Re: [lm-sensors] [PATCH] hwmon: (max6650) Rename the device ids to contain the hwmon suffix

[Lee Jones]

> >> >> On Mon, Feb 10, 2014 at 4:38 PM, Jean Delvare <jdelvare@xxxxxxx> wrote:
> >> >> > Additionally, dashes are explicitly forbidden in hwmon
> >> >> > device names.
> >> >>
> >> >> Also, where is that documented?
> >> >
> >> > In Documentation/hwmon/sysfs-interface:
> >> >
> >> > *********************
> >> > * Global attributes *
> >> > *********************
> >> >
> >> > name            The chip name.
> >> >                 This should be a short, lowercase string, not containing
> >> >                 spaces nor dashes, representing the chip name. This is
> >> >                 the only mandatory attribute.
> >> >                 I2C devices get this attribute created automatically.
> >> >                 RO
> >>
> >> Time to revisit this decision....
> >>
> >> So, based on the fact that children device names usually contain
> >> dashes, I do not understand why hwmon would be any special in this
> >> regard. It is possible that the hwmon developers have not faced much
> >> MFD situation before, and so, this was not considered to be handled
> >> like in other subsystems.
> >>
> >> I am proposing to change this "rule"...  Any objection?
> >
> > Prior to proposing such an invasive change which is highly likely to
> > come up against heavy opposition,
> 
> It is possible that someone does not understand why you think it may
> be invasive, right? Could you please explain the reason for that?

The reason is a good one. In the kernel we make every attempt not to
break userspace. By that I mean _any_ userspace application. Userspace
applications which interface with the kernel can do so via a variety of
methods. One of those is Sysfs, where this name you are attempting to
change appears. The userspace applications already mentioned parse for
these devices, regex:ing for '-' separators. If you add an additional
'-' separator there is a chance that these applications will get
confused and break without warning. 

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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