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Message-ID: <643a0d80-3d99-420e-9e77-acc67728fbe7@gmail.com>
Date: Mon, 22 Apr 2024 12:10:39 +0800
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Subject: Re: [PATCH v7 3/3] pinctrl: nuvoton: Add ma35d1 pinctrl and GPIO
 driver
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: linus.walleij@linaro.org, robh+dt@kernel.org,
 krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org,
 p.zabel@pengutronix.de, j.neuschaefer@gmx.net,
 linux-arm-kernel@lists.infradead.org, linux-gpio@vger.kernel.org,
 devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
 ychuang3@nuvoton.com, schung@nuvoton.com
References: <20240409095637.2135-1-ychuang570808@gmail.com>
 <20240409095637.2135-4-ychuang570808@gmail.com>
 <ZhZTsV3RKpuyeUr4@surfacebook.localdomain>
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From: Jacky Huang <ychuang570808@gmail.com>
In-Reply-To: <ZhZTsV3RKpuyeUr4@surfacebook.localdomain>
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Dear Andy,


On 2024/4/10 下午 04:54, Andy Shevchenko wrote:
>> +#define MA35_GP_MODE_MASK_WIDTH              2
>> +
>> +#define MA35_GP_SLEWCTL_MASK_WIDTH   2
> I looked at the code how you use these... Oh, please switch to FIELD_GET() /
> FIELD_PREP() (don't forget to include bitfield.h)
>
> ...
>
> ...
>> +             regval &= ~GENMASK(setting->shift + MA35_MFP_BITS_PER_PORT - 1,
>> +                                setting->shift);
> This will generate an awful code. Use respective FIELD_*() macros.
>
> ...
>
>> +     regval &= ~GENMASK(gpio * MA35_GP_MODE_MASK_WIDTH - 1,
>> +                        gpio * MA35_GP_MODE_MASK_WIDTH);
>> +     regval |= mode << gpio * MA35_GP_MODE_MASK_WIDTH;
> Ditto.
>
> ...
>
>> +     regval &= GENMASK(gpio * MA35_GP_MODE_MASK_WIDTH - 1,
>> +                       gpio * MA35_GP_MODE_MASK_WIDTH);
>> +
>> +     return regval >> gpio * MA35_GP_MODE_MASK_WIDTH;
> Ditto.
>
> ...
>
>

Allow me to remove irrelevant parts.

I attempted to follow your advice and use FIELD_GET() and FIELD_PREP(), 
but found
it impractical. The reason is that these two macros require their 'mask' 
argument
to be a constant, otherwise compilation errors occur, which is the issue 
I encountered.
Since the mask here is calculated and not a constant, compilation errors 
occur.

Taking MA35_GP_REG_MODE as an example, within 32 bits, every 2 bits 
represent
the mode of a GPIO pin, and the mask is obtained by GENMASK(gpio * 2 -1, 
gpio * 2),
where the 'gpio' argument is a variable, not a constant, leading to 
compilation
errors.

Due to this reason, I will leave this part unchanged, or do you have any 
other suggestions?


Best Regards,
Jacky Huang