Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1229759 > unrolled thread

Driver for Microchip digital potentiometers, v2

Back to article view | Back to linux.kernel

Contents

  Driver for Microchip digital potentiometers, v2 Peter Rosin <peda@lysator.liu.se> - 2015-09-21 23:30 +0200
    Re: Driver for Microchip digital potentiometers, v2 Lars-Peter Clausen <lars@metafoo.de> - 2015-09-22 10:20 +0200

#1229759 — Driver for Microchip digital potentiometers, v2

From: Peter Rosin <peda@axentia.se>

Hi!

This is a new attempt for a driver for these chips. It is a
complete rewrite since the first version which was a dirty
misc driver (plagiarized from another misc driver) that got
shredded in review.

I don't know if I should have added a new unit "ohms", or if
it is ok to only provide "steps"? One could also imagine that
a digital pot can be used to implement a DAC, or something
else, so maybe the actual unit should be somehow configurable?
On the other hand, all of that could in theory be handled
later.

Was it right to add the drivers/iio/pot directory? Should it
have been drivers/iio/potentiometer? What about rheostats
which are very similar? Anyway, I just wanted to say that
I'm not attached to the naming.

This is my first interaction with IIO, please bear with me.

I have admittedly only tested the driver with a MCP4651 chip,
but that one is the biggest in the family...

Changes since v1:
- Make it an IIO driver instead
- Don't convolute the code with big obscure macros
- Inline the bits from mcp4xxx_dpot.h that are actually used
  and drop that file
- Better Changelog

Cheers,
Peter

Peter Rosin (1):
  iio: mcp4xxx_dpot: Driver for Microchip digital potentiometers

 MAINTAINERS                    |    5 +
 drivers/iio/Kconfig            |    1 +
 drivers/iio/Makefile           |    1 +
 drivers/iio/pot/Kconfig        |   20 ++++
 drivers/iio/pot/Makefile       |    6 ++
 drivers/iio/pot/mcp4xxx_dpot.c |  218 ++++++++++++++++++++++++++++++++++++++++
 6 files changed, 251 insertions(+)
 create mode 100644 drivers/iio/pot/Kconfig
 create mode 100644 drivers/iio/pot/Makefile
 create mode 100644 drivers/iio/pot/mcp4xxx_dpot.c

-- 
1.7.10.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [next] | [standalone]

#1229971

On 09/21/2015 11:18 PM, Peter Rosin wrote:
> From: Peter Rosin <peda@axentia.se>
> 
> Hi!
> 
> This is a new attempt for a driver for these chips. It is a
> complete rewrite since the first version which was a dirty
> misc driver (plagiarized from another misc driver) that got
> shredded in review.

Yeah, we need to move the ad_dpot driver over to IIO at some point. The main
issue is that we need to retain the old ABI (at least optionally).

> I don't know if I should have added a new unit "ohms", or if
> it is ok to only provide "steps"? One could also imagine that
> a digital pot can be used to implement a DAC, or something
> else, so maybe the actual unit should be somehow configurable?

Steps are the steps you make with your feet, so that wouldn't be the right
thing here. The right channel type is resistance and the unit is Ohm. You
can use a dpot for a lot of things, e.g. a LED, that doesn't mean we should
have the option to expose this device as a LED device. If something uses the
rdac to implement another function that should be a separate driver being
registered to the rdac.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web