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Date: Sun, 29 Jul 2012 10:54:42 +0800
From: Axel Lin <axel.lin@...il.com>
To: linux-kernel@...r.kernel.org
Cc: Feng Tang <feng.tang@...el.com>,
Tomoya MORINAGA <tomoya.rohm@...il.com>,
Grant Likely <grant.likely@...retlab.ca>,
Linus Walleij <linus.walleij@...aro.org>
Subject: [PATCH RFT 1/2] gpio: gpio-ml-ioh: Use spinlock for register access
protection
gpio_chip.can_sleep is 0, but current code uses mutex in ioh_gpio_set,
ioh_gpio_get and ioh_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@...il.com>
---
drivers/gpio/gpio-ml-ioh.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/gpio/gpio-ml-ioh.c b/drivers/gpio/gpio-ml-ioh.c
index db01f15..6a29ee1 100644
--- a/drivers/gpio/gpio-ml-ioh.c
+++ b/drivers/gpio/gpio-ml-ioh.c
@@ -87,8 +87,7 @@ struct ioh_gpio_reg_data {
* @gpio_use_sel: Save GPIO_USE_SEL1~4 register for PM
* @ch: Indicate GPIO channel
* @irq_base: Save base of IRQ number for interrupt
- * @spinlock: Used for register access protection in
- * interrupt context ioh_irq_type and PM;
+ * @spinlock: Used for register access protection
*/
struct ioh_gpio {
void __iomem *base;
@@ -97,7 +96,6 @@ struct ioh_gpio {
struct gpio_chip gpio;
struct ioh_gpio_reg_data ioh_gpio_reg;
u32 gpio_use_sel;
- struct mutex lock;
int ch;
int irq_base;
spinlock_t spinlock;
@@ -109,8 +107,9 @@ static void ioh_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
{
u32 reg_val;
struct ioh_gpio *chip = container_of(gpio, struct ioh_gpio, gpio);
+ unsigned long flags;
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->spinlock, flags);
reg_val = ioread32(&chip->reg->regs[chip->ch].po);
if (val)
reg_val |= (1 << nr);
@@ -118,7 +117,7 @@ static void ioh_gpio_set(struct gpio_chip *gpio, unsigned nr, int val)
reg_val &= ~(1 << nr);
iowrite32(reg_val, &chip->reg->regs[chip->ch].po);
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->spinlock, flags);
}
static int ioh_gpio_get(struct gpio_chip *gpio, unsigned nr)
@@ -134,8 +133,9 @@ static int ioh_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
struct ioh_gpio *chip = container_of(gpio, struct ioh_gpio, gpio);
u32 pm;
u32 reg_val;
+ unsigned long flags;
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->spinlock, flags);
pm = ioread32(&chip->reg->regs[chip->ch].pm) &
((1 << num_ports[chip->ch]) - 1);
pm |= (1 << nr);
@@ -148,7 +148,7 @@ static int ioh_gpio_direction_output(struct gpio_chip *gpio, unsigned nr,
reg_val &= ~(1 << nr);
iowrite32(reg_val, &chip->reg->regs[chip->ch].po);
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->spinlock, flags);
return 0;
}
@@ -157,13 +157,14 @@ static int ioh_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
{
struct ioh_gpio *chip = container_of(gpio, struct ioh_gpio, gpio);
u32 pm;
+ unsigned long flags;
- mutex_lock(&chip->lock);
+ spin_lock_irqsave(&chip->spinlock, flags);
pm = ioread32(&chip->reg->regs[chip->ch].pm) &
((1 << num_ports[chip->ch]) - 1);
pm &= ~(1 << nr);
iowrite32(pm, &chip->reg->regs[chip->ch].pm);
- mutex_unlock(&chip->lock);
+ spin_unlock_irqrestore(&chip->spinlock, flags);
return 0;
}
@@ -447,7 +448,6 @@ static int __devinit ioh_gpio_probe(struct pci_dev *pdev,
chip->base = base;
chip->reg = chip->base;
chip->ch = i;
- mutex_init(&chip->lock);
spin_lock_init(&chip->spinlock);
ioh_gpio_setup(chip, num_ports[i]);
ret = gpiochip_add(&chip->gpio);
--
1.7.9.5
--
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