linux-kernel - Re: [PATCH v2 04/15] mmc: mmci: Add support for setting pad type via pinctrl

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Message-ID: <0c73774b-f06e-2db8-ef50-3bf590b57cff@st.com>
Date:   Thu, 18 Jan 2018 13:35:05 +0000
From:   Patrice CHOTARD <patrice.chotard@...com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
CC:     Russell King <linux@...linux.org.uk>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...eaurora.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexandre TORGUE <alexandre.torgue@...com>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
        linux-clk <linux-clk@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        Andrea Merello <andrea.merello@...il.com>
Subject: Re: [PATCH v2 04/15] mmc: mmci: Add support for setting pad type via
 pinctrl

Hi Ulf

On 01/17/2018 10:34 AM, Ulf Hansson wrote:
> [...]
> 
>>          /*
>> @@ -1616,6 +1625,32 @@ static int mmci_probe(struct amba_device *dev,
>>          host = mmc_priv(mmc);
>>          host->mmc = mmc;
>>
>> +       /*
>> +        * Some variant (STM32) doesn't have opendrain bit, nevertheless
>> +        * pins can be set accordingly using pinctrl
>> +        */
>> +       if (!variant->opendrain) {
>> +               host->pinctrl = devm_pinctrl_get(&dev->dev);
>> +               if (IS_ERR(host->pinctrl)) {
>> +                       dev_err(&dev->dev, "failed to get pinctrl");
>> +                       goto host_free;
>> +               }
>> +
>> +               host->pins_default = pinctrl_lookup_state(host->pinctrl,
>> +                                                         PINCTRL_STATE_DEFAULT);
>> +               if (IS_ERR(host->pins_default)) {
>> +                       dev_warn(mmc_dev(mmc), "Can't select default pins\n");
>> +                       host->pins_default = NULL;
> 
> This is wrong, I think you should bail out and return the error code instead.

Ok

> 
> Moreover, calling pinctrl_select_state() from ->set_ios by using a
> NULL state, will likely trigger a NULL pointer deference bug in the
> pinctrl layer.

Regarding pinctrl_select_state() call with a NULL state, this case is 
managed inside pinctrl_state(), but ok, it will be more elegant to exit 
directly in case of no DT pins definition found.

> 
>> +               }
>> +
>> +               host->pins_opendrain = pinctrl_lookup_state(host->pinctrl,
>> +                                                           MMCI_PINCTRL_STATE_OPENDRAIN);
>> +               if (IS_ERR(host->pins_opendrain)) {
>> +                       dev_warn(mmc_dev(mmc), "Can't select opendrain pins\n");
>> +                       host->pins_opendrain = NULL;
> 
> Ditto.

ok

Thanks

Patrice
> 
>> +               }
>> +       }
>> +
> 
> [...]
> 
> Kind regards
> Uffe
>