drm/msm/hdmi: Set up runtime PM for HDMI

Enable rudimentary runtime PM in the HDMI driver. We can't really do
agressive PM toggling at the moment because we need to leave the hpd
clocks enabled all the time. There isn't much benefit of creating
suspend/resume ops to toggle clocks either.

We just make sure that we configure the power domain in the HDMI bridge's
enable/disable paths, and the HDMI connector's detect() op.
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/hdmi/hdmi.c

@@ -239,6 +239,8 @@ static struct hdmi *msm_hdmi_init(struct platform_device *pdev)
 		hdmi->pwr_clks[i] = clk;
 	}
 
+	pm_runtime_enable(&pdev->dev);
+
 	hdmi->workq = alloc_ordered_workqueue("msm_hdmi", 0);
 
 	hdmi->i2c = msm_hdmi_i2c_init(hdmi);

drivers/gpu/drm/msm/hdmi/hdmi_bridge.c

@@ -35,6 +35,8 @@ static void msm_hdmi_power_on(struct drm_bridge *bridge)
 	const struct hdmi_platform_config *config = hdmi->config;
 	int i, ret;
 
+	pm_runtime_get_sync(&hdmi->pdev->dev);
+
 	for (i = 0; i < config->pwr_reg_cnt; i++) {
 		ret = regulator_enable(hdmi->pwr_regs[i]);
 		if (ret) {
@@ -84,6 +86,8 @@ static void power_off(struct drm_bridge *bridge)
 					config->pwr_reg_names[i], ret);
 		}
 	}
+
+	pm_runtime_put_autosuspend(&hdmi->pdev->dev);
 }
 
 #define AVI_IFRAME_LINE_NUMBER 1

drivers/gpu/drm/msm/hdmi/hdmi_connector.c

@@ -137,6 +137,36 @@ static int gpio_config(struct hdmi *hdmi, bool on)
 	return ret;
 }
 
+static void enable_hpd_clocks(struct hdmi *hdmi, bool enable)
+{
+	const struct hdmi_platform_config *config = hdmi->config;
+	struct device *dev = &hdmi->pdev->dev;
+	int i, ret;
+
+	if (enable) {
+		for (i = 0; i < config->hpd_clk_cnt; i++) {
+			if (config->hpd_freq && config->hpd_freq[i]) {
+				ret = clk_set_rate(hdmi->hpd_clks[i],
+						   config->hpd_freq[i]);
+				if (ret)
+					dev_warn(dev,
+						 "failed to set clk %s (%d)\n",
+						 config->hpd_clk_names[i], ret);
+			}
+
+			ret = clk_prepare_enable(hdmi->hpd_clks[i]);
+			if (ret) {
+				dev_err(dev,
+					"failed to enable hpd clk: %s (%d)\n",
+					config->hpd_clk_names[i], ret);
+			}
+		}
+	} else {
+		for (i = config->hpd_clk_cnt - 1; i >= 0; i--)
+			clk_disable_unprepare(hdmi->hpd_clks[i]);
+	}
+}
+
 static int hpd_enable(struct hdmi_connector *hdmi_connector)
 {
 	struct hdmi *hdmi = hdmi_connector->hdmi;
@@ -167,22 +197,8 @@ static int hpd_enable(struct hdmi_connector *hdmi_connector)
 		goto fail;
 	}
 
-	for (i = 0; i < config->hpd_clk_cnt; i++) {
-		if (config->hpd_freq && config->hpd_freq[i]) {
-			ret = clk_set_rate(hdmi->hpd_clks[i],
-					config->hpd_freq[i]);
-			if (ret)
-				dev_warn(dev, "failed to set clk %s (%d)\n",
-						config->hpd_clk_names[i], ret);
-		}
-
-		ret = clk_prepare_enable(hdmi->hpd_clks[i]);
-		if (ret) {
-			dev_err(dev, "failed to enable hpd clk: %s (%d)\n",
-					config->hpd_clk_names[i], ret);
-			goto fail;
-		}
-	}
+	pm_runtime_get_sync(dev);
+	enable_hpd_clocks(hdmi, true);
 
 	msm_hdmi_set_mode(hdmi, false);
 	msm_hdmi_phy_reset(hdmi);
@@ -225,8 +241,8 @@ static void hdp_disable(struct hdmi_connector *hdmi_connector)
 
 	msm_hdmi_set_mode(hdmi, false);
 
-	for (i = 0; i < config->hpd_clk_cnt; i++)
-		clk_disable_unprepare(hdmi->hpd_clks[i]);
+	enable_hpd_clocks(hdmi, false);
+	pm_runtime_put_autosuspend(dev);
 
 	ret = gpio_config(hdmi, false);
 	if (ret)
@@ -285,7 +301,16 @@ void msm_hdmi_connector_irq(struct drm_connector *connector)
 
 static enum drm_connector_status detect_reg(struct hdmi *hdmi)
 {
-	uint32_t hpd_int_status = hdmi_read(hdmi, REG_HDMI_HPD_INT_STATUS);
+	uint32_t hpd_int_status;
+
+	pm_runtime_get_sync(&hdmi->pdev->dev);
+	enable_hpd_clocks(hdmi, true);
+
+	hpd_int_status = hdmi_read(hdmi, REG_HDMI_HPD_INT_STATUS);
+
+	enable_hpd_clocks(hdmi, false);
+	pm_runtime_put_autosuspend(&hdmi->pdev->dev);
+
 	return (hpd_int_status & HDMI_HPD_INT_STATUS_CABLE_DETECTED) ?
 			connector_status_connected : connector_status_disconnected;
 }