iio: sx9500: add power management

Signed-off-by: Vlad Dogaru <vlad.dogaru@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/proximity/sx9500.c

@@ -18,6 +18,7 @@
 #include <linux/acpi.h>
 #include <linux/gpio/consumer.h>
 #include <linux/regmap.h>
+#include <linux/pm.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
@@ -89,6 +90,8 @@ struct sx9500_data {
 	bool event_enabled[SX9500_NUM_CHANNELS];
 	bool trigger_enabled;
 	u16 *buffer;
+	/* Remember enabled channels and sample rate during suspend. */
+	unsigned int suspend_ctrl0;
 };
 
 static const struct iio_event_spec sx9500_events[] = {
@@ -720,6 +723,49 @@ static int sx9500_remove(struct i2c_client *client)
 	return 0;
 }
 
+#ifdef CONFIG_PM_SLEEP
+static int sx9500_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct sx9500_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = regmap_read(data->regmap, SX9500_REG_PROX_CTRL0,
+			  &data->suspend_ctrl0);
+	if (ret < 0)
+		goto out;
+
+	/*
+	 * Scan period doesn't matter because when all the sensors are
+	 * deactivated the device is in sleep mode.
+	 */
+	ret = regmap_write(data->regmap, SX9500_REG_PROX_CTRL0, 0);
+
+out:
+	mutex_unlock(&data->mutex);
+	return ret;
+}
+
+static int sx9500_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
+	struct sx9500_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	ret = regmap_write(data->regmap, SX9500_REG_PROX_CTRL0,
+			   data->suspend_ctrl0);
+	mutex_unlock(&data->mutex);
+
+	return ret;
+}
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops sx9500_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sx9500_suspend, sx9500_resume)
+};
+
 static const struct acpi_device_id sx9500_acpi_match[] = {
 	{"SSX9500", 0},
 	{ },
@@ -736,6 +782,7 @@ static struct i2c_driver sx9500_driver = {
 	.driver = {
 		.name	= SX9500_DRIVER_NAME,
 		.acpi_match_table = ACPI_PTR(sx9500_acpi_match),
+		.pm = &sx9500_pm_ops,
 	},
 	.probe		= sx9500_probe,
 	.remove		= sx9500_remove,