Re: [PATCH 02/15] GPIO: port LoCoMo gpio support from old driver
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From: Linus Walleij <hidden>
Date: 2014-10-31 07:48:35
Also in:
alsa-devel, linux-arm-kernel, linux-gpio, linux-input, linux-leds, linux-spi
On Tue, Oct 28, 2014 at 1:01 AM, Dmitry Eremin-Solenikov [off-list ref] wrote:
Add gpiolib driver for gpio pins placed on the LoCoMo GA. Signed-off-by: Dmitry Eremin-Solenikov <redacted>
(...)
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+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.
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+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).
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+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?
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+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