Hi Micke,
On 08.11.2019 13:30, Micke Prag wrote:
Den 11/8/19 kl. 11:01 AM, skrev Piotr Dymacz:
Hi Micke,
On 08.11.2019 08:36, Micke Prag wrote:
In commit 00ea16557d [1] the way usb is initiated was changed. Instead
of initiate both ehci-platform and ci_hdrc the bootstrap status register
is checked and used to determine which platform to initiate.
There were other changes later, see for example 57c641ba6e.
Yes, I was looking at the code after this commit when making my
conclusions above. But 00ea16557d is the commit that breaks the board
initially.
Unfortunately this break my board since the gpio used to determine this
is used for other purposes.
This means your board has a wrong bootstrap configuration and you
should make sure GPIO for host/device mode has correct initialization
value.
Yes, it is correct the bootstrap is not correct at hardware level. But
there is 30 k+ boards out in the world so fixing this now is a bit
late... ;)
dev-usb.h only exposes one function:
void ath79_register_usb(void);
so there is not much to alter the way usb is initiated.
I tried to write to the bootstrap register but unfortunately this did
not seem to work:
u32 t;
t = ath79_reset_rr(AR933X_RESET_REG_BOOTSTRAP);
pr_warn("ath79: Register before %X", t);
t |= AR933X_BOOTSTRAP_USB_MODE_HOST;
ath79_reset_wr(AR933X_RESET_REG_BOOTSTRAP, t);
pr_warn("ath79: Register after %X",
ath79_reset_rr(AR933X_RESET_REG_BOOTSTRAP));
Gives the following output:
ath79: Register before 42202
ath79: Register after 42202
USB mode in AR9331 is selected at power on, based on GPIO13 value and
I'm not aware of any other/software ways to change it. AFAIK, only
QCA9563 allows to switch between host and device modes 'on the fly'.
Is was working before 00ea16557d so simply initialize ehci-platform
instead ci_hdrc will fix it. Unfortunately I cannot find a way to tell
ath79_register_usb to force it into host mode in my board file instead
of reading the bootstrap register.
Do you want to tell me that a board with wrong bootstrap configuration
and USB switched to device mode was able to use the bus in host mode?
IIRC, during my tests I found that this bootstrap option makes the D+
line to gets pulled-up to VBUS and there was no way to change it back.
I would need to make some more tests to confirm that, though.
--
Cheers,
Piotr
Writing to the bootstrap register was a workaround I tried. In the
datasheet this register should be read/write. I don't know if my code
for writing the register is wrong or it is simply not possible to write
into this register.
How can I solve this?
Only in hardware I suppose (setup correct initial value on GPIO13).
It could also be solved by telling the module to force it into host mode
and not reading the bootstrap register. I am not sure the best approach
for this that would be accepted upstream.
Adding a parameter to ath79_register_usb() could be one option?
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