iio: sx9310: Enable vdd and svdd regulators at probe

Enable the main power supply (vdd) and digital IO power supply (svdd)
during probe so that the i2c communication and device works properly on
boards that aggressively power gate these supplies.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Daniel Campello <campello@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/proximity/sx9310.c

@@ -20,6 +20,7 @@
 #include <linux/module.h>
 #include <linux/pm.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 
 #include <linux/iio/buffer.h>
@@ -120,6 +121,7 @@ struct sx9310_data {
 	struct i2c_client *client;
 	struct iio_trigger *trig;
 	struct regmap *regmap;
+	struct regulator_bulk_data supplies[2];
 	/*
 	 * Last reading of the proximity status for each channel.
 	 * We only send an event to user space when this changes.
@@ -874,6 +876,13 @@ static int sx9310_set_indio_dev_name(struct device *dev,
 	return 0;
 }
 
+static void sx9310_regulator_disable(void *_data)
+{
+	struct sx9310_data *data = _data;
+
+	regulator_bulk_disable(ARRAY_SIZE(data->supplies), data->supplies);
+}
+
 static int sx9310_probe(struct i2c_client *client)
 {
 	int ret;
@@ -887,6 +896,8 @@ static int sx9310_probe(struct i2c_client *client)
 
 	data = iio_priv(indio_dev);
 	data->client = client;
+	data->supplies[0].supply = "vdd";
+	data->supplies[1].supply = "svdd";
 	mutex_init(&data->mutex);
 	init_completion(&data->completion);
 
@@ -894,6 +905,21 @@ static int sx9310_probe(struct i2c_client *client)
 	if (IS_ERR(data->regmap))
 		return PTR_ERR(data->regmap);
 
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->supplies),
+				      data->supplies);
+	if (ret)
+		return ret;
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(data->supplies), data->supplies);
+	if (ret)
+		return ret;
+	/* Must wait for Tpor time after initial power up */
+	usleep_range(1000, 1100);
+
+	ret = devm_add_action_or_reset(dev, sx9310_regulator_disable, data);
+	if (ret)
+		return ret;
+
 	ret = regmap_read(data->regmap, SX9310_REG_WHOAMI, &data->whoami);
 	if (ret) {
 		dev_err(dev, "error in reading WHOAMI register: %d", ret);