From: Paul Cercueil <paul.cercu...@analog.com>

The scale can now be obtained with the "in_voltage_scale" file.
By default, the scale returned corresponds to the internal VREF of 2.5V.

It is possible to use an external VREF (through the REFIN/REFOUT pin of
the chip), by passing a regulator to the driver. The scale will then be
calculated according to the voltage reported by the regulator.

Signed-off-by: Paul Cercueil <paul.cercu...@analog.com>
Co-developed-by: Beniamin Bia <beniamin....@analog.com>
Signed-off-by: Beniamin Bia <beniamin....@analog.com>
---
 drivers/iio/adc/ad7091r-base.c | 42 +++++++++++++++++++++++++++++++++-
 drivers/iio/adc/ad7091r-base.h |  1 +
 drivers/iio/adc/ad7091r5.c     |  5 ++++
 3 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/ad7091r-base.c b/drivers/iio/adc/ad7091r-base.c
index 140413329754..d416f0912531 100644
--- a/drivers/iio/adc/ad7091r-base.c
+++ b/drivers/iio/adc/ad7091r-base.c
@@ -14,6 +14,7 @@
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
 
 #define AD7091R_REG_RESULT  0
 #define AD7091R_REG_CHANNEL 1
@@ -42,6 +43,7 @@ enum ad7091r_mode {
 struct ad7091r_state {
        struct device *dev;
        struct regmap *map;
+       struct regulator *reg;
        const struct ad7091r_chip_info *chip_info;
        enum ad7091r_mode mode;
 };
@@ -139,6 +141,21 @@ static int ad7091r_read_raw(struct iio_dev *iio_dev,
                ret = IIO_VAL_INT;
                break;
 
+       case IIO_CHAN_INFO_SCALE:
+               if (st->reg) {
+                       ret = regulator_get_voltage(st->reg);
+                       if (ret < 0)
+                               goto unlock;
+
+                       *val = ret / 1000;
+               } else {
+                       *val = st->chip_info->vref_mV;
+               }
+
+               *val2 = chan->scan_type.realbits;
+               ret = IIO_VAL_FRACTIONAL_LOG2;
+               break;
+
        default:
                ret = -EINVAL;
                break;
@@ -215,6 +232,18 @@ int ad7091r_probe(struct device *dev, const char *name,
                        return ret;
        }
 
+       st->reg = devm_regulator_get_optional(dev, "vref");
+       if (IS_ERR(st->reg)) {
+               if (PTR_ERR(st->reg) == EPROBE_DEFER)
+                       return -EPROBE_DEFER;
+
+               st->reg = NULL;
+       } else {
+               ret = regulator_enable(st->reg);
+               if (ret)
+                       return ret;
+       }
+
        /* Use command mode by default */
        ret = ad7091r_set_mode(st, AD7091R_MODE_COMMAND);
        if (ret < 0)
@@ -222,18 +251,29 @@ int ad7091r_probe(struct device *dev, const char *name,
 
        ret = iio_device_register(iio_dev);
        if (ret)
-               return ret;
+               goto err_disable_reg;
 
        dev_dbg(dev, "Probed\n");
        return 0;
+
+err_disable_reg:
+       if (st->reg)
+               regulator_disable(st->reg);
+
+       return ret;
 }
 EXPORT_SYMBOL_GPL(ad7091r_probe);
 
 int ad7091r_remove(struct device *dev)
 {
        struct iio_dev *iio_dev = dev_get_drvdata(dev);
+       struct ad7091r_state *st = iio_priv(iio_dev);
 
        iio_device_unregister(iio_dev);
+
+       if (st->reg)
+               regulator_disable(st->reg);
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(ad7091r_remove);
diff --git a/drivers/iio/adc/ad7091r-base.h b/drivers/iio/adc/ad7091r-base.h
index 7a29f86ea82b..cec4fb75fecc 100644
--- a/drivers/iio/adc/ad7091r-base.h
+++ b/drivers/iio/adc/ad7091r-base.h
@@ -18,6 +18,7 @@ struct ad7091r_state;
 struct ad7091r_chip_info {
        unsigned int num_channels;
        const struct iio_chan_spec *channels;
+       unsigned int vref_mV;
 };
 
 extern const struct regmap_config ad7091r_regmap_config;
diff --git a/drivers/iio/adc/ad7091r5.c b/drivers/iio/adc/ad7091r5.c
index 1ba838c58c31..65bcd8bb692a 100644
--- a/drivers/iio/adc/ad7091r5.c
+++ b/drivers/iio/adc/ad7091r5.c
@@ -35,10 +35,13 @@ static const struct iio_event_spec ad7091r5_events[] = {
 #define AD7091R_CHANNEL(idx, bits, ev, num_ev) { \
        .type = IIO_VOLTAGE, \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+       .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
        .indexed = 1, \
        .channel = idx, \
        .event_spec = ev, \
        .num_event_specs = num_ev, \
+       .scan_type.storagebits = 16, \
+       .scan_type.realbits = bits, \
 }
 static const struct iio_chan_spec ad7091r5_channels_irq[] = {
        AD7091R_CHANNEL(0, 12, ad7091r5_events, ARRAY_SIZE(ad7091r5_events)),
@@ -58,11 +61,13 @@ static const struct iio_chan_spec ad7091r5_channels_noirq[] 
= {
 static const struct ad7091r_chip_info ad7091r5_chip_info_irq = {
        .channels = ad7091r5_channels_irq,
        .num_channels = ARRAY_SIZE(ad7091r5_channels_irq),
+       .vref_mV = 2500,
 };
 
 static const struct ad7091r_chip_info ad7091r5_chip_info_noirq = {
        .channels = ad7091r5_channels_noirq,
        .num_channels = ARRAY_SIZE(ad7091r5_channels_noirq),
+       .vref_mV = 2500,
 };
 
 static int ad7091r5_i2c_probe(struct i2c_client *i2c,
-- 
2.17.1

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