iio: adc: ad7923: support extended range

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 Firmware property to allow for the
extended range while keeping the default behavior if nothing is provided.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220912081223.173584-3-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ad7923.c b/drivers/iio/adc/ad7923.c
index 502253f..9d6bf6d 100644 (file)
--- a/drivers/iio/adc/ad7923.c
+++ b/drivers/iio/adc/ad7923.c
@@ -8,6 +8,7 @@
 
 #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>
@@ -300,6 +301,7 @@ static void ad7923_regulator_disable(void *data)
 
 static int ad7923_probe(struct spi_device *spi)
 {
+       u32 ad7923_range = AD7923_RANGE;
        struct ad7923_state *st;
        struct iio_dev *indio_dev;
        const struct ad7923_chip_info *info;
@@ -311,8 +313,11 @@ static int ad7923_probe(struct spi_device *spi)
 
        st = iio_priv(indio_dev);
 
+       if (device_property_read_bool(&spi->dev, "adi,range-double"))
+               ad7923_range = 0;
+
        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];