mfd: usbio: gpio read payload reduces 4 bytes #14
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| ret = usb_control_msg_send(bridge->udev, bridge->ep0, 0, | ||
| USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 0, 0, | ||
| header, actual, timeout, GFP_KERNEL); | ||
| header, actual - 4, timeout, GFP_KERNEL); |
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Have you tested this pull request?
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This N-4 bytes payload length is defined in USBIO bridge protocol revision 1.0. In previous version 0.7, the format is N-bytes. Merge this request will be risky to break systems running older FW version.
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is it possible to have a check to decide which protocol to go?
something like :
old device go:
ret = usb_control_msg_send(bridge->udev, bridge->ep0, 0, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 0, 0, header, actual, timeout, GFP_KERNEL);
new device go:
ret = usb_control_msg_send(bridge->udev, bridge->ep0, 0, USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT, 0, 0, header, actual - 4, timeout, GFP_KERNEL);
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is it possible to have a check to decide which protocol to go?
done
This N-4 bytes payload length is defined in USBIO bridge protocol revision 1.0. In previous version 0.7, the format is N-bytes. Merge this request will be risky to break systems running older FW version.
how about creating a function to check the protocol version based on the HID?
Have you tested this pull request?
yes
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Wouldn't it make more sense to do the check once during instance creation, and save the result in a flag? Instead of doing it for each transfer?
Following the vision driver protocol, the payload length for gpio read needs to be reduced by 4 bytes because the value field doesn't need to be sent in the request. Signed-off-by: Jason Chen <jason.z.chen@intel.corp-partner.google.com>
Following the vision driver protocol, the payload length for gpio read needs to be reduced by 4 bytes because the value field doesn't need to be sent in the request.