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@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpio-ml-ioh.c b/drivers/gpio/gpio-ml-ioh.c
index db01f15..6a29ee1 100644 (file)
--- 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);