[PATCH v4 3/3] coresight-tnoc: Add runtime PM support for Interconnect TNOC

[Yuanfang Zhang <yuanfang.zhang@oss.qualcomm.com>]

This patch adds runtime power management support for platform-based
CoreSight Interconnect TNOC (ITNOC) devices. It introduces suspend and
resume callbacks to manage the APB clock (`pclk`) during device runtime
transitions.

Signed-off-by: Yuanfang Zhang <yuanfang.zhang@oss.qualcomm.com>
---
 drivers/hwtracing/coresight/coresight-tnoc.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-tnoc.c b/drivers/hwtracing/coresight/coresight-tnoc.c
index 5be882300d79bc0173aa6a19d7da1d48c4aaca9c..2c5370497076536bfa868f0d80db775ef242968b 100644
--- a/drivers/hwtracing/coresight/coresight-tnoc.c
+++ b/drivers/hwtracing/coresight/coresight-tnoc.c
@@ -301,6 +301,28 @@ static void itnoc_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 }
 
+#ifdef CONFIG_PM
+static int itnoc_runtime_suspend(struct device *dev)
+{
+	struct trace_noc_drvdata *drvdata = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(drvdata->pclk);
+
+	return 0;
+}
+
+static int itnoc_runtime_resume(struct device *dev)
+{
+	struct trace_noc_drvdata *drvdata = dev_get_drvdata(dev);
+
+	return clk_prepare_enable(drvdata->pclk);
+}
+#endif
+
+static const struct dev_pm_ops itnoc_dev_pm_ops = {
+	SET_RUNTIME_PM_OPS(itnoc_runtime_suspend, itnoc_runtime_resume, NULL)
+};
+
 static const struct of_device_id itnoc_of_match[] = {
 	{ .compatible = "qcom,coresight-itnoc" },
 	{}
@@ -314,6 +336,7 @@ static struct platform_driver itnoc_driver = {
 		.name = "coresight-itnoc",
 		.of_match_table = itnoc_of_match,
 		.suppress_bind_attrs = true,
+		.pm = &itnoc_dev_pm_ops,
 	},
 };
 

-- 
2.34.1