Hi Geert,
On Thu, Mar 22, 2018 at 6:55 PM, Geert Uytterhoeven
<ge...@linux-m68k.org> wrote:
> Hi Magnus,
>
> On Wed, Mar 21, 2018 at 11:34 AM, Geert Uytterhoeven
> <ge...@linux-m68k.org> wrote:
>> On Tue, Mar 20, 2018 at 9:20 AM, Magnus Damm <magnus.d...@gmail.com> wrote:
>>> From: Magnus Damm <damm+rene...@opensource.se>
>>>
>>> Booting sh73a0 KZM9G results in the following on the console:
>>>
>>> [ 0.030000] renesas_intc_irqpin e6900000.interrupt-controller: driving 8
>>> irqs
>>> [ 0.040000] random: crng init done
>>> [ 0.120000] irq 35: nobody cared (try booting with the "irqpoll" option)
>>> [ 0.120000] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.16.0-rc5 #4
>>> [ 0.120000] Hardware name: Generic SH73A0 (Flattened Device Tree)
>>> ...
>>> [ 0.120000] Disabling IRQ #35
>>> [ 0.120000] renesas_intc_irqpin e6900004.interrupt-controller: driving 8
>>> irqs
>>
>> Thanks for bringing this to my attention again. I always assumed it was one
>> of
>> the IIO devices keeping an IRQ line asserted, but it turns out I was wrong...
>>
>>> Judging by the friendly board documentation there is nothing hooked up to
>>> that IRQ line. I wish we had proper schematics and not a less detailed
>>> board manual.
>>
>> Oh there is: PORT54/IRQ10/FSICCK is driven by the same 11.2896 MHz
>> oscillator (OSC4) as FSIACK.
>>
>>> With this patch I've tried to extend the irqpin driver to mask all
>>> interrupts
>>> on boot but it does not seem to help. Perhaps the PFC hardware needs to be
>>> configured somehow. More effort is needed to solve this issue.
>>
>> That pin is part of the HDMI interface, cfr. section 5.27.
>>
>> I've tried the below, but it doesn't work, as the interrupt controller is
>> probed
>> before the pfc (it has to, due to dependencies from pfc on irqpin[0-3]).
>>
>> --- a/arch/arm/boot/dts/sh73a0-kzm9g.dts
>> +++ b/arch/arm/boot/dts/sh73a0-kzm9g.dts
>> @@ -331,6 +331,15 @@
>> };
>>
>> &pfc {
>> + pinctrl-0 = <&fsic_pins>;
>> + pinctrl-names = "default";
>> +
>> + fsic_pins: hdmi {
>> + /* FSICCK is driven by OSC4, causing interrupt storm */
>> + groups = "fsic_mclk_in";
>> + function = "fsic";
>> + };
>> +
>> i2c3_pins: i2c3 {
>> groups = "i2c3_1";
>> function = "i2c3";
>>
>> So probably we need some early quirk in pfc-sh73a0.c, to configure the
>> pin as fsicck on kzm9g.
>
> That's done by switching PORT54 from FN0 to FN6, i.e. changing 0xe6051036
> from 0xa0 to 0xa6.
>
> I did that from U-Boot, and verified it's still that way when the PFC driver
> initializes, but it doesn't help, with or without your patch.
>
> So it seems more likely the intc-irqpin driver is not disabling interrupts
> that
> are not requested?
Thanks for checking. Yeah the interrupt disabling poriton in the
driver might not work as expected. Also there is that "control-parent"
workaround in the driver as well, and perhaps combined with that the
PFC is not working as expected might result in spurious interrupts -
not sure.
I wonder if we still get interrupts if we configure the pin as GPIO?
Thanks,
/ magnus
