Re: [PATCH] iio: adc: ad7791: fix IRQ flags

From: "Nuno Sá" <noname.nuno@gmail.com>
To: "Jonathan Cameron" <jic23@kernel.org>, "Nuno Sá" <nuno.sa@analog.com>
Cc: linux-iio@vger.kernel.org, Lars-Peter Clausen <lars@metafoo.de>,
	Michael Hennerich <Michael.Hennerich@analog.com>
Subject: Re: [PATCH] iio: adc: ad7791: fix IRQ flags
Date: Mon, 06 Feb 2023 12:13:50 +0100	[thread overview]
Message-ID: <e619b7ba249457a542f04a198133e4ba9255d16c.camel@gmail.com> (raw)
In-Reply-To: <e60e97d614a03c5a6e1e86b330a3d3ae47d3d220.camel@gmail.com>

On Mon, 2023-01-30 at 10:01 +0100, Nuno Sá wrote:
> On Sat, 2023-01-21 at 16:58 +0000, Jonathan Cameron wrote:
> > On Fri, 20 Jan 2023 13:46:45 +0100
> > Nuno Sá <nuno.sa@analog.com> wrote:
> > 
> > > The interrupt is triggered on the falling edge rather than being
> > > a
> > > level
> > > low interrupt.
> > > 
> > > Fixes: da4d3d6bb9f6 ("iio: adc: ad-sigma-delta: Allow custom IRQ
> > > flags")
> > > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > 
> > What are the symptoms of this?  Given the ad_sigma_delta.c irq
> > handler
> > disables the interrupt until after the data read is done (at which
> > point the
> > level is presumably high again), I don't immediately see why the
> > change
> > here has any impact - either we trigger on the fall, or on the fact
> > it
> > has become low..
> > 
> > 
> 
> Honestly I did not checked this in any HW. This was just by
> inspecting
> the datasheet and confirming that the LOW IRQ is not coherent with
> what
> we have in other sigma delta ADCs.
> 
> However, after some git blaming, I found this [1] which shows that
> this
> might be an issue...
> 
> Hmm, maybe makes sense to add a link to the bellow patch in the
> commit
> description...
>  
> [1]:
> https://lore.kernel.org/linux-iio/20200113102653.20900-3-alexandru.tachici@analog.com
> /
> 
> - Nuno Sá

Hi Jonathan,

Anything that I should do in this one? As I did not tested it, it might
not be a real issue but I still think the patch is good even though it
might not deserve a Fixes tag...

- Nuno Sá