usb: dwc3: rockchip: fix rk3399 dwc3 host power on fail

RK3399 Excavator Board has an USB 3.0 PHY power on issue
when Type-A USB 3.0 Host port connects with an USB 3.0
device and do system PM suspend/resume test.

When the issue happens, we gets the following error log:

phy phy-ff800000.phy.4: phy poweron failed --> -110
dpm_run_callback(): platform_pm_resume+0x0/0x54 returns -110
PM: Device fe900000.dwc3 failed to resume: error -110
xhci-hcd xhci-hcd.12.auto: port 0 resume PLC timeout

It's because that the Type-C PHY docs say that the DWC3
controller "needs to be held in reset to set the PIPE
power state in P2 before initializing the Type-C PHY",
but actually the PIPE is in P0 state because an USB 3.0
device is connected, and the current code doesn't reset
the DWC3 controller upon PM resume.

This patch prevents powering off the USB 3.0 PHY of
RK3399 Type-A USB 3.0 Host port when system enters
syspend. As a side effect, the power consumption in
standby mode will increase. However, if you want to
optimize the power consumption in standby mode and
allow the USB device to be reenumerated upon PM resume,
you can add a property "needs-reset-on-resume" in
DWC3 DTS like this:

&usbdrd3_1 {
	needs-reset-on-resume;
};

Change-Id: Ia1cdf6e09cac520e99931a15423b8de7be2ba52b
Signed-off-by: William Wu <william.wu@rock-chips.com>

1 files changed, 20 insertions, 1 deletions

diff --git a/drivers/usb/dwc3/dwc3-rockchip.c b/drivers/usb/dwc3/dwc3-rockchip.c
index 9b549b48f74f..4810d45deeed 100644
--- a/drivers/usb/dwc3/dwc3-rockchip.c
+++ b/drivers/usb/dwc3/dwc3-rockchip.c
@@ -50,6 +50,7 @@ struct dwc3_rockchip {
 	bool			skip_suspend;
 	bool			suspended;
 	bool			force_mode;
+	bool			reset_on_resume;
 	enum usb_dr_mode	original_dr_mode;
 	struct device		*dev;
 	struct clk		**clks;
@@ -659,6 +660,9 @@ static void dwc3_rockchip_async_probe(void *data, async_cookie_t cookie)
 
 	mutex_lock(&rockchip->lock);
 
+	rockchip->reset_on_resume =
+		device_property_read_bool(dev, "needs-reset-on-resume");
+
 	if (rockchip->edev) {
 		ret = extcon_register_notifier(rockchip->edev, EXTCON_USB,
 					       &rockchip->device_nb);
@@ -704,6 +708,21 @@ static void dwc3_rockchip_async_probe(void *data, async_cookie_t cookie)
 		 * usb device to be reenumerated.
 		 */
 		rockchip->connected = true;
+
+		if (!rockchip->reset_on_resume &&
+		    of_machine_is_compatible("rockchip,rk3399")) {
+			/*
+			 * RK3399 USB 3.0 PHY is Type-C PHY, needs to
+			 * power on USB 3.0 PHY here in addition to
+			 * dwc3_core_init() to prevent it powering
+			 * off USB 3.0 PHY during suspend.
+			 */
+			ret = phy_power_on(dwc->usb3_generic_phy);
+			if (ret < 0) {
+				dev_err(dwc->dev, "Failed to power on usb3 phy\n");
+				goto err;
+			}
+		}
 	}
 
 	ret = sysfs_create_group(&dev->kobj, &dwc3_rockchip_attr_group);
@@ -958,7 +977,7 @@ static int __maybe_unused dwc3_rockchip_resume(struct device *dev)
 	struct dwc3_rockchip *rockchip = dev_get_drvdata(dev);
 	struct dwc3 *dwc = rockchip->dwc;
 
-	if (!rockchip->connected) {
+	if (!rockchip->connected || rockchip->reset_on_resume) {
 		reset_control_assert(rockchip->otg_rst);
 		udelay(1);
 		reset_control_deassert(rockchip->otg_rst);