staging: iio: adc: ad7280a: power down the device on error in probe

Power down the device if anything goes wrong after the SPI has been
setup correctly in the probe function.

Existing code that toggles the AD7280A_CTRL_LB_SWRST bit inside
ad7280_chain_setup function is responsible for powering up the device.
Signed-off-by: Slawomir Stepien <sst@poczta.fm>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/adc/ad7280a.c

@@ -350,29 +350,38 @@ static int ad7280_chain_setup(struct ad7280_state *st)
 			   AD7280A_CTRL_LB_MUST_SET |
 			   st->ctrl_lb);
 	if (ret)
-		return ret;
+		goto error_power_down;
 
 	ret = ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_READ, 1,
 			   AD7280A_CONTROL_LB << 2);
 	if (ret)
-		return ret;
+		goto error_power_down;
 
 	for (n = 0; n <= AD7280A_MAX_CHAIN; n++) {
 		ret = __ad7280_read32(st, &val);
 		if (ret)
-			return ret;
+			goto error_power_down;
 
 		if (val == 0)
 			return n - 1;
 
-		if (ad7280_check_crc(st, val))
-			return -EIO;
+		if (ad7280_check_crc(st, val)) {
+			ret = -EIO;
+			goto error_power_down;
+		}
 
-		if (n != ad7280a_devaddr(val >> 27))
-			return -EIO;
+		if (n != ad7280a_devaddr(val >> 27)) {
+			ret = -EIO;
+			goto error_power_down;
 		}
+	}
+	ret = -EFAULT;
 
-	return -EFAULT;
+error_power_down:
+	ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CONTROL_HB, 1,
+		     AD7280A_CTRL_HB_PWRDN_SW | st->ctrl_hb);
+
+	return ret;
 }
 
 static ssize_t ad7280_show_balance_sw(struct device *dev,
@@ -892,7 +901,7 @@ static int ad7280_probe(struct spi_device *spi)
 
 	ret = ad7280_channel_init(st);
 	if (ret < 0)
-		return ret;
+		goto error_power_down;
 
 	indio_dev->num_channels = ret;
 	indio_dev->channels = st->channels;
@@ -941,6 +950,9 @@ static int ad7280_probe(struct spi_device *spi)
 error_free_channels:
 	kfree(st->channels);
 
+error_power_down:
+	ad7280_write(st, AD7280A_DEVADDR_MASTER, AD7280A_CONTROL_HB, 1,
+		     AD7280A_CTRL_HB_PWRDN_SW | st->ctrl_hb);
 	return ret;
 }