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 | 28 +++++++++-------------------
 1 file changed, 9 insertions(+), 19 deletions(-)

diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
index 7871552ce5ac..0e830a17fc19 100644
--- a/drivers/iio/adc/ad7606.c
+++ b/drivers/iio/adc/ad7606.c
@@ -470,8 +470,6 @@ 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 */
-	fsleep(2);
 
 	return ret;
 }
@@ -486,8 +484,6 @@ 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 */
-	fsleep(2);
 
 	return ret;
 }
@@ -563,13 +559,7 @@ static irqreturn_t ad7606_trigger_handler(int irq, void *p)
 error_ret:
 	iio_trigger_notify_done(indio_dev->trig);
 	/* The rising edge of the CONVST signal starts a new conversion. */
-	if (st->gpio_convst) {
-		gpiod_set_value(st->gpio_convst, 1);
-	} else {
-		ret = ad7606_pwm_set_high(st)
-		if (ret < 0)
-			dev_err(st->dev, "Could not set PWM to high.");
-	}
+	gpiod_set_value(st->gpio_convst, 1);
 
 	return IRQ_HANDLED;
 }
@@ -900,10 +890,7 @@ static int ad7606_buffer_postenable(struct iio_dev *indio_dev)
 {
 	struct ad7606_state *st = iio_priv(indio_dev);
 
-	if (st->gpio_convst)
-		gpiod_set_value(st->gpio_convst, 1);
-	else
-		return ad7606_pwm_set_high(st);
+	gpiod_set_value(st->gpio_convst, 1);
 
 	return 0;
 }
@@ -912,10 +899,7 @@ static int ad7606_buffer_predisable(struct iio_dev *indio_dev)
 {
 	struct ad7606_state *st = iio_priv(indio_dev);
 
-	if (st->gpio_convst)
-		gpiod_set_value(st->gpio_convst, 0);
-	else
-		return ad7606_pwm_set_low(st);
+	gpiod_set_value(st->gpio_convst, 0);
 
 	return 0;
 }
@@ -1210,6 +1194,12 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
 
 		indio_dev->setup_ops = &ad7606_backend_buffer_ops;
 	} else {
+
+		/* 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");
+
 		init_completion(&st->completion);
 		st->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
 						  indio_dev->name,

-- 
2.34.1