Hi Andrew,
> > Just maybe mine small remark. IMHO the reset shall not pollute the
> > IRQ hander. The RESETC is just set on the initialization phase and
> > only then shall be served. Please correct me if I'm wrong, but it
> > will not be handled during "normal" operation.
>
> This is something i also wondered. Maybe if the firmware in the
> MAC-PHY crashes, burns, and a watchdog reset it, could it assert
> RESETC? I think maybe a WARN_ON_ONCE() for RESETC in the interrupt
> handler would be useful, but otherwise ignore it. Probe can then poll
> during its reset.
>
> > > + regval = RESETC;
> > > + /* SPI host should write RESETC
> > > bit with one to
> > > + * clear the reset interrupt
> > > status.
> > > + */
> > > + ret = oa_tc6_perform_ctrl(tc6,
> > > OA_TC6_STS0,
> > > +
> > > ®val, 1, true,
> > > +
> > > false);
> >
> > Is this enough to have the IRQ_N deasserted (i.e. pulled HIGH)?
> >
> > The documentation states it clearly that one also needs to set SYNC
> > bit (BIT(15)) in the OA_CONFIG0 register (which would have the
> > 0x8006 value).
> >
> > Mine problem is that even after writing 0x40 to OA_STATUS0 and
> > 0x8006 to OA_CONFIG0 the IRQ_N is still LOW (it is pulled up via
> > 10K resistor).
> >
> > (I'm able to read those registers and those show expected values)
>
> What does STATUS0 and STATUS1 contain?
STATUS0 => 0x40, which is expected.
Then I do write 0x40 to STATUS0 -> bit6 (RESETC) is R/W1C
After reading the same register - I do receive 0x00 (it has been
cleared).
Then I write 0x8006 to OA_CONFIG0.
(Those two steps are regarded as "configuration" of LAN865x device in
the documentation)
In this patch set -> the OA_COFIG0 also has the 0x6 added to indicate
the SPI transfer chunk.
Dump of OA registers:
{0x11, 0x7c1b3, 0x5e5, 0x0, 0x8006, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0,
0x3000, 0x1fbf, 0x3ffe0003, 0x0, 0x0}
Status 0 (0x8) -> 0x0
Status 1 (0x9) -> 0x0
> That might be a dumb question,
> i've not read the details for interrupt handling yet, but maybe there
> is another interrupt pending? Or the interrupt mask needs writing?
All the interrupts on MASK{01} are masked.
Changing it to:
sts &= ~(OA_IMASK0_TXPEM | OA_IMASK0_TXBOEM | OA_IMASK0_TXBUEM |
OA_IMASK0_RXBOEM | OA_IMASK0_LOFEM | OA_IMASK0_HDREM
doesn't fix this problem.
>
> > Was it on purpose to not use the RST_N pin to perform GPIO based
> > reset?
> >
> > When I generate reset pulse (and keep it for low for > 5us) the
> > IRQ_N gets high. After some time it gets low (as expected). But
> > then it doesn't get high any more.
>
> Does the standard say RST_N is mandatory to be controlled by software?
> I could imagine RST_N is tied to the board global reset when the power
> supply is stable.
It can be GPIO controlled. However, it is not required. I've tied it to
3V3 and also left NC, but no change.
> Software reset is then used at probe time.
I've reconfigured the board to use only SW based reset (i.e. set bit0
in OA_RESET - 0x3).
>
> So this could be a board design decision. I can see this code getting
> extended in the future, an optional gpiod passed to the core for it to
> use.
I can omit the RST_N control. I'd just expect the IRQ_N to be high
after reset.
>
> > > msecs_to_jiffies(1));
> >
> > Please also clarify - does the LAN8651 require up to 1ms "settle
> > down" (after reset) time before it gets operational again?
>
> If this is not part of the standard, it really should be in the MAC
> driver, or configurable, since different devices might need different
> delays. But ideally, if the status bit says it is good to go, i would
> really expect it to be good to go. So this probably should be a
> LAN8651 quirk.
The documentation is silent about the "settle down time". The only
requirements is for RST_N assertion > 5us. However, when the IRQ_N goes
low, and the interrupt is served - it happens that I cannot read ID
from the chip via SPI.
>
> Andrew
Best regards,
Lukasz Majewski
--
DENX Software Engineering GmbH, Managing Director: Erika Unter
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@xxxxxxx
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