On 11/05/2014 09:02 PM, Dmitry Eremin-Solenikov wrote:
2014-11-03 16:41 GMT+03:00 Linus Walleij <linus.walleij@xxxxxxxxxx>:
On Fri, Oct 31, 2014 at 10:54 AM, Dmitry Eremin-Solenikov
<dbaryshkov@xxxxxxxxx> wrote:
2014-10-31 10:42 GMT+03:00 Linus Walleij <linus.walleij@xxxxxxxxxx>:
It seems some DAC handling is part of the MFD driver, and we recently
discussed that MFD should not be doing misc stuff but mainly act as
arbiter and switching station.
Can you please move the DAC parts of the driver to
drivers/iio/dac?
The IIO DAC subsystem will likely add other goodies to
the driver for free and give a nice API to consumers.
I wanted this part to be as simple as possible. I will look into IIO
DAC subsystem.
The DAC is as simple 2 channel 8-bit i2c device connected to a separate i2c bus
controlled through a register in LoCoMo device. One channel is used
for backlight,
other will be used for volume control. So (in theory) I can add the
following device
chain: locomo -> i2c-locomo -> m62332 -> IIO DAC client. However isn't that
quite an overkill for just backlight & volume control? Please advice me on this.
The point is still the same: no unrelated code in drivers/mfd,
then either use IIO DAC as a middle layer or sink the DAC handling
into respective subdriver, i.e. push it into the backlight or
volume directly then.
The problem is that the DAC is equally used by backlight and by sound
device (WIP).
That shouldn't be a problem. The IIO API allows different consumers to
request different channels of a converter. You can write a generic IIO based
backlight driver and a generic IIO based volume control driver. This makes
it possible to re-use them in other circuits with other DACs but the same
application.
What about true i2c device driver sitting in drivers/misc and exporting a regmap
of 2 8-bit registers?
If it is a generic DAC it should go into drivers/iio/, this will allow code
sharing and code re-usability. Given the simplicity of the DAC there might
even be other existing drivers that can be used to control it.
- Lars
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