scsi: ufs: host: mediatek: Support UFS PHY runtime PM and correct sequence

Add support for UFS PHY runtime power management by probing the PHY
device and enabling its runtime PM. Ensure the correct sequence of
operations during suspend and resume: PHY suspend -> UFS suspend -> UFS
resume -> PHY resume.  Improve power management efficiency and system
stability with this enhancement.

Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

Author: ptr324

drivers/ufs/host/ufs-mediatek.c

@@ -2243,10 +2243,12 @@ static const struct ufs_hba_variant_ops ufs_hba_mtk_vops = {
 static int ufs_mtk_probe(struct platform_device *pdev)
 {
 	int err;
-	struct device *dev = &pdev->dev;
-	struct device_node *reset_node;
-	struct platform_device *reset_pdev;
+	struct device *dev = &pdev->dev, *phy_dev = NULL;
+	struct device_node *reset_node, *phy_node = NULL;
+	struct platform_device *reset_pdev, *phy_pdev = NULL;
 	struct device_link *link;
+	struct ufs_hba *hba;
+	struct ufs_mtk_host *host;
 
 	reset_node = of_find_compatible_node(NULL, NULL,
 					     "ti,syscon-reset");
@@ -2273,13 +2275,44 @@ static int ufs_mtk_probe(struct platform_device *pdev)
 	}
 
 skip_reset:
+	/* find phy node */
+	phy_node = of_parse_phandle(dev->of_node, "phys", 0);
+
+	if (phy_node) {
+		phy_pdev = of_find_device_by_node(phy_node);
+		if (!phy_pdev)
+			goto skip_phy;
+		phy_dev = &phy_pdev->dev;
+
+		pm_runtime_set_active(phy_dev);
+		pm_runtime_enable(phy_dev);
+		pm_runtime_get_sync(phy_dev);
+
+		put_device(phy_dev);
+		dev_info(dev, "phys node found\n");
+	} else {
+		dev_notice(dev, "phys node not found\n");
+	}
+
+skip_phy:
 	/* perform generic probe */
 	err = ufshcd_pltfrm_init(pdev, &ufs_hba_mtk_vops);
-
-out:
-	if (err)
+	if (err) {
 		dev_err(dev, "probe failed %d\n", err);
+		goto out;
+	}
+
+	hba = platform_get_drvdata(pdev);
+	if (!hba)
+		goto out;
+
+	if (phy_node && phy_dev) {
+		host = ufshcd_get_variant(hba);
+		host->phy_dev = phy_dev;
+	}
 
+out:
+	of_node_put(phy_node);
 	of_node_put(reset_node);
 	return err;
 }
@@ -2343,6 +2376,7 @@ static int ufs_mtk_system_resume(struct device *dev)
 static int ufs_mtk_runtime_suspend(struct device *dev)
 {
 	struct ufs_hba *hba = dev_get_drvdata(dev);
+	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
 	struct arm_smccc_res res;
 	int ret = 0;
 
@@ -2355,17 +2389,24 @@ static int ufs_mtk_runtime_suspend(struct device *dev)
 	if (ufs_mtk_is_rtff_mtcmos(hba))
 		ufs_mtk_mtcmos_ctrl(false, res);
 
+	if (host->phy_dev)
+		pm_runtime_put_sync(host->phy_dev);
+
 	return 0;
 }
 
 static int ufs_mtk_runtime_resume(struct device *dev)
 {
 	struct ufs_hba *hba = dev_get_drvdata(dev);
+	struct ufs_mtk_host *host = ufshcd_get_variant(hba);
 	struct arm_smccc_res res;
 
 	if (ufs_mtk_is_rtff_mtcmos(hba))
 		ufs_mtk_mtcmos_ctrl(true, res);
 
+	if (host->phy_dev)
+		pm_runtime_get_sync(host->phy_dev);
+
 	ufs_mtk_dev_vreg_set_lpm(hba, false);
 
 	return ufshcd_runtime_resume(dev);

drivers/ufs/host/ufs-mediatek.h

@@ -193,6 +193,7 @@ struct ufs_mtk_host {
 	bool is_mcq_intr_enabled;
 	int mcq_nr_intr;
 	struct ufs_mtk_mcq_intr_info mcq_intr_info[UFSHCD_MAX_Q_NR];
+	struct device *phy_dev;
 };
 
 /* MTK delay of autosuspend: 500 ms */