gpio_desc *hpd_gpio;
 
+	struct edid *edid;
+
 	struct drm_display_mode override_mode;
 
 	enum drm_panel_orientation orientation;
@@ -334,25 +339,39 @@ static int panel_simple_disable(struct drm_panel *panel)
 	return 0;
 }
 
+static int panel_simple_suspend(struct device *dev)
+{
+	struct panel_simple *p = dev_get_drvdata(dev);
+
+	gpiod_set_value_cansleep(p->enable_gpio, 0);
+	regulator_disable(p->supply);
+	p->unprepared_time = ktime_get();
+
+	kfree(p->edid);
+	p->edid = NULL;
+
+	return 0;
+}
+
 static int panel_simple_unprepare(struct drm_panel *panel)
 {
 	struct panel_simple *p = to_panel_simple(panel);
+	int ret;
 
-	if (p->prepared_time == 0)
+	/* Unpreparing when already unprepared is a no-op */
+	if (!p->prepared)
 		return 0;
 
-	gpiod_set_value_cansleep(p->enable_gpio, 0);
-
-	regulator_disable(p->supply);
-
-	p->prepared_time = 0;
-	p->unprepared_time = ktime_get();
+	pm_runtime_mark_last_busy(panel->dev);
+	ret = pm_runtime_put_autosuspend(panel->dev);
+	if (ret < 0)
+		return ret;
+	p->prepared = false;
 
 	return 0;
 }
 
-static int panel_simple_get_hpd_gpio(struct device *dev,
-				     struct panel_simple *p, bool from_probe)
+static int panel_simple_get_hpd_gpio(struct device *dev, struct panel_simple *p)
 {
 	int err;
 
@@ -360,38 +379,28 @@ static int panel_simple_get_hpd_gpio(struct device *dev,
 	if (IS_ERR(p->hpd_gpio)) {
 		err = PTR_ERR(p->hpd_gpio);
 
-		/*
-		 * If we're called from probe we won't consider '-EPROBE_DEFER'
-		 * to be an error--we'll leave the error code in "hpd_gpio".
-		 * When we try to use it we'll try again.  This allows for
-		 * circular dependencies where the component providing the
-		 * hpd gpio needs the panel to init before probing.
-		 */
-		if (err != -EPROBE_DEFER || !from_probe) {
+		if (err != -EPROBE_DEFER)
 			dev_err(dev, "failed to get 'hpd' GPIO: %d\n", err);
-			return err;
-		}
+
+		return err;
 	}
 
 	return 0;
 }
 
-static int panel_simple_prepare_once(struct drm_panel *panel)
+static int panel_simple_prepare_once(struct panel_simple *p)
 {
-	struct panel_simple *p = to_panel_simple(panel);
+	struct device *dev = p->base.dev;
 	unsigned int delay;
 	int err;
 	int hpd_asserted;
 	unsigned long hpd_wait_us;
 
-	if (p->prepared_time != 0)
-		return 0;
-
 	panel_simple_wait(p->unprepared_time, p->desc->delay.unprepare);
 
 	err = regulator_enable(p->supply);
 	if (err < 0) {
-		dev_err(panel->dev, "failed to enable supply: %d\n", err);
+		dev_err(dev, "failed to enable supply: %d\n", err);
 		return err;
 	}
 
@@ -404,12 +413,6 @@ static int panel_simple_prepare_once(struct drm_panel *panel)
 		msleep(delay);
 
 	if (p->hpd_gpio) {
-		if (IS_ERR(p->hpd_gpio)) {
-			err = panel_simple_get_hpd_gpio(panel->dev, p, false);
-			if (err)
-				goto error;
-		}
-
 		if (p->desc->delay.hpd_absent_delay)
 			hpd_wait_us = p->desc->delay.hpd_absent_delay * 1000UL;
 		else
@@ -423,7 +426,7 @@ static int panel_simple_prepare_once(struct drm_panel *panel)
 
 		if (err) {
 			if (err != -ETIMEDOUT)
-				dev_err(panel->dev,
+				dev_err(dev,
 					"error waiting for hpd GPIO: %d\n", err);
 			goto error;
 		}
@@ -447,25 +450,46 @@ error:
  */
 #define MAX_PANEL_PREPARE_TRIES		5
 
