On 13:51 Mon 20 Feb     , Russell King - ARM Linux wrote:

On Mon, Feb 20, 2012 at 02:35:57PM +0100, Jean Delvare wrote:

quoted

On Mon, 20 Feb 2012 12:50:54 +0000, Russell King - ARM Linux wrote:

quoted

What is linux specific is specifying the _delay_ rather than specifying
the bus frequency.  So as soon as you're trying to justify not adding
the units because they may be linux specific, you've already lost that
argument by using a delay rather than a bus frequency.  You can't have
it both ways.

While I am not much into DT and did not follow this thread too
carefully... I seem to understand that the dispute is mainly on
frequency vs. udelay specification for the bus speed, Jean-Christophe
arguing that hardware-specific delays are added when changing e.g. a
GPIO pin output value and thus the frequency can't be guaranteed. Do I
get this right?

This sub-thread is more about the units of the properties rather
than the properties themselves.

What's being proposed is to have two properties, one named 'udelay'
which takes microseconds, and one named 'timeout' which takes
milliseconds.

I'm saying that's a completely absurd proposal, as the proposal is
for two opaque numeric properties with different units.  At least
make the units the same, or as Karol said, incorporate the units
into the property names.

At least we can then create new properties in the future of we need
to change the units, rather than thinking up a different name for
'timeout'.

please read the binding

we have 2 properties

 - udelay: delay between GPIO operations (may depend on each platform)
 - timeout: timeout to get data (ms)

 please do not mixed them together

udelay is related to bus frequency

timeout is implelentation detail, that allow to parameter the timeout og i2c
bit algo when reading the scl on slow device

Best Regards,
J.