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SubjectRe: [PATCH v1 1/2] pinctrl: pinctrl-loongson2: add pinctrl driver support
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在 2022/10/21 下午5:45, Linus Walleij 写道:
> Hi Yinbo,
>
> thanks for your patch!
>
> On Fri, Oct 21, 2022 at 3:27 AM Yinbo Zhu <zhuyinbo@loongson.cn> wrote:
>
>> The loongson2 SoC has a few pins that can be used as GPIOs or take
>> multiple other functions. Add a driver for the pinmuxing.
>>
>> There is currently no support for GPIO pin pull-up and pull-down.
>>
>> Signed-off-by: zhanghongchen <zhanghongchen@loongson.cn>
>> Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
>
> (...)
>
>> +static int loongson2_pmx_set_mux(struct pinctrl_dev *pcdev, unsigned int func_num,
>> + unsigned int group_num)
>> +{
>> + struct loongson2_pinctrl *pctrl = pinctrl_dev_get_drvdata(pcdev);
>> + unsigned long reg = (unsigned long)pctrl->reg_base +
>> + loongson2_pmx_groups[group_num].reg;
>> + unsigned int mux_bit = loongson2_pmx_groups[group_num].bit;
>> + unsigned int val;
>> + unsigned long flags;
>> +
>> + raw_spin_lock_irqsave(&pctrl->lock, flags);
>> + val = readl((void *)reg);
>> + if (func_num == 0)
>> + val &= ~(1<<mux_bit);
>> + else
>> + val |= (1<<mux_bit);
>> + writel(val, (void *)reg);
>> + raw_spin_unlock_irqrestore(&pctrl->lock, flags);
>
> Can you explain in the commit message or with a comment in the code
> why you have to use a raw spinlock for this?
>
> We usually only use raw spinlocks for things like low level
> interrupt handlers...
>
> My guess is that you can replace this with an ordinary spinlock.
I was refer other platform, eg. pinctrl-amd.c, if the ordinary spinlock
was more appropriate I will use the ordinary spinlock.

TKs
Yinbo.
>
> Yours,
> Linus Walleij
>

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