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gpio: flush direction status in gpiochip_lock_as_irq()

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As irqchip and gpiochip functions are orthogonal, the IRQ
set-up or something else can have changed the direction of
the GPIO line from what the GPIO descriptor knows when we
get into gpiochip_lock_as_irq(). Make sure to re-read the
direction setting if we have the .get_direction() callback
enabled for the chip.

Else we get problems like this:

iio iio:device2: interrupts on the rising edge
gpio gpiochip2: (8012e080.gpio): gpiochip_lock_as_irq:
  tried to flag a GPIO set as output for IRQ
gpio gpiochip2: (8012e080.gpio): unable to lock HW IRQ 0 for IRQ
genirq: Failed to request resources for l3g4200d-trigger
  (irq 111) on irqchip nmk1-32-63
iio iio:device2: failed to request trigger IRQ.
st-gyro-i2c: probe of 2-0068 failed with error -22

Fixes: 72d320006177 ("gpio: set up initial state from .get_direction()")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij 2016-05-25 10:56:03 +02:00
parent 320a6480ef
commit 9c10280d85
1 changed files with 17 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/gpio/gpiolib.c
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@ -2066,17 +2066,30 @@ EXPORT_SYMBOL_GPL(gpiod_to_irq);
*/
int gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
{
if (offset >= chip->ngpio)
return -EINVAL;
struct gpio_desc *desc;
if (test_bit(FLAG_IS_OUT, &chip->gpiodev->descs[offset].flags)) {
desc = gpiochip_get_desc(chip, offset);
if (IS_ERR(desc))
return PTR_ERR(desc);
/* Flush direction if something changed behind our back */
if (chip->get_direction) {
int dir = chip->get_direction(chip, offset);
if (dir)
clear_bit(FLAG_IS_OUT, &desc->flags);
else
set_bit(FLAG_IS_OUT, &desc->flags);
}
if (test_bit(FLAG_IS_OUT, &desc->flags)) {
chip_err(chip,
"%s: tried to flag a GPIO set as output for IRQ\n",
__func__);
return -EIO;
}
set_bit(FLAG_USED_AS_IRQ, &chip->gpiodev->descs[offset].flags);
set_bit(FLAG_USED_AS_IRQ, &desc->flags);
return 0;
}
EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq);