[v2,0/2] fix fwnode_irq_get_byname() returnvalue

Message

Matti Vaittinen Oct. 25, 2022, 3:11 p.m. UTC

The fix fwnode_irq_get_byname() may have returned zero if mapping the
IRQ fails. This contradicts the documentation. Furthermore, returning
zero or errno on error is unepected and can easily lead to problems
like:

int probe(foo)
{
...
	ret = fwnode_irq_get_byname(...);
	if (ret < 0)
		return ret;
...
}

or

int probe(foo)
{
...
	ret = fwnode_irq_get_byname(...);
	if (ret <= 0)
		return ret;
...
}

which are both likely to be wrong. First treats zero as successful call and
misses the IRQ mapping failure. Second returns zero from probe even though
it detects the IRQ mapping failure correvtly.

Here we change the fwnode_irq_get_byname() to always return a negative
errno upon failure. I have also audited following callers:

drivers/i2c/i2c-smbus.c
drivers/iio/accel/adxl355_core.c
drivers/iio/gyro/fxas21002c_core.c
drivers/iio/imu/adis16480.c
drivers/iio/imu/bmi160/bmi160_core.c
drivers/iio/imu/bmi160/bmi160_core.c

and it seems to me these calls will be Ok after the change. The
i2c-smbus.c will gain a functional change (bugfix?) as after this patch
the probe will return -EINVAL should the IRQ mapping fail. The series
will also adjust the return value check for zero to be omitted.

Changelog v1 => v2:
 - minor styling

---

Matti Vaittinen (2):
  drivers: fwnode: fix fwnode_irq_get_byname()
  i2c: i2c-smbus: fwnode_irq_get_byname() return value fix

 drivers/base/property.c | 9 +++++++--
 drivers/i2c/i2c-smbus.c | 2 +-
 2 files changed, 8 insertions(+), 3 deletions(-)


base-commit: 247f34f7b80357943234f93f247a1ae6b6c3a740