[PATCH v5 10/15] 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 | 71 ++++++++++++++++++++++++++++++++-
 include/drm/bridge/dw_dp.h              |  3 ++
 2 files changed, 72 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
index 9975df8ea37e..bcf7ad84f217 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
@@ -328,6 +328,7 @@ struct dw_dp {
 	struct dw_dp_link link;
 	struct dw_dp_plat_data plat_data;
 	u8 pixel_mode;
+	bool usbc_mode;
 
 	struct drm_bridge *next_bridge;
 
@@ -1467,6 +1468,11 @@ static ssize_t dw_dp_aux_transfer(struct drm_dp_aux *aux,
 	if (WARN_ON(msg->size > 16))
 		return -E2BIG;
 
+	PM_RUNTIME_ACQUIRE_IF_ENABLED_AUTOSUSPEND(dp->dev, pm);
+	ret = PM_RUNTIME_ACQUIRE_ERR(&pm);
+	if (ret)
+		return ret;
+
 	switch (msg->request & ~DP_AUX_I2C_MOT) {
 	case DP_AUX_NATIVE_WRITE:
 	case DP_AUX_I2C_WRITE:
@@ -1720,6 +1726,8 @@ static void dw_dp_bridge_atomic_enable(struct drm_bridge *bridge,
 	struct drm_connector_state *conn_state;
 	int ret;
 
+	pm_runtime_get_sync(dp->dev);
+
 	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
 	if (!connector) {
 		dev_err(dp->dev, "failed to get connector\n");
@@ -1774,6 +1782,7 @@ static void dw_dp_bridge_atomic_disable(struct drm_bridge *bridge,
 	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)
@@ -1794,6 +1803,10 @@ static enum drm_connector_status dw_dp_bridge_detect(struct drm_bridge *bridge,
 {
 	struct dw_dp *dp = bridge_to_dp(bridge);
 
+	PM_RUNTIME_ACQUIRE_IF_ENABLED_AUTOSUSPEND(dp->dev, pm);
+	if (PM_RUNTIME_ACQUIRE_ERR(&pm))
+		return connector_status_disconnected;
+
 	if (!dw_dp_hpd_detect(dp))
 		return connector_status_disconnected;
 
@@ -1973,10 +1986,17 @@ static irqreturn_t dw_dp_irq(int irq, void *data)
 {
 	struct dw_dp *dp = data;
 	u32 value;
+	int ret;
+
+	ret = pm_runtime_get_if_active(dp->dev);
+	if (ret <= 0)
+		return IRQ_NONE;
 
 	regmap_read(dp->regmap, DW_DP_GENERAL_INTERRUPT, &value);
-	if (!value)
+	if (!value) {
+		pm_runtime_put_autosuspend(dp->dev);
 		return IRQ_NONE;
+	}
 
 	if (value & HPD_EVENT)
 		dw_dp_handle_hpd_event(dp);
@@ -1986,6 +2006,7 @@ static irqreturn_t dw_dp_irq(int irq, void *data)
 		complete(&dp->complete);
 	}
 
+	pm_runtime_put_autosuspend(dp->dev);
 	return IRQ_HANDLED;
 }
 
@@ -2073,10 +2094,15 @@ int dw_dp_bind(struct dw_dp *dp, struct drm_encoder *encoder)
 	}
 
 	if (dw_dp_is_routed_to_usb_c(encoder)) {
+		dp->usbc_mode = true;
 		dev_dbg(dev, "USB-C mode\n");
 
 		if (dp->plat_data.hpd_sw_sel)
 			dp->plat_data.hpd_sw_sel(dp->plat_data.data, 1);
+	} else {
+		dp->usbc_mode = false;
+		/* Keep runtime PM enabled to have working native HPD IRQ */
+		pm_runtime_get_sync(dp->dev);
 	}
 
 	dw_dp_init_hw(dp);
@@ -2084,13 +2110,17 @@ int dw_dp_bind(struct dw_dp *dp, struct drm_encoder *encoder)
 	ret = phy_init(dp->phy);
 	if (ret) {
 		dev_err_probe(dev, ret, "phy init failed\n");
-		goto put_next_bridge;
+		goto put_runtime_pm;
 	}
 
 	enable_irq(dp->irq);
 
 	return 0;
 
+put_runtime_pm:
+	if (!dp->usbc_mode)
+		pm_runtime_put_sync(dp->dev);
+
 put_next_bridge:
 	drm_bridge_put(dp->next_bridge);
 
@@ -2106,6 +2136,8 @@ EXPORT_SYMBOL_GPL(dw_dp_bind);
 
 void dw_dp_unbind(struct dw_dp *dp)
 {
+	if (!dp->usbc_mode)
+		pm_runtime_put_sync(dp->dev);
 	disable_irq(dp->irq);
 	cancel_work_sync(&dp->hpd_work);
 	phy_exit(dp->phy);
@@ -2208,6 +2240,41 @@ 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)
+{
+	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);
+
+	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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