[PATCH v2] iio: adc: ti-ads1015: fix conversion when CONFIG_PM is not set

[Maxim Kochetkov <fido_max@xxxxxxxx>]

To stop conversion ads1015_set_power_state function call unimplemented
function __pm_runtime_suspend from pm_runtime_put_autosuspend
if CONFIG_PM is not set.
In case of CONFIG_PM is not set:

static inline int __pm_runtime_suspend(struct device *dev, int rpmflags)
{
	return -ENOSYS;
}

so ads1015_read_raw failed at:
		ret = ads1015_set_power_state(data, false);
		if (ret < 0)
			goto release_direct;

If CONFIG_PM is disabled, there is no need to start/stop conversion.
Fix it by adding return 0 function variant if CONFIG_PM is not set.

Signed-off-by: Maxim Kochetkov <fido_max@xxxxxxxx>
Tested-by: Maxim Kiselev <bigunclemax@xxxxxxxxx>
---
 drivers/iio/adc/ti-ads1015.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/iio/adc/ti-ads1015.c b/drivers/iio/adc/ti-ads1015.c
index 5ea4f45d6bad..64fe3b2a6ec6 100644
--- a/drivers/iio/adc/ti-ads1015.c
+++ b/drivers/iio/adc/ti-ads1015.c
@@ -316,6 +316,7 @@ static const struct iio_chan_spec ads1115_channels[] = {
 	IIO_CHAN_SOFT_TIMESTAMP(ADS1015_TIMESTAMP),
 };
 
+#ifdef CONFIG_PM
 static int ads1015_set_power_state(struct ads1015_data *data, bool on)
 {
 	int ret;
@@ -333,6 +334,15 @@ static int ads1015_set_power_state(struct ads1015_data *data, bool on)
 	return ret < 0 ? ret : 0;
 }
 
+#else /* !CONFIG_PM */
+
+static int ads1015_set_power_state(struct ads1015_data *data, bool on)
+{
+	return 0;
+}
+
+#endif /* !CONFIG_PM */
+
 static
 int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val)
 {
-- 
2.27.0