USB: dwc2: Don't turn off the usbphy in suspend if wakeup is enabled

If the 'snps,need-phy-for-wake' is set in the device tree then:

- We know that we can wakeup, so call device_set_wakeup_capable().
  The USB core will use this knowledge to enable wakeup by default.
- We know that we should keep the PHY on during suspend if something
  on our root hub needs remote wakeup.  This requires the patch (USB:
  Export usb_wakeup_enabled_descendants()).  Note that we don't keep
  the PHY on at suspend time if it's not needed because it would be a
  power draw.

If we later find some users of dwc2 that can support wakeup without
keeping the PHY on we may want to add a way to call
device_set_wakeup_capable() without keeping the PHY on at suspend
time.

Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Chris Zhong <zyw@rock-chips.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 152ac41dfb2d91bc9424d1b01f28bea18e01afd9..d08d070a0fb6f5989ba64d17d2623a7dfe817dae 100644 (file)
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -861,6 +861,9 @@ struct dwc2_hregs_backup {
  * @hibernated:                True if core is hibernated
  * @reset_phy_on_wake: Quirk saying that we should assert PHY reset on a
  *                     remote wakeup.
+ * @phy_off_for_suspend: Status of whether we turned the PHY off at suspend.
+ * @need_phy_for_wake: Quirk saying that we should keep the PHY on at
+ *                     suspend if we need USB to wake us up.
  * @frame_number:       Frame number read from the core. For both device
  *                     and host modes. The value ranges are from 0
  *                     to HFNUM_MAX_FRNUM.
@@ -1049,6 +1052,8 @@ struct dwc2_hsotg {
        unsigned int ll_hw_enabled:1;
        unsigned int hibernated:1;
        unsigned int reset_phy_on_wake:1;
+       unsigned int need_phy_for_wake:1;
+       unsigned int phy_off_for_suspend:1;
        u16 frame_number;
 
        struct phy *phy;
@@ -1438,6 +1443,7 @@ int dwc2_restore_host_registers(struct dwc2_hsotg *hsotg);
 int dwc2_host_enter_hibernation(struct dwc2_hsotg *hsotg);
 int dwc2_host_exit_hibernation(struct dwc2_hsotg *hsotg,
                               int rem_wakeup, int reset);
+bool dwc2_host_can_poweroff_phy(struct dwc2_hsotg *dwc2);
 static inline void dwc2_host_schedule_phy_reset(struct dwc2_hsotg *hsotg)
 { schedule_work(&hsotg->phy_reset_work); }
 #else
@@ -1463,6 +1469,8 @@ static inline int dwc2_host_enter_hibernation(struct dwc2_hsotg *hsotg)
 static inline int dwc2_host_exit_hibernation(struct dwc2_hsotg *hsotg,
                                             int rem_wakeup, int reset)
 { return 0; }
+static inline bool dwc2_host_can_poweroff_phy(struct dwc2_hsotg *dwc2)
+{ return false; }
 static inline void dwc2_host_schedule_phy_reset(struct dwc2_hsotg *hsotg) {}
 
 #endif

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index 2192a2873c7c056e44f2a66a0fe75d29e29bfb50..4c78a390c958fe464a15a8c2b20d96cd79839498 100644 (file)
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -5587,3 +5587,22 @@ int dwc2_host_exit_hibernation(struct dwc2_hsotg *hsotg, int rem_wakeup,
        dev_dbg(hsotg->dev, "Host hibernation restore complete\n");
        return ret;
 }
+
+bool dwc2_host_can_poweroff_phy(struct dwc2_hsotg *dwc2)
+{
+       struct usb_device *root_hub = dwc2_hsotg_to_hcd(dwc2)->self.root_hub;
+
+       /* If the controller isn't allowed to wakeup then we can power off. */
+       if (!device_may_wakeup(dwc2->dev))
+               return true;
+
+       /*
+        * We don't want to power off the PHY if something under the
+        * root hub has wakeup enabled.
+        */
+       if (usb_wakeup_enabled_descendants(root_hub))
+               return false;
+
+       /* No reason to keep the PHY powered, so allow poweroff */
+       return true;
+}

diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index d10a7f8daec34577d50aaf42a18b37c79eb2e285..3e6c3c8a32ff2dc5af47619a33bf0d51be8e9563 100644 (file)
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -447,6 +447,10 @@ static int dwc2_driver_probe(struct platform_device *dev)
        if (retval)
                goto error;
 
+       hsotg->need_phy_for_wake =
+               of_property_read_bool(dev->dev.of_node,
+                                     "snps,need-phy-for-wake");
+
        /*
         * Reset before dwc2_get_hwparams() then it could get power-on real
         * reset value form registers.
@@ -478,6 +482,14 @@ static int dwc2_driver_probe(struct platform_device *dev)
                hsotg->gadget_enabled = 1;
        }
 
+       /*
+        * If we need PHY for wakeup we must be wakeup capable.
+        * When we have a device that can wake without the PHY we
+        * can adjust this condition.
+        */
+       if (hsotg->need_phy_for_wake)
+               device_set_wakeup_capable(&dev->dev, true);
+
        hsotg->reset_phy_on_wake =
                of_property_read_bool(dev->dev.of_node,
                                      "snps,reset-phy-on-wake");
@@ -516,13 +528,17 @@ static int dwc2_driver_probe(struct platform_device *dev)
 static int __maybe_unused dwc2_suspend(struct device *dev)
 {
        struct dwc2_hsotg *dwc2 = dev_get_drvdata(dev);
+       bool is_device_mode = dwc2_is_device_mode(dwc2);
        int ret = 0;
 
-       if (dwc2_is_device_mode(dwc2))
+       if (is_device_mode)
                dwc2_hsotg_suspend(dwc2);
 
-       if (dwc2->ll_hw_enabled)
+       if (dwc2->ll_hw_enabled &&
+           (is_device_mode || dwc2_host_can_poweroff_phy(dwc2))) {
                ret = __dwc2_lowlevel_hw_disable(dwc2);
+               dwc2->phy_off_for_suspend = true;
+       }
 
        return ret;
 }
@@ -532,11 +548,12 @@ static int __maybe_unused dwc2_resume(struct device *dev)
        struct dwc2_hsotg *dwc2 = dev_get_drvdata(dev);
        int ret = 0;
 
-       if (dwc2->ll_hw_enabled) {
+       if (dwc2->phy_off_for_suspend && dwc2->ll_hw_enabled) {
                ret = __dwc2_lowlevel_hw_enable(dwc2);
                if (ret)
                        return ret;
        }
+       dwc2->phy_off_for_suspend = false;
 
        if (dwc2_is_device_mode(dwc2))
                ret = dwc2_hsotg_resume(dwc2);