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gpiochip_reserve()
Add a new function gpiochip_reserve() to reserve ranges of gpios that platform code has pre-allocated. That is, this marks gpio numbers which will be claimed by drivers that haven't yet been loaded, and thus are not available for dynamic gpio number allocation. [akpm@linux-foundation.org: remove unneeded __must_check] [david-b@pacbell.net: don't export gpiochip_reserve (section fix)] Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -43,6 +43,7 @@ struct gpio_desc {
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/* flag symbols are bit numbers */
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/* flag symbols are bit numbers */
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#define FLAG_REQUESTED 0
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#define FLAG_REQUESTED 0
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#define FLAG_IS_OUT 1
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#define FLAG_IS_OUT 1
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#define FLAG_RESERVED 2
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#ifdef CONFIG_DEBUG_FS
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#ifdef CONFIG_DEBUG_FS
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const char *label;
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const char *label;
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@ -88,9 +89,10 @@ static int gpiochip_find_base(int ngpio)
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int base = -ENOSPC;
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int base = -ENOSPC;
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for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
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for (i = ARCH_NR_GPIOS - 1; i >= 0 ; i--) {
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struct gpio_chip *chip = gpio_desc[i].chip;
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struct gpio_desc *desc = &gpio_desc[i];
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struct gpio_chip *chip = desc->chip;
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if (!chip) {
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if (!chip && !test_bit(FLAG_RESERVED, &desc->flags)) {
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spare++;
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spare++;
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if (spare == ngpio) {
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if (spare == ngpio) {
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base = i;
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base = i;
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@ -98,7 +100,8 @@ static int gpiochip_find_base(int ngpio)
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}
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}
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} else {
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} else {
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spare = 0;
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spare = 0;
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i -= chip->ngpio - 1;
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if (chip)
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i -= chip->ngpio - 1;
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}
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}
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}
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}
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@ -107,6 +110,47 @@ static int gpiochip_find_base(int ngpio)
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return base;
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return base;
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}
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}
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/**
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* gpiochip_reserve() - reserve range of gpios to use with platform code only
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* @start: starting gpio number
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* @ngpio: number of gpios to reserve
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* Context: platform init, potentially before irqs or kmalloc will work
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*
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* Returns a negative errno if any gpio within the range is already reserved
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* or registered, else returns zero as a success code. Use this function
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* to mark a range of gpios as unavailable for dynamic gpio number allocation,
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* for example because its driver support is not yet loaded.
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*/
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int __init gpiochip_reserve(int start, int ngpio)
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{
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int ret = 0;
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unsigned long flags;
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int i;
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if (!gpio_is_valid(start) || !gpio_is_valid(start + ngpio))
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return -EINVAL;
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spin_lock_irqsave(&gpio_lock, flags);
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for (i = start; i < start + ngpio; i++) {
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struct gpio_desc *desc = &gpio_desc[i];
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if (desc->chip || test_bit(FLAG_RESERVED, &desc->flags)) {
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ret = -EBUSY;
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goto err;
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}
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set_bit(FLAG_RESERVED, &desc->flags);
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}
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pr_debug("%s: reserved gpios from %d to %d\n",
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__func__, start, start + ngpio - 1);
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err:
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spin_unlock_irqrestore(&gpio_lock, flags);
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return ret;
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}
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/**
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/**
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* gpiochip_add() - register a gpio_chip
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* gpiochip_add() - register a gpio_chip
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* @chip: the chip to register, with chip->base initialized
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* @chip: the chip to register, with chip->base initialized
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@ -74,6 +74,7 @@ struct gpio_chip {
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extern const char *gpiochip_is_requested(struct gpio_chip *chip,
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extern const char *gpiochip_is_requested(struct gpio_chip *chip,
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unsigned offset);
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unsigned offset);
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extern int __init __must_check gpiochip_reserve(int start, int ngpio);
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/* add/remove chips */
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/* add/remove chips */
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extern int gpiochip_add(struct gpio_chip *chip);
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extern int gpiochip_add(struct gpio_chip *chip);
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