Hi Philby,
On Wed, Mar 17, 2010 at 16:58:44, Philby John wrote:
> On 03/17/2010 02:20 AM, Kevin Hilman wrote:
> > Philby John<pjohn@xxxxxxxxxx> writes:
> >
> >> On 02/08/2010 04:05 PM, Nori, Sekhar wrote:
> >>> Hi Philby,
> >>>
> >>> On Fri, Feb 05, 2010 at 19:23:43, Philby John wrote:
> >>>> Hello Sekhar,
> >>>>
> >>>
> >>> [...]
> >>>
> >>>>>> +/* Generate a pulse on the i2c clock pin. */
> >>>>>> +static void generic_i2c_clock_pulse(unsigned int scl_pin)
> >>>>>> +{
> >>>>>> + u16 i;
> >>>>>> +
> >>>>>> + if (scl_pin) {
> >>>>>> + /* Send high and low on the SCL line */
> >>>>>> + for (i = 0; i< 9; i++) {
> >>>>>> + gpio_set_value(scl_pin, 0);
> >>>>>> + udelay(20);
> >>>>>> + gpio_set_value(scl_pin, 1);
> >>>>>> + udelay(20);
> >>>>>> + }
> >>>>>
> >>>>> Before using the pins as GPIO, you would have to set the
> >>>>> functionality of these pins as GPIO. You had this code in
> >>>>> previous incarnations of this patch - not sure why it is
> >>>>> dropped now.
> >>>>>
> >>
> >> I now think that the previous versions were incorrect since
> >> davinci_cfg_reg() does not set the scl or sda pins for gpio
> >> functionality. Instead they set them as scl or sda which is not what
> >> we want at the time of pulsing. The previous versions used
> >> gpio_set_value() in disable_i2c_pins() and then called
> >> davinci_cfg_reg(). After which it called pulse_i2c_clock().
> >>
> >> Please correct me if my interpretation of the code is incorrect.
> >
> > Can we get some resolution here?
> >
> > I have a queue of davinci i2c patches waiting to go upstream, and I'd
> > like to get them in for 2.6.35.
> >
> > The current i2c series is in the 'davinci-i2c' branch of davinci git.
>
> To quote Sekhar, "...Right. It is only an enhancement (and only good
> to have at that). This should not stop the current patch from getting
> in." So this patch is good to make it to 2.6.35
How about the using the "free data format" method that Brad was
suggesting [1]? That sounds like a much simpler approach than the
GPIO muxing method that this patch is adopting.
I think we should try that method before accepting this approach
as the final one.
Thanks,
Sekhar
[1] http://www.mail-archive.com/linux-i2c@xxxxxxxxxxxxxxx/msg02800.html
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