Re: [PATCH 2/2] mrst_max3110: fix SPI UART interrupt parameters

[David Cohen]

On 10/22/2013 11:27 PM, Alexander Shiyan wrote:
> > On 10/22/2013 01:30 PM, David Cohen wrote:
> > > On 10/22/2013 12:46 PM, Alexander Shiyan wrote:
> > > > > The change in the max3110 driver makes the IRQ handling threaded, now
> > > > > the handler is called only once per received character. Without that
> > > > > change, we had many (more than 100) interrupts per one received
> > > > > character.
> > > > >
> > > > > Unfortunately, SFI interface does not support IRQ polarity and
> > > > > triggering modes, so we have to keep the hacks as hard-coded device
> > > > > names and IRQ numbers until we switch to ACPI.
> > > > >
> > > > > Edge-triggered IRQ still supported to keep old platforms working.
> > > > > Use platform data to pass the irq mode argument.
> > > > >
> > > > > Signed-off-by: Ivan Gorinov <ivan.gorinov@xxxxxxxxx>
> > > > > Signed-off-by: Li Ning <ning.li@xxxxxxxxx>
> > > > > Signed-off-by: David Cohen <david.a.cohen@xxxxxxxxxxxxxxx>
> > > > ...
> > > > > +++ b/include/linux/serial_max3110.h
> > > > > @@ -0,0 +1,16 @@
> > > > > +#ifndef _LINUX_SERIAL_MAX3110_H
> > > > > +#define _LINUX_SERIAL_MAX3110_H
> > > > > +
> > > > > +/**
> > > > > + * struct plat_max3110 - MAX3110 SPI UART platform data
> > > > > + * @irq_edge_trigger: if IRQ is edge triggered
> > > > > + *
> > > > > + * You should use this structure in your machine description to specify
> > > > > + * how the MAX3110 is connected.
> > > > > + *
> > > > > + */
> > > > > +struct plat_max3110 {
> > > > > +    int irq_edge_triggered;
> > > > > +};
> > > > > +
> > > > > +#endif
> > > > > --
> > > >
> > > > Is just resource->flags for IRQ can be reused for handle such case?
> > >
> > > I believe your suggestion makes perfect sense. I'll rework it.
> >
> > Looks like isp_device has no place for 'resource'. In this case pdata
> > seems to be the way to go here.
> > Or maybe there's a better way to recommend?
>
> What do you mean by the isp_device?

Allow me to correct my typo: I meant spi_device (this is a spi
device/driver).

> My idea is always use threaded irq and passing flags into request.
> Like as:
> unsigned long flags = res->flags & IORESOURCE_BITS;
> ...
> request_threaded_irq(max->irq, serial_m3110_irq, IRQF_ONESHOT | flags, "max3110", max);


Oh, maybe we were talking about different things afterall :)
The reason this struct plat_max3110 was created is to allow platform
code (located under arch/x86/platform/intel-mid/device_libs/) to define
the irq edge type.
When I saw your comment I though you were referring to struct resource
(which has IORESOURCE_IRQ_* flags). But unlike platform_device,
spi_device has no struct resource * to replace the need of struct
plat_max3110.

OTOH your suggestion can replace this piece of code:

@@ -68,6 +69,7 @@ struct uart_max3110 {
        u8 clock;
        u8 parity, word_7bits;
        u16 irq;
+       u16 irq_edge_triggered;

        unsigned long uart_flags;

I'll check again the patch and possibly make the changes.

Thanks,

David Cohen
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