linux-kernel - Re: [PATCH v3 07/14] mfd: mt6370: Add Mediatek MT6370 support

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Message-ID: <CABtFH5K_vB5Rmo+2zAJ8PuMeMvC9x-yhDL93ByOLD+gc2maQYg@mail.gmail.com>
Date:   Fri, 24 Jun 2022 18:19:35 +0800
From:   ChiaEn Wu <peterwu.pub@...il.com>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     Lee Jones <lee.jones@...aro.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        Jingoo Han <jingoohan1@...il.com>, Pavel Machek <pavel@....cz>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Sebastian Reichel <sre@...nel.org>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Guenter Roeck <linux@...ck-us.net>,
        "Krogerus, Heikki" <heikki.krogerus@...ux.intel.com>,
        Helge Deller <deller@....de>,
        ChiaEn Wu <chiaen_wu@...htek.com>,
        Alice Chen <alice_chen@...htek.com>,
        cy_huang <cy_huang@...htek.com>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux LED Subsystem <linux-leds@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        "moderated list:ARM/Mediatek SoC support" 
        <linux-mediatek@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux PM <linux-pm@...r.kernel.org>,
        USB <linux-usb@...r.kernel.org>,
        linux-iio <linux-iio@...r.kernel.org>,
        "open list:FRAMEBUFFER LAYER" <linux-fbdev@...r.kernel.org>,
        szuni chen <szunichen@...il.com>
Subject: Re: [PATCH v3 07/14] mfd: mt6370: Add Mediatek MT6370 support

Hi Andy,

Thanks for your helpful comments! We have some questions below.

Andy Shevchenko <andy.shevchenko@...il.com> 於 2022年6月24日 週五 凌晨2:01寫道：
>
> On Thu, Jun 23, 2022 at 1:59 PM ChiaEn Wu <peterwu.pub@...il.com> wrote:
> >
> > From: ChiYuan Huang <cy_huang@...htek.com>
> >
> > Add Mediatek MT6370 MFD support.
>
> ...
>
> > +config MFD_MT6370
> > +       tristate "Mediatek MT6370 SubPMIC"
> > +       select MFD_CORE
> > +       select REGMAP_I2C
> > +       select REGMAP_IRQ
> > +       depends on I2C
> > +       help
> > +         Say Y here to enable MT6370 SubPMIC functional support.
> > +         It consists of a single cell battery charger with ADC monitoring, RGB
> > +         LEDs, dual channel flashlight, WLED backlight driver, display bias
> > +         voltage supply, one general purpose LDO, and the USB Type-C & PD
> > +         controller complies with the latest USB Type-C and PD standards.
>
> What will be the module name in case it's chosen to be built as a module?

OK, we will add related text in the next patch! Thanks!

>
> ...
>
> >  obj-$(CONFIG_INTEL_SOC_PMIC_BXTWC)  += intel_soc_pmic_bxtwc.o
> >  obj-$(CONFIG_INTEL_SOC_PMIC_CHTWC)     += intel_soc_pmic_chtwc.o
> >  obj-$(CONFIG_INTEL_SOC_PMIC_CHTDC_TI)  += intel_soc_pmic_chtdc_ti.o
> >  obj-$(CONFIG_MFD_MT6360)       += mt6360-core.o
> > +obj-$(CONFIG_MFD_MT6370)       += mt6370.o
> >  mt6397-objs                    := mt6397-core.o mt6397-irq.o mt6358-irq.o
> >  obj-$(CONFIG_MFD_MT6397)       += mt6397.o
> >  obj-$(CONFIG_INTEL_SOC_PMIC_MRFLD)     += intel_soc_pmic_mrfld.o
>
> This whole bunch of drivers is in the wrong place in Makefile.
>
> https://lore.kernel.org/all/20220616182524.7956-2-andriy.shevchenko@linux.intel.com/
>

hmm... So shall we need to cherry-pick your this patch first,
then modify the Makefile before the next submission??

> ...
>
> > +#define MT6370_REG_MAXADDR     0x1FF
>
> Wondering if (BIT(10) - 1) gives a better hint on how hardware limits
> this (so it will be clear it's 10-bit address).

well... This "0x1FF" is just a virtual mapping value to map the max
address of the PMU bank(0x1XX).
So, I feel its means is different from using (BIT(10) - 1) here.

>
> ...
>
> > +static int mt6370_check_vendor_info(struct mt6370_info *info)
> > +{
> > +       unsigned int devinfo;
> > +       int ret;
> > +
> > +       ret = regmap_read(info->regmap, MT6370_REG_DEV_INFO, &devinfo);
> > +       if (ret)
> > +               return ret;
> > +
> > +       switch (FIELD_GET(MT6370_VENID_MASK, devinfo)) {
> > +       case MT6370_VENID_RT5081:
> > +       case MT6370_VENID_RT5081A:
> > +       case MT6370_VENID_MT6370:
> > +       case MT6370_VENID_MT6371:
> > +       case MT6370_VENID_MT6372P:
> > +       case MT6370_VENID_MT6372CP:
>
> return 0;
>
> > +               break;
> > +       default:
> > +               dev_err(info->dev, "Unknown Vendor ID 0x%02x\n", devinfo);
> > +               return -ENODEV;
> > +       }
> > +
> > +       return 0;
>
> ...and drop these two lines?

OK! We will refine it in the next patch!

>
> > +}
>
> ...
>
> > +       bank_idx = *(u8 *)reg_buf;
> > +       bank_addr = *(u8 *)(reg_buf + 1);
>
> Why not
>
>   const u8 *u8_buf = reg_buf;
>
>   bank_idx = u8_buf[0];
>   bank_addr = u8_buf[1];
>
> ?

We will refine it in the next patch! Thanks!

>
> ...
>
> > +       if (ret < 0)
> > +               return ret;
> > +       else if (ret != val_size)
>
> Redundant 'else'.

I'm not quite sure what you mean, so I made the following changes first.
------------------------------------
       if (ret < 0)
              return ret;
       if (ret != val_size)
              return -EIO;
------------------------------------
I don't know if it meets your expectations??

>
> > +               return -EIO;
>
> ...
>
> > +       bank_idx = *(u8 *)data;
> > +       bank_addr = *(u8 *)(data + 1);
>
> As per above.
>
> --
> With Best Regards,
> Andy Shevchenko

Best regards,
ChiaEn Wu