Bluetooth: btusb: add sysfs attribute to control USB alt setting

When a Bluetooth raw socket is open, the HCI event related to SCO
connection changes are not dispatched to the hci_event module, and
the underlying Bluetooth controller's USB Interface 1 will not be
updated accordingly.

This patch adds `isoc_alt` sysfs attribute, allowing user space
to update the alternate setting of the USB interface alternate
setting as needed.

Signed-off-by: Ying Hsu <yinghsu@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index 20ba8ceff7d1ba01cd8174715cf1ca438745ec3f..de0b4d99fcbf8461c3ed90a316e701cc74ae73e9 100644 (file)
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -3647,6 +3647,32 @@ static const struct file_operations force_poll_sync_fops = {
        .llseek         = default_llseek,
 };
 
+static ssize_t isoc_alt_show(struct device *dev,
+                            struct device_attribute *attr,
+                            char *buf)
+{
+       struct btusb_data *data = dev_get_drvdata(dev);
+
+       return sysfs_emit(buf, "%d\n", data->isoc_altsetting);
+}
+
+static ssize_t isoc_alt_store(struct device *dev,
+                             struct device_attribute *attr,
+                             const char *buf, size_t count)
+{
+       struct btusb_data *data = dev_get_drvdata(dev);
+       int alt;
+       int ret;
+
+       if (kstrtoint(buf, 10, &alt))
+               return -EINVAL;
+
+       ret = btusb_switch_alt_setting(data->hdev, alt);
+       return ret < 0 ? ret : count;
+}
+
+static DEVICE_ATTR_RW(isoc_alt);
+
 static int btusb_probe(struct usb_interface *intf,
                       const struct usb_device_id *id)
 {
@@ -4010,6 +4036,10 @@ static int btusb_probe(struct usb_interface *intf,
                                                 data->isoc, data);
                if (err < 0)
                        goto out_free_dev;
+
+               err = device_create_file(&intf->dev, &dev_attr_isoc_alt);
+               if (err)
+                       goto out_free_dev;
        }
 
        if (IS_ENABLED(CONFIG_BT_HCIBTUSB_BCM) && data->diag) {
@@ -4056,8 +4086,10 @@ static void btusb_disconnect(struct usb_interface *intf)
        hdev = data->hdev;
        usb_set_intfdata(data->intf, NULL);
 
-       if (data->isoc)
+       if (data->isoc) {
+               device_remove_file(&intf->dev, &dev_attr_isoc_alt);
                usb_set_intfdata(data->isoc, NULL);
+       }
 
        if (data->diag)
                usb_set_intfdata(data->diag, NULL);