Commit 45897809 authored by Julia Cartwright's avatar Julia Cartwright Committed by Linus Walleij
Browse files

gpio: 104-dio-48e: make use of raw_spinlock variants 



The 104-dio-48e 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 21d01c9c

drivers/gpio/gpio-104-dio-48e.c

+19 −19
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ struct dio48e_gpio { 
	unsigned char io_state[6];

	unsigned char out_state[6];

	unsigned char control[2];

	spinlock_t lock;

	raw_spinlock_t lock;

	unsigned base;

	unsigned char irq_mask;

};
@@ -78,7 +78,7 @@ static int dio48e_gpio_direction_input(struct gpio_chip *chip, unsigned offset) 
	unsigned long flags;

	unsigned control;



	spin_lock_irqsave(&dio48egpio->lock, flags);

	raw_spin_lock_irqsave(&dio48egpio->lock, flags);



	/* Check if configuring Port C */

	if (io_port == 2 || io_port == 5) {
@@ -103,7 +103,7 @@ static int dio48e_gpio_direction_input(struct gpio_chip *chip, unsigned offset) 
	control &= ~BIT(7);

	outb(control, control_addr);



	spin_unlock_irqrestore(&dio48egpio->lock, flags);

	raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);



	return 0;

}
@@ -120,7 +120,7 @@ static int dio48e_gpio_direction_output(struct gpio_chip *chip, unsigned offset, 
	unsigned long flags;

	unsigned control;



	spin_lock_irqsave(&dio48egpio->lock, flags);

	raw_spin_lock_irqsave(&dio48egpio->lock, flags);



	/* Check if configuring Port C */

	if (io_port == 2 || io_port == 5) {
@@ -153,7 +153,7 @@ static int dio48e_gpio_direction_output(struct gpio_chip *chip, unsigned offset, 
	control &= ~BIT(7);

	outb(control, control_addr);



	spin_unlock_irqrestore(&dio48egpio->lock, flags);

	raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);



	return 0;

}
@@ -167,17 +167,17 @@ static int dio48e_gpio_get(struct gpio_chip *chip, unsigned offset) 
	unsigned long flags;

	unsigned port_state;



	spin_lock_irqsave(&dio48egpio->lock, flags);

	raw_spin_lock_irqsave(&dio48egpio->lock, flags);



	/* ensure that GPIO is set for input */

	if (!(dio48egpio->io_state[port] & mask)) {

		spin_unlock_irqrestore(&dio48egpio->lock, flags);

		raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);

		return -EINVAL;

	}



	port_state = inb(dio48egpio->base + in_port);



	spin_unlock_irqrestore(&dio48egpio->lock, flags);

	raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);



	return !!(port_state & mask);

}
@@ -190,7 +190,7 @@ static void dio48e_gpio_set(struct gpio_chip *chip, unsigned offset, int value) 
	const unsigned out_port = (port > 2) ? port + 1 : port;

	unsigned long flags;



	spin_lock_irqsave(&dio48egpio->lock, flags);

	raw_spin_lock_irqsave(&dio48egpio->lock, flags);



	if (value)

		dio48egpio->out_state[port] |= mask;
@@ -199,7 +199,7 @@ static void dio48e_gpio_set(struct gpio_chip *chip, unsigned offset, int value) 


	outb(dio48egpio->out_state[port], dio48egpio->base + out_port);



	spin_unlock_irqrestore(&dio48egpio->lock, flags);

	raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);

}



static void dio48e_gpio_set_multiple(struct gpio_chip *chip,
@@ -225,14 +225,14 @@ static void dio48e_gpio_set_multiple(struct gpio_chip *chip, 
		out_port = (port > 2) ? port + 1 : port;

		bitmask = mask[BIT_WORD(i)] & bits[BIT_WORD(i)];



		spin_lock_irqsave(&dio48egpio->lock, flags);

		raw_spin_lock_irqsave(&dio48egpio->lock, flags);



		/* update output state data and set device gpio register */

		dio48egpio->out_state[port] &= ~mask[BIT_WORD(i)];

		dio48egpio->out_state[port] |= bitmask;

		outb(dio48egpio->out_state[port], dio48egpio->base + out_port);



		spin_unlock_irqrestore(&dio48egpio->lock, flags);

		raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);



		/* prepare for next gpio register set */

		mask[BIT_WORD(i)] >>= gpio_reg_size;
@@ -255,7 +255,7 @@ static void dio48e_irq_mask(struct irq_data *data) 
	if (offset != 19 && offset != 43)

		return;



	spin_lock_irqsave(&dio48egpio->lock, flags);

	raw_spin_lock_irqsave(&dio48egpio->lock, flags);



	if (offset == 19)

		dio48egpio->irq_mask &= ~BIT(0);
@@ -266,7 +266,7 @@ static void dio48e_irq_mask(struct irq_data *data) 
		/* disable interrupts */

		inb(dio48egpio->base + 0xB);



	spin_unlock_irqrestore(&dio48egpio->lock, flags);

	raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);

}



static void dio48e_irq_unmask(struct irq_data *data)
@@ -280,7 +280,7 @@ static void dio48e_irq_unmask(struct irq_data *data) 
	if (offset != 19 && offset != 43)

		return;



	spin_lock_irqsave(&dio48egpio->lock, flags);

	raw_spin_lock_irqsave(&dio48egpio->lock, flags);



	if (!dio48egpio->irq_mask) {

		/* enable interrupts */
@@ -293,7 +293,7 @@ static void dio48e_irq_unmask(struct irq_data *data) 
	else

		dio48egpio->irq_mask |= BIT(1);



	spin_unlock_irqrestore(&dio48egpio->lock, flags);

	raw_spin_unlock_irqrestore(&dio48egpio->lock, flags);

}



static int dio48e_irq_set_type(struct irq_data *data, unsigned flow_type)
@@ -329,11 +329,11 @@ static irqreturn_t dio48e_irq_handler(int irq, void *dev_id) 
		generic_handle_irq(irq_find_mapping(chip->irqdomain,

			19 + gpio*24));



	spin_lock(&dio48egpio->lock);

	raw_spin_lock(&dio48egpio->lock);



	outb(0x00, dio48egpio->base + 0xF);



	spin_unlock(&dio48egpio->lock);

	raw_spin_unlock(&dio48egpio->lock);



	return IRQ_HANDLED;

}
@@ -388,7 +388,7 @@ static int dio48e_probe(struct device *dev, unsigned int id) 
	dio48egpio->chip.set_multiple = dio48e_gpio_set_multiple;

	dio48egpio->base = base[id];



	spin_lock_init(&dio48egpio->lock);

	raw_spin_lock_init(&dio48egpio->lock);



	err = devm_gpiochip_add_data(dev, &dio48egpio->chip, dio48egpio);

	if (err) {

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