[PATCH v2 4/5] iio: dac: ad5504: fix scale via output-range-microvolt

[Taha Ed-Dafili <0rayn.dev@gmail.com>]

The AD5504 full-scale range is hardware-determined by the
R_SEL pin (0-30V or 0-60V). Previously, the driver incorrectly used the
VCC regulator voltage to calculate the scale.

Update the probe function to read the standard "output-range-microvolt"
property as a two-element array to determine the correct full-scale range.
Use the MILLI macro for clearer millivolt assignments and simplify the
probe logic using a local device pointer.

Suggested-by: David Lechner <dlechner@baylibre.com>
Suggested-by: Andy Shevchenko <andy@kernel.org>
Signed-off-by: Taha Ed-Dafili <0rayn.dev@gmail.com>
---
 drivers/iio/dac/ad5504.c | 43 ++++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 19 deletions(-)

diff --git a/drivers/iio/dac/ad5504.c b/drivers/iio/dac/ad5504.c
index e71218c44982..cd563460fc0a 100644
--- a/drivers/iio/dac/ad5504.c
+++ b/drivers/iio/dac/ad5504.c
@@ -12,10 +12,12 @@
 #include <linux/kernel.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/property.h>
 #include <linux/regulator/consumer.h>
 #include <linux/spi/spi.h>
 #include <linux/sysfs.h>
 #include <linux/types.h>
+#include <linux/units.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
@@ -271,28 +273,31 @@ static const struct iio_chan_spec ad5504_channels[] = {
 
 static int ad5504_probe(struct spi_device *spi)
 {
-	const struct ad5504_platform_data *pdata = dev_get_platdata(&spi->dev);
+	struct device *dev = &spi->dev;
+	const struct ad5504_platform_data *pdata = dev_get_platdata(dev);
 	struct iio_dev *indio_dev;
 	struct ad5504_state *st;
 	int ret;
+	u32 range[2];
 
-	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
 	if (!indio_dev)
 		return -ENOMEM;
 
 	st = iio_priv(indio_dev);
 
-	ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vcc");
-	if (ret < 0 && ret != -ENODEV)
+	ret = devm_regulator_get_enable(dev, "vcc");
+	if (ret)
 		return ret;
-	if (ret == -ENODEV) {
-		if (pdata->vref_mv)
-			st->vref_mv = pdata->vref_mv;
-		else
-			dev_warn(&spi->dev, "reference voltage unspecified\n");
-	} else {
-		st->vref_mv = ret / 1000;
-	}
+
+	st->vref_mv = 60 * MILLI;
+	ret = device_property_read_u32_array(dev, "output-range-microvolt",
+					     range, 2);
+	if (!ret && range[1] == 30 * MICRO)
+		st->vref_mv = 30 * MILLI;
+
+	if (pdata && pdata->vref_mv)
+		st->vref_mv = pdata->vref_mv;
 
 	st->spi = spi;
 	indio_dev->name = spi_get_device_id(st->spi)->name;
@@ -305,17 +310,17 @@ static int ad5504_probe(struct spi_device *spi)
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
 	if (spi->irq) {
-		ret = devm_request_threaded_irq(&spi->dev, spi->irq,
-					   NULL,
-					   &ad5504_event_handler,
-					   IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
-					   spi_get_device_id(st->spi)->name,
-					   indio_dev);
+		ret = devm_request_threaded_irq(dev, spi->irq,
+						NULL,
+						&ad5504_event_handler,
+						IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+						spi_get_device_id(st->spi)->name,
+						indio_dev);
 		if (ret)
 			return ret;
 	}
 
-	return devm_iio_device_register(&spi->dev, indio_dev);
+	return devm_iio_device_register(dev, indio_dev);
 }
 
 static const struct spi_device_id ad5504_id[] = {
-- 
2.47.3