linux-kernel - Re: [1/2] pmbus: added tps544c20 driver with trimming support

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Message-ID: <47c2dd13-c357-56fa-6886-08ce6e2b9d92@nokia.com>
Date:   Mon, 23 Oct 2017 15:34:24 +0200
From:   Romain Porte <romain.porte@...ia.com>
To:     Guenter Roeck <linux@...ck-us.net>
Cc:     linux-hwmon@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [1/2] pmbus: added tps544c20 driver with trimming support

On 21/10/2017 18:20, Guenter Roeck wrote:
> This should be part of device programming in manufacturing, just like,
> say, current calibration. It should not be user programmable, even less so
> runtime programmable. On top of that, we definitely don't want to make
> STORE_USER_ALL available to user space. Both can too easily result in
> a bricked device (bad enough that the register values are writable using
> i2cset).
After some work, I have tested accessing these registers using i2cget 
and i2cset and I can reproduce all the features I have implemented in 
this driver. I think am going to re-implement my calibration procedure 
using i2cget and i2cset in userspace.

I thought it could be a good idea to make this accessible by sysfs 
entries. Since one must read the datasheet for calibrating the 
component, I guess it is not a big deal to have users to find register 
addresses/sizes and write to them using userspace commands instead of 
(over?)simplifying it by providing dedicated sysfs entries.

Romain.