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Subject[PATCH v3 2/4] iio: adc: ad7091r5: Add scale and external VREF support
Date
From: Paul Cercueil <paul.cercueil@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.cercueil@analog.com>
Co-developed-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
---
Changes in v3:
-type cast from void* in remove function removed
-error checking for devm_add_action_or_reset

drivers/iio/adc/ad7091r-base.c | 41 ++++++++++++++++++++++++++++++++++
drivers/iio/adc/ad7091r-base.h | 1 +
drivers/iio/adc/ad7091r5.c | 5 +++++
3 files changed, 47 insertions(+)

diff --git a/drivers/iio/adc/ad7091r-base.c b/drivers/iio/adc/ad7091r-base.c
index 2ebc40dfd927..abb0d9c2ea9c 100644
--- a/drivers/iio/adc/ad7091r-base.c
+++ b/drivers/iio/adc/ad7091r-base.c
@@ -11,6 +11,7 @@
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>

#include "ad7091r-base.h"

@@ -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;
struct mutex lock;
@@ -142,6 +144,21 @@ 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;
@@ -184,6 +201,14 @@ static irqreturn_t ad7091r_event_handler(int irq, void *private)
return IRQ_HANDLED;
}

+static void ad7091r_remove(void *data)
+{
+ struct ad7091r_state *st = data;
+
+ if (st->reg)
+ regulator_disable(st->reg);
+}
+
int ad7091r_probe(struct device *dev, const char *name,
const struct ad7091r_chip_info *chip_info,
struct regmap *map, int irq)
@@ -217,6 +242,22 @@ 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;
+ }
+
+ ret = devm_add_action_or_reset(dev, ad7091r_remove, st);
+ if (ret)
+ return ret;
+
/* Use command mode by default to convert only desired channels*/
ret = ad7091r_set_mode(st, AD7091R_MODE_COMMAND);
if (ret)
diff --git a/drivers/iio/adc/ad7091r-base.h b/drivers/iio/adc/ad7091r-base.h
index 5f1147735953..76b76968d071 100644
--- a/drivers/iio/adc/ad7091r-base.h
+++ b/drivers/iio/adc/ad7091r-base.h
@@ -14,6 +14,7 @@ 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 f7b3326032e8..73d18ddfd2c9 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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