linux-kernel - Re: [PATCH 3/3] watchdog: mt7621-wdt: avoid globals and arch dependencies

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Message-ID: <CAMhs-H8O634ZbRW7BVkQmTA=B7p3Osu6d9hFGZ7DqXtXydkHBQ@mail.gmail.com>
Date:   Fri, 10 Feb 2023 12:35:59 +0100
From:   Sergio Paracuellos <sergio.paracuellos@...il.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     linux-watchdog@...r.kernel.org, wim@...ux-watchdog.org,
        linux@...ck-us.net, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, matthias.bgg@...il.com,
        arinc.unal@...nc9.com, tsbogend@...ha.franken.de,
        p.zabel@...gutronix.de, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-mips@...r.kernel.org
Subject: Re: [PATCH 3/3] watchdog: mt7621-wdt: avoid globals and arch dependencies

Hi Krzysztof,

On Fri, Feb 10, 2023 at 12:02 PM Krzysztof Kozlowski
<krzysztof.kozlowski@...aro.org> wrote:
>
> On 10/02/2023 07:56, Sergio Paracuellos wrote:
> > MT7621 SoC has a system controller node. Watchdog need to access to reset
> > status register. Ralink architecture and related driver are old and from
> > the beggining they ar providing some architecture dependent operations
> > for accessing this shared registers through 'asm/mach-ralink/ralink_regs.h'
> > header file. However this is not ideal from a driver perspective which can
> > just access to the system controller registers in am arch independent way
> > using regmap syscon APIs. Hence, add a new structure for driver data and
> > use it along the code. This way architecture dependencies and global vars
> > are not needed anymore. Update Kconfig accordingly to select new added
> > dependencies and allow driver to be compile tested.
> >
> > Signed-off-by: Sergio Paracuellos <sergio.paracuellos@...il.com>
> > ---
> >  drivers/watchdog/Kconfig      |   4 +-
> >  drivers/watchdog/mt7621_wdt.c | 121 ++++++++++++++++++++++------------
> >  2 files changed, 83 insertions(+), 42 deletions(-)
> >
>
>
> > -
> >  static int mt7621_wdt_probe(struct platform_device *pdev)
> >  {
> > +     struct device_node *np = pdev->dev.of_node;
> >       struct device *dev = &pdev->dev;
> > -     mt7621_wdt_base = devm_platform_ioremap_resource(pdev, 0);
> > -     if (IS_ERR(mt7621_wdt_base))
> > -             return PTR_ERR(mt7621_wdt_base);
> > +     struct watchdog_device *mt7621_wdt;
> > +     struct mt7621_wdt_data *drvdata;
> > +     int err;
> > +
> > +     drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
> > +     if (!drvdata)
> > +             return -ENOMEM;
> >
> > -     mt7621_wdt_reset = devm_reset_control_get_exclusive(dev, NULL);
> > -     if (!IS_ERR(mt7621_wdt_reset))
> > -             reset_control_deassert(mt7621_wdt_reset);
> > +     drvdata->sysc = syscon_regmap_lookup_by_phandle(np, "ralink,sysctl");
> > +     if (IS_ERR(drvdata->sysc))
> > +             return PTR_ERR(drvdata->sysc);
>
> You claim in commit title that you remove some global usage, but you add
> here several new features and refactor the code significantly. You need
> to split refactorings, improvements from completely new features. The
> entire patch is very difficult to understand in current form.

I am removing global usage and architecture dependencies using a
watchdog driver data structure so I thought the changes were easy
enough to review in this way. It seems they are not according to your
reply :). If preferred I can split this in two commits:
- Avoid globals using and introducing all the related new driver data
structure.
- Add request for regmap syscon from the phandle and remove the
architecture dependent calls and includes.

Thanks in advance for your comments.

Best regards,
    Sergio Paracuellos

>
> Best regards,
> Krzysztof
>