[PATCH v4 0/4] Add support for ADAQ776x-1 ADC Family

[PATCH v4 0/4] Add support for ADAQ776x-1 ADC Family

[Jonathan Santos]

This adds support for the ADAQ7767-1, ADAQ7768-1 and ADAQ7769-1 devices. 

The ADAQ7768-1 and ADAQ7769-1 integrate a programmable gain amplifier (PGA)
with 7 and 8 gain options, respectively. The ADAQ7767-1 and ADAQ7769-1 
also feature a 3-pin selectable Anti-aliasing filter (AAF) gain.

---
Changes in v4:
* Removed u64_fract type patch, as it is not used. u32_fract is sufficient
  for the PGA gain calculations.
* Added new patch adding BASIS_POINTS macro to units.h.
* Included pga-gpios property for parts that support PGA gain.
  Before we were using the internal gpio controller to manage the PGA pins,
  but still exposing the controller for external use (causing possible conflicts).
* Addressed other review comments, see individual patches.
* Link to v3: https://lore.kernel.org/linux-iio/cover.1757001160.git.Jonathan.Santos@analog.com/T/#t

Changes in v3:
* Renamed adi,gain-milli to adi,aaf-gain-bp. Now it represents basis points
  (one hundredth of a percent).
* ad7768_channel_masks removed along with available_masks element in
  ad7768_chip_info struct. It does not add anything for single channels,
  so not needed, at least for now.
* New patch adding 64-bit fractional number types to math.h.
* Moved aaf gain parsing to its own function, and now returning after
  warning to avoid setting a variable when it shouldn't (avoid confusion).
* ad7768_set_pga_gain(): removed the pgia enable check, relying on the
  regmap cache.
* Addressed other review comments, see individual patches.

Changes in v2:
* adi,aaf-gain property renamed to adi,gain-milli. Default value added.
* fixed some commit messages. 
* Added 'select RATIONAL' to Kconfig.
* Added lock to protect PGA value access.
* rewrote AAF gain check and replaced error returns with warnings.
* Addressed other review comments, see individual patches.
* Link to v1: https://lore.kernel.org/linux-iio/cover.1754617360.git.Jonathan.Santos@analog.com/T/#t
---

Jonathan Santos (4):
  dt-bindings: iio: adc: ad7768-1: add new supported parts
  iio: adc: ad7768-1: introduce chip info for future multidevice support
  units: add BASIS_POINTS macro
  iio: adc: ad7768-1: add support for ADAQ776x-1 ADC Family

 .../bindings/iio/adc/adi,ad7768-1.yaml        |  64 ++-
 drivers/iio/adc/Kconfig                       |   1 +
 drivers/iio/adc/ad7768-1.c                    | 386 ++++++++++++++++--
 include/linux/units.h                         |   2 +
 4 files changed, 422 insertions(+), 31 deletions(-)


base-commit: f9e05791642810a0cf6237d39fafd6fec5e0b4bb
-- 
2.34.1

[PATCH v4 1/4] dt-bindings: iio: adc: ad7768-1: add new supported parts

[Jonathan Santos]

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, and for PGA gain, supported by ADAQ7768-1
and ADAQ7769-1:
	adi,aaf-gain-bp
	pga-gpios

Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
---
v4 Changes:
* Inspired by [1], Included pga-gpios property for parts that support PGA gain.
  Before we were using the internal gpio controller to manage the PGA pins,
  but still exposing the controller for external use (causing possible conflicts).
  Using pga-gpios we can let the consumer define the pins to be used for PGA,
  even from the internal gpio controller (but not limited by that). The problem
  with that approach is the deadlock described in the last patch from this set.

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.

[1]: https://lore.kernel.org/linux-iio/318c31e023ebe30cc99b8743e87e869bf5e1f12b.1760984107.git.marcelo.schmitt@analog.com/
---
 .../bindings/iio/adc/adi,ad7768-1.yaml        | 64 +++++++++++++++++--
 1 file changed, 60 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
index c06d0fc791d3..dfa2d7fa9fb3 100644
--- a/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7768-1.yaml
@@ -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 <michael.hennerich@analog.com>
 
 description: |
-  Datasheet at:
-    https://www.analog.com/media/en/technical-documentation/data-sheets/ad7768-1.pdf
+  Analog Devices AD7768-1 24-Bit Single Channel Low Power sigma-delta ADC family
+
+  https://www.analog.com/media/en/technical-documentation/data-sheets/ad7768-1.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/adaq7767-1.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/adaq7768-1.pdf
+  https://www.analog.com/media/en/technical-documentation/data-sheets/adaq7769-1.pdf
 
