A-Team_Digital_Solutions/android_kernel_motorola_sm6375
Watch
2
0
Fork
You've already forked android_kernel_motorola_sm6375
 0
mirror of https://github.com/BobTheBlinker/android_kernel_motorola_sm6375.git synced 2026-10-29 19:21:31 -04:00
Code Issues Projects Releases Packages Wiki Activity

gpiochip_reserve()

Browse source 
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.

[[email protected]: remove unneeded __must_check]
[[email protected]: don't export gpiochip_reserve (section fix)]
Signed-off-by: Anton Vorontsov <[email protected]>
Signed-off-by: David Brownell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Anton Vorontsov 2008-04-28 02:14:47 -07:00 • committed by Linus Torvalds
commit 169b6a7a6e
2 changed files with 48 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

50
drivers/gpio/gpiolib.c
View file

@ -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))
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