On Tue, Oct 28, 2014 at 1:01 AM, Dmitry Eremin-Solenikov
<dbaryshkov@xxxxxxxxx> wrote:
> Add gpiolib driver for gpio pins placed on the LoCoMo GA.
>
> Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@xxxxxxxxx>
(...)
> +static int locomo_gpio_get(struct gpio_chip *chip,
> + unsigned offset)
> +{
> + struct locomo_gpio *lg = container_of(chip, struct locomo_gpio, gpio);
> +
> + return readw(lg->regs + LOCOMO_GPL) & (1 << offset);
Do this:
#include <linux/bitops.h>
return !!(readw(lg->regs + LOCOMO_GPL) & BIT(offset));
So you clamp the returned value to a bool.
> +static void __locomo_gpio_set(struct gpio_chip *chip,
> + unsigned offset, int value)
> +{
> + struct locomo_gpio *lg = container_of(chip, struct locomo_gpio, gpio);
> + u16 r;
> +
> + r = readw(lg->regs + LOCOMO_GPO);
> + if (value)
> + r |= 1 << offset;
r |= BIT(offset);
> + else
> + r &= ~(1 << offset);
r &= BIT(offset);
(etc, everywhere this pattern occurs).
> +static void locomo_gpio_set(struct gpio_chip *chip,
> + unsigned offset, int value)
> +{
> + struct locomo_gpio *lg = container_of(chip, struct locomo_gpio, gpio);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&lg->lock, flags);
> +
> + __locomo_gpio_set(chip, offset, value);
> +
> + spin_unlock_irqrestore(&lg->lock, flags);
If you actually always have to be getting and releasing a spin lock around
the register writes, contemplate using regmap-mmio because that
is part of what it does.
But is this locking really necessary?
> +static int locomo_gpio_remove(struct platform_device *pdev)
> +{
> + struct locomo_gpio *lg = platform_get_drvdata(pdev);
> + int ret;
> +
> + ret = gpiochip_remove(&lg->gpio);
> + if (ret) {
> + dev_err(&pdev->dev, "Can't remove gpio chip: %d\n", ret);
> + return ret;
> + }
The return value from gpiochip_remove() has been removed in v3.18-rc1
so this will not compile.
Yours,
Linus Walleij
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