[PATCH v6 6/6] phy: fsl-imx8mq-usb: keep PHY power domain runtime always-on for i.MX8MP

[Xu Yang]

From: Xu Yang <xu.yang_2@xxxxxxx>

On i.MX8MP, the USB PHY has a dedicated power domain that was previously
never powered off at runtime. With the introduction of runtime PM support,
the power domain will be powered off if the device is runtime suspended,
which breaks USB wakeup functionality.

To preserve wakeup functionality, mark the PHY power domain as runtime
always-on for i.MX8MP platform. To limit the behavior to i.MX8MP, add a
need_genpd_rpm_on to imx8mq_usb_phy_drvdata and set it as true for i.MX8MP.

Signed-off-by: Xu Yang <xu.yang_2@xxxxxxx>

---
Changes in v6:
 - set need_genpd_rpm_on flag for i.MX8MP and call dev_pm_genpd_rpm_always_on()
   if the flag is true
Changes in v5:
 - no changes
Changes in v4:
 - no changes
Changes in v3:
 - new patch
---
 drivers/phy/freescale/phy-fsl-imx8mq-usb.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
index f0bdfa75d586..2398bda50eb8 100644
--- a/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
+++ b/drivers/phy/freescale/phy-fsl-imx8mq-usb.c
@@ -9,6 +9,7 @@
 #include <linux/of.h>
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
+#include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
 #include <linux/regulator/consumer.h>
 #include <linux/regmap.h>
@@ -134,6 +135,7 @@ struct imx8mq_usb_phy {
 
 struct imx8mq_usb_phy_drvdata {
 	const struct phy_ops *ops;
+	bool need_genpd_rpm_on;
 };
 
 static void tca_blk_orientation_set(struct tca_blk *tca,
@@ -669,6 +671,7 @@ static const struct imx8mq_usb_phy_drvdata imx8mq_usb_phy_data = {
 
 static const struct imx8mq_usb_phy_drvdata imx8mp_usb_phy_data = {
 	.ops = &imx8mp_usb_phy_ops,
+	.need_genpd_rpm_on = true,
 };
 
 static const struct imx8mq_usb_phy_drvdata imx95_usb_phy_data = {
@@ -739,6 +742,12 @@ static int imx8mq_usb_phy_probe(struct platform_device *pdev)
 	if (!phy_data)
 		return -EINVAL;
 
+	if (phy_data->need_genpd_rpm_on) {
+		ret = dev_pm_genpd_rpm_always_on(dev, true);
+		if (ret)
+			return dev_err_probe(dev, ret, "failed to set genpd rpm always on\n");
+	}
+
 	imx_phy->phy = devm_phy_create(dev, NULL, phy_data->ops);
 	if (IS_ERR(imx_phy->phy))
 		return PTR_ERR(imx_phy->phy);

-- 
2.34.1