iio: magnetometer: rm3100: Stop abusing the ->currentmode

This is an internal variable for the core, here it is set to a "default"
value by the driver in order to later be able to perform checks against
it. None of this is needed because this check actually cares about the
buffers being enabled or not. So it is an unproper side-channel access
to the information "are the buffers enabled?", returned officially by
the iio_buffer_enabled() helper. Use this helper instead.

Cc: Song Qiang <songqiang1304521@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/r/20220207143840.707510-3-miquel.raynal@bootlin.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/magnetometer/rm3100-core.c

@@ -141,18 +141,10 @@ static irqreturn_t rm3100_irq_handler(int irq, void *d)
 	struct iio_dev *indio_dev = d;
 	struct rm3100_data *data = iio_priv(indio_dev);
 
-	switch (indio_dev->currentmode) {
-	case INDIO_DIRECT_MODE:
+	if (!iio_buffer_enabled(indio_dev))
 		complete(&data->measuring_done);
-		break;
-	case INDIO_BUFFER_TRIGGERED:
+	else
 		iio_trigger_poll(data->drdy_trig);
-		break;
-	default:
-		dev_err(indio_dev->dev.parent,
-			"device mode out of control, current mode: %d",
-			indio_dev->currentmode);
-	}
 
 	return IRQ_WAKE_THREAD;
 }
@@ -377,7 +369,7 @@ static int rm3100_set_samp_freq(struct iio_dev *indio_dev, int val, int val2)
 			goto unlock_return;
 	}
 
-	if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+	if (iio_buffer_enabled(indio_dev)) {
 		/* Writing TMRC registers requires CMM reset. */
 		ret = regmap_write(regmap, RM3100_REG_CMM, 0);
 		if (ret < 0)
@@ -553,7 +545,6 @@ int rm3100_common_probe(struct device *dev, struct regmap *regmap, int irq)
 	indio_dev->channels = rm3100_channels;
 	indio_dev->num_channels = ARRAY_SIZE(rm3100_channels);
 	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_TRIGGERED;
-	indio_dev->currentmode = INDIO_DIRECT_MODE;
 
 	if (!irq)
 		data->use_interrupt = false;