iio: accel: kxcjk1013: Add rudimentary regulator support

kxcjk1013 devices have VDD and VDDIO power lines. Need
to make sure the regulators are enabled before any
communication with kxcjk1013. This patch introduces
vdd/vddio regulators for kxcjk1013.
Signed-off-by: Devajith V S <devajithvs@gmail.com>
Link: https://lore.kernel.org/r/20201213172437.2779-2-devajithvs@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/accel/kxcjk-1013.c

@@ -14,6 +14,7 @@
 #include <linux/acpi.h>
 #include <linux/pm.h>
 #include <linux/pm_runtime.h>
+#include <linux/regulator/consumer.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/buffer.h>
@@ -133,6 +134,7 @@ enum kx_acpi_type {
 };
 
 struct kxcjk1013_data {
+	struct regulator_bulk_data regulators[2];
 	struct i2c_client *client;
 	struct iio_trigger *dready_trig;
 	struct iio_trigger *motion_trig;
@@ -1300,6 +1302,13 @@ static const char *kxcjk1013_match_acpi_device(struct device *dev,
 	return dev_name(dev);
 }
 
+static void kxcjk1013_disable_regulators(void *d)
+{
+	struct kxcjk1013_data *data = d;
+
+	regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
+}
+
 static int kxcjk1013_probe(struct i2c_client *client,
 			   const struct i2c_device_id *id)
 {
@@ -1330,6 +1339,29 @@ static int kxcjk1013_probe(struct i2c_client *client,
 			return ret;
 	}
 
+	data->regulators[0].supply = "vdd";
+	data->regulators[1].supply = "vddio";
+	ret = devm_regulator_bulk_get(&client->dev, ARRAY_SIZE(data->regulators),
+				      data->regulators);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "Failed to get regulators\n");
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(data->regulators),
+				    data->regulators);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(&client->dev, kxcjk1013_disable_regulators, data);
+	if (ret)
+		return ret;
+
+	/*
+	 * A typical delay of 10ms is required for powering up
+	 * according to the data sheets of supported chips.
+	 * Hence double that to play safe.
+	 */
+	msleep(20);
+
 	if (id) {
 		data->chipset = (enum kx_chipset)(id->driver_data);
 		name = id->name;