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gpio: gpio_{request,free}() now required (feature removal)

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We want to phase out the GPIO "autorequest" mechanism in gpiolib and
require all callers to use gpio_request().

 - Update feature-removal-schedule
 - Update the documentation now
 - Convert the relevant pr_warning() in gpiolib to a WARN()
   so folk using this mechanism get a noisy stack dump

Some drivers and board init code will probably need to change.
Implementations not using gpiolib will still be fine; they are already
required to implement gpio_{request,free}() stubs.

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>
This commit is contained in:
David Brownell
2009-04-02 16:57:06 -07:00
committed by Linus Torvalds
parent 926b663ce8
commit 8a0cecffeb
3 changed files with 27 additions and 18 deletions
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12
drivers/gpio/gpiolib.c
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@@ -69,20 +69,24 @@ static inline void desc_set_label(struct gpio_desc *d, const char *label)
* those calls have no teeth) we can't avoid autorequesting. This nag
* message should motivate switching to explicit requests... so should
* the weaker cleanup after faults, compared to gpio_request().
*
* NOTE: the autorequest mechanism is going away; at this point it's
* only "legal" in the sense that (old) code using it won't break yet,
* but instead only triggers a WARN() stack dump.
*/
static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset)
{
if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
struct gpio_chip *chip = desc->chip;
int gpio = chip->base + offset;
const struct gpio_chip *chip = desc->chip;
const int gpio = chip->base + offset;
if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
"autorequest GPIO-%d\n", gpio)) {
if (!try_module_get(chip->owner)) {
pr_err("GPIO-%d: module can't be gotten \n", gpio);
clear_bit(FLAG_REQUESTED, &desc->flags);
/* lose */
return -EIO;
}
pr_warning("GPIO-%d autorequested\n", gpio);
desc_set_label(desc, "[auto]");
/* caller must chip->request() w/o spinlock */
if (chip->request)