Now that userspace can discover the constraints keeping a port powered, require
it to explicitly disable hotplug capability before powering off a port. This
makes the 'connect_type' attribute writable, and must be set to 'hardwired'
before a port is a candidate for poweroff.
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-usb | 2 ++
drivers/usb/core/port.c | 36 ++++++++++++++++++++++++++++++-
2 files changed, 37 insertions(+), 1 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-usb b/Documentation/ABI/testing/sysfs-bus-usb
index 91bfcfcfbfe3..65db3a686de9 100644
--- a/Documentation/ABI/testing/sysfs-bus-usb
+++ b/Documentation/ABI/testing/sysfs-bus-usb
@@ -160,6 +160,8 @@ Description:
port
'pm_qos_no_power_off': child inactive, pm qos flag keeps
power enabled
+ 'hotplug': child inactive, remaining powered to detect
+ hotplug events
'wakeup enabled': child inactive, port kept powered to
handle remote wakeup events
'persist disabled': child inactive, but child device
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index f7d1cd8a97d3..977e5b137b79 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -46,7 +46,38 @@ static ssize_t connect_type_show(struct device *dev,
return sprintf(buf, "%s\n", result);
}
-static DEVICE_ATTR_RO(connect_type);
+
+static ssize_t connect_type_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct usb_port *port_dev = to_usb_port(dev);
+ ssize_t sz = len;
+ int i;
+ struct action { const char *str; enum usb_port_connect_type type; };
+ static const struct action action[] = {
+ { .str = "hotplug", .type = USB_PORT_CONNECT_TYPE_HOT_PLUG, },
+ { .str = "hardwired", .type = USB_PORT_CONNECT_TYPE_HARD_WIRED },
+ };
+
+ if (buf[len-1] == '\n' || buf[len-1] == '\0')
+ sz--;
+
+ for (i = 0; i < ARRAY_SIZE(action); i++) {
+ const struct action *act = &action[i];
+
+ if (sz == strlen(act->str)
+ && strncmp(buf, act->str, sz) == 0) {
+ pm_runtime_get_sync(&port_dev->dev);
+ port_dev->connect_type = act->type;
+ pm_runtime_put_sync(&port_dev->dev);
+ return len;
+ }
+ }
+
+ return -EINVAL;
+}
+
+static DEVICE_ATTR_RW(connect_type);
static struct attribute *port_dev_attrs[] = {
&dev_attr_connect_type.attr,
@@ -103,6 +134,9 @@ static const char *power_on_reason(struct usb_port *port_dev)
if (dev_pm_qos_flags(&port_dev->dev, flag) == PM_QOS_FLAGS_ALL)
return "pm_qos_no_power_off";
+ if (port_dev->connect_type < USB_PORT_CONNECT_TYPE_HARD_WIRED)
+ return "hotplug";
+
udev = usb_port_get_child(port_dev);
if (udev && udev->do_remote_wakeup)
reason = "wakeup enabled";
--
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