* [RFC] Creating an eeprom class
@ 2013-01-20 18:08 Thomas De Schampheleire
2013-01-20 22:39 ` Greg KH
0 siblings, 1 reply; 6+ messages in thread
From: Thomas De Schampheleire @ 2013-01-20 18:08 UTC (permalink / raw)
To: linux-kernel, David Brownell, Wolfram Sang, Anatolij Gustschin,
Frodo Looijaard, Philip Edelbrock, Greg Kroah-Hartman,
Ben Gardner
Cc: Ronny Meeus, Thomas De Schampheleire
[plaintext and fixed address of David Brownell]
Hi,
Several of the eeprom drivers that live in drivers/misc/eeprom export
a binary sysfs file 'eeprom'. If a userspace program or script wants
to access this file, it needs to know the full path, for example:
/sys/bus/spi/devices/spi32766.0/eeprom
The problem with this approach is that it requires knowledge about the
hardware configuration: is the eeprom on the SPI bus, the I2C bus, or
maybe memory mapped?
It would therefore be more interesting to have a bus-agnostic way to
access this eeprom file, for example:
/sys/class/eeprom/eeprom0/eeprom
Maybe it'd be even better to use a more generic class name than
'eeprom', since there are several types of eeprom-like devices that
you could export this way.
Or should we rather hook the eeprom code into the mtd subsystem?
What is your opinion?
Thanks,
Thomas
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] Creating an eeprom class
2013-01-20 18:08 [RFC] Creating an eeprom class Thomas De Schampheleire
@ 2013-01-20 22:39 ` Greg KH
2013-01-21 7:25 ` Thomas De Schampheleire
0 siblings, 1 reply; 6+ messages in thread
From: Greg KH @ 2013-01-20 22:39 UTC (permalink / raw)
To: Thomas De Schampheleire
Cc: linux-kernel, David Brownell, Wolfram Sang, Anatolij Gustschin,
Frodo Looijaard, Philip Edelbrock, Ben Gardner, Ronny Meeus
On Sun, Jan 20, 2013 at 07:08:28PM +0100, Thomas De Schampheleire wrote:
> [plaintext and fixed address of David Brownell]
David passed away a year or so ago, so that's really not going to help :(
> Hi,
>
> Several of the eeprom drivers that live in drivers/misc/eeprom export
> a binary sysfs file 'eeprom'. If a userspace program or script wants
> to access this file, it needs to know the full path, for example:
>
> /sys/bus/spi/devices/spi32766.0/eeprom
>
> The problem with this approach is that it requires knowledge about the
> hardware configuration: is the eeprom on the SPI bus, the I2C bus, or
> maybe memory mapped?
>
> It would therefore be more interesting to have a bus-agnostic way to
> access this eeprom file, for example:
> /sys/class/eeprom/eeprom0/eeprom
>
> Maybe it'd be even better to use a more generic class name than
> 'eeprom', since there are several types of eeprom-like devices that
> you could export this way.
Does all of the existing "eeprom" devices use the same userspace
interface? If so, yes, having a "class" would make sense.
> Or should we rather hook the eeprom code into the mtd subsystem?
Why mtd?
thanks,
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] Creating an eeprom class
2013-01-20 22:39 ` Greg KH
@ 2013-01-21 7:25 ` Thomas De Schampheleire
2013-01-22 0:14 ` Greg KH
0 siblings, 1 reply; 6+ messages in thread
From: Thomas De Schampheleire @ 2013-01-21 7:25 UTC (permalink / raw)
To: Greg KH
Cc: linux-kernel, Wolfram Sang, Anatolij Gustschin, Frodo Looijaard,
Philip Edelbrock, Ben Gardner, Ronny Meeus
On Sun, Jan 20, 2013 at 11:39 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Sun, Jan 20, 2013 at 07:08:28PM +0100, Thomas De Schampheleire wrote:
>> [plaintext and fixed address of David Brownell]
>
> David passed away a year or so ago, so that's really not going to help :(
So sorry to hear that, I was not aware...
>
>> Hi,
>>
>> Several of the eeprom drivers that live in drivers/misc/eeprom export
>> a binary sysfs file 'eeprom'. If a userspace program or script wants
>> to access this file, it needs to know the full path, for example:
>>
>> /sys/bus/spi/devices/spi32766.0/eeprom
>>
>> The problem with this approach is that it requires knowledge about the
>> hardware configuration: is the eeprom on the SPI bus, the I2C bus, or
>> maybe memory mapped?
>>
>> It would therefore be more interesting to have a bus-agnostic way to
>> access this eeprom file, for example:
>> /sys/class/eeprom/eeprom0/eeprom
>>
>> Maybe it'd be even better to use a more generic class name than
>> 'eeprom', since there are several types of eeprom-like devices that
>> you could export this way.
>
> Does all of the existing "eeprom" devices use the same userspace
> interface? If so, yes, having a "class" would make sense.
All but one do. That one (eeprom_93cx6.c) exports its read/write
functions to other kernel code, and is used in several
wireless/ethernet drivers.
>
>> Or should we rather hook the eeprom code into the mtd subsystem?
>
> Why mtd?
Because an eeprom is a piece of memory. Maybe mtd is overkill in term
of the operations supported, but from a high-level perspective an
eeprom is a memory technology device, right?
