dt-bindings: usb: snps,dwc3: Add 'snps,parkmode-disable-hs-quirk' quirk
authorStanley Chang <stanley_chang@realtek.com>
Wed, 19 Apr 2023 02:00:43 +0000 (10:00 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 20 Apr 2023 09:18:12 +0000 (11:18 +0200)
commit4a2f152af1c478d42bd4f535788d4dbec015704f
tree80efb1bf3bdc5b315ff7ed133a8e674e646b2920
parentd21a797a3eeb2b001e07ff943e5611eab67a71a3
dt-bindings: usb: snps,dwc3: Add 'snps,parkmode-disable-hs-quirk' quirk

Add a new 'snps,parkmode-disable-hs-quirk' DT quirk to dwc3 core for
disable the high-speed parkmode.

For some USB wifi devices, if enable this feature it will reduce the
performance. Therefore, add an option for disabling HS park mode by
device-tree.

In Synopsys's dwc3 data book:
In a few high speed devices when an IN request is sent within 900ns of the
ACK of the previous packet, these devices send a NAK. When connected to
these devices, if required, the software can disable the park mode if you
see performance drop in your system. When park mode is disabled,
pipelining of multiple packet is disabled and instead one packet at a time
is requested by the scheduler. This allows up to 12 NAKs in a micro-frame
and improves performance of these slow devices.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
Link: https://lore.kernel.org/r/20230419020044.15475-2-stanley_chang@realtek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/devicetree/bindings/usb/snps,dwc3.yaml