-static int panel_simple_prepare(struct drm_panel *panel)
+static int panel_simple_resume(struct device *dev)
 {
+	struct panel_simple *p = dev_get_drvdata(dev);
 	int ret;
 	int try;
 
 	for (try = 0; try < MAX_PANEL_PREPARE_TRIES; try++) {
-		ret = panel_simple_prepare_once(panel);
+		ret = panel_simple_prepare_once(p);
 		if (ret != -ETIMEDOUT)
 			break;
 	}
 
 	if (ret == -ETIMEDOUT)
-		dev_err(panel->dev, "Prepare timeout after %d tries\n", try);
+		dev_err(dev, "Prepare timeout after %d tries\n", try);
 	else if (try)
-		dev_warn(panel->dev, "Prepare needed %d retries\n", try);
+		dev_warn(dev, "Prepare needed %d retries\n", try);
 
 	return ret;
 }
 
+static int panel_simple_prepare(struct drm_panel *panel)
+{
+	struct panel_simple *p = to_panel_simple(panel);
+	int ret;
+
+	/* Preparing when already prepared is a no-op */
+	if (p->prepared)
+		return 0;
+
+	ret = pm_runtime_get_sync(panel->dev);
+	if (ret < 0) {
+		pm_runtime_put_autosuspend(panel->dev);
+		return ret;
+	}
+
+	p->prepared = true;
+
+	return 0;
+}
+
 static int panel_simple_enable(struct drm_panel *panel)
 {
 	struct panel_simple *p = to_panel_simple(panel);
@@ -491,13 +515,16 @@ static int panel_simple_get_modes(struct drm_panel *panel,
 
 	/* probe EDID if a DDC bus is available */
 	if (p->ddc) {
-		struct edid *edid = drm_get_edid(connector, p->ddc);
+		pm_runtime_get_sync(panel->dev);
 
-		drm_connector_update_edid_property(connector, edid);
-		if (edid) {
-			num += drm_add_edid_modes(connector, edid);
-			kfree(edid);
-		}
+		if (!p->edid)
+			p->edid = drm_get_edid(connector, p->ddc);
+
+		if (p->edid)
+			num += drm_add_edid_modes(connector, p->edid);
+
+		pm_runtime_mark_last_busy(panel->dev);
+		pm_runtime_put_autosuspend(panel->dev);
 	}
 
 	/* add hard-coded panel modes */
@@ -649,7 +676,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
 
 	panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd");
 	if (!panel->no_hpd) {
-		err = panel_simple_get_hpd_gpio(dev, panel, true);
+		err = panel_simple_get_hpd_gpio(dev, panel);
 		if (err)
 			return err;
 	}
@@ -748,18 +775,31 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
 		break;
 	}
 
+	dev_set_drvdata(dev, panel);
+
+	/*
+	 * We use runtime PM for prepare / unprepare since those power the panel
+	 * on and off and those can be very slow operations. This is important
+	 * to optimize powering the panel on briefly to read the EDID before
+	 * fully enabling the panel.
+	 */
+	pm_runtime_enable(dev);
+	pm_runtime_set_autosuspend_delay(dev, 1000);
+	pm_runtime_use_autosuspend(dev);
+
 	drm_panel_init(&panel->base, dev, &panel_simple_funcs, connector_type);
 
 	err = drm_panel_of_backlight(&panel->base);
 	if (err)
-		goto free_ddc;
+		goto disable_pm_runtime;
 
 	drm_panel_add(&panel->base);
 
-	dev_set_drvdata(dev, panel);
-
 	return 0;
 
+disable_pm_runtime:
+	pm_runtime_dont_use_autosuspend(dev);
+	pm_runtime_disable(dev);
 free_ddc:
 	if (panel->ddc)
 		put_device(&panel->ddc->dev);
@@ -775,6 +815,8 @@ static int panel_simple_remove(struct device *dev)
 	drm_panel_disable(&panel->base);
 	drm_panel_unprepare(&panel->base);
 
+	pm_runtime_dont_use_autosuspend(dev);
+	pm_runtime_disable(dev);
 	if (panel->ddc)
 		put_device(&panel->ddc->dev);
 
@@ -4603,10 +4645,17 @@ static void panel_simple_platform_shutdown(struct platform_device *pdev)
 	panel_simple_shutdown(&pdev->dev);
 }
 
+static const struct dev_pm_ops panel_simple_pm_ops = {
+	SET_RUNTIME_PM_OPS(panel_simple_suspend, panel_simple_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				pm_runtime_force_resume)
+};
+
 static struct platform_driver panel_simple_platform_driver = {
 	.driver = {
 		.name = "panel-simple",
 		.of_match_table = platform_of_match,
+		.pm = &panel_simple_pm_ops,
 	},
 	.probe = panel_simple_platform_probe,
 	.remove = panel_simple_platform_remove,
@@ -4901,6 +4950,7 @@ static struct mipi_dsi_driver panel_simple_dsi_driver = {
 	.driver = {
 		.name = "panel-simple-dsi",
 		.of_match_table = dsi_of_match,
+		.pm = &panel_simple_pm_ops,
 	},
 	.probe = panel_simple_dsi_probe,
 	.remove = panel_simple_dsi_remove,