From: John Youn <johnyoun@xxxxxxxxxxxx>
This commit allows a gadget that does not support SuperSpeed to indicate
that it supports LPM. It does this by setting the 'lpm_capable' flag in
the gadget structure.
If a gadget sets this, the composite gadget framework will set the
bcdUSB to 0x0201 to indicate that this supports BOS descriptors, and
also return a USB 2.0 Extension descriptor as part of the BOS descriptor
set.
See USB 2.0 LPM ECN Section 3.
Signed-off-by: John Youn <johnyoun@xxxxxxxxxxxx>
Signed-off-by: Sevak Arakelyan <sevaka@xxxxxxxxxxxx>
---
drivers/usb/gadget/composite.c | 8 ++++++--
include/linux/usb/gadget.h | 3 +++
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index abec93ab81ee..d62f53d7f418 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1608,7 +1608,10 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
cdev->desc.bcdUSB = cpu_to_le16(0x0210);
}
} else {
- cdev->desc.bcdUSB = cpu_to_le16(0x0200);
+ if (gadget->lpm_capable)
+ cdev->desc.bcdUSB = cpu_to_le16(0x0201);
+ else
+ cdev->desc.bcdUSB = cpu_to_le16(0x0200);
}
value = min(w_length, (u16) sizeof cdev->desc);
@@ -1639,7 +1642,8 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
value = min(w_length, (u16) value);
break;
case USB_DT_BOS:
- if (gadget_is_superspeed(gadget)) {
+ if (gadget_is_superspeed(gadget) ||
+ gadget->lpm_capable) {
value = bos_desc(cdev);
value = min(w_length, (u16) value);
}
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index e4516e9ded0f..927df464100d 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -352,6 +352,8 @@ struct usb_gadget_ops {
* @deactivated: True if gadget is deactivated - in deactivated state it cannot
* be connected.
* @connected: True if gadget is connected.
+ * @lpm_capable: If the gadget max_speed is FULL or HIGH, this flag
+ * indicates that it supports LPM as per the LPM ECN & errata.
*
* Gadgets have a mostly-portable "gadget driver" implementing device
* functions, handling all usb configurations and interfaces. Gadget
@@ -404,6 +406,7 @@ struct usb_gadget {
unsigned is_selfpowered:1;
unsigned deactivated:1;
unsigned connected:1;
+ unsigned lpm_capable:1;
};
#define work_to_gadget(w) (container_of((w), struct usb_gadget, work))
--
2.11.0
--
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