On Tue, Oct 28, 2014 at 1:01 AM, Dmitry Eremin-Solenikov dbaryshkov@gmail.com wrote:
Add gpiolib driver for gpio pins placed on the LoCoMo GA.
Signed-off-by: Dmitry Eremin-Solenikov dbaryshkov@gmail.com
(...)
+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);
elser &= ~(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