On Mon, Nov 12, 2018 at 08:58:24PM -0800, Nicolin Chen wrote:

Hi Guenter,

On Mon, Nov 12, 2018 at 08:32:48PM -0800, Guenter Roeck wrote:

quoted

On Mon, Nov 12, 2018 at 08:23:53PM -0800, Nicolin Chen wrote:

quoted

INA3221 supports both continuous and single-shot modes. When
running in the continuous mode, it keeps measuring the inputs
and converting them to the data register even if there are no
users reading the data out. In this use case, this could be a
power waste.

So this patch adds a single-shot mode support so that ina3221
could do measurement and conversion only if users trigger it,
depending on the use case where it only needs to poll data in
a lower frequency.

The change also exposes "mode" and "available_modes" nodes to
allow users to switch between two operating modes.

Lots and lots of complexity for little gain. Sorry, I don't see
the point of this change.

The chip is causing considerable power waste on battery-powered
devices so we typically use it running in the single-shot mode.

And you need to be able to do that with a sysfs attribute ?
Are you planning to have some code switching back and forth
between the modes ?

You'll need to provide a good rationale why this needs to be
runtime configurable.

Guenter

Although the chip now can be powered down, but we still need to
occasionally poll it for power measurement and critical alerts,
so single-shot mode is the best choice for us, considering that
the power-down-and-up routine would be way heavier.

I could understand that you don't really like it, but it's some
feature that we truly need. Do you have any suggestion to write
the code that can make it more convincing to you?

Thanks
Nicolin