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>

diff --git a/drivers/gpio/gpio-pch.c b/drivers/gpio/gpio-pch.c
index 139ad3e..4ad0c4f 100644 (file)
--- 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);