[PATCH 1/3] i2c: omap: Do not enable the irq always

[Shubhrajyoti Datta]

On Fri, Oct 12, 2012 at 7:56 PM, Kevin Hilman
<khilman at deeprootsystems.com> wrote:
> +Kalle, Grygorii, Huzefa
>
> Shubhrajyoti D <shubhrajyoti at ti.com> writes:
>
>> Enable the irq in the transfer and disable it after the
>> transfer is done.
>>
>> Signed-off-by: Shubhrajyoti D <shubhrajyoti at ti.com>
>> ---
>>  drivers/i2c/busses/i2c-omap.c |    3 +++
>>  1 files changed, 3 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
>> index b6c6b95..ce41596 100644
>> --- a/drivers/i2c/busses/i2c-omap.c
>> +++ b/drivers/i2c/busses/i2c-omap.c
>> @@ -625,6 +625,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>>       if (IS_ERR_VALUE(r))
>>               goto out;
>>
>> +     enable_irq(dev->irq);
>>       r = omap_i2c_wait_for_bb(dev);
>>       if (r < 0)
>>               goto out;
>> @@ -654,6 +655,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>>
>>       omap_i2c_wait_for_bb(dev);
>>  out:
>> +     disable_irq(dev->irq);
>
> When using runtime PM with auto-suspend timeouts, why would you disable
> the IRQ before the runtime suspend handlers have run?
>
> If you really want to do this, you probably should have these in the
> runtime PM callbacks.

OK.

>  But I'll wait until you add a more descriptive
> changelog before I can really tell why this is being done.  Based on the
> discussion in the patch from Kalle, I'm assuming this is to prevent
> interrups when I2C is being used by co-processors.  If so, plese
> describe in the changelog.

OK.

>
> That being said, doesn't the runtime suspend callback already disable
> IRQs at the device level instead of the INTC level?

My idea is that the device may get reconfigured by the other processor.
I felt intc is the only way. do you agree?


>
> Kevin
>
>>       pm_runtime_mark_last_busy(dev->dev);
>>       pm_runtime_put_autosuspend(dev->dev);
>>       return r;
>> @@ -1179,6 +1181,7 @@ omap_i2c_probe(struct platform_device *pdev)
>>               goto err_unuse_clocks;
>>       }
>>
>> +     disable_irq(dev->irq);
>>       adap = &dev->adapter;
>>       i2c_set_adapdata(adap, dev);
>>       adap->owner = THIS_MODULE;
> --
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