 properties:
   compatible:
-    const: adi,ad7768-1
+    enum:
+      - adi,ad7768-1
+      - adi,adaq7767-1
+      - adi,adaq7768-1
+      - adi,adaq7769-1
 
   reg:
     maxItems: 1
@@ -58,6 +66,25 @@ 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+.
+    enum: [1430, 3640, 10000]
+    default: 10000
+
+  pga-gpios:
+    description:
+      GAIN 0, GAIN1 and GAIN2 pins for gain selection. For devices that have
+      PGA configuration input pins, pga-gpios must be defined.
+    minItems: 3
+    maxItems: 3
+
   adi,sync-in-gpios:
     maxItems: 1
     description:
@@ -147,6 +174,35 @@ patternProperties:
 allOf:
   - $ref: /schemas/spi/spi-peripheral-props.yaml#
 
+  # AAF Gain property only applies to ADAQ7767-1 and ADAQ7769-1 devices
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - adi,adaq7767-1
+              - adi,adaq7769-1
+    then:
+      required:
+        - adi,aaf-gain-bp
+    else:
+      properties:
+        adi,aaf-gain-bp: false
+
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - adi,adaq7768-1
+              - adi,adaq7769-1
+    then:
+      required:
+        - pga-gpios
+    else:
+      properties:
+        pga-gpios: false
+
 unevaluatedProperties: false
 
 examples:
-- 
2.34.1

[PATCH v4 2/4] iio: adc: ad7768-1: introduce chip info for future multidevice support

[Jonathan Santos]

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

Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
---
v4 Changes:
* Dropped chip info check and moved the st->chip assignment early in the
  probe function.
* Addressed indentation inconsistencies in AD7768_CHAN macro.

v3 Changes:
* ad7768_channel_masks removed along with available_masks element in
  ad7768_chip_info struct. It does not add anything for single channels,
  so not needed, at least for now.
* fixed inconsistency in spaces before \ in AD7768_CHAN macro.

v2 Changes:
* removed AD7768_CHAN_INFO_NONE macro.
* reordered fields in ad7768_chip_info struct.
* removed trailing comma.
---
 drivers/iio/adc/ad7768-1.c | 64 ++++++++++++++++++++++++--------------
 1 file changed, 41 insertions(+), 23 deletions(-)

diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index d96802b7847a..89b0ca8f584c 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -213,6 +213,12 @@ static const struct iio_scan_type ad7768_scan_type[] = {
 	},
 };
 
+struct ad7768_chip_info {
+	const char *name;
+	const struct iio_chan_spec *channel_spec;
+	int num_channels;
+};
+
 struct ad7768_state {
 	struct spi_device *spi;
 	struct regmap *regmap;
@@ -234,6 +240,7 @@ struct ad7768_state {
 	struct gpio_desc *gpio_reset;
 	const char *labels[AD7768_MAX_CHANNELS];
 	struct gpio_chip gpiochip;
+	const struct ad7768_chip_info *chip;
 	bool en_spi_sync;
 	/*
 	 * DMA (thus cache coherency maintenance) may require the
@@ -748,24 +755,28 @@ static const struct iio_chan_spec_ext_info ad7768_ext_info[] = {
 	{ }
 };
 
+#define AD7768_CHAN(_idx, _msk_avail) \
+{ \
+	.type = IIO_VOLTAGE, \
+	.info_mask_separate_available = _msk_avail, \
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+				    BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) | \
+				    BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
+	.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), \
+}
+
 static const struct iio_chan_spec ad7768_channels[] = {
-	{
-		.type = IIO_VOLTAGE,
-		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
-		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |
-					    BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY) |
-					    BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
-		.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 = 0,
-		.scan_index = 0,
-		.has_ext_scan_type = 1,
-		.ext_scan_type = ad7768_scan_type,
-		.num_ext_scan_type = ARRAY_SIZE(ad7768_scan_type),
-	},
+	AD7768_CHAN(0, 0),
 };
 
 static int ad7768_read_raw(struct iio_dev *indio_dev,
@@ -1321,6 +1332,12 @@ static int ad7768_register_regulators(struct device *dev, struct ad7768_state *s
 	return 0;
 }
 
+static const struct ad7768_chip_info ad7768_chip_info = {
+	.name = "ad7768-1",
+	.channel_spec = ad7768_channels,
+	.num_channels = ARRAY_SIZE(ad7768_channels),
+};
+
 static int ad7768_probe(struct spi_device *spi)
 {
 	struct ad7768_state *st;
@@ -1347,6 +1364,7 @@ static int ad7768_probe(struct spi_device *spi)
 			return ret;
 	}
 
+	st->chip = spi_get_device_match_data(spi);
 	st->spi = spi;
 
 	st->regmap = devm_regmap_init_spi(spi, &ad7768_regmap_config);
@@ -1371,9 +1389,9 @@ static int ad7768_probe(struct spi_device *spi)
 
 	st->mclk_freq = clk_get_rate(st->mclk);
 
