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Commit e1e37d6c authored by Julia Cartwright's avatar Julia Cartwright Committed by Linus Walleij
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gpio: 104-idi-48: make use of raw_spinlock variants 



The 104-idi-48 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: default avatarJulia Cartwright <julia@ni.com>
Acked-by: default avatarWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent ea38ce08

drivers/gpio/gpio-104-idi-48.c

+10 −8
Original line number Original line Diff line number Diff line
@@ -51,7 +51,7 @@ MODULE_PARM_DESC(irq, "ACCES 104-IDI-48 interrupt line numbers"); 
 */

 */

struct idi_48_gpio {

struct idi_48_gpio {

	struct gpio_chip chip;

	struct gpio_chip chip;

	spinlock_t lock;

	raw_spinlock_t lock;

	spinlock_t ack_lock;

	spinlock_t ack_lock;

	unsigned char irq_mask[6];

	unsigned char irq_mask[6];

	unsigned base;

	unsigned base;
@@ -112,11 +112,12 @@ static void idi_48_irq_mask(struct irq_data *data) 
			if (!idi48gpio->irq_mask[boundary]) {

			if (!idi48gpio->irq_mask[boundary]) {

				idi48gpio->cos_enb &= ~BIT(boundary);

				idi48gpio->cos_enb &= ~BIT(boundary);





				spin_lock_irqsave(&idi48gpio->lock, flags);

				raw_spin_lock_irqsave(&idi48gpio->lock, flags);





				outb(idi48gpio->cos_enb, idi48gpio->base + 7);

				outb(idi48gpio->cos_enb, idi48gpio->base + 7);





				spin_unlock_irqrestore(&idi48gpio->lock, flags);

				raw_spin_unlock_irqrestore(&idi48gpio->lock,

						           flags);

			}

			}





			return;

			return;
@@ -145,11 +146,12 @@ static void idi_48_irq_unmask(struct irq_data *data) 
			if (!prev_irq_mask) {

			if (!prev_irq_mask) {

				idi48gpio->cos_enb |= BIT(boundary);

				idi48gpio->cos_enb |= BIT(boundary);





				spin_lock_irqsave(&idi48gpio->lock, flags);

				raw_spin_lock_irqsave(&idi48gpio->lock, flags);





				outb(idi48gpio->cos_enb, idi48gpio->base + 7);

				outb(idi48gpio->cos_enb, idi48gpio->base + 7);





				spin_unlock_irqrestore(&idi48gpio->lock, flags);

				raw_spin_unlock_irqrestore(&idi48gpio->lock,

						           flags);

			}

			}





			return;

			return;
@@ -186,11 +188,11 @@ static irqreturn_t idi_48_irq_handler(int irq, void *dev_id) 




	spin_lock(&idi48gpio->ack_lock);

	spin_lock(&idi48gpio->ack_lock);





	spin_lock(&idi48gpio->lock);

	raw_spin_lock(&idi48gpio->lock);





	cos_status = inb(idi48gpio->base + 7);

	cos_status = inb(idi48gpio->base + 7);





	spin_unlock(&idi48gpio->lock);

	raw_spin_unlock(&idi48gpio->lock);





	/* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */

	/* IRQ Status (bit 6) is active low (0 = IRQ generated by device) */

	if (cos_status & BIT(6)) {

	if (cos_status & BIT(6)) {
@@ -256,7 +258,7 @@ static int idi_48_probe(struct device *dev, unsigned int id) 
	idi48gpio->chip.get = idi_48_gpio_get;

	idi48gpio->chip.get = idi_48_gpio_get;

	idi48gpio->base = base[id];

	idi48gpio->base = base[id];





	spin_lock_init(&idi48gpio->lock);

	raw_spin_lock_init(&idi48gpio->lock);

	spin_lock_init(&idi48gpio->ack_lock);

	spin_lock_init(&idi48gpio->ack_lock);





	err = devm_gpiochip_add_data(dev, &idi48gpio->chip, idi48gpio);

	err = devm_gpiochip_add_data(dev, &idi48gpio->chip, idi48gpio);