iio: adc: ad9467: fix reset gpio handling

The reset gpio was being handled with inverted polarity. This means that
as far as gpiolib is concerned we were actually leaving the pin asserted
(in theory, this would mean reset). However, inverting the polarity in
devicetree made things work. Fix it by doing it the proper way and how
gpiolib expects it to be done.

While at it, moved the handling to it's own function and dropped
'reset_gpio' from the 'struct ad9467_state' as we only need it during
probe. On top of that, refactored things so that we now request the gpio
asserted (i.e in reset) and then de-assert it. Also note that we now use
gpiod_set_value_cansleep() instead of gpiod_direction_output() as we
already request the pin as output.

Fixes: ad6797120238 ("iio: adc: ad9467: add support AD9467 ADC")
Reviewed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20231207-iio-backend-prep-v2-1-a4a33bc4d70e@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 18 insertions, 13 deletions

diff --git a/drivers/iio/adc/ad9467.c b/drivers/iio/adc/ad9467.c
index 39eccc28debe..4fb9e48dc782 100644
--- a/drivers/iio/adc/ad9467.c
+++ b/drivers/iio/adc/ad9467.c
@@ -121,7 +121,6 @@ struct ad9467_state {
 	unsigned int			output_mode;
 
 	struct gpio_desc		*pwrdown_gpio;
-	struct gpio_desc		*reset_gpio;
 };
 
 static int ad9467_spi_read(struct spi_device *spi, unsigned int reg)
@@ -378,6 +377,21 @@ static int ad9467_preenable_setup(struct adi_axi_adc_conv *conv)
 	return ad9467_outputmode_set(st->spi, st->output_mode);
 }
 
+static int ad9467_reset(struct device *dev)
+{
+	struct gpio_desc *gpio;
+
+	gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
+	if (IS_ERR_OR_NULL(gpio))
+		return PTR_ERR_OR_ZERO(gpio);
+
+	fsleep(1);
+	gpiod_set_value_cansleep(gpio, 0);
+	fsleep(10 * USEC_PER_MSEC);
+
+	return 0;
+}
+
 static int ad9467_probe(struct spi_device *spi)
 {
 	const struct ad9467_chip_info *info;
@@ -408,18 +422,9 @@ static int ad9467_probe(struct spi_device *spi)
 	if (IS_ERR(st->pwrdown_gpio))
 		return PTR_ERR(st->pwrdown_gpio);
 
-	st->reset_gpio = devm_gpiod_get_optional(&spi->dev, "reset",
-						 GPIOD_OUT_LOW);
-	if (IS_ERR(st->reset_gpio))
-		return PTR_ERR(st->reset_gpio);
-
-	if (st->reset_gpio) {
-		udelay(1);
-		ret = gpiod_direction_output(st->reset_gpio, 1);
-		if (ret)
-			return ret;
-		mdelay(10);
-	}
+	ret = ad9467_reset(&spi->dev);
+	if (ret)
+		return ret;
 
 	conv->chip_info = &info->axi_adc_info;