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doc: usb: ci-hdrc-usb2: add property non-zero-ttctrl-ttha

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If this property is not set, the max packet size is 1023 bytes, and if
the total of packet size for pervious transactions are more than 256 bytes,
it can't accept any transactions within this frame. The use case is single
transaction, but higher frame rate.

If this property is set, the max packet size is 188 bytes, it can handle
more transactions than above case, it can accept transactions until it
considers the left room size within frame is less than 188 bytes, software
needs to make sure it does not send more than 90%
maximum_periodic_data_per_frame. The use case is multiple transactions, but
less frame rate.

Signed-off-by: Peter Chen <peter.chen@nxp.com>
This commit is contained in:
Peter Chen 2016-02-01 14:28:57 +08:00
parent aa7381876c
commit 4670ba6c9e
1 changed files with 16 additions and 0 deletions
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16
Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
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@ -60,6 +60,22 @@ Optional properties:
be specified.
- phy-clkgate-delay-us: the delay time (us) between putting the PHY into
low power mode and gating the PHY clock.
- non-zero-ttctrl-ttha: after setting this property, the value of register
ttctrl.ttha will be 0x7f; if not, the value will be 0x0, this is the default
value. It needs to be very carefully for setting this property, it is
recommended that consult with your IC engineer before setting this value.
On the most of chipidea platforms, the "usage_tt" flag at RTL is 0, so this
property only affects siTD.
If this property is not set, the max packet size is 1023 bytes, and if
the total of packet size for pervious transactions are more than 256 bytes,
it can't accept any transactions within this frame. The use case is single
transaction, but higher frame rate.
If this property is set, the max packet size is 188 bytes, it can handle
more transactions than above case, it can accept transactions until it
considers the left room size within frame is less than 188 bytes, software
needs to make sure it does not send more than 90%
maximum_periodic_data_per_frame. The use case is multiple transactions, but
less frame rate.
i.mx specific properties
- fsl,usbmisc: phandler of non-core register device, with one