linux-kernel - Re: [PATCH v5 09/10] gpio: Add a driver for Cadence I3C GPIO expander

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Date:   Tue, 26 Jun 2018 22:07:03 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Boris Brezillon <boris.brezillon@...tlin.com>
Cc:     Wolfram Sang <wsa@...-dreams.de>,
        linux-i2c <linux-i2c@...r.kernel.org>,
        Jonathan Corbet <corbet@....net>,
        Linux Documentation List <linux-doc@...r.kernel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Arnd Bergmann <arnd@...db.de>,
        Przemyslaw Sroka <psroka@...ence.com>,
        Arkadiusz Golec <agolec@...ence.com>,
        Alan Douglas <adouglas@...ence.com>,
        Bartosz Folta <bfolta@...ence.com>,
        Damian Kos <dkos@...ence.com>,
        Alicja Jurasik-Urbaniak <alicja@...ence.com>,
        Cyprian Wronka <cwronka@...ence.com>,
        Suresh Punnoose <sureshp@...ence.com>,
        Rafal Ciepiela <rafalc@...ence.com>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        Nishanth Menon <nm@...com>, Rob Herring <robh+dt@...nel.org>,
        Pawel Moll <pawel.moll@....com>,
        Mark Rutland <mark.rutland@....com>,
        Ian Campbell <ijc+devicetree@...lion.org.uk>,
        Kumar Gala <galak@...eaurora.org>,
        devicetree <devicetree@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Vitor Soares <Vitor.Soares@...opsys.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        Xiang Lin <Xiang.Lin@...aptics.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Sekhar Nori <nsekhar@...com>, Przemyslaw Gaj <pgaj@...ence.com>
Subject: Re: [PATCH v5 09/10] gpio: Add a driver for Cadence I3C GPIO expander

On Fri, Jun 22, 2018 at 1:49 PM, Boris Brezillon
<boris.brezillon@...tlin.com> wrote:
> Add a driver for Cadence I3C GPIO expander.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@...tlin.com>

> +       scratchbuf = kmalloc(sizeof(*scratchbuf) * 2, GFP_KERNEL);

kmalloc_array() ?

> +       ret = i3c_device_do_priv_xfers(gpioc->i3cdev, xfers,
> +                                      ARRAY_SIZE(xfers));

One line?


> +static void cdns_i3c_gpio_set_multiple(struct gpio_chip *g,
> +                                      unsigned long *mask,
> +                                      unsigned long *bits)
> +{
> +       struct cdns_i3c_gpio *gpioc = gpioc_to_cdns_gpioc(g);
> +       u8 newovr;
> +       int ret;
> +
> +       newovr = (gpioc->ovr & ~(*mask)) | (*bits & *mask);
> +       if (newovr == gpioc->ovr)
> +               return;
> +
> +       ret = cdns_i3c_gpio_write_reg(gpioc, OVR, newovr);
> +       if (!ret)
> +               gpioc->ovr = newovr;

You don't change mask here, why do you need a pointer to it?

> +}

> +static int cdns_i3c_gpio_get_multiple(struct gpio_chip *g,
> +                                     unsigned long *mask,
> +                                     unsigned long *bits)
> +{
> +       struct cdns_i3c_gpio *gpioc = gpioc_to_cdns_gpioc(g);
> +       int ret;
> +       u8 ivr;
> +
> +       ret = cdns_i3c_gpio_read_reg(gpioc, IVR, &ivr);
> +       if (ret)
> +               return ret;
> +
> +       *bits = ivr & *mask & gpioc->dir;
> +       *bits |= gpioc->ovr & *mask & ~gpioc->dir;

Ditto.

> +
> +       return 0;
> +}

> +static void cdns_i3c_gpio_ibi_handler(struct i3c_device *i3cdev,
> +                                     const struct i3c_ibi_payload *payload)
> +{
> +       struct cdns_i3c_gpio *gpioc = i3cdev_get_drvdata(i3cdev);

> +       u8 isr = 0;

Perhaps you need to check the result of _read_reg() below instead of
dummy assignment?

> +       int i;
> +
> +       cdns_i3c_gpio_read_reg(gpioc, ISR, &isr);

> +       for (i = 0; i < 8; i++) {
> +               unsigned int irq;
> +
> +               if (!(BIT(i) & isr & gpioc->imr))
> +                       continue;

for_each_set_bit() ?

> +
> +               irq = irq_find_mapping(gpioc->gpioc.irq.domain, i);
> +               handle_nested_irq(irq);
> +       }
> +}

> +static const struct i3c_device_id cdns_i3c_gpio_ids[] = {
> +       I3C_DEVICE(0x1c9, 0x0, NULL),

> +       { /* sentinel */ },

Slightly better without comma.

> +};
> +MODULE_DEVICE_TABLE(i3c, cdns_i3c_gpio_ids);

-- 
With Best Regards,
Andy Shevchenko