[PATCH] iio: accel: bma400: Ensure VDDIO is enable defore reading the chip ID.

* [PATCH] iio: accel: bma400: Ensure VDDIO is enable defore reading the chip ID.
@ 2022-10-02 14:41 Jonathan Cameron
  2022-10-28 13:07 ` Dan Robertson
  0 siblings, 1 reply; 3+ messages in thread
From: Jonathan Cameron @ 2022-10-02 14:41 UTC (permalink / raw)
  To: linux-iio; +Cc: Jonathan Cameron, Dan Robertson

From: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The regulator enables were after the check on the chip variant, which was
very unlikely to return a correct value when not powered.
Presumably all the device anyone is testing on have a regulator that
is already powered up when this code runs for reasons beyond the scope
of this driver. Move the read call down a few lines.

Fixes: 3cf7ded15e40 ("iio: accel: bma400: basic regulator support")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Dan Robertson <dan@dlrobertson.com>
---
 drivers/iio/accel/bma400_core.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/iio/accel/bma400_core.c b/drivers/iio/accel/bma400_core.c
index e8de88e6cfb9..81bfec9e20cc 100644
--- a/drivers/iio/accel/bma400_core.c
+++ b/drivers/iio/accel/bma400_core.c
@@ -869,18 +869,6 @@ static int bma400_init(struct bma400_data *data)
 	unsigned int val;
 	int ret;
 
-	/* Try to read chip_id register. It must return 0x90. */
-	ret = regmap_read(data->regmap, BMA400_CHIP_ID_REG, &val);
-	if (ret) {
-		dev_err(data->dev, "Failed to read chip id register\n");
-		return ret;
-	}
-
-	if (val != BMA400_ID_REG_VAL) {
-		dev_err(data->dev, "Chip ID mismatch\n");
-		return -ENODEV;
-	}
-
 	data->regulators[BMA400_VDD_REGULATOR].supply = "vdd";
 	data->regulators[BMA400_VDDIO_REGULATOR].supply = "vddio";
 	ret = devm_regulator_bulk_get(data->dev,
@@ -902,6 +890,18 @@ static int bma400_init(struct bma400_data *data)
 	if (ret)
 		return ret;
 
+	/* Try to read chip_id register. It must return 0x90. */
+	ret = regmap_read(data->regmap, BMA400_CHIP_ID_REG, &val);
+	if (ret) {
+		dev_err(data->dev, "Failed to read chip id register\n");
+		return ret;
+	}
+
+	if (val != BMA400_ID_REG_VAL) {
+		dev_err(data->dev, "Chip ID mismatch\n");
+		return -ENODEV;
+	}
+
 	ret = bma400_get_power_mode(data);
 	if (ret) {
 		dev_err(data->dev, "Failed to get the initial power-mode\n");
-- 
2.37.2


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