[alsa-devel] [PATCH v4 7/9] davinci: MMC/SD support for Omapl138-Hawkboar

Jon Povey Jon.Povey at racelogic.co.uk
Tue Oct 19 03:54:13 CEST 2010

Victor Rodriguez wrote:
> On Mon, Oct 18, 2010 at 8:16 PM, Jon Povey
> <Jon.Povey at racelogic.co.uk> wrote:
>> davinci-linux-open-source-bounces at linux.davincidsp.com wrote:
>>> I think that you mean that I should not call gpio_direction_input if
>>> gpio_request failed am I right ?
>> Yes, if gpio_request() fails that means you have not claimed that
>> gpio, something else is using it already or it's not available due
>> to other misconfiguration.
>> So you shouldn't be trying to set its direction or anything like
>> that.

> Yes you are right and as I understand gpio_request will give a 0 if it
> success and because of that the warning never will appear, if there is
> a problem there will be a -1 and the warning will be printed. I could
> fix this with a return that breaks the code like this
>        ret = gpio_request(DA850_HAWK_MMCSD_CD_PIN, "MMC CD\n");
>                if (ret) { pr_warning("%s: can not open GPIO %d\n",
>                        __func__, DA850_HAWK_MMCSD_CD_PIN);
>        return; }
>        gpio_direction_input(DA850_HAWK_MMCSD_CD_PIN);
> Is this ok ?

I haven't seen the rest of your code to tell if that is OK, but
not calling any other gpio_* functions if the request fails is
the right idea.

You may need to do more cleanup to gracefuly handle the failure,
like returning an error value at least.

Jon Povey
jon.povey at racelogic.co.uk

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