Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6] / drivers / gpio / gpiolib.c

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 2ba6127c4fae5f2c7dcc8af3b39d021cc7a25c95..beaf6b3a37dcefb0b2c1d8c8f79b7db2713dba45 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -43,6 +43,7 @@ struct gpio_desc {
 /* flag symbols are bit numbers */
 #define FLAG_REQUESTED 0
 #define FLAG_IS_OUT    1
+#define FLAG_RESERVED  2
 
 #ifdef CONFIG_DEBUG_FS
        const char              *label;
@@ -88,9 +89,10 @@ static int gpiochip_find_base(int ngpio)
        int base = -ENOSPC;
 
        for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
-               struct gpio_chip *chip = gpio_desc[i].chip;
+               struct gpio_desc *desc = &gpio_desc[i];
+               struct gpio_chip *chip = desc->chip;
 
-               if (!chip) {
+               if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) {
                        spare++;
                        if (spare == ngpio) {
                                base = i;
@@ -98,7 +100,8 @@ static int gpiochip_find_base(int ngpio)
                        }
                } else {
                        spare = 0;
-                       i -= chip->ngpio - 1;
+                       if (chip)
+                               i -= chip->ngpio - 1;
                }
        }
 
@@ -107,6 +110,47 @@ static int gpiochip_find_base(int ngpio)
        return base;
 }
 
+/**
+ * gpiochip_reserve() - reserve range of gpios to use with platform code only
+ * @start: starting gpio number
+ * @ngpio: number of gpios to reserve
+ * Context: platform init, potentially before irqs or kmalloc will work
+ *
+ * Returns a negative errno if any gpio within the range is already reserved
+ * or registered, else returns zero as a success code.  Use this function
+ * to mark a range of gpios as unavailable for dynamic gpio number allocation,
+ * for example because its driver support is not yet loaded.
+ */
+int __init gpiochip_reserve(int start, int ngpio)
+{
+       int ret = 0;
+       unsigned long flags;
+       int i;
+
+       if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio - 1))
+               return -EINVAL;
+
+       spin_lock_irqsave(&gpio_lock, flags);
+
+       for (i = start; i < start + ngpio; i++) {
+               struct gpio_desc *desc = &gpio_desc[i];
+
+               if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) {
+                       ret = -EBUSY;
+                       goto err;
+               }
+
+               set_bit(FLAG_RESERVED, &desc->flags);
+       }
+
+       pr_debug("%s: reserved gpios from %d to %d\n",
+                __func__, start, start + ngpio - 1);
+err:
+       spin_unlock_irqrestore(&gpio_lock, flags);
+
+       return ret;
+}
+
 /**
  * gpiochip_add() - register a gpio_chip
  * @chip: the chip to register, with chip->base initialized
@@ -126,7 +170,7 @@ int gpiochip_add(struct gpio_chip *chip)
        unsigned        id;
        int             base = chip->base;
 
-       if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio))
+       if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
                        && base >= 0) {
                status = -EINVAL;
                goto fail;
@@ -163,7 +207,7 @@ fail:
        /* failures here can mean systems won't boot... */
        if (status)
                pr_err("gpiochip_add: gpios %d..%d (%s) not registered\n",
-                       chip->base, chip->base + chip->ngpio,
+                       chip->base, chip->base + chip->ngpio - 1,
                        chip->label ? : "generic");
        return status;
 }
@@ -338,7 +382,7 @@ fail:
        spin_unlock_irqrestore(&gpio_lock, flags);
        if (status)
                pr_debug("%s: gpio-%d status %d\n",
-                       __FUNCTION__, gpio, status);
+                       __func__, gpio, status);
        return status;
 }
 EXPORT_SYMBOL_GPL(gpio_direction_input);
@@ -376,7 +420,7 @@ fail:
        spin_unlock_irqrestore(&gpio_lock, flags);
        if (status)
                pr_debug("%s: gpio-%d status %d\n",
-                       __FUNCTION__, gpio, status);
+                       __func__, gpio, status);
        return status;
 }
 EXPORT_SYMBOL_GPL(gpio_direction_output);