Re: [PATCH v4 1/1] iio:pressure: initial zpa2326 barometer support

[Gregor Boirie <gregor.boirie@parrot.com>]

Hi,

On 09/10/2016 05:37 PM, Jonathan Cameron wrote:
> On 09/09/16 16:01, Gregor Boirie wrote:
>> Introduce driver for Murata ZPA2326 pressure and temperature sensor:
>> http://www.murata.com/en-us/products/productdetail?partno=ZPA2326-0311A-R
>>
>> Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
> This looks pretty good to me now.  A few minor bits and bobs inline.
>
> I almost took it as is, but would like to have it sit on the list
> in it's current form for a few more days anyway so might as well get
> these few corners tidied up!
[...]
>
> +/*
> + * Debugfs stuff
> + *
> + * We want to prevent debugfs hooks from altering configuration while chip
> + * sampling is ongoing to preserve data consistency. Moreover, a few registers,
> + * when read, change hardware state, e.g. interrupt acknowlege on read. This is
> + * why debugfs read and write hooks acquire exclusive access to register space.
> + *
> + * Also note this is mostly unusable with power management enabled systems since
> + * registers content is lost during power off -> on transitions.
> + */
> It would be nice perhaps to tighten up the range of addresses that
> we are protecting.  Thus allow reading of any addresses that are not
> 'fragile'.  Only supported limited debug access is hardly a big
> issue however ;)
Quite frankly, I wonder if this debugfs stuff should not be thrown away 
given that
regmap already provides a way to access registers over debugfs (with 
very limited
protection...).
What do you think ?

[...]

Regards,
Grégor.