-	indio_dev->channels = ad7768_channels;
-	indio_dev->num_channels = ARRAY_SIZE(ad7768_channels);
-	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->channels = st->chip->channel_spec;
+	indio_dev->num_channels = st->chip->num_channels;
+	indio_dev->name = st->chip->name;
 	indio_dev->info = &ad7768_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
@@ -1390,7 +1408,7 @@ static int ad7768_probe(struct spi_device *spi)
 
 	init_completion(&st->completion);
 
-	ret = ad7768_set_channel_label(indio_dev, ARRAY_SIZE(ad7768_channels));
+	ret = ad7768_set_channel_label(indio_dev, st->chip->num_channels);
 	if (ret)
 		return ret;
 
@@ -1409,13 +1427,13 @@ static int ad7768_probe(struct spi_device *spi)
 }
 
 static const struct spi_device_id ad7768_id_table[] = {
-	{ "ad7768-1", 0 },
+	{ "ad7768-1", (kernel_ulong_t)&ad7768_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, ad7768_id_table);
 
 static const struct of_device_id ad7768_of_match[] = {
-	{ .compatible = "adi,ad7768-1" },
+	{ .compatible = "adi,ad7768-1", .data = &ad7768_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ad7768_of_match);
-- 
2.34.1

[PATCH v4 3/4] units: add BASIS_POINTS macro

[Jonathan Santos]

Add macro for basis points unit, defined as a 1/100th of a percent.

Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
---
v4 Changes:
* New patch.
---
 include/linux/units.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/units.h b/include/linux/units.h
index 00e15de33eca..da2c24fe5ee7 100644
--- a/include/linux/units.h
+++ b/include/linux/units.h
@@ -21,6 +21,8 @@
 #define PICO	1000000000000ULL
 #define FEMTO	1000000000000000ULL
 
+#define BASIS_POINTS 10000UL
+
 #define NANOHZ_PER_HZ		1000000000UL
 #define MICROHZ_PER_HZ		1000000UL
 #define MILLIHZ_PER_HZ		1000UL
-- 
2.34.1

[PATCH v4 4/4] iio: adc: ad7768-1: add support for ADAQ776x-1 ADC Family

[Jonathan Santos]

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 controlled by GPIOs provided in
the device tree.

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

Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
---
v4 Changes:
* replaced shift_right() with '>>' operator in the ad7768_fill_scale_tbl()
  function.
* Refactored ad7768_parse_aaf_gain () as requested.
* renamed ad7768_register_regulators() to ad7768_register_vcm_regulator()
  to better reflect its purpose (not sure if this is ok to do).
* Replaced u64_fract with u32_fract -> after reviewing the numbers again, I
  realized that u32_fract is sufficient for these calculations.
* addressed minor suggestions.
* Adopted a new approach to manage the PGA GPIOs, using pga-gpios property.
  This avoids possible conflicts when the internal gpio controller is used
  externally (and also allows hardwiring, as soon as the gpio interface 
  supports it). However, using GPIOs from the device's own controller causes
  a deadlock when claiming direct mode in the ad7768_gpio_get() function.
  This happens because the direct mode remains locked by the ad7768_write_raw()
  function. I have kept this approach for now to discuss a way around this
  problem. It would be good to have the flexibility provided by pga-gpios 
  property.

v3 Changes:
* Fixed trailing comma issues.
* Addressed other minor issues related to dead code, variable declaration,
  etc.
* removed unnecessary comments and relocating some local variables.
* replaced mutex_init() with devm_mutex_init().
* adopted different variables for the input and output of 
  rational_best_approximation(). Also used a u64_fract for the inputs, but 
  kept the unsigned long for the outputs, because could not create a unsigned
  long fraction number type.
* ad7768_set_pga_gain(): removed the pgia enable check, relying on the
  regmap cache.
* Moved aaf gain parsing to its own function, and now returning after
  warning to avoid setting a variable when it shouldn't (avoid confusion).
* AAF gain is now in basis point units, so related multipliers and dividers
  are adjusted accordingly.

