linux-kernel - Re: [PATCH v2 08/10] gpio: Add gpio driver for Actions OWL S900 SoC

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Date:   Wed, 21 Feb 2018 21:13:53 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Andreas Färber <afaerber@...e.de>,
        刘炜 <liuwei@...ions-semi.com>,
        mp-cs@...ions-semi.com, 96boards@...obotics.com,
        devicetree <devicetree@...r.kernel.org>,
        Daniel Thompson <daniel.thompson@...aro.org>,
        amit.kucheria@...aro.org,
        linux-arm Mailing List <linux-arm-kernel@...ts.infradead.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        hzhang@...obotics.com, bdong@...obotics.com
Subject: Re: [PATCH v2 08/10] gpio: Add gpio driver for Actions OWL S900 SoC

On Wed, Feb 21, 2018 at 6:00 PM, Manivannan Sadhasivam
<manivannan.sadhasivam@...aro.org> wrote:
> Add gpio driver for Actions Semi OWL family S900 SoC. Set of registers
> controlling the gpio shares the same register range with pinctrl block.
>
> GPIO registers are organized as 6 banks and each bank controls the
> maximum of 32 gpios.

> +static void owl_gpio_set_reg(void __iomem *base, unsigned int pin, int flag)
> +{
> +       u32 val;
> +
> +       if (flag) {
> +               val = readl(base);
> +               val |= BIT(pin);
> +               writel(val, base);
> +       } else {
> +               val = readl(base);
> +               val &= ~BIT(pin);
> +               writel(val, base);
> +       }
> +}

Why not to use the same pattern as below?

readl()
if ()
 ...
else
...
writel()

?

> +static void owl_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
> +{
> +       struct owl_gpio *gpio = gpiochip_get_data(chip);
> +       const struct owl_gpio_port *port = gpio->port;
> +       void __iomem *gpio_base = gpio->base + port->offset;
> +       u32 val;
> +
> +       val = readl(gpio_base + GPIO_DAT);
> +
> +       if (value)
> +               val |= BIT(offset);
> +       else
> +               val &= ~BIT(offset);
> +
> +       writel(val, gpio_base + GPIO_DAT);
> +}


-- 
With Best Regards,
Andy Shevchenko