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authorJulia Cartwright <julia@ni.com>2017-03-09 10:21:58 -0600
committerLinus Walleij <linus.walleij@linaro.org>2017-03-16 21:52:10 +0100
commit8c41ab4f0521918452851392ed40ed03923623e2 (patch)
treede1c12ec2f416c97c75d88ef79659f252a230f90
parenta0a584f0e92af068f4308586bad1ca5ea1e28d79 (diff)
gpio: zx: make use of raw_spinlock variants
The zx gpio driver currently implements an irq_chip for handling interrupts; due to how irq_chip handling is done, it's necessary for the irq_chip methods to be invoked from hardirq context, even on a a real-time kernel. Because the spinlock_t type becomes a "sleeping" spinlock w/ RT kernels, it is not suitable to be used with irq_chips. A quick audit of the operations under the lock reveal that they do only minimal, bounded work, and are therefore safe to do under a raw spinlock. Signed-off-by: Julia Cartwright <julia@ni.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
-rw-r--r--drivers/gpio/gpio-zx.c24
1 files changed, 12 insertions, 12 deletions
diff --git a/drivers/gpio/gpio-zx.c b/drivers/gpio/gpio-zx.c
index 93de8be0d885..be3a87da8438 100644
--- a/drivers/gpio/gpio-zx.c
+++ b/drivers/gpio/gpio-zx.c
@@ -41,7 +41,7 @@
#define ZX_GPIO_NR 16
struct zx_gpio {
- spinlock_t lock;
+ raw_spinlock_t lock;
void __iomem *base;
struct gpio_chip gc;
@@ -56,11 +56,11 @@ static int zx_direction_input(struct gpio_chip *gc, unsigned offset)
if (offset >= gc->ngpio)
return -EINVAL;
- spin_lock_irqsave(&chip->lock, flags);
+ raw_spin_lock_irqsave(&chip->lock, flags);
gpiodir = readw_relaxed(chip->base + ZX_GPIO_DIR);
gpiodir &= ~BIT(offset);
writew_relaxed(gpiodir, chip->base + ZX_GPIO_DIR);
- spin_unlock_irqrestore(&chip->lock, flags);
+ raw_spin_unlock_irqrestore(&chip->lock, flags);
return 0;
}
@@ -75,7 +75,7 @@ static int zx_direction_output(struct gpio_chip *gc, unsigned offset,
if (offset >= gc->ngpio)
return -EINVAL;
- spin_lock_irqsave(&chip->lock, flags);
+ raw_spin_lock_irqsave(&chip->lock, flags);
gpiodir = readw_relaxed(chip->base + ZX_GPIO_DIR);
gpiodir |= BIT(offset);
writew_relaxed(gpiodir, chip->base + ZX_GPIO_DIR);
@@ -84,7 +84,7 @@ static int zx_direction_output(struct gpio_chip *gc, unsigned offset,
writew_relaxed(BIT(offset), chip->base + ZX_GPIO_DO1);
else
writew_relaxed(BIT(offset), chip->base + ZX_GPIO_DO0);
- spin_unlock_irqrestore(&chip->lock, flags);
+ raw_spin_unlock_irqrestore(&chip->lock, flags);
return 0;
}
@@ -118,7 +118,7 @@ static int zx_irq_type(struct irq_data *d, unsigned trigger)
if (offset < 0 || offset >= ZX_GPIO_NR)
return -EINVAL;
- spin_lock_irqsave(&chip->lock, flags);
+ raw_spin_lock_irqsave(&chip->lock, flags);
gpioiev = readw_relaxed(chip->base + ZX_GPIO_IV);
gpiois = readw_relaxed(chip->base + ZX_GPIO_IVE);
@@ -151,7 +151,7 @@ static int zx_irq_type(struct irq_data *d, unsigned trigger)
writew_relaxed(gpioi_epos, chip->base + ZX_GPIO_IEP);
writew_relaxed(gpioi_eneg, chip->base + ZX_GPIO_IEN);
writew_relaxed(gpioiev, chip->base + ZX_GPIO_IV);
- spin_unlock_irqrestore(&chip->lock, flags);
+ raw_spin_unlock_irqrestore(&chip->lock, flags);
return 0;
}
@@ -184,12 +184,12 @@ static void zx_irq_mask(struct irq_data *d)
u16 mask = BIT(irqd_to_hwirq(d) % ZX_GPIO_NR);
u16 gpioie;
- spin_lock(&chip->lock);
+ raw_spin_lock(&chip->lock);
gpioie = readw_relaxed(chip->base + ZX_GPIO_IM) | mask;
writew_relaxed(gpioie, chip->base + ZX_GPIO_IM);
gpioie = readw_relaxed(chip->base + ZX_GPIO_IE) & ~mask;
writew_relaxed(gpioie, chip->base + ZX_GPIO_IE);
- spin_unlock(&chip->lock);
+ raw_spin_unlock(&chip->lock);
}
static void zx_irq_unmask(struct irq_data *d)
@@ -199,12 +199,12 @@ static void zx_irq_unmask(struct irq_data *d)
u16 mask = BIT(irqd_to_hwirq(d) % ZX_GPIO_NR);
u16 gpioie;
- spin_lock(&chip->lock);
+ raw_spin_lock(&chip->lock);
gpioie = readw_relaxed(chip->base + ZX_GPIO_IM) & ~mask;
writew_relaxed(gpioie, chip->base + ZX_GPIO_IM);
gpioie = readw_relaxed(chip->base + ZX_GPIO_IE) | mask;
writew_relaxed(gpioie, chip->base + ZX_GPIO_IE);
- spin_unlock(&chip->lock);
+ raw_spin_unlock(&chip->lock);
}
static struct irq_chip zx_irqchip = {
@@ -230,7 +230,7 @@ static int zx_gpio_probe(struct platform_device *pdev)
if (IS_ERR(chip->base))
return PTR_ERR(chip->base);
- spin_lock_init(&chip->lock);
+ raw_spin_lock_init(&chip->lock);
if (of_property_read_bool(dev->of_node, "gpio-ranges")) {
chip->gc.request = gpiochip_generic_request;
chip->gc.free = gpiochip_generic_free;