Add support for ADAQ776x-1 ADC Family

Add compatibles for supported parts in the ad7768-1 family:

	ADAQ7767-1, ADAQ7768-1 and ADAQ7769-1

Add property and checks for AFF gain, supported by ADAQ7767-1 and ADAQ7769-1 parts:
adi,aaf-gain-bp

Signed-off-by Jonathan Santos <[email protected]>

---
v3 Changes:
* Renamed adi,gain-milli to adi,aaf-gain-bp. Now it represents basis points (one hundredth of a percent) as suggested by Krzysztof. Description was adjusted.
Note: permille (1/1000) was also suggested as unit for this property.

v2 Changes:
* adi,aaf-gain property renamed to adi,gain-milli. Description was simplified.
* default value add to adi,gain-milli.

---
 .../bindings/iio/adc/adi,ad7768-1.yaml        | 44 +++++++++++++++++--
 1 file changed, 40 insertions(+), 4 deletions(-)

Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml +1 -1

index c06d0fc791d3..c2ad8e585586 100644
@@ -4,18 +4,26 @@
 $id: http://devicetree.org/schemas/iio/adc/adi,ad7768-1.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Analog Devices AD7768-1 ADC device driver
+title: Analog Devices AD7768-1 ADC family
 
 maintainers:
   - Michael Hennerich <[email protected]>

Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml +18 -1

 properties:
   compatible:
-    const: adi,ad7768-1
+    enum:
+      - adi,ad7768-1
+      - adi,adaq7767-1
+      - adi,adaq7768-1
+      - adi,adaq7769-1
 
   reg:
     maxItems: 1

@@ -58,6 +66,19 @@ properties:
     description:
       ADC reference voltage supply
 
+  adi,aaf-gain-bp:
+    description: |
+       Specifies the gain applied by the Analog Anti-Aliasing Filter (AAF)
+       to the ADC input in basis points (one hundredth of a percent).
+       The hardware gain is determined by which input pin(s) the signal goes
+       through into the AAF. The possible connections are:
+       * For the ADAQ7767-1: Input connected to IN1±, IN2± or IN3±.
+       * For the ADAQ7769-1: OUT_PGA pin connected to IN1_AAF+, IN2_AAF+,
+         or IN3_AAF+.
+    $ref: /schemas/types.yaml#/definitions/uint16
+    enum: [1430, 3640, 10000]
+    default: 10000
+

Add Chip info struct in SPI device to store channel information for each supported part.

+#define AD7768_CHAN(_idx, _msk_avail) { \

drivers/iio/adc/ad7768-1.c +11 -0

+	.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
+	.ext_info = ad7768_ext_info, \
+	.indexed = 1, \
+	.channel = _idx, \
+	.scan_index = _idx, \
+	.has_ext_scan_type = 1, \
+	.ext_scan_type = ad7768_scan_type, \
+	.num_ext_scan_type = ARRAY_SIZE(ad7768_scan_type), \
+}

drivers/iio/adc/ad7768-1.c +1 -0

+	indio_dev->channels = st->chip->channel_spec;

Add Chip info struct in SPI device to store channel information for each supported part.

drivers/iio/adc/ad7768-1.c +4 -0

+	if (!st->chip)
+		return dev_err_probe(&spi->dev, -ENODEV,
+				     "Could not find chip info data\n");
+

Extend fractional numbers types to include __u64 and __s64 data types.

Add support for ADAQ7767/68/69-1 series, which includes PGIA and Anti-aliasing filter (AAF) gains. Unlike the AD7768-1, they do not provide a VCM regulator interface.

drivers/iio/adc/ad7768-1.c +20 -0

+static void ad7768_fill_scale_tbl(struct iio_dev *dev)
+{
+	struct ad7768_state *st = iio_priv(dev);
+	const struct iio_scan_type *scan_type;
+	int val, val2, tmp0, tmp1, i;
+	struct u64_fract fract;
+	unsigned long n, d;
+	u64 tmp2;
+
+	scan_type = iio_get_current_scan_type(dev, &dev->channels[0]);
+	if (scan_type->sign == 's')
+		val2 = scan_type->realbits - 1;
+	else
+		val2 = scan_type->realbits;
+
+	for (i = 0; i < st->chip->num_pga_modes; i++) {
+		/* Convert gain to a fraction format */
+		fract.numerator = st->chip->pga_gains[i];
+		fract.denominator = MILLI;
+		if (st->chip->has_variable_aaf) {

drivers/iio/adc/ad7768-1.c +6 -0

+		tmp0 = div_u64_rem(tmp2, NANO, &tmp1);
+		st->scale_tbl[i][0] = tmp0; /* Integer part */
+		st->scale_tbl[i][1] = abs(tmp1); /* Fractional part */
+	}
+}
+

drivers/iio/adc/ad7768-1.c +13 -1

+	if (ret)
+		return ret;
+
+	st->pga_gain_mode = gain_mode;
+
+	return 0;
+}
+
 static int ad7768_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
 {
 	struct iio_dev *indio_dev = gpiochip_get_data(chip);

@@ -778,6 +925,10 @@ static const struct iio_chan_spec ad7768_channels[] = {
 	AD7768_CHAN(0, 0),
 };
 
