st_pressure: lps22: unused default data

[Michael Nosthoff <posted@heine.so>]

Hi,

I have an LPS22 sensor which i used sucessfully with Kernel 4.9. Upon
switching to 4.14 it was not loading properly anymore. This failure
occured:

[    3.827094] iio iio:device1: DRDY on pdata not valid.
[    3.832578] st-press-i2c: probe of 0-005c failed with error -22

So I started digging. It started working again when I add this entry
to my devicetree:

st,drdy-int-pin = <1>;

So it seems the default value seems to be not set in 4.14 but was in 4.9

I came to the conclusion that the problem happens in
drivers/iio/pressure/st_pressure_core.c in

st_press_common_probe:


struct st_sensors_platform_data *pdata =
	(struct st_sensors_platform_data *)press_data->dev->platform_data;
...
if (!pdata && press_data->sensor_settings->drdy_irq.addr)
	pdata =	(struct st_sensors_platform_data *)&default_press_pdata;

err = st_sensors_init_sensor(indio_dev, press_data->dev->platform_data);


If pdata is not set (which is correct in my case) it gets assigned a
default value. But in the call to st_sensors_init_sensor it's still
using the data stored in press_data.

Okay, simple solution would be to pass pdata here as well. But I'm a
bit confused about the commit [1] which introduced this. pdata is not
used anymore in this function, so it seems completely useless to set it
there. And so I don't understand what the commit tries to achieve at all
besides never using the default data.

Any Ideas?

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/iio/pressure/st_pressure_core.c?id=7383d44b84c94aaca4bf695a6bd8a69f2295ef1a
-- 
Regards,
Michael