Quick clarification here, Dave, about your:

I'm not familiar enough with the omap to know the answer to that. Most
of the SPI stuff I've worked with has separate MOSI/MISO lines. The
hardware would need special support to support both 3-wire and 4-wire
(since in 3-wire the MOSI/MISO share a pin), and I don't know what the
OMAP has.

The 3-wire ADC 1278 is MISO, MOSI, Clock.

No Chip Select.
Like if 1278 bends the SPI protocol.
The question of how, is asked at TI and pending .

(in 1278 terminology the three wires are DOUT, DIN, SCLK)

Ion A. Beza.
 
On Thu, Feb 25, 2010 at 10:18 AM, Dave Hylands <dhylands@gmail.com> wrote:
Hi Tony,

On Thu, Feb 25, 2010 at 9:58 AM, Tony Oxendahl <toxend@gmail.com> wrote:
> Dave, thanks for taking interest in this matter.
>
> Regarding your:
>
>> > It sounds like maybe your probe routine isn't being called. The string
>> > passed to the driver register MUST exactly match the string in the
>> > board file.
>
> in board-overo.c I declared .modalias="adc1278".
> According to the documentation spi-summary this declaration should bind the
> ADC
> driver, adc1278.c (which is a copy of ads7846.c to be tweaked later-on),
> when the initialization code (like scripts in /etc/init.d and rc.d) runs at
> boot.
> This should take care of the first problem, the detection problem: the probe
> routine
> in adc1278.c should be called.
> (like the probe routine in ads7846.c was called; that's why I am using 7846
> as a working
> model on how s)

So this is where things are a little hazy for me. I've never used the
modalias stuff, so I'm not quite sure of the implications.

After your system has booted up, what does

ls /sys/class/platform/devices
ls /sys/class/platform/drivers

show?

I don't have my gumstix readily available right now, so I'm looking at
one of my boards at work.

> In the log of the boot file you see messages written by me, like
>
> Ion's test 9: SPI clock is enabled here.
>
> which is a change I made (a printk(...)) in omap2_mcspi.c.
> Why would this change be updated and changes I make similarly in ads7846.c
> aren't?

Probably because omap2_mcspi.c is statically linked into the kernel,
and ads7846.c is compiled into a loadable module, and you're only
updating the kernel (statically compiled stuff) and not the loadable
modules.

> What do I need to do, in commands to update all my changes?

I'm not sure what the "correct" OE way to do things is.

You can copy the ads7846.ko file (or whatever it's called) from your
build environment to your board. It goes somewhere in the
/lib/modules/2.6.xxx directory tree (find the location of the old
one),

> Finally for now, regarding the second issue, driver that I am making,
> adc1278.c, once again,
> does the controller driver omap2_mcspi.c apply to a 3-wire ADC 1278, or it
> applies only to 4-wire
> SPI?

I'm not familiar enough with the omap to know the answer to that. Most
of the SPI stuff I've worked with has separate MOSI/MISO lines. The
hardware would need special support to support both 3-wire and 4-wire
(since in 3-wire the MOSI/MISO share a pin), and I don't know what the
OMAP has.

--
Dave Hylands
Shuswap, BC, Canada
http://www.DaveHylands.com/

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