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Date: Thu, 9 Mar 2017 10:21:57 -0600
From: Julia Cartwright <julia@...com>
To: William Breathitt Gray <vilhelm.gray@...il.com>,
Linus Walleij <linus.walleij@...aro.org>,
Alexandre Courbot <gnurou@...il.com>
CC: <linux-kernel@...r.kernel.org>,
Thomas Gleixner <tglx@...utronix.de>,
<linux-gpio@...r.kernel.org>
Subject: [PATCH 10/19] gpio: ws16c48: make use of raw_spinlock variants
The ws16c48 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@...com>
---
drivers/gpio/gpio-ws16c48.c | 46 ++++++++++++++++++++++-----------------------
1 file changed, 23 insertions(+), 23 deletions(-)
diff --git a/drivers/gpio/gpio-ws16c48.c b/drivers/gpio/gpio-ws16c48.c
index 901b5ccb032d..87d63695dfcf 100644
--- a/drivers/gpio/gpio-ws16c48.c
+++ b/drivers/gpio/gpio-ws16c48.c
@@ -51,7 +51,7 @@ struct ws16c48_gpio {
struct gpio_chip chip;
unsigned char io_state[6];
unsigned char out_state[6];
- spinlock_t lock;
+ raw_spinlock_t lock;
unsigned long irq_mask;
unsigned long flow_mask;
unsigned base;
@@ -73,13 +73,13 @@ static int ws16c48_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
const unsigned mask = BIT(offset % 8);
unsigned long flags;
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->io_state[port] |= mask;
ws16c48gpio->out_state[port] &= ~mask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return 0;
}
@@ -92,7 +92,7 @@ static int ws16c48_gpio_direction_output(struct gpio_chip *chip,
const unsigned mask = BIT(offset % 8);
unsigned long flags;
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->io_state[port] &= ~mask;
if (value)
@@ -101,7 +101,7 @@ static int ws16c48_gpio_direction_output(struct gpio_chip *chip,
ws16c48gpio->out_state[port] &= ~mask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return 0;
}
@@ -114,17 +114,17 @@ static int ws16c48_gpio_get(struct gpio_chip *chip, unsigned offset)
unsigned long flags;
unsigned port_state;
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* ensure that GPIO is set for input */
if (!(ws16c48gpio->io_state[port] & mask)) {
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return -EINVAL;
}
port_state = inb(ws16c48gpio->base + port);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return !!(port_state & mask);
}
@@ -136,11 +136,11 @@ static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
const unsigned mask = BIT(offset % 8);
unsigned long flags;
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* ensure that GPIO is set for output */
if (ws16c48gpio->io_state[port] & mask) {
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return;
}
@@ -150,7 +150,7 @@ static void ws16c48_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
ws16c48gpio->out_state[port] &= ~mask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
@@ -178,14 +178,14 @@ static void ws16c48_gpio_set_multiple(struct gpio_chip *chip,
iomask = mask[BIT_WORD(i)] & ~ws16c48gpio->io_state[port];
bitmask = iomask & bits[BIT_WORD(i)];
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
/* update output state data and set device gpio register */
ws16c48gpio->out_state[port] &= ~iomask;
ws16c48gpio->out_state[port] |= bitmask;
outb(ws16c48gpio->out_state[port], ws16c48gpio->base + port);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
/* prepare for next gpio register set */
mask[BIT_WORD(i)] >>= gpio_reg_size;
@@ -207,7 +207,7 @@ static void ws16c48_irq_ack(struct irq_data *data)
if (port > 2)
return;
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
port_state = ws16c48gpio->irq_mask >> (8*port);
@@ -216,7 +216,7 @@ static void ws16c48_irq_ack(struct irq_data *data)
outb(port_state | mask, ws16c48gpio->base + 8 + port);
outb(0xC0, ws16c48gpio->base + 7);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static void ws16c48_irq_mask(struct irq_data *data)
@@ -232,7 +232,7 @@ static void ws16c48_irq_mask(struct irq_data *data)
if (port > 2)
return;
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->irq_mask &= ~mask;
@@ -240,7 +240,7 @@ static void ws16c48_irq_mask(struct irq_data *data)
outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
outb(0xC0, ws16c48gpio->base + 7);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static void ws16c48_irq_unmask(struct irq_data *data)
@@ -256,7 +256,7 @@ static void ws16c48_irq_unmask(struct irq_data *data)
if (port > 2)
return;
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
ws16c48gpio->irq_mask |= mask;
@@ -264,7 +264,7 @@ static void ws16c48_irq_unmask(struct irq_data *data)
outb(ws16c48gpio->irq_mask >> (8*port), ws16c48gpio->base + 8 + port);
outb(0xC0, ws16c48gpio->base + 7);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
}
static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
@@ -280,7 +280,7 @@ static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
if (port > 2)
return -EINVAL;
- spin_lock_irqsave(&ws16c48gpio->lock, flags);
+ raw_spin_lock_irqsave(&ws16c48gpio->lock, flags);
switch (flow_type) {
case IRQ_TYPE_NONE:
@@ -292,7 +292,7 @@ static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
ws16c48gpio->flow_mask &= ~mask;
break;
default:
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return -EINVAL;
}
@@ -300,7 +300,7 @@ static int ws16c48_irq_set_type(struct irq_data *data, unsigned flow_type)
outb(ws16c48gpio->flow_mask >> (8*port), ws16c48gpio->base + 8 + port);
outb(0xC0, ws16c48gpio->base + 7);
- spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
+ raw_spin_unlock_irqrestore(&ws16c48gpio->lock, flags);
return 0;
}
@@ -387,7 +387,7 @@ static int ws16c48_probe(struct device *dev, unsigned int id)
ws16c48gpio->chip.set_multiple = ws16c48_gpio_set_multiple;
ws16c48gpio->base = base[id];
- spin_lock_init(&ws16c48gpio->lock);
+ raw_spin_lock_init(&ws16c48gpio->lock);
err = devm_gpiochip_add_data(dev, &ws16c48gpio->chip, ws16c48gpio);
if (err) {
--
2.11.1
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