linux-kernel - Re: [PATCH v2] pinctrl: mediatek: Fix multiple registration issue.

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Date:	Wed, 26 Aug 2015 14:11:28 +0200
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Axel Lin <axel.lin@...ics.com>
Cc:	Hongzhou Yang <hongzhou.yang@...iatek.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Daniel Kurtz <djkurtz@...omium.org>,
	Yingjoe Chen <yingjoe.chen@...iatek.com>,
	Antoine Tenart <antoine.tenart@...e-electrons.com>,
	Maoguang Meng <maoguang.meng@...iatek.com>,
	Masahiro Yamada <yamada.masahiro@...ionext.com>,
	Chaotian Jing <chaotian.jing@...iatek.com>,
	"linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	linux-mediatek@...ts.infradead.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	biao.huang@...iatek.com, Sascha Hauer <kernel@...gutronix.de>,
	srv_heupstream@...iatek.com
Subject: Re: [PATCH v2] pinctrl: mediatek: Fix multiple registration issue.

On Thu, Aug 20, 2015 at 5:49 AM, Axel Lin <axel.lin@...ics.com> wrote:
> 2015-08-20 11:38 GMT+08:00 Hongzhou Yang <hongzhou.yang@...iatek.com>:
>> Since our common driver need support main chip and PMU
>> at the same time, that means it will register two
>> pinctrl device, and the pinctrl_desc structure should
>> be used two times.
>>
>> But pinctrl_desc use global static definition, then
>> the latest registered pinctrl device will overwrite
>> the old one's, all members in pinctrl_desc will set to
>> the new one's, such as name, pins and pins numbers, etc.
>> This is a bug. Changing to use devm_kzalloc to fix it.
>>
>> Cc: stable@...r.kernel.org # v4.1+
>> Signed-off-by: Hongzhou Yang <hongzhou.yang@...iatek.com>
>> ---
>>  Use dynamic allocation to fix multiple registration issue.
>>
>>  drivers/pinctrl/mediatek/pinctrl-mtk-common.c |   26 ++++++++++++++-----------
>>  drivers/pinctrl/mediatek/pinctrl-mtk-common.h |    1 +
>>  2 files changed, 16 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
>> index ad1ea16..911c736 100644
>> --- a/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
>> +++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
>> @@ -1202,12 +1202,6 @@ static int mtk_pctrl_build_state(struct platform_device *pdev)
>>         return 0;
>>  }
>>
>> -static struct pinctrl_desc mtk_pctrl_desc = {
>> -       .confops        = &mtk_pconf_ops,
>> -       .pctlops        = &mtk_pctrl_ops,
>> -       .pmxops         = &mtk_pmx_ops,
>> -};
>> -
>>  int mtk_pctrl_init(struct platform_device *pdev,
>>                 const struct mtk_pinctrl_devdata *data,
>>                 struct regmap *regmap)
>> @@ -1265,12 +1259,22 @@ int mtk_pctrl_init(struct platform_device *pdev,
>>
>>         for (i = 0; i < pctl->devdata->npins; i++)
>>                 pins[i] = pctl->devdata->pins[i].pin;
>> -       mtk_pctrl_desc.name = dev_name(&pdev->dev);
>> -       mtk_pctrl_desc.owner = THIS_MODULE;
>> -       mtk_pctrl_desc.pins = pins;
>> -       mtk_pctrl_desc.npins = pctl->devdata->npins;
>> +
>> +       pctl->pctl_desc = devm_kzalloc(&pdev->dev, sizeof(*pctl->pctl_desc),
>> +                               GFP_KERNEL);
>> +       if (!pctl->pctl_desc)
>> +               return -ENOMEM;
>> +
>> +       pctl->pctl_desc->name = dev_name(&pdev->dev);
>> +       pctl->pctl_desc->owner = THIS_MODULE;
>> +       pctl->pctl_desc->pins = pins;
>> +       pctl->pctl_desc->npins = pctl->devdata->npins;
>> +       pctl->pctl_desc->confops = &mtk_pconf_ops;
>> +       pctl->pctl_desc->pctlops = &mtk_pctrl_ops;
>> +       pctl->pctl_desc->pmxops = &mtk_pmx_ops;
>>         pctl->dev = &pdev->dev;
>> -       pctl->pctl_dev = pinctrl_register(&mtk_pctrl_desc, &pdev->dev, pctl);
>> +
>> +       pctl->pctl_dev = pinctrl_register(pctl->pctl_desc, &pdev->dev, pctl);
>>         if (IS_ERR(pctl->pctl_dev)) {
>>                 dev_err(&pdev->dev, "couldn't register pinctrl driver\n");
>>                 return PTR_ERR(pctl->pctl_dev);
>> diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common.h b/drivers/pinctrl/mediatek/pinctrl-mtk-common.h
>> index 30213e5..93d6f5b 100644
>> --- a/drivers/pinctrl/mediatek/pinctrl-mtk-common.h
>> +++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common.h
>> @@ -256,6 +256,7 @@ struct mtk_pinctrl_devdata {
>>  struct mtk_pinctrl {
>>         struct regmap   *regmap1;
>>         struct regmap   *regmap2;
>> +       struct pinctrl_desc *pctl_desc;
> Use
> struct pinctrl_desc pctl_desc;
>
> Then you can remove the devm_kzalloc.

I agree with Axel, use a true member instead of a pointer
and you get something simpler.

Yours,
Linus Walleij
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