staging: iio: ad799x: remove some unneeded IS_ERR() checks

My static checker is upset that we check IS_ERR(t->reg) when we know it
is not an ERR_PTR.

Checking for IS_ERR() twice is often a sign of confusion and buggy code.
In this case, if the call to "ret = regulator_enable(st->vref);" fails,
then we call "regulator_disable(st->vref);" and that's a mistake because
"st->vref" is not enabled.

I fixed these problems and Hartmut Knaack pointed out a couple unneeded
IS_ERR() checks in ad799x_remove() so I have removed those as well.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 6 insertions, 9 deletions

diff --git a/drivers/iio/adc/ad799x.c b/drivers/iio/adc/ad799x.c
index 16a8b14b1921..39b4cb48d738 100644
--- a/drivers/iio/adc/ad799x.c
+++ b/drivers/iio/adc/ad799x.c
@@ -717,7 +717,7 @@ static int ad799x_probe(struct i2c_client *client,
         ret = iio_triggered_buffer_setup(indio_dev, NULL,
                 &ad799x_trigger_handler, NULL);
         if (ret)
-                goto error_disable_reg;
+                goto error_disable_vref;
 
         if (client->irq > 0) {
                 ret = devm_request_threaded_irq(&client->dev,
@@ -739,11 +739,10 @@ static int ad799x_probe(struct i2c_client *client,
 
 error_cleanup_ring:
         iio_triggered_buffer_cleanup(indio_dev);
+error_disable_vref:
+        regulator_disable(st->vref);
 error_disable_reg:
-        if (!IS_ERR(st->vref))
-                regulator_disable(st->vref);
-        if (!IS_ERR(st->reg))
-                regulator_disable(st->reg);
+        regulator_disable(st->reg);
 
         return ret;
 }
@@ -756,10 +755,8 @@ static int ad799x_remove(struct i2c_client *client)
         iio_device_unregister(indio_dev);
 
         iio_triggered_buffer_cleanup(indio_dev);
-        if (!IS_ERR(st->vref))
-                regulator_disable(st->vref);
-        if (!IS_ERR(st->reg))
-                regulator_disable(st->reg);
+        regulator_disable(st->vref);
+        regulator_disable(st->reg);
         kfree(st->rx_buf);
 
         return 0;