usbcore: add sysfs support to xHCI usb2 hardware LPM

This patch adds sysfs support to xHCI usb2 hardware LPM, so developer can
enable and disable usb2 hardware LPM manually for test purpose.

Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 58 insertions, 1 deletions

diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index cf05b97693ea..662c0cf3a3e1 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -412,6 +412,56 @@ set_level(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR(level, S_IRUGO | S_IWUSR, show_level, set_level);
 
+static ssize_t
+show_usb2_hardware_lpm(struct device *dev, struct device_attribute *attr,
+                                char *buf)
+{
+        struct usb_device *udev = to_usb_device(dev);
+        const char *p;
+
+        if (udev->usb2_hw_lpm_enabled == 1)
+                p = "enabled";
+        else
+                p = "disabled";
+
+        return sprintf(buf, "%s\n", p);
+}
+
+static ssize_t
+set_usb2_hardware_lpm(struct device *dev, struct device_attribute *attr,
+                const char *buf, size_t count)
+{
+        struct usb_device *udev = to_usb_device(dev);
+        bool value;
+        int ret;
+
+        usb_lock_device(udev);
+
+        ret = strtobool(buf, &value);
+
+        if (!ret)
+                ret = usb_set_usb2_hardware_lpm(udev, value);
+
+        usb_unlock_device(udev);
+
+        if (!ret)
+                return count;
+
+        return ret;
+}
+
+static DEVICE_ATTR(usb2_hardware_lpm, S_IRUGO | S_IWUSR, show_usb2_hardware_lpm,
+                        set_usb2_hardware_lpm);
+
+static struct attribute *usb2_hardware_lpm_attr[] = {
+        &dev_attr_usb2_hardware_lpm.attr,
+        NULL,
+};
+static struct attribute_group usb2_hardware_lpm_attr_group = {
+        .name   = power_group_name,
+        .attrs  = usb2_hardware_lpm_attr,
+};
+
 static struct attribute *power_attrs[] = {
         &dev_attr_autosuspend.attr,
         &dev_attr_level.attr,
@@ -428,13 +478,20 @@ static int add_power_attributes(struct device *dev)
 {
         int rc = 0;
 
-        if (is_usb_device(dev))
+        if (is_usb_device(dev)) {
+                struct usb_device *udev = to_usb_device(dev);
                 rc = sysfs_merge_group(&dev->kobj, &power_attr_group);
+                if (udev->usb2_hw_lpm_capable == 1)
+                        rc = sysfs_merge_group(&dev->kobj,
+                                        &usb2_hardware_lpm_attr_group);
+        }
+
         return rc;
 }
 
 static void remove_power_attributes(struct device *dev)
 {
+        sysfs_unmerge_group(&dev->kobj, &usb2_hardware_lpm_attr_group);
         sysfs_unmerge_group(&dev->kobj, &power_attr_group);
 }