From 7cb6580c0b2690e5c6ac1acd9375fa55d72af289 Mon Sep 17 00:00:00 2001
From: Axel Lin <axel.lin@gmail.com>
Date: Sun, 29 Jul 2012 10:55:54 +0800
Subject: [PATCH] gpio: gpio-pch: Use spinlock for register access protection
gpio_chip.can_sleep is 0, but current code uses mutex in pch_gpio_set
pch_gpio_get and pch_gpio_direction_input functions.
Thus those functions are not callable from interrupt context.
This patch converts mutex into spinlock.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/gpio/gpio-pch.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
diff --git a/drivers/gpio/gpio-pch.c b/drivers/gpio/gpio-pch.c
index 139ad3e20011..4ad0c4f9171c 100644
--- a/drivers/gpio/gpio-pch.c
+++ b/drivers/gpio/gpio-pch.c
@@ -92,9 +92,7 @@ struct pch_gpio_reg_data {
* @lock: Used for register access protection
* @irq_base: Save base of IRQ number for interrupt
* @ioh: IOH ID
- * @spinlock: Used for register access protection in
- * interrupt context pch_irq_mask,
- * pch_irq_unmask and pch_irq_type;
+ * @spinlock: Used for register access protection
*/
struct pch_gpio {
void __iomem *base;
@@ -102,7 +100,6 @@ struct pch_gpio {
struct device *dev;
struct gpio_chip gpio;
struct pch_gpio_reg_data pch_gpio_reg;
- struct mutex lock;
int irq_base;
enum pch_type_t ioh;
spinlock_t spinlock;
@@ -112,8 +109,9 @@ static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
{
u32 reg_val;
struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
+ unsigned long flags;
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->spinlock, flags);
reg_val = ioread32(&chip->reg->po);
if (val)
reg_val |= (1 << nr);
@@ -121,7 +119,7 @@ static void pch_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
reg_val &= ~(1 << nr);
iowrite32(reg_val, &chip->reg->po);
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->spinlock, flags);
}
static int pch_gpio_get(struct gpio_chip *gpio, unsigned nr)
@@ -137,8 +135,9 @@ static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
u32 pm;
u32 reg_val;
+ unsigned long flags;
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->spinlock, flags);
pm = ioread32(&chip->reg->pm) & ((1 << gpio_pins[chip->ioh]) - 1);
pm |= (1 << nr);
iowrite32(pm, &chip->reg->pm);
@@ -149,8 +148,7 @@ static int pch_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
else
reg_val &= ~(1 << nr);
iowrite32(reg_val, &chip->reg->po);
-
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->spinlock, flags);
return 0;
}
@@ -159,12 +157,13 @@ static int pch_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
{
struct pch_gpio *chip = container_of(gpio, struct pch_gpio, gpio);
u32 pm;
+ unsigned long flags;
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->spinlock, flags);
pm = ioread32(&chip->reg->pm) & ((1 << gpio_pins[chip->ioh]) - 1);
pm &= ~(1 << nr);
iowrite32(pm, &chip->reg->pm);
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->spinlock, flags);
return 0;
}
@@ -387,7 +386,6 @@ static int __devinit pch_gpio_probe(struct pci_dev *pdev,
chip->reg = chip->base;
pci_set_drvdata(pdev, chip);
- mutex_init(&chip->lock);
spin_lock_init(&chip->spinlock);
pch_gpio_setup(chip);
ret = gpiochip_add(&chip->gpio);
--
2.30.9