Introduce kernel feature CONFIG_USB_OTG20 and related
gadget_is_otg20() API for supporting OTG20 compliant
drivers.
This patch also updated usb_otg_descritpor.
Signed-off-by: Macpaul Lin <macpaul@xxxxxxxxx>
---
changes for v2:
- Add USB_OTG_ADP definition in ch9.h.
changes for v3:
- ch9.h: replace a tab to space when check #ifdef on CONFIG_USB_OTG20.
- ch9.h: split structure usb_otg_descriptor into usb_otg_descriptor
and usb_otg_descriptor20 because some OTG 2.0 hardware can support
OTG 1.3 and 2.0 by configuration dynamically.
- gadget.h: fix the description of function gadget_is_otg20().
- Kconfig: renew and fix the description of OTG 2.0 kernel option.
changes for v4:
- fix description of each git commits.
drivers/usb/core/Kconfig | 18 ++++++++++++++++++
include/linux/usb/gadget.h | 23 +++++++++++++++++++++++
include/uapi/linux/usb/ch9.h | 10 ++++++++++
3 files changed, 51 insertions(+)
diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index cc0ced0..11c7501 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -55,6 +55,24 @@ config USB_OTG
Select this only if your board has Mini-AB/Micro-AB
connector.
+config USB_OTG20
+ bool "OTG 2.0 support"
+ depends on USB_OTG
+ help
+ There are some incompatibilities in both HNP and SRP between
+ the 1.3 and 2.0 versions of the OTG supplement. Such as timing
+ criterions which might be controlled only by circuit. These may
+ lead to interoperability issues when using these protocols. However,
+ some OTG 2.0 devices can be compatible with those 1.3 devices.
+ If both the gadget hardware and driver support OTG 2.0, the driver
+ should set is_otg20 flag as true when initializing its own usb_gadget
+ structure.
+
+ This feature is still under developing.
+
+ Select this only if your board support OTG 2.0's hardware
+ requirements.
+
config USB_OTG_WHITELIST
bool "Rely on OTG and EH Targeted Peripherals List"
depends on USB
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 4f3dfb7..c63a8db 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -514,6 +514,8 @@ struct usb_gadget_ops {
* @sg_supported: true if we can handle scatter-gather
* @is_otg: True if the USB device port uses a Mini-AB jack, so that the
* gadget driver must provide a USB OTG descriptor.
+ * @is_otg20: True if the USB hardware supports OTG 2.0 specification.
+ * The gadget driver must provide USB OTG 2.0 descriptor.
* @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
* is in the Mini-AB jack, and HNP has been used to switch roles
* so that the "A" device currently acts as A-Peripheral, not A-Host.
@@ -562,6 +564,7 @@ struct usb_gadget {
unsigned sg_supported:1;
unsigned is_otg:1;
+ unsigned is_otg20:1;
unsigned is_a_peripheral:1;
unsigned b_hnp_enable:1;
unsigned a_hnp_support:1;
@@ -637,6 +640,22 @@ static inline int gadget_is_otg(struct usb_gadget *g)
}
/**
+ * gadget_is_otg20 - return true iff the hardware is OTG 2.0-ready
+ * @g: controller that might supports OTG 2.0 specification.
+ *
+ * This is a runtime test, since kernels with a USB-OTG stack sometimes
+ * run on boards which supports OTG 2.0,
+ */
+static inline int gadget_is_otg20(struct usb_gadget *g)
+{
+#ifdef CONFIG_USB_OTG20
+ return g->is_otg20;
+#else
+ return 0;
+#endif
+}
+
+/**
* usb_gadget_frame_number - returns the current frame number
* @gadget: controller that reports the frame number
*
@@ -835,6 +854,10 @@ static inline int usb_gadget_disconnect(struct usb_gadget *gadget)
* having called usb_gadget_disconnect(), and the USB host stack has
* initialized.
*
+ * If gadget->is_otg20 is true, the gadget driver must provide an OTG 2.0
+ * descriptor during enumeration, and related behavior must compliant with
+ * OTG 2.0 specificaiton.
+ *
* Drivers use hardware-specific knowledge to configure the usb hardware.
* endpoint addressing is only one of several hardware characteristics that
* are in descriptors the ep0 implementation returns from setup() calls.
diff --git a/include/uapi/linux/usb/ch9.h b/include/uapi/linux/usb/ch9.h
index aa33fd1..1a50d78 100644
--- a/include/uapi/linux/usb/ch9.h
+++ b/include/uapi/linux/usb/ch9.h
@@ -674,9 +674,19 @@ struct usb_otg_descriptor {
__u8 bmAttributes; /* support for HNP, SRP, etc */
} __attribute__ ((packed));
+/* USB_DT_OTG (from OTG 2.0 supplement) */
+struct usb_otg_descriptor20 {
+ __u8 bLength;
+ __u8 bDescriptorType;
+
+ __u8 bmAttributes; /* support for HNP, SRP, etc */
+ __le16 bcdOTG; /* Support OTG 2.0 */
+} __attribute__ ((packed));
+
/* from usb_otg_descriptor.bmAttributes */
#define USB_OTG_SRP (1 << 0)
#define USB_OTG_HNP (1 << 1) /* swap host/device roles */
+#define USB_OTG_ADP (1 << 2) /* support ADP */
/*-------------------------------------------------------------------------*/
--
1.8.3.2
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