iio: imu: bmi160: added regulator support

Add vdd-supply and vddio-supply support.

While working on an msm8916 device and having explicit declarations for
regulators, without setting these regulators to regulators-always-on it
happened those lines weren't ready because they could have been controlled
by other components, causing failure in module's probe.

This patch aim is to solve this situation by adding regulators control
during bmi160_chip_init() and bmi160_chip_uninit(), assuring power to
this component.
Signed-off-by: Jonathan Albrieux <jonathan.albrieux@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/bmi160/bmi160.h

@@ -3,10 +3,12 @@
 #define BMI160_H_
 
 #include <linux/iio/iio.h>
+#include <linux/regulator/consumer.h>
 
 struct bmi160_data {
 	struct regmap *regmap;
 	struct iio_trigger *trig;
+	struct regulator_bulk_data supplies[2];
 };
 
 extern const struct regmap_config bmi160_regmap_config;

drivers/iio/imu/bmi160/bmi160_core.c

@@ -15,6 +15,7 @@
 #include <linux/delay.h>
 #include <linux/irq.h>
 #include <linux/of_irq.h>
+#include <linux/regulator/consumer.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/triggered_buffer.h>
@@ -709,6 +710,12 @@ static int bmi160_chip_init(struct bmi160_data *data, bool use_spi)
 	unsigned int val;
 	struct device *dev = regmap_get_device(data->regmap);
 
+	ret = regulator_bulk_enable(ARRAY_SIZE(data->supplies), data->supplies);
+	if (ret) {
+		dev_err(dev, "Failed to enable regulators: %d\n", ret);
+		return ret;
+	}
+
 	ret = regmap_write(data->regmap, BMI160_REG_CMD, BMI160_CMD_SOFTRESET);
 	if (ret)
 		return ret;
@@ -793,9 +800,16 @@ int bmi160_probe_trigger(struct iio_dev *indio_dev, int irq, u32 irq_type)
 static void bmi160_chip_uninit(void *data)
 {
 	struct bmi160_data *bmi_data = data;
+	struct device *dev = regmap_get_device(bmi_data->regmap);
+	int ret;
 
 	bmi160_set_mode(bmi_data, BMI160_GYRO, false);
 	bmi160_set_mode(bmi_data, BMI160_ACCEL, false);
+
+	ret = regulator_bulk_disable(ARRAY_SIZE(bmi_data->supplies),
+				     bmi_data->supplies);
+	if (ret)
+		dev_err(dev, "Failed to disable regulators: %d\n", ret);
 }
 
 int bmi160_core_probe(struct device *dev, struct regmap *regmap,
@@ -815,6 +829,16 @@ int bmi160_core_probe(struct device *dev, struct regmap *regmap,
 	dev_set_drvdata(dev, indio_dev);
 	data->regmap = regmap;
 
+	data->supplies[0].supply = "vdd";
+	data->supplies[1].supply = "vddio";
+	ret = devm_regulator_bulk_get(dev,
+				      ARRAY_SIZE(data->supplies),
+				      data->supplies);
+	if (ret) {
+		dev_err(dev, "Failed to get regulators: %d\n", ret);
+		return ret;
+	}
+
 	ret = bmi160_chip_init(data, use_spi);
 	if (ret)
 		return ret;