[PATCH] usb: core: adds support for PM control of specific USB dev skip suspend.

[huanglei814 <huanglei814@163.com>]

From: huanglei <huanglei@kylinos.cn>

All USB devices are brought into suspend power state after system suspend.
It is desirable for some specific manufacturers buses to keep their devices
in normal state even after system suspend.

Signed-off-by: huanglei <huanglei@kylinos.cn>
---
 drivers/usb/core/Kconfig     | 12 ++++++++++++
 drivers/usb/core/driver.c    | 14 ++++++++++++++
 drivers/usb/host/xhci-plat.c |  7 +++++++
 include/linux/usb.h          |  9 +++++++++
 4 files changed, 42 insertions(+)

diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index 58e3ca7e4793..fe178c90d167 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -143,3 +143,15 @@ config USB_DEFAULT_AUTHORIZATION_MODE
 	  ACPI selecting value 2 is analogous to selecting value 0.
 
 	  If unsure, keep the default value.
+
+config USB_SKIP_SUSPEND
+	bool "Vendor USB support skip suspend"
+	depends on USB
+	default n
+	help
+	  Select this the associate USB devices will skip suspend when pm control.
+
+	  This option adds support skip suspend for PM control of USB devices
+	  in specific manufacturers platforms.
+
+	  If unsure, keep the default value.
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 0c3f12daac79..05fe921f8297 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1583,6 +1583,15 @@ int usb_suspend(struct device *dev, pm_message_t msg)
 	struct usb_device	*udev = to_usb_device(dev);
 	int r;
 
+#ifdef CONFIG_USB_SKIP_SUSPEND
+	if (udev->bus->skip_suspend && (msg.event == PM_EVENT_SUSPEND)) {
+		if (udev->state != USB_STATE_SUSPENDED)
+			dev_err(dev, "abort suspend\n");
+
+		return 0;
+	}
+#endif
+
 	unbind_no_pm_drivers_interfaces(udev);
 
 	/* From now on we are sure all drivers support suspend/resume
@@ -1619,6 +1628,11 @@ int usb_resume(struct device *dev, pm_message_t msg)
 	struct usb_device	*udev = to_usb_device(dev);
 	int			status;
 
+#ifdef CONFIG_USB_SKIP_SUSPEND
+	if (udev->bus->skip_suspend && (msg.event == PM_EVENT_RESUME))
+		return 0;
+#endif
+
 	/* For all calls, take the device back to full power and
 	 * tell the PM core in case it was autosuspended previously.
 	 * Unbind the interfaces that will need rebinding later,
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index ecaa75718e59..8cbc666ab5c6 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -265,6 +265,13 @@ int xhci_plat_probe(struct platform_device *pdev, struct device *sysdev, const s
 		if (device_property_read_bool(tmpdev, "xhci-skip-phy-init-quirk"))
 			xhci->quirks |= XHCI_SKIP_PHY_INIT;
 
+#ifdef CONFIG_USB_SKIP_SUSPEND
+		if (device_property_read_bool(tmpdev, "usb-skip-suspend")) {
+			hcd_to_bus(hcd)->skip_suspend = true;
+			hcd_to_bus(xhci->shared_hcd)->skip_suspend = true;
+		}
+#endif
+
 		device_property_read_u32(tmpdev, "imod-interval-ns",
 					 &xhci->imod_interval);
 	}
diff --git a/include/linux/usb.h b/include/linux/usb.h
index 672d8fc2abdb..5f88850fc42d 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -487,6 +487,15 @@ struct usb_bus {
 	struct mon_bus *mon_bus;	/* non-null when associated */
 	int monitored;			/* non-zero when monitored */
 #endif
+
+#ifdef CONFIG_USB_SKIP_SUSPEND
+	unsigned int skip_suspend;	/* All USB devices are brought into suspend
+					 * power state after system suspend. It is
+					 * desirable for some specific manufacturers
+					 * buses to keep their devices in normal
+					 * state even after system suspend.
+					 */
+#endif
 };
 
 struct usb_dev_state;
-- 
2.17.1