From 76251db8656194d27629300c852b53c471e9b586 Mon Sep 17 00:00:00 2001 From: Enric Balletbo i Serra Date: Mon, 16 Jul 2018 12:25:47 +0200 Subject: [PATCH] usb: dwc3: of-simple: reset host controller at suspend/resume If we power off the SoC logic rail in S3, we can find that the Type-C PHY can't initialize correctly after system resume. We need to toggle the USB3-OTG reset before trying to initialize the PHY, or else it times out. phy phy-ff800000.phy.9: phy poweron failed --> -110 dwc3 fe900000.dwc3: failed to initialize core dwc3: probe of fe900000.dwc3 failed with error -110 Note that the RK3399 TRM suggests that we should keep the whole usb3 controller in reset for the duration of the Type-C PHY initialization. However, it's hard to assert the reset in the current framework of reset. We're still skeptical about that, and we haven't yet found a case where this seems to have mattered. This approach is much easier, it simply holds the USB3-OTG reset while device is supended. The dwc3 core is going to reinitialize the controller at suspend/resume anyway (including a "soft reset"), so it should be safe to do this. Signed-off-by: Enric Balletbo i Serra Signed-off-by: Felipe Balbi --- drivers/usb/dwc3/dwc3-of-simple.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/drivers/usb/dwc3/dwc3-of-simple.c b/drivers/usb/dwc3/dwc3-of-simple.c index dbeff5e6ad14..40bf9e0bbc59 100644 --- a/drivers/usb/dwc3/dwc3-of-simple.c +++ b/drivers/usb/dwc3/dwc3-of-simple.c @@ -28,6 +28,7 @@ struct dwc3_of_simple { int num_clocks; struct reset_control *resets; bool pulse_resets; + bool need_reset; }; static int dwc3_of_simple_clk_init(struct dwc3_of_simple *simple, int count) @@ -93,6 +94,13 @@ static int dwc3_of_simple_probe(struct platform_device *pdev) platform_set_drvdata(pdev, simple); simple->dev = dev; + /* + * Some controllers need to toggle the usb3-otg reset before trying to + * initialize the PHY, otherwise the PHY times out. + */ + if (of_device_is_compatible(np, "rockchip,rk3399-dwc3")) + simple->need_reset = true; + if (of_device_is_compatible(np, "amlogic,meson-axg-dwc3") || of_device_is_compatible(np, "amlogic,meson-gxl-dwc3")) { shared_resets = true; @@ -201,9 +209,30 @@ static int dwc3_of_simple_runtime_resume(struct device *dev) return 0; } + +static int dwc3_of_simple_suspend(struct device *dev) +{ + struct dwc3_of_simple *simple = dev_get_drvdata(dev); + + if (simple->need_reset) + reset_control_assert(simple->resets); + + return 0; +} + +static int dwc3_of_simple_resume(struct device *dev) +{ + struct dwc3_of_simple *simple = dev_get_drvdata(dev); + + if (simple->need_reset) + reset_control_deassert(simple->resets); + + return 0; +} #endif static const struct dev_pm_ops dwc3_of_simple_dev_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(dwc3_of_simple_suspend, dwc3_of_simple_resume) SET_RUNTIME_PM_OPS(dwc3_of_simple_runtime_suspend, dwc3_of_simple_runtime_resume, NULL) };