[PATCH v7 12/18] drm/bridge: synopsys: dw-dp: Add Runtime PM support

Add runtime PM stubs to the Synopsys DesignWare DisplayPort bridge
driver. Support is not enabled automatically and must be hooked up
in the vendor specific glue code.

Signed-off-by: Sebastian Reichel <[email protected]>
---
 drivers/gpu/drm/bridge/synopsys/dw-dp.c | 126 ++++++++++++++++++++++++++++++--
 include/drm/bridge/dw_dp.h              |   3 +
 2 files changed, 121 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
index d4f75b7f85d0..8b650f904575 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
@@ -328,6 +328,9 @@ struct dw_dp {
 	struct dw_dp_link link;
 	struct dw_dp_plat_data plat_data;
 	u8 pixel_mode;
+	bool usbc_mode;
+	bool pm_active;
+	bool drm_bound;
 
 	struct drm_bridge *next_bridge;
 
@@ -1467,6 +1470,11 @@ static ssize_t dw_dp_aux_transfer(struct drm_dp_aux *aux,
 	if (WARN_ON(msg->size > 16))
 		return -E2BIG;
 
+	PM_RUNTIME_ACQUIRE_AUTOSUSPEND(dp->dev, pm);
+	ret = PM_RUNTIME_ACQUIRE_ERR(&pm);
+	if (ret)
+		return ret;
+
 	reinit_completion(&dp->complete);
 
 	switch (msg->request & ~DP_AUX_I2C_MOT) {
@@ -1664,6 +1672,13 @@ static void dw_dp_bridge_atomic_enable(struct drm_bridge *bridge,
 	struct drm_connector_state *conn_state;
 	int ret;
 
+	ret = pm_runtime_get_active(dp->dev, RPM_TRANSPARENT);
+	if (ret) {
+		dev_err(dp->dev, "runtime PM failure\n");
+		return;
+	}
+	dp->pm_active = true;
+
 	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
 	if (!connector) {
 		dev_err(dp->dev, "failed to get connector\n");
@@ -1714,10 +1729,15 @@ static void dw_dp_bridge_atomic_disable(struct drm_bridge *bridge,
 {
 	struct dw_dp *dp = bridge_to_dp(bridge);
 
+	if (!dp->pm_active)
+		return;
+	dp->pm_active = false;
+
 	dw_dp_video_disable(dp);
 	dw_dp_link_disable(dp);
 	bitmap_zero(dp->sdp_reg_bank, SDP_REG_BANK_SIZE);
 	dw_dp_reset(dp);
+	pm_runtime_put_autosuspend(dp->dev);
 }
 
 static bool dw_dp_hpd_detect_link(struct dw_dp *dp, struct drm_connector *connector)
@@ -1738,6 +1758,10 @@ static enum drm_connector_status dw_dp_bridge_detect(struct drm_bridge *bridge,
 {
 	struct dw_dp *dp = bridge_to_dp(bridge);
 
+	PM_RUNTIME_ACQUIRE_AUTOSUSPEND(dp->dev, pm);
+	if (PM_RUNTIME_ACQUIRE_ERR(&pm))
+		return connector_status_disconnected;
+
 	if (!dw_dp_hpd_detect(dp))
 		return connector_status_disconnected;
 
@@ -1920,6 +1944,11 @@ static void dw_dp_hpd_work(struct work_struct *work)
 	bool long_hpd;
 	int ret;
 
+	PM_RUNTIME_ACQUIRE_AUTOSUSPEND(dp->dev, pm);
+	ret = PM_RUNTIME_ACQUIRE_ERR(&pm);
+	if (ret)
+		return;
+
 	mutex_lock(&dp->irq_lock);
 	long_hpd = dp->hotplug.long_hpd;
 	mutex_unlock(&dp->irq_lock);
@@ -2059,25 +2088,52 @@ int dw_dp_bind(struct dw_dp *dp, struct drm_encoder *encoder)
 		goto put_next_bridge;
 	}
 
-	if (dw_dp_is_routed_to_usb_c(encoder)) {
-		dev_dbg(dev, "USB-C mode\n");
+	dp->usbc_mode = dw_dp_is_routed_to_usb_c(encoder);
 
-		if (dp->plat_data.hpd_sw_sel)
-			dp->plat_data.hpd_sw_sel(dp->plat_data.data, 1);
+	ret = pm_runtime_get_active(dev, RPM_TRANSPARENT);
+	if (ret) {
+		dev_err_probe(dev, ret, "Failed to get runtime PM\n");
+		goto put_next_bridge;
 	}
 
-	dw_dp_init_hw(dp);
+	/* resume once if runtime PM is disabled */
+	if (!pm_runtime_enabled(dev)) {
+		ret = dw_dp_runtime_resume(dp);
+		if (ret)
+			goto put_runtime_pm;
+	}
+
+	if (dp->plat_data.hpd_sw_sel)
+		dp->plat_data.hpd_sw_sel(dp->plat_data.data, dp->usbc_mode);
 
 	ret = phy_init(dp->phy);
 	if (ret) {
 		dev_err_probe(dev, ret, "phy init failed\n");
-		goto put_next_bridge;
+		goto put_manual_pm;
 	}
 
