Davinci: gpio - fine grained locking

This patch eliminates the global gpio_lock, and implements a per-controller
lock instead.  This also switches to irqsave/irqrestore locks in case gpios
are manipulated in isr.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Tested-by: Sandeep Paulraj <s-paulraj@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

2 files changed, 8 insertions, 4 deletions

diff --git a/arch/arm/mach-davinci/gpio.c b/arch/arm/mach-davinci/gpio.c
index e422cd300d4c..b62d5e2bd37e 100644
--- a/arch/arm/mach-davinci/gpio.c
+++ b/arch/arm/mach-davinci/gpio.c
@@ -33,8 +33,6 @@ struct davinci_gpio_regs {
         u32     intstat;
 };
 
-static DEFINE_SPINLOCK(gpio_lock);
-
 #define chip2controller(chip)   \
         container_of(chip, struct davinci_gpio_controller, chip)
 
@@ -83,10 +81,11 @@ static inline int __davinci_direction(struct gpio_chip *chip,
 {
         struct davinci_gpio_controller *d = chip2controller(chip);
         struct davinci_gpio_regs __iomem *g = d->regs;
+        unsigned long flags;
         u32 temp;
         u32 mask = 1 << offset;
 
-        spin_lock(&gpio_lock);
+        spin_lock_irqsave(&d->lock, flags);
         temp = __raw_readl(&g->dir);
         if (out) {
                 temp &= ~mask;
@@ -95,7 +94,7 @@ static inline int __davinci_direction(struct gpio_chip *chip,
                 temp |= mask;
         }
         __raw_writel(temp, &g->dir);
-        spin_unlock(&gpio_lock);
+        spin_unlock_irqrestore(&d->lock, flags);
 
         return 0;
 }
@@ -175,6 +174,8 @@ static int __init davinci_gpio_setup(void)
                 if (chips[i].chip.ngpio > 32)
                         chips[i].chip.ngpio = 32;
 
+                spin_lock_init(&chips[i].lock);
+
                 regs = gpio2regs(base);
                 chips[i].regs = regs;
                 chips[i].set_data = &regs->set_data;
diff --git a/arch/arm/mach-davinci/include/mach/gpio.h b/arch/arm/mach-davinci/include/mach/gpio.h
index 9a71a26eb77f..504cc180a60b 100644
--- a/arch/arm/mach-davinci/include/mach/gpio.h
+++ b/arch/arm/mach-davinci/include/mach/gpio.h
@@ -14,6 +14,8 @@
 #define __DAVINCI_GPIO_H
 
 #include <linux/io.h>
+#include <linux/spinlock.h>
+
 #include <asm-generic/gpio.h>
 
 #include <mach/irqs.h>
@@ -52,6 +54,7 @@ enum davinci_gpio_type {
 struct davinci_gpio_controller {
         struct gpio_chip        chip;
         int                     irq_base;
+        spinlock_t              lock;
         void __iomem            *regs;
         void __iomem            *set_data;
         void __iomem            *clr_data;