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gpio: pci-idio-16: make use of raw_spinlock variants 

The pci-idio-16 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>
Acked-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
zero-colors
Julia Cartwright 2017-03-21 17:43:09 -05:00 committed by Linus Walleij
parent 3906e8089a
commit ea38ce081d
1 changed files with 14 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
drivers/gpio/gpio-pci-idio-16.c
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@ -59,7 +59,7 @@ struct idio_16_gpio_reg {
*/
struct idio_16_gpio {
struct gpio_chip chip;
spinlock_t lock;
raw_spinlock_t lock;
struct idio_16_gpio_reg __iomem *reg;
unsigned long irq_mask;
};
@ -121,7 +121,7 @@ static void idio_16_gpio_set(struct gpio_chip *chip, unsigned int offset,
} else
base = &idio16gpio->reg->out0_7;
spin_lock_irqsave(&idio16gpio->lock, flags);
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
if (value)
out_state = ioread8(base) | mask;
@ -130,7 +130,7 @@ static void idio_16_gpio_set(struct gpio_chip *chip, unsigned int offset,
iowrite8(out_state, base);
spin_unlock_irqrestore(&idio16gpio->lock, flags);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
@ -140,7 +140,7 @@ static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
unsigned long flags;
unsigned int out_state;
spin_lock_irqsave(&idio16gpio->lock, flags);
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
/* process output lines 0-7 */
if (*mask & 0xFF) {
@ -160,7 +160,7 @@ static void idio_16_gpio_set_multiple(struct gpio_chip *chip,
iowrite8(out_state, &idio16gpio->reg->out8_15);
}
spin_unlock_irqrestore(&idio16gpio->lock, flags);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
static void idio_16_irq_ack(struct irq_data *data)
@ -177,11 +177,11 @@ static void idio_16_irq_mask(struct irq_data *data)
idio16gpio->irq_mask &= ~mask;
if (!idio16gpio->irq_mask) {
spin_lock_irqsave(&idio16gpio->lock, flags);
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
iowrite8(0, &idio16gpio->reg->irq_ctl);
spin_unlock_irqrestore(&idio16gpio->lock, flags);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
}
@ -196,11 +196,11 @@ static void idio_16_irq_unmask(struct irq_data *data)
idio16gpio->irq_mask |= mask;
if (!prev_irq_mask) {
spin_lock_irqsave(&idio16gpio->lock, flags);
raw_spin_lock_irqsave(&idio16gpio->lock, flags);
ioread8(&idio16gpio->reg->irq_ctl);
spin_unlock_irqrestore(&idio16gpio->lock, flags);
raw_spin_unlock_irqrestore(&idio16gpio->lock, flags);
}
}
@ -229,11 +229,11 @@ static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
struct gpio_chip *const chip = &idio16gpio->chip;
int gpio;
spin_lock(&idio16gpio->lock);
raw_spin_lock(&idio16gpio->lock);
irq_status = ioread8(&idio16gpio->reg->irq_status);
spin_unlock(&idio16gpio->lock);
raw_spin_unlock(&idio16gpio->lock);
/* Make sure our device generated IRQ */
if (!(irq_status & 0x3) || !(irq_status & 0x4))
@ -242,12 +242,12 @@ static irqreturn_t idio_16_irq_handler(int irq, void *dev_id)
for_each_set_bit(gpio, &idio16gpio->irq_mask, chip->ngpio)
generic_handle_irq(irq_find_mapping(chip->irqdomain, gpio));
spin_lock(&idio16gpio->lock);
raw_spin_lock(&idio16gpio->lock);
/* Clear interrupt */
iowrite8(0, &idio16gpio->reg->in0_7);
spin_unlock(&idio16gpio->lock);
raw_spin_unlock(&idio16gpio->lock);
return IRQ_HANDLED;
}
@ -302,7 +302,7 @@ static int idio_16_probe(struct pci_dev *pdev, const struct pci_device_id *id)
idio16gpio->chip.set = idio_16_gpio_set;
idio16gpio->chip.set_multiple = idio_16_gpio_set_multiple;
spin_lock_init(&idio16gpio->lock);
raw_spin_lock_init(&idio16gpio->lock);
err = devm_gpiochip_add_data(dev, &idio16gpio->chip, idio16gpio);
if (err) {