Thanks,
Thomas
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] Creating an eeprom class
2013-01-21 7:25 ` Thomas De Schampheleire
@ 2013-01-22 0:14 ` Greg KH
0 siblings, 0 replies; 6+ messages in thread
From: Greg KH @ 2013-01-22 0:14 UTC (permalink / raw)
To: Thomas De Schampheleire
Cc: linux-kernel, Wolfram Sang, Anatolij Gustschin, Frodo Looijaard,
Philip Edelbrock, Ben Gardner, Ronny Meeus
On Mon, Jan 21, 2013 at 08:25:59AM +0100, Thomas De Schampheleire wrote:
> On Sun, Jan 20, 2013 at 11:39 PM, Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Sun, Jan 20, 2013 at 07:08:28PM +0100, Thomas De Schampheleire wrote:
> >> [plaintext and fixed address of David Brownell]
> >
> > David passed away a year or so ago, so that's really not going to help :(
>
> So sorry to hear that, I was not aware...
>
> >
> >> Hi,
> >>
> >> Several of the eeprom drivers that live in drivers/misc/eeprom export
> >> a binary sysfs file 'eeprom'. If a userspace program or script wants
> >> to access this file, it needs to know the full path, for example:
> >>
> >> /sys/bus/spi/devices/spi32766.0/eeprom
> >>
> >> The problem with this approach is that it requires knowledge about the
> >> hardware configuration: is the eeprom on the SPI bus, the I2C bus, or
> >> maybe memory mapped?
> >>
> >> It would therefore be more interesting to have a bus-agnostic way to
> >> access this eeprom file, for example:
> >> /sys/class/eeprom/eeprom0/eeprom
> >>
> >> Maybe it'd be even better to use a more generic class name than
> >> 'eeprom', since there are several types of eeprom-like devices that
> >> you could export this way.
> >
> > Does all of the existing "eeprom" devices use the same userspace
> > interface? If so, yes, having a "class" would make sense.
>
> All but one do. That one (eeprom_93cx6.c) exports its read/write
> functions to other kernel code, and is used in several
> wireless/ethernet drivers.
Then it shouldn't be used here, right?
> >> Or should we rather hook the eeprom code into the mtd subsystem?
> >
> > Why mtd?
>
> Because an eeprom is a piece of memory. Maybe mtd is overkill in term
> of the operations supported, but from a high-level perspective an
> eeprom is a memory technology device, right?
Everything is a memory device in the end :)
Feel free to send patches, but I don't think this is really a big deal
that deserves this type of change at the moment. Feel free to prove me
wrong though.
greg k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] Creating an eeprom class
@ 2014-01-22 13:25 Laszlo Papp
2014-01-22 17:18 ` Curt Brune
0 siblings, 1 reply; 6+ messages in thread
From: Laszlo Papp @ 2014-01-22 13:25 UTC (permalink / raw)
To: LKML; +Cc: patrickdepinguin, gregkh, linux-i2c, curt
> On Sun, Jan 20, 2013 at 07:08:28PM +0100, Thomas De Schampheleire wrote:
>> [plaintext and fixed address of David Brownell]
>
> David passed away a year or so ago, so that's really not going to help :(
>
>> Hi,
>>
>> Several of the eeprom drivers that live in drivers/misc/eeprom export
>> a binary sysfs file 'eeprom'. If a userspace program or script wants
>> to access this file, it needs to know the full path, for example:
>>
>> /sys/bus/spi/devices/spi32766.0/eeprom
>>
>> The problem with this approach is that it requires knowledge about the
>> hardware configuration: is the eeprom on the SPI bus, the I2C bus, or
>> maybe memory mapped?
>>
>> It would therefore be more interesting to have a bus-agnostic way to
>> access this eeprom file, for example:
>> /sys/class/eeprom/eeprom0/eeprom
>>
>> Maybe it'd be even better to use a more generic class name than
>> 'eeprom', since there are several types of eeprom-like devices that
>> you could export this way.
>
> Does all of the existing "eeprom" devices use the same userspace
> interface? If so, yes, having a "class" would make sense.
Was there any progress done? I saw the following thread, too, so
including CC in the loop:
http://www.spinics.net/lists/linux-i2c/msg13141.html
Needless to say that I am writing this email because I would also be
interested in a handy and convenient class interface - as opposed to
the raw bus specific path -, similarly to hwmon, gpio, leds, etc.
I could probably even try to volunteer, with very limited resources
admittedly, to get some driver done for our EEPROM if that is needed.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC] Creating an eeprom class
2014-01-22 13:25 Laszlo Papp
@ 2014-01-22 17:18 ` Curt Brune
0 siblings, 0 replies; 6+ messages in thread
From: Curt Brune @ 2014-01-22 17:18 UTC (permalink / raw)
To: Laszlo Papp; +Cc: LKML, patrickdepinguin, gregkh, linux-i2c
Hi Laszlo,
On Wed Jan 22 13:25, Laszlo Papp wrote:
>
> Was there any progress done? I saw the following thread, too, so
> including CC in the loop:
> http://www.spinics.net/lists/linux-i2c/msg13141.html
>
I have patches that adds a "eeprom_dev" class that I described in the
above thread. The patches also show how to register the at24 driver
with the EEPROM class.
We have been using the patch in production for almost a year now, with
good success.
I will send the patches to linux-i2c@vget.kernel.org shortly.
Cheers,
Curt
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2014-01-22 17:26 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-01-20 18:08 [RFC] Creating an eeprom class Thomas De Schampheleire
2013-01-20 22:39 ` Greg KH
2013-01-21 7:25 ` Thomas De Schampheleire
2013-01-22 0:14 ` Greg KH
2014-01-22 13:25 Laszlo Papp
2014-01-22 17:18 ` Curt Brune
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