/* 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;
if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
pr_warning("GPIO-%d autorequested\n", (int)(desc - gpio_desc));
desc_set_label(desc, "[auto]");
+ if (!try_module_get(desc->chip->owner))
+ pr_err("GPIO-%d: module can't be gotten \n",
+ (int)(desc - gpio_desc));
}
}
return gpio_desc[gpio].chip;
}
+/* dynamic allocation of GPIOs, e.g. on a hotplugged device */
+static int gpiochip_find_base(int ngpio)
+{
+ int i;
+ int spare = 0;
+ int base = -ENOSPC;
+
+ for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
+ struct gpio_desc *desc = &gpio_desc[i];
+ struct gpio_chip *chip = desc->chip;
+
+ if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) {
+ spare++;
+ if (spare == ngpio) {
+ base = i;
+ break;
+ }
+ } else {
+ spare = 0;
+ if (chip)
+ i -= chip->ngpio - 1;
+ }
+ }
+
+ if (gpio_is_valid(base))
+ pr_debug("%s: found new base at %d\n", __func__, base);
+ 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
* Returns a negative errno if the chip can't be registered, such as
* because the chip->base is invalid or already associated with a
* different chip. Otherwise it returns zero as a success code.
+ *
+ * If chip->base is negative, this requests dynamic assignment of
+ * a range of valid GPIOs.
*/
int gpiochip_add(struct gpio_chip *chip)
{
unsigned long flags;
int status = 0;
unsigned id;
+ int base = chip->base;
- /* NOTE chip->base negative is reserved to mean a request for
- * dynamic allocation. We don't currently support that.
- */
-
- if (chip->base < 0 || (chip->base + chip->ngpio) >= ARCH_NR_GPIOS) {
+ if ((!gpio_is_valid(base) || !gpio_is_valid(base + chip->ngpio - 1))
+ && base >= 0) {
status = -EINVAL;
goto fail;
}
spin_lock_irqsave(&gpio_lock, flags);
+ if (base < 0) {
+ base = gpiochip_find_base(chip->ngpio);
+ if (base < 0) {
+ status = base;
+ goto fail_unlock;
+ }
+ chip->base = base;
+ }
+
/* these GPIO numbers must not be managed by another gpio_chip */
- for (id = chip->base; id < chip->base + chip->ngpio; id++) {
+ for (id = base; id < base + chip->ngpio; id++) {
if (gpio_desc[id].chip != NULL) {
status = -EBUSY;
break;
}
}
if (status == 0) {
- for (id = chip->base; id < chip->base + chip->ngpio; id++) {
+ for (id = base; id < base + chip->ngpio; id++) {
gpio_desc[id].chip = chip;
gpio_desc[id].flags = 0;
}
}
+fail_unlock:
spin_unlock_irqrestore(&gpio_lock, flags);
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;
}
spin_lock_irqsave(&gpio_lock, flags);
- if (gpio >= ARCH_NR_GPIOS)
+ if (!gpio_is_valid(gpio))
goto done;
desc = &gpio_desc[gpio];
if (desc->chip == NULL)
goto done;
+ if (!try_module_get(desc->chip->owner))
+ goto done;
+
/* NOTE: gpio_request() can be called in early boot,
* before IRQs are enabled.
*/
if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
desc_set_label(desc, label ? : "?");
status = 0;
- } else
+ } else {
status = -EBUSY;
+ module_put(desc->chip->owner);
+ }
done:
if (status)
unsigned long flags;
struct gpio_desc *desc;
- if (gpio >= ARCH_NR_GPIOS) {
+ if (!gpio_is_valid(gpio)) {
WARN_ON(extra_checks);
return;
}
spin_lock_irqsave(&gpio_lock, flags);
desc = &gpio_desc[gpio];
- if (desc->chip && test_and_clear_bit(FLAG_REQUESTED, &desc->flags))
+ if (desc->chip && test_and_clear_bit(FLAG_REQUESTED, &desc->flags)) {
desc_set_label(desc, NULL);
- else
+ module_put(desc->chip->owner);
+ } else
WARN_ON(extra_checks);
spin_unlock_irqrestore(&gpio_lock, flags);
{
unsigned gpio = chip->base + offset;
- if (gpio >= ARCH_NR_GPIOS || gpio_desc[gpio].chip != chip)
+ if (!gpio_is_valid(gpio) || gpio_desc[gpio].chip != chip)
return NULL;
if (test_bit(FLAG_REQUESTED, &gpio_desc[gpio].flags) == 0)
return NULL;
spin_lock_irqsave(&gpio_lock, flags);
- if (gpio >= ARCH_NR_GPIOS)
+ if (!gpio_is_valid(gpio))
goto fail;
chip = desc->chip;
if (!chip || !chip->get || !chip->direction_input)
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);
spin_lock_irqsave(&gpio_lock, flags);
- if (gpio >= ARCH_NR_GPIOS)
+ if (!gpio_is_valid(gpio))
goto fail;
chip = desc->chip;
if (!chip || !chip->set || !chip->direction_output)
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);
/* REVISIT this isn't locked against gpio_chip removal ... */
- for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
+ for (gpio = 0; gpio_is_valid(gpio); gpio++) {
if (chip == gpio_desc[gpio].chip)
continue;
chip = gpio_desc[gpio].chip;
projects / linux-2.6-omap-h63xx.git / blobdiff