[PATCH 2/3] i2c: sh_mobile: Use platform_get_irq_optional() to get the interrupt

[Arnd Bergmann]

On Wed, Feb 9, 2022 at 4:48 PM Sergei Shtylyov
<sergei.shtylyov at gmail.com> wrote:
> On 2/9/22 6:18 PM, Arnd Bergmann wrote:
> >>> since 2009 after 1e1030dccb10 ("sh: nmi_debug support."). On a
> >>
> >>    Mhm... this commit changes the SH3 code while SH778x are SH4A, no?
> >
> > This code is shared between both:
> >
> > arch/sh/kernel/cpu/sh4/Makefile:common-y        += $(addprefix
> > ../sh3/, entry.o ex.o)
>
>    Ah, quite convoluted! :-)
>    So you mean thet broke the delivery of EVT 0x200 when mucking with NMI?

Yes, exactly: If I read this right, the added code:

+       shlr2   r4
+       shlr    r4
+       mov     r4, r0          ! save vector->jmp table offset for later
+
+       shlr2   r4              ! vector to IRQ# conversion
+       add     #-0x10, r4
+
+       cmp/pz  r4              ! is it a valid IRQ?
+       bt      10f

gets the vector (0x200 for this device), shifts it five bits to 0x10,
and subtracts 0x10,
then branches to do_IRQ if the interrupt number is non-zero, otherwise it goes
through the exception_handling_table.

         Arnd