phy: renesas: rcar-gen3-usb2: Add suspend/resume support

The Renesas RZ/G3S supports a power saving mode where power to most of the
SoC components is turned off. The USB PHY is among these components.
Because of this the settings applied in driver probe need to be executed
also on resume path. On suspend path only reset signal need to be asserted.
Add suspend/resume support.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patch.msgid.link/20251119120418.686224-3-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

Author: claudiubeznea

drivers/phy/renesas/phy-rcar-gen3-usb2.c

@@ -132,6 +132,7 @@ struct rcar_gen3_chan {
 	struct device *dev;	/* platform_device's device */
 	const struct rcar_gen3_phy_drv_data *phy_data;
 	struct extcon_dev *extcon;
+	struct reset_control *rstc;
 	struct rcar_gen3_phy rphys[NUM_OF_PHYS];
 	struct regulator *vbus;
 	struct work_struct work;
@@ -778,38 +779,24 @@ static void rcar_gen3_reset_assert(void *data)
 static int rcar_gen3_phy_usb2_init_bus(struct rcar_gen3_chan *channel)
 {
 	struct device *dev = channel->dev;
-	struct reset_control *rstc;
 	int ret;
 	u32 val;
 
 	if (!channel->phy_data->init_bus)
 		return 0;
 
-	rstc = devm_reset_control_array_get_shared(dev);
-	if (IS_ERR(rstc))
-		return PTR_ERR(rstc);
-
 	ret = pm_runtime_resume_and_get(dev);
 	if (ret)
 		return ret;
 
-	ret = reset_control_deassert(rstc);
-	if (ret)
-		goto rpm_put;
-
-	ret = devm_add_action_or_reset(dev, rcar_gen3_reset_assert, rstc);
-	if (ret)
-		goto rpm_put;
-
 	val = readl(channel->base + USB2_AHB_BUS_CTR);
 	val &= ~USB2_AHB_BUS_CTR_MBL_MASK;
 	val |= USB2_AHB_BUS_CTR_MBL_INCR4;
 	writel(val, channel->base + USB2_AHB_BUS_CTR);
 
-rpm_put:
 	pm_runtime_put(dev);
 
-	return ret;
+	return 0;
 }
 
 static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
@@ -849,6 +836,18 @@ static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
 		}
 	}
 
+	channel->rstc = devm_reset_control_array_get_optional_shared(dev);
+	if (IS_ERR(channel->rstc))
+		return PTR_ERR(channel->rstc);
+
+	ret = reset_control_deassert(channel->rstc);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, rcar_gen3_reset_assert, channel->rstc);
+	if (ret)
+		return ret;
+
 	/*
 	 * devm_phy_create() will call pm_runtime_enable(&phy->dev);
 	 * And then, phy-core will manage runtime pm for this device.
@@ -937,10 +936,38 @@ static void rcar_gen3_phy_usb2_remove(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 };
 
+static int rcar_gen3_phy_usb2_suspend(struct device *dev)
+{
+	struct rcar_gen3_chan *channel = dev_get_drvdata(dev);
+
+	return reset_control_assert(channel->rstc);
+}
+
+static int rcar_gen3_phy_usb2_resume(struct device *dev)
+{
+	struct rcar_gen3_chan *channel = dev_get_drvdata(dev);
+	int ret;
+
+	ret = reset_control_deassert(channel->rstc);
+	if (ret)
+		return ret;
+
+	ret = rcar_gen3_phy_usb2_init_bus(channel);
+	if (ret)
+		reset_control_assert(channel->rstc);
+
+	return ret;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(rcar_gen3_phy_usb2_pm_ops,
+				rcar_gen3_phy_usb2_suspend,
+				rcar_gen3_phy_usb2_resume);
+
 static struct platform_driver rcar_gen3_phy_usb2_driver = {
 	.driver = {
 		.name		= "phy_rcar_gen3_usb2",
 		.of_match_table	= rcar_gen3_phy_usb2_match_table,
+		.pm		= pm_ptr(&rcar_gen3_phy_usb2_pm_ops),
 	},
 	.probe	= rcar_gen3_phy_usb2_probe,
 	.remove = rcar_gen3_phy_usb2_remove,