Since the pwm was introduced before backend, there was a mock use, with
a GPIO emulation. Now that iio backend is introduced, the mock use can
be removed.

Signed-off-by: Guillaume Stols <gstols@baylibre.com>
---
 drivers/iio/adc/ad7606.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
index d86eb7c3e4f7..7d02aad45242 100644
--- a/drivers/iio/adc/ad7606.c
+++ b/drivers/iio/adc/ad7606.c
@@ -473,8 +473,6 @@ static int ad7606_pwm_set_high(struct ad7606_state *st)
 	cnvst_pwm_state.duty_cycle = cnvst_pwm_state.period;
 
 	ret = pwm_apply_might_sleep(st->cnvst_pwm, &cnvst_pwm_state);
-	/* sleep 2 µS to let finish the current pulse */
-	fleep(2)
 
 	return ret;
 }
@@ -492,8 +490,6 @@ static int ad7606_pwm_set_low(struct ad7606_state *st)
 	cnvst_pwm_state.duty_cycle = 0;
 
 	ret = pwm_apply_might_sleep(st->cnvst_pwm, &cnvst_pwm_state);
-	/* sleep 2 µS to let finish the current pulse */
-	fleep(2)
 
 	return ret;
 }
@@ -576,7 +572,6 @@ static irqreturn_t ad7606_trigger_handler(int irq, void *p)
 	iio_trigger_notify_done(indio_dev->trig);
 	/* The rising edge of the CONVST signal starts a new conversion. */
 	gpiod_set_value(st->gpio_convst, 1);
-	ad7606_pwm_set_high(st);
 
 	return IRQ_HANDLED;
 }
@@ -900,7 +895,6 @@ static int ad7606_buffer_postenable(struct iio_dev *indio_dev)
 	struct ad7606_state *st = iio_priv(indio_dev);
 
 	gpiod_set_value(st->gpio_convst, 1);
-	ad7606_pwm_set_high(st);
 
 	return 0;
 }
@@ -910,7 +904,6 @@ static int ad7606_buffer_predisable(struct iio_dev *indio_dev)
 	struct ad7606_state *st = iio_priv(indio_dev);
 
 	gpiod_set_value(st->gpio_convst, 0);
-	ad7606_pwm_set_low(st);
 
 	return 0;
 }
@@ -1204,6 +1197,12 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 		indio_dev->setup_ops = &ad7606_pwm_buffer_ops;
 	} else {
 		init_completion(&st->completion);
+
+		/* Reserve the PWM use only for backend (force gpio_convst definition) */
+		if (!st->gpio_convst)
+			return dev_err_probe(dev, -EINVAL,
+					     "No backend, connect convst to a GPIO");
+
 		st->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
 						  indio_dev->name,
 						  iio_device_id(indio_dev));

-- 
2.34.1