Re: [PATCHv2 1/2] ads7846: OMAP3: Removal of warnings backtrace in bootup

[Igor Grinberg <grinberg@compulab.co.il>]

Hi,

On 02/03/11 13:28, ABRAHAM, KISHON VIJAY wrote:

> On Thu, Feb 3, 2011 at 4:42 PM, Igor Grinberg <grinberg@compulab.co.il> wrote:
>>
>> On 02/03/11 13:00, Poddar, Sourav wrote:
>>
>>> On Thu, Feb 3, 2011 at 3:47 PM, Igor Grinberg <grinberg@compulab.co.il> wrote:
>>>> if (pdata->get_pendown_state) {
>>>>        ts->get_pendown_state = pdata->get_pendown_state;
>>>>        ts->gpio_pendown = -1;
>>>>        return 0;
>>>> }
>>> Yes we can do so .I initialise it at a place where other variables
>>>  where initialised.
>>>
>>>>> Also, why don't we use -EINVAL for the invalid gpio number instead of -1 constant?
>>>>>
>>>  I used -1 because conditional check done in probe ads7846_probe function
>>>  used this value.
>>>
>>>   err_free_gpio:
>>>         if (ts->gpio_pendown != -1)
>>>                 gpio_free(ts->gpio_pendown);
>>>
>> Well I understand that and that's why in my proposal I used -1 also, but
>> I thought we can make it even better if we switch to -EINVAL
>> (though wanted to check if there are any reasonable objections)
>> and while you are at this, may be you are willing also to submit a patch for this?
>   I guess instead of -EINVAL, -EIO should be initialized to
> ts->gpio_pendown since that
>   would be more appropriate for gpio

Well, the common practice is to use -EINVAL for gpio _numbers_,
I have not seen anyone using -EIO for this.

>  and as Balbi suggested it would
> be better to use
>   gpio_is_valid() for checking this error condition.

Of course gpio_is_valid() should be used for testing the gpio.
The -EINVAL in turn should be used for _setting_ the invalid value for that gpio.
My suggestion for -EINVAL is related to the initialization:

if (pdata->get_pendown_state) {
       ts->get_pendown_state = pdata->get_pendown_state;
       ts->gpio_pendown = -EINVAL;
       return 0;
}


-- 
Regards,
Igor.