iio: magnetometer: st_magn: Provide default platform data

Provide default platform data for magnetometer in case it supports DRDY.

One case is LSM9DS0 IMU, on which it is the case. Since accelerometer
is using INT1, default magnetometer to INT2.

While at it, update description of the drdy_int_pin field.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210414195454.84183-3-andriy.shevchenko@linux.intel.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/magnetometer/st_magn_core.c

@@ -383,6 +383,11 @@ static const struct st_sensor_settings st_magn_sensors_settings[] = {
 	},
 };
 
+/* Default magn DRDY is available on INT2 pin */
+static const struct st_sensors_platform_data default_magn_pdata = {
+	.drdy_int_pin = 2,
+};
+
 static int st_magn_read_raw(struct iio_dev *indio_dev,
 			struct iio_chan_spec const *ch, int *val,
 							int *val2, long mask)
@@ -490,6 +495,7 @@ EXPORT_SYMBOL(st_magn_get_settings);
 int st_magn_common_probe(struct iio_dev *indio_dev)
 {
 	struct st_sensor_data *mdata = iio_priv(indio_dev);
+	struct st_sensors_platform_data *pdata = dev_get_platdata(mdata->dev);
 	int err;
 
 	indio_dev->modes = INDIO_DIRECT_MODE;
@@ -510,7 +516,10 @@ int st_magn_common_probe(struct iio_dev *indio_dev)
 	mdata->current_fullscale = &mdata->sensor_settings->fs.fs_avl[0];
 	mdata->odr = mdata->sensor_settings->odr.odr_avl[0].hz;
 
-	err = st_sensors_init_sensor(indio_dev, NULL);
+	if (!pdata)
+		pdata = (struct st_sensors_platform_data *)&default_magn_pdata;
+
+	err = st_sensors_init_sensor(indio_dev, pdata);
 	if (err < 0)
 		goto st_magn_power_off;
 

include/linux/platform_data/st_sensors_pdata.h

@@ -13,8 +13,9 @@
 /**
  * struct st_sensors_platform_data - Platform data for the ST sensors
  * @drdy_int_pin: Redirect DRDY on pin 1 (1) or pin 2 (2).
- *	Available only for accelerometer and pressure sensors.
+ *	Available only for accelerometer, magnetometer and pressure sensors.
  *	Accelerometer DRDY on LSM330 available only on pin 1 (see datasheet).
+ *	Magnetometer DRDY is supported only on LSM9DS0.
  * @open_drain: set the interrupt line to be open drain if possible.
  * @spi_3wire: enable spi-3wire mode.
  * @pullups: enable/disable i2c controller pullup resistors.