linux-kernel - Re: [PATCH v4 06/11] gpio: add support for the sl28cpld GPIO controller

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Date:   Fri, 5 Jun 2020 15:00:48 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Michael Walle <michael@...le.cc>
Cc:     "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-hwmon@...r.kernel.org, linux-pwm@...r.kernel.org,
        linux-watchdog@...r.kernel.org,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Rob Herring <robh+dt@...nel.org>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Lee Jones <lee.jones@...aro.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Shawn Guo <shawnguo@...nel.org>, Li Yang <leoyang.li@....com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <maz@...nel.org>, Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH v4 06/11] gpio: add support for the sl28cpld GPIO controller

On Fri, Jun 5, 2020 at 12:14 AM Michael Walle <michael@...le.cc> wrote:

> Add support for the GPIO controller of the sl28 board management
> controller. This driver is part of a multi-function device.
>
> A controller has 8 lines. There are three different flavors:
> full-featured GPIO with interrupt support, input-only and output-only.

...

> +#include <linux/of_device.h>

I think also not needed.
But wait...

> +       return devm_regmap_add_irq_chip_np(dev, dev_of_node(dev), regmap,

It seems regmap needs to be converted to use fwnode.

> +                                          irq, IRQF_SHARED | IRQF_ONESHOT, 0,
> +                                          irq_chip, &gpio->irq_data);

...

> +       if (!pdev->dev.parent)
> +               return -ENODEV;

Are we expecting to get shot into foot? I mean why we need this check?

> +       dev_id = platform_get_device_id(pdev);
> +       if (dev_id)
> +               type = dev_id->driver_data;

Oh, no. In new code we don't need this. We have facilities to provide
platform data in a form of fwnode.

> +       else
> +               type = (uintptr_t)of_device_get_match_data(&pdev->dev);

So does this. device_get_match_data().

> +       if (!type)
> +               return -ENODEV;

...

> +       if (irq_support &&

Why do you need this flag? Can't simple IRQ number be sufficient?

> +           device_property_read_bool(&pdev->dev, "interrupt-controller")) {
> +               irq = platform_get_irq(pdev, 0);
> +               if (irq < 0)
> +                       return irq;
> +
> +               ret = sl28cpld_gpio_irq_init(&pdev->dev, gpio, regmap,
> +                                            base, irq);
> +               if (ret)
> +                       return ret;
> +
> +               config.irq_domain = regmap_irq_get_domain(gpio->irq_data);
> +       }

...

> +static const struct of_device_id sl28cpld_gpio_of_match[] = {

> +       { .compatible = "kontron,sl28cpld-gpio",
> +         .data = (void *)SL28CPLD_GPIO },
> +       { .compatible = "kontron,sl28cpld-gpi",
> +         .data = (void *)SL28CPLD_GPI },
> +       { .compatible = "kontron,sl28cpld-gpo",
> +         .data = (void *)SL28CPLD_GPO },

All above can be twice less LOCs.

> +       {},

No comma.

> +};


...

> +               .name = KBUILD_MODNAME,

This actually not good idea in long term. File name can change and break an ABI.

-- 
With Best Regards,
Andy Shevchenko