[Gta04-owner] suspend current, USB-PHY, EHCI, module...

Dr. H. Nikolaus Schaller hns at goldelico.com
Tue Nov 26 17:42:32 CET 2013


Hi Neil,
I stumbled over this page

http://code.metager.de/source/history/linux/stable/drivers/usb/host/ehci-omap.c

where it appears to show the commit log of the OMAP specific EHCI drivers.

There are interesting things about fixes for suspend/resume and even hidden
and undocumented control registers on the SoC that may play a role in
the power demand of the PHY and the EHCI and how they suspend/wake up.

Since this reminds me of the symptom of applying a RESET to the PHY chip
making power consumption raise. Maybe, the EHCI is powering up.
 
Maybe going through it may revel some other idea.

In parallel I have checked the options to improve the hardware in the GTA04A5
board. I have found these chips to replace the SMSC USB3322

Candidates (unfortunately none is small or has REFCLK):
* Cypress CY7C68003-24LQXI
* TI TUSB2210/2211
* NXP ISP1703

Unfortunately the TI and the NXP chips are at least twice as large so that we
can't fit them in place of the USB3322. The Cypress chip is as small as the
SMSC but lacks the REFCLK line and needs a 26MHz clock input so that I
don't know yet if it can be used with a DM3730 at all. Finally the ISP1703
(although even tested and recommended by TI) is no longer in production.
An ISP1705 may also fit.

So it looks as if we have to live with the USB3322 in the GTA04A5 as well.

BR,
Nikolaus



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