Re: [PATCH 6/6] i2c: davinci: bus recovery procedure to clear the bus

[Philby John <pjohn-Igf4POYTYCDQT0dZR+AlfA@public.gmane.org>]

On 03/17/2010 02:20 AM, Kevin Hilman wrote:
> Philby John<pjohn-Igf4POYTYCDQT0dZR+AlfA@public.gmane.org>  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

>
> Please submit an updated version so we can get this stuff upstream.

Right, the enhancement has now been sent.

Regards,
Philby