linux-kernel - Re: [PATCH] driver: base: pinctrl: return error from pinctrl_bind

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Message-ID: <57D80212.7060303@mentor.com>
Date:   Tue, 13 Sep 2016 19:11:38 +0530
From:   Deepak Das <deepak_das@...tor.com>
To:     Linus Walleij <linus.walleij@...aro.org>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        vzapolsk <Vladimir_Zapolskiy@...tor.com>
Subject: Re: [PATCH] driver: base: pinctrl: return error from
 pinctrl_bind_pins()



On Tuesday 13 September 2016 05:29 PM, Linus Walleij wrote:
> On Tue, Sep 13, 2016 at 9:13 AM, Deepak <deepak_das@...tor.com> wrote:
>
>> strict pin controller returns -EINVAL in case of pin request which
>> is already claimed by somebody else.
>> Following is the sequence of calling pin_request() from
>> pinctrl_bind_pins():-
>> pinctrl_bind_pins()->pinctrl_select_state()->pinmux_enable_setting()->
>> pin_request()
>>
>> But pinctrl_bind_pins() only returns -EPROBE_DEFER which makes device
>> driver probe successful even if the pin request is rejected by the pin
>> controller subsystem.
>>
>> This commit modifies pinctrl_bind_pins() to return error if the pin is
>> rejected by pin control subsystem.
>>
>> Signed-off-by: Deepak Das <deepak_das@...tor.com>
>
> Aha
>
>>       /* Only return deferrals */
>> -    if (ret != -EPROBE_DEFER)
>> +    if ((ret != -EPROBE_DEFER) && (ret != -EINVAL))
>>           ret = 0;
>
> I rewrote this when applying, like this:
>
> -       /* Only return deferrals */
> -       if (ret != -EPROBE_DEFER)
> -               ret = 0;
> +       /* Return deferrals */
> +       if (ret == -EPROBE_DEFER)
> +               return ret;
> +       if (ret == -EINVAL) {
> +               dev_err(dev, "could not initialize pin control state\n");
> +               return ret;
> +       }
> +       /* We ignore errors like -ENOENT meaning no pinctrl state */
>
> -       return ret;
> +       return 0;
>
> Can you confim that this works for you too?

Yes, This works for me as well but do we really need this extra error 
message ?
error message is printed before returning -EINVAL from most places, 
Although I did not checked all places. For example, error message in 
pin_request():-
dev_err(pctldev->dev, "pin %s already requested by %s; cannot claim for 
%s\n", desc->name, desc->mux_owner, owner);

Thanks,
Deepak Das
>
> Yours,
> Linus Walleij
>