[PATCH 2/3] iio: adc: ad7923: support extended range

["Nuno Sá" <nuno.sa@analog.com>]

By default the driver was always setting the RANGE bit which means that
the analog input goes from 0 to VREF. However, we might want to have 0
to 2xVREF. This change adds a new FW property to allow for the range
selection while keeping the default behavior if nothing is provided.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 drivers/iio/adc/ad7923.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ad7923.c b/drivers/iio/adc/ad7923.c
index 910cf05e75cd..4bd0ae209d18 100644
--- a/drivers/iio/adc/ad7923.c
+++ b/drivers/iio/adc/ad7923.c
@@ -6,8 +6,10 @@
  * Copyright 2012 CS Systemes d'Information
  */
 
+#include <linux/bitfield.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
+#include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
 #include <linux/spi/spi.h>
@@ -45,6 +47,8 @@
 /* val = value, dec = left shift, bits = number of bits of the mask */
 #define EXTRACT(val, dec, bits)		(((val) >> (dec)) & ((1 << (bits)) - 1))
 
+#define AD7923_RANGE_0_VREF	1
+
 struct ad7923_state {
 	struct spi_device		*spi;
 	struct spi_transfer		ring_xfer[5];
@@ -300,6 +304,7 @@ static void ad7923_regulator_disable(void *data)
 
 static int ad7923_probe(struct spi_device *spi)
 {
+	u32 ad7923_range = FIELD_PREP(AD7923_RANGE, AD7923_RANGE_0_VREF), val;
 	struct ad7923_state *st;
 	struct iio_dev *indio_dev;
 	const struct ad7923_chip_info *info;
@@ -311,8 +316,17 @@ static int ad7923_probe(struct spi_device *spi)
 
 	st = iio_priv(indio_dev);
 
+	ret = device_property_read_u32(&spi->dev, "adi,range-select", &val);
+	if (!ret) {
+		if (val > AD7923_RANGE_0_VREF)
+			return dev_err_probe(&spi->dev, -EINVAL,
+					     "Invalid range (%u) selected\n", val);
+
+		ad7923_range = FIELD_PREP(AD7923_RANGE, val);
+	}
+
 	st->spi = spi;
-	st->settings = AD7923_CODING | AD7923_RANGE |
+	st->settings = AD7923_CODING | ad7923_range |
 			AD7923_PM_MODE_WRITE(AD7923_PM_MODE_OPS);
 
 	info = &ad7923_chip_info[spi_get_device_id(spi)->driver_data];
-- 
2.37.3