[lkml]   [2019]   [Mar]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v2 1/3] iio: light: Add driver for ap3216c
On Mon, 4 Mar 2019 11:25:01 -0500
Sven Van Asbroeck <> wrote:

> On Sun, Mar 3, 2019 at 9:38 AM Jonathan Cameron <> wrote:
> >
> > Hmm. Just been thinking a bit about the events on here and wondered
> > if it is possible to mask them through careful use of the threshold
> > values - i.e. can we stop the hardware generating the interrupts for
> > the ones we don't want. It would be unusual for hardware to be
> > designed where this wasn't possible.
> Excellent point! People with power / battery constraints take a dim view of
> receiving interrupts when no-one wants them. So disabling them in h/w
> is definitely the way to go, if possible.
> And yes, this also makes a non-issue of thresh_en visibility concerns, if any.
> >
> > Alternatively if you have a scope or equivalent to verify if it is doing
> > these as a multi byte read and working that would be even better.
> > It is not uncommon for hardware to implement fairly standard i2c features
> > like this and not document them because they weren't what the test code
> > the docs writer got given does! (may not be true here of course)
> Or alternatively, the current chip rev supports undocumented multi-reads,
> and the next revision silently drops support, thereby breaking the driver...
> Been there, done that, got the T-shirt :(

Indeed it's a risk. Sadly hardware guys never have a 'we mustn't break
software' rule like we do for userspace!


 \ /
  Last update: 2019-03-09 18:34    [W:0.055 / U:0.696 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site