On Sun, Feb 21, 2021 at 02:05:07PM +0000, Jonathan Cameron wrote: > On Fri, 19 Feb 2021 17:51:37 +0900 > William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote: > > > On Sun, Feb 14, 2021 at 06:09:13PM +0000, Jonathan Cameron wrote: > > > On Fri, 12 Feb 2021 21:13:43 +0900 > > > William Breathitt Gray <vilhelm.gray@xxxxxxxxx> wrote: > > > > > > > The Generic Counter chrdev interface expects users to supply extension > > > > IDs in order to select extensions for requests. In order for users to > > > > know what extension ID belongs to which extension this information must > > > > be exposed. The extension*_name attribute provides a way for users to > > > > discover what extension ID belongs to which extension by reading the > > > > respective extension name for an extension ID. > > > > > > > > Cc: David Lechner <david@xxxxxxxxxxxxxx> > > > > Cc: Gwendal Grignou <gwendal@xxxxxxxxxxxx> > > > > Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx> > > > > Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx> > > > > --- > > > > Documentation/ABI/testing/sysfs-bus-counter | 9 ++++ > > > > drivers/counter/counter-sysfs.c | 51 +++++++++++++++++---- > > > > 2 files changed, 50 insertions(+), 10 deletions(-) > > > > > > > > diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter > > > > index 6353f0a2f8f8..847e96f19d19 100644 > > > > --- a/Documentation/ABI/testing/sysfs-bus-counter > > > > +++ b/Documentation/ABI/testing/sysfs-bus-counter > > > > @@ -100,6 +100,15 @@ Description: > > > > Read-only attribute that indicates whether excessive noise is > > > > present at the channel Y counter inputs. > > > > > > > > +What: /sys/bus/counter/devices/counterX/countY/extensionZ_name > > > > +What: /sys/bus/counter/devices/counterX/extensionZ_name > > > > +What: /sys/bus/counter/devices/counterX/signalY/extensionZ_name > > > > +KernelVersion: 5.13 > > > > +Contact: linux-iio@xxxxxxxxxxxxxxx > > > > +Description: > > > > + Read-only attribute that indicates the component name of > > > > + Extension Z. > > > > > > Good to say what form this takes. > > > > Do you mean a description like this: "Read-only string attribute that > > indicates the component name of Extension Z"? > > My expectation would be that the possible strings are tightly constrained > (perhaps via review). So I'd like to see what they are and a brief description > of what each one means. > > Jonathan Okay I see what you mean now. These names will match the sysfs attribute filenames. So for example, if Extension 9 of Count 2 of Counter device is /sys/bus/counter/devices/counter4/count2/ceiling, then the attribute /sys/bus/counter/devices/counter4/count2/extension9_name will hold a value of "ceiling". The idea is that the user walks down through each extension*_name to find sysfs attribute name for the Extension that they want. When they find the desired Extension name in say sysfs attribute extension9_name, then they know 9 is the ID number for that Extension. There is an alternative design I was considering: instead of extension*_name attributes, we could have each Extension sysfs attribute have a matching *_extension_id attribute which provides the respective Extension ID. So for example, using the same Extension as before: /sys/bus/counter/devices/counter4/count2/ceiling_extension_id will hold a value of 9. Do you think this alternative design would be more intuitive to users? William Breathitt Gray
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