+static const struct iio_chan_spec adaq776x_channels[] = {
+	AD7768_CHAN(0, BIT(IIO_CHAN_INFO_SCALE)),
+};
+
 static int ad7768_read_raw(struct iio_dev *indio_dev,
 			   struct iio_chan_spec const *chan,
 			   int *val, int *val2, long info)

@@ -805,7 +956,19 @@ static int ad7768_read_raw(struct iio_dev *indio_dev,
 		return IIO_VAL_INT;
 
 	case IIO_CHAN_INFO_SCALE:
-		*val = (st->vref_uv * 2) / 1000;
+		if (st->chip->has_pga) {

drivers/iio/adc/ad7768-1.c +2 -0

+
+		*val = temp;
 		*val2 = scan_type->realbits;
 
 		return IIO_VAL_FRACTIONAL_LOG2;

drivers/iio/adc/ad7768-1.c +23 -0

+		return 0;
+	}
+
+	if (aaf_gain_provided) {
+		switch (val) {
+		case 10000:
+			st->aaf_gain = AD7768_AAF_IN1;
+			break;
+		case 3640:
+			st->aaf_gain = AD7768_AAF_IN2;
+			break;
+		case 1430:
+			st->aaf_gain = AD7768_AAF_IN3;
+			break;
+		default:
+			return dev_err_probe(dev, -EINVAL,
+					     "Invalid firmware provided AAF gain\n");
+		}
+	}
+
+	return 0;
+}
+

drivers/iio/adc/ad7768-1.c +5 -0

+		if (ret)
+			return ret;
+	}
+
+	ret = ad7768_parse_aaf_gain(&spi->dev, st);
 	if (ret)
 		return ret;
 

Add support for ADAQ7767/68/69-1 series, which includes PGIA and Anti-aliasing filter (AAF) gains. Unlike the AD7768-1, they do not provide a VCM regulator interface.

The PGA gain is configured in run-time through the scale attribute, if supported by the device. PGA is enabled and controlled by the GPIO controller (GPIOs 0, 1 and 2) provided by the device with the SPI interface.

The AAF gain is defined by hardware connections and should be specified in the device tree.

drivers/iio/adc/ad7768-1.c +11 -0

+		rational_best_approximation(fract.numerator, fract.denominator,
+					    INT_MAX, INT_MAX, &n, &d);
+
+		val = mult_frac(st->vref_uv, d, n);
+		/* Would multiply by NANO here, but value is already in milli */
+		tmp2 = shift_right((u64)val * MICRO, val2);
+		tmp0 = div_u64_rem(tmp2, NANO, &tmp1);
+		st->scale_tbl[i][0] = tmp0; /* Integer part */
+		st->scale_tbl[i][1] = abs(tmp1); /* Fractional part */
+	}
+}

+}

drivers/iio/adc/ad7768-1.c +14 -0

+		int gain_mode;
+
+		if (!st->chip->has_pga)
+			return -EOPNOTSUPP;
+
+		if (scan_type->sign == 's')
+			gain_mode = ad7768_calc_pga_gain(st, val, val2,
+							 scan_type->realbits - 1);
+		else
+			gain_mode = ad7768_calc_pga_gain(st, val, val2,
+							 scan_type->realbits);
+
+		return ad7768_set_pga_gain(st, gain_mode);
+	}

drivers/iio/adc/ad7768-1.c +17 -0

+		switch (val) {
+		case 10000:
+			st->aaf_gain = AD7768_AAF_IN1;
+			break;
+		case 3640:
+			st->aaf_gain = AD7768_AAF_IN2;
+			break;
+		case 1430:
+			st->aaf_gain = AD7768_AAF_IN3;
+			break;
+		default:
+			return dev_err_probe(dev, -EINVAL,
+					     "Invalid firmware provided AAF gain\n");
+		}
+	}
+	return 0;
+}

On Fri, Sep 05, 2025 at 06:49:42AM -0300, Jonathan Santos wrote:

drivers/iio/adc/ad7768-1.c static int ad7768_reg_access(struct iio_dev *indio_dev, · line 547

Quoted 4 lines

drivers/iio/adc/ad7768-1.c +4 -0

+	if (scan_type->sign == 's')
+		val2 = scan_type->realbits - 1;
+	else
+		val2 = scan_type->realbits;

Wasn't smatch happy about this check?

drivers/iio/adc/ad7768-1.c static int ad7768_reg_access(struct iio_dev *indio_dev, · line 543

Quoted 11 lines

drivers/iio/adc/ad7768-1.c +10 -0

+static void ad7768_fill_scale_tbl(struct iio_dev *dev)
+{
+	struct ad7768_state *st = iio_priv(dev);
+	const struct iio_scan_type *scan_type;
+	int val, val2, tmp0, tmp1, i;
+	struct u64_fract fract;
+	unsigned long n, d;
+	u64 tmp2;
+
+	scan_type = iio_get_current_scan_type(dev, &dev->channels[0]);  

Is it usual patter in IIO? Otherwise it can be written as

	scan_type = iio_get_current_scan_type(dev, dev->channels);

Quoted 5 lines

drivers/iio/adc/ad7768-1.c +4 -0

+	if (scan_type->sign == 's')
+		val2 = scan_type->realbits - 1;
+	else
+		val2 = scan_type->realbits;