Dear Timur Tabi,
In message <4aa15ede.6080...@freescale.com> you wrote:
>
> Well, that's an extreme case that is board-specific. Perhaps I should do
> this:
>
> #ifndef CONFIG_I2C_TIMEOUT
> #define CONFIG_I2C_TIMEOUT1000
> #endif
OK.
> Also, should we be using the same value for the time
Dear Scott Wood,
In message <20090904183645.gb20...@b07421-ec1.am.freescale.net> you wrote:
>
> > CONFIG_SYS_HZ is a constant of 1000. We do not change constants.
>
> We shouldn't call them CONFIGurable, then. :-)
Agreed. This should never have made it into public code. But it
slipped through so
Wolfgang Denk wrote:
> Dear Scott Wood,
>
> In message <20090904183437.ga20...@b07421-ec1.am.freescale.net> you wrote:
>>> milliseconds, i. e. a time. "(CONFIG_SYS_HZ / 4)" is a frequency,
>>> i. e. not a time, but the inverse of it.
>>>
>>> It is plain wront to write "250 per second" when you mea
Dear Scott Wood,
In message <20090904183437.ga20...@b07421-ec1.am.freescale.net> you wrote:
>
> > milliseconds, i. e. a time. "(CONFIG_SYS_HZ / 4)" is a frequency,
> > i. e. not a time, but the inverse of it.
> >
> > It is plain wront to write "250 per second" when you mean "250 milliseconds"
>
Wolfgang Denk wrote:
> Probably not. If you place a read request to a slow device it may
> take tens of milliseconds, or even longer - I have no idea. IIRC we
> had a box with a LCD display connected over I2C, which didn't ent
> into production as originally designed because writing t
On Fri, Sep 04, 2009 at 10:31:00AM +0200, Wolfgang Denk wrote:
> > CONFIG_HZ is 1000, so I2C_TIMEOUT is equal to 250. However, the way
> > it's used, 250 isn't the number of ticks per second, it's used as
> > number of microseconds. If CONFIG_HZ is changed to 100, does that
> > mean that we want
On Fri, Sep 04, 2009 at 05:29:48PM +0200, Wolfgang Denk wrote:
> > >> Kumar, any thoughts? Is there something sneaky going on here, or did
> > >> you just misinterpret the value of I2C_TIMEOUT?
> > >
> > > I guess I2C_TIMEOUT might always have been misinterpeted.
> >
> > I think the original cod
Dear Timur Tabi,
In message <4aa132b3.3050...@freescale.com> you wrote:
> Peter Tyser wrote:
> > If this is the case, the timeout should be the maximum (or reasonable
> > maximum) time an I2C transaction could take.
>
> How long is that? Is one millisecond good enough?
Probably not. If you plac
Dear Peter Tyser,
In message <1252078092.6005.63.ca...@localhost.localdomain> you wrote:
>
> > > Wrong Question. I don't know enough about the I2C protocol. Why is
> > > i2c_wait4bus necessary?
> >
> > Ok, why is it necessary?
>
> Freescale's I2C core supports multiple masters. I'd guess that
>
On Fri, 2009-09-04 at 10:30 -0500, Timur Tabi wrote:
> Peter Tyser wrote:
> > If this is the case, the timeout should be the maximum (or reasonable
> > maximum) time an I2C transaction could take.
>
> How long is that? Is one millisecond good enough?
The timeout in i2c_wait4bus() could potential
Peter Tyser wrote:
> If this is the case, the timeout should be the maximum (or reasonable
> maximum) time an I2C transaction could take.
How long is that? Is one millisecond good enough?
--
Timur Tabi
Linux kernel developer at Freescale
___
U-Boot ma
Dear Timur Tabi,
In message <4aa12e52.2080...@freescale.com> you wrote:
>
> > Wrong Question. I don't know enough about the I2C protocol. Why is
> > i2c_wait4bus necessary?
>
> Ok, why is it necessary?
Maybe we should remove it, when nobody knows why it's needed.
> >> Kumar, any thoughts? Is
On Fri, 2009-09-04 at 10:12 -0500, Timur Tabi wrote:
> Wolfgang Denk wrote:
>
> > Wrong Question. I don't know enough about the I2C protocol. Why is
> > i2c_wait4bus necessary?
>
> Ok, why is it necessary?
Freescale's I2C core supports multiple masters. I'd guess that
i2c_wait4bus() is used to
Dear Timur Tabi,
In message you
wrote:
>
> > I cannot answer this question. I don't even understand why the
> > i2c_wait4bus() function is needed at all.
>
> Can you explain? I don't know enough about the I2C protocol. Why is
> i2c_wait4bus unnecessary?
Wrong Question. I don't know enough
Wolfgang Denk wrote:
> Wrong Question. I don't know enough about the I2C protocol. Why is
> i2c_wait4bus necessary?
Ok, why is it necessary?
>
>> Kumar, any thoughts? Is there something sneaky going on here, or did
>> you just misinterpret the value of I2C_TIMEOUT?
>
> I guess I2C_TIMEOUT mig
On Fri, Sep 4, 2009 at 4:25 AM, Wolfgang Denk wrote:
> There are actually two parts in Timur's mail:
>
> 1) First part is the question if the timeout, which is currently set
> to 250 us, should be raised to 1,000 us.
>
> I cannot answer this question. I don't even understand why the
> i2c_wa
Dear Heiko Schocher,
In message <4aa0bec5.3010...@denx.de> you wrote:
>
> > CONFIG_HZ is 1000, so I2C_TIMEOUT is equal to 250. However, the way it's
> > used, 250 isn't the number of ticks per second, it's used as number of
> > microseconds. If CONFIG_HZ is changed to 100, does that mean that
Dear Timur Tabi,
In message <4a9fdf1e.4090...@freescale.com> you wrote:
> Currently we define I2C_TIMEOUT like this:
>
> #define I2C_TIMEOUT (CONFIG_SYS_HZ / 4)
= 250, that is.
> CONFIG_HZ is 1000, so I2C_TIMEOUT is equal to 250. However, the way it's
> used, 250 isn't the number of ticks p
Hello Timur,
Timur Tabi wrote:
> Currently we define I2C_TIMEOUT like this:
>
> #define I2C_TIMEOUT (CONFIG_SYS_HZ / 4)
>
> I'm seeing some I2C instability on a new board I'm working on, especially
> with SPD. If I change the above to
>
> #define I2C_TIMEOUT (CONFIG_SYS_HZ / 2)
>
> The
Currently we define I2C_TIMEOUT like this:
#define I2C_TIMEOUT (CONFIG_SYS_HZ / 4)
I'm seeing some I2C instability on a new board I'm working on, especially with
SPD. If I change the above to
#define I2C_TIMEOUT (CONFIG_SYS_HZ / 2)
The problems go away (or at least, so far appear to)
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