+	dp->drm_bound = true;
 	enable_irq(dp->irq);
 
+	/*
+	 * USB-C has out-of-band hotplug detection, so device may enter
+	 * runtime suspend. Native mode needs to be resumed for working
+	 * hotplug detection.
+	 */
+	if (dp->usbc_mode) {
+		dev_dbg(dev, "USB-C mode\n");
+		pm_runtime_put_autosuspend(dp->dev);
+	}
+
 	return 0;
 
+put_manual_pm:
+	if (!pm_runtime_enabled(dev))
+		dw_dp_runtime_suspend(dp);
+
+put_runtime_pm:
+	pm_runtime_put_sync(dp->dev);
+
 put_next_bridge:
 	drm_bridge_put(dp->next_bridge);
 
@@ -2090,9 +2146,22 @@ EXPORT_SYMBOL_GPL(dw_dp_bind);
 
 void dw_dp_unbind(struct dw_dp *dp)
 {
+	if (dp->usbc_mode)
+		pm_runtime_get_sync(dp->dev);
+
+	dp->drm_bound = false;
 	disable_irq(dp->irq);
+
 	cancel_work_sync(&dp->hpd_work);
 	phy_exit(dp->phy);
+
+	/* Last PM runtime suspend must be done with drm_bound = false */
+	pm_runtime_put_sync(dp->dev);
+
+	/* suspend once if runtime PM is disabled */
+	if (!pm_runtime_enabled(dp->dev))
+		dw_dp_runtime_suspend(dp);
+
 	drm_bridge_put(dp->next_bridge);
 	drm_dp_aux_unregister(&dp->aux);
 }
@@ -2151,13 +2220,13 @@ struct dw_dp *dw_dp_probe(struct platform_device *pdev, const struct dw_dp_plat_
 		return ERR_CAST(dp->phy);
 	}
 
-	dp->apb_clk = devm_clk_get_enabled(dev, "apb");
+	dp->apb_clk = devm_clk_get(dev, "apb");
 	if (IS_ERR(dp->apb_clk)) {
 		dev_err_probe(dev, PTR_ERR(dp->apb_clk), "failed to get apb clock\n");
 		return ERR_CAST(dp->apb_clk);
 	}
 
-	dp->aux_clk = devm_clk_get_enabled(dev, "aux");
+	dp->aux_clk = devm_clk_get(dev, "aux");
 	if (IS_ERR(dp->aux_clk)) {
 		dev_err_probe(dev, PTR_ERR(dp->aux_clk), "failed to get aux clock\n");
 		return ERR_CAST(dp->aux_clk);
@@ -2202,6 +2271,47 @@ struct dw_dp *dw_dp_probe(struct platform_device *pdev, const struct dw_dp_plat_
 }
 EXPORT_SYMBOL_GPL(dw_dp_probe);
 
+int dw_dp_runtime_suspend(struct dw_dp *dp)
+{
+	if (dp->drm_bound)
+		disable_irq(dp->irq);
+
+	clk_disable_unprepare(dp->aux_clk);
+	clk_disable_unprepare(dp->apb_clk);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_dp_runtime_suspend);
+
+int dw_dp_runtime_resume(struct dw_dp *dp)
+{
+	int ret;
+
+	ret = clk_prepare_enable(dp->apb_clk);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(dp->aux_clk);
+	if (ret) {
+		clk_disable_unprepare(dp->apb_clk);
+		return ret;
+	}
+
+	dw_dp_init_hw(dp);
+
+	/*
+	 * HPD_HOT_PLUG bit is asserted only after the sink holds HPD
+	 * high for at least 100ms.
+	 */
+	msleep(110);
+
+	if (dp->drm_bound)
+		enable_irq(dp->irq);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_dp_runtime_resume);
+
 MODULE_AUTHOR("Andy Yan <[email protected]>");
 MODULE_DESCRIPTION("DW DP Core Library");
 MODULE_LICENSE("GPL");
diff --git a/include/drm/bridge/dw_dp.h b/include/drm/bridge/dw_dp.h
index 79b2cdf0df99..f20d2c2c40ca 100644
--- a/include/drm/bridge/dw_dp.h
+++ b/include/drm/bridge/dw_dp.h
@@ -29,4 +29,7 @@ int dw_dp_bind(struct dw_dp *dp, struct drm_encoder *encoder);
 void dw_dp_unbind(struct dw_dp *dp);
 
 struct dw_dp *dw_dp_probe(struct platform_device *pdev, const struct dw_dp_plat_data *plat_data);
+
+int dw_dp_runtime_suspend(struct dw_dp *dp);
+int dw_dp_runtime_resume(struct dw_dp *dp);
 #endif /* __DW_DP__ */

-- 
2.53.0


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