v2 Changes:
* Added more details to the commit message.
* Some devices does not provide VCM regulator, so a new field in
  the chip info struct was added to indicate this.
* Added 'select RATIONAL' to Kconfig. Kernel test robot pointed out
  compilation error due to undefined reference to 
  rational_best_approximation().
* Added lock to protect PGA value access.
* precision in the PGA calculation is now dependent of the channel sign
  (signed or unsigned).
* went back to the original scale computation: (st->vref_uv * 2) / 2^n
  instead of st->vref_uv / 2^(n-1).
* rewrote AAF gain check and replaced error returns with warnings. I the
  AAF gain is not provided, a default value is used.
* Addressed other minor suggestions.
---
 drivers/iio/adc/Kconfig    |   1 +
 drivers/iio/adc/ad7768-1.c | 322 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 319 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 58da8255525e..396f6d45fd6d 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -387,6 +387,7 @@ config AD7768_1
 	depends on SPI
 	select REGULATOR
 	select REGMAP_SPI
+	select RATIONAL
 	select IIO_BUFFER
 	select IIO_TRIGGER
 	select IIO_TRIGGERED_BUFFER
diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index 89b0ca8f584c..40fb26ca3804 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -6,6 +6,7 @@
  */
 #include <linux/array_size.h>
 #include <linux/bitfield.h>
+#include <linux/cleanup.h>
 #include <linux/clk.h>
 #include <linux/completion.h>
 #include <linux/delay.h>
@@ -14,8 +15,12 @@
 #include <linux/gpio/driver.h>
 #include <linux/gpio/consumer.h>
 #include <linux/interrupt.h>
+#include <linux/limits.h>
+#include <linux/math.h>
 #include <linux/minmax.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/rational.h>
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/regulator/driver.h>
@@ -107,10 +112,15 @@
 
 #define AD7768_VCM_OFF			0x07
 
+#define ADAQ776X_GAIN_MAX_NANO		(128 * NANO)
+#define ADAQ776X_MAX_GAIN_MODES		8
+
 #define AD7768_TRIGGER_SOURCE_SYNC_IDX 0
 
 #define AD7768_MAX_CHANNELS 1
 
+#define ADAQ7768_PGA_PINS 3
+
 enum ad7768_conv_mode {
 	AD7768_CONTINUOUS,
 	AD7768_ONE_SHOT,
@@ -153,6 +163,51 @@ enum ad7768_scan_type {
 	AD7768_SCAN_TYPE_HIGH_SPEED,
 };
 
+enum {
+	AD7768_PGA_GAIN_0,
+	AD7768_PGA_GAIN_1,
+	AD7768_PGA_GAIN_2,
+	AD7768_PGA_GAIN_3,
+	AD7768_PGA_GAIN_4,
+	AD7768_PGA_GAIN_5,
+	AD7768_PGA_GAIN_6,
+	AD7768_PGA_GAIN_7,
+};
+
+enum {
+	AD7768_AAF_IN1,
+	AD7768_AAF_IN2,
+	AD7768_AAF_IN3,
+};
+
+/* PGA and AAF gains in V/V */
+static const int adaq7768_gains[] = {
+	[AD7768_PGA_GAIN_0] = 325,	/* 0.325 */
+	[AD7768_PGA_GAIN_1] = 650,	/* 0.650 */
+	[AD7768_PGA_GAIN_2] = 1300,	/* 1.300 */
+	[AD7768_PGA_GAIN_3] = 2600,	/* 2.600 */
+	[AD7768_PGA_GAIN_4] = 5200,	/* 5.200 */
+	[AD7768_PGA_GAIN_5] = 10400,	/* 10.400 */
+	[AD7768_PGA_GAIN_6] = 20800,	/* 20.800 */
+};
+
+static const int adaq7769_gains[] = {
+	[AD7768_PGA_GAIN_0] = 1000,	/* 1.000 */
+	[AD7768_PGA_GAIN_1] = 2000,	/* 2.000 */
+	[AD7768_PGA_GAIN_2] = 4000,	/* 4.000 */
+	[AD7768_PGA_GAIN_3] = 8000,	/* 8.000 */
+	[AD7768_PGA_GAIN_4] = 16000,	/* 16.000 */
+	[AD7768_PGA_GAIN_5] = 32000,	/* 32.000 */
+	[AD7768_PGA_GAIN_6] = 64000,	/* 64.000 */
+	[AD7768_PGA_GAIN_7] = 128000,	/* 128.000 */
+};
+
+static const int ad7768_aaf_gains_bp[] = {
+	[AD7768_AAF_IN1] = 10000,	/* 1.000 */
+	[AD7768_AAF_IN2] = 3640,	/* 0.364 */
+	[AD7768_AAF_IN3] = 1430,	/* 0.143 */
+};
+
 /* -3dB cutoff frequency multipliers (relative to ODR) for each filter type. */
 static const int ad7768_filter_3db_odr_multiplier[] = {
 	[AD7768_FILTER_SINC5] = 204,		/* 0.204 */
@@ -217,6 +272,13 @@ struct ad7768_chip_info {
 	const char *name;
 	const struct iio_chan_spec *channel_spec;
 	int num_channels;
+	const int *pga_gains;
+	int num_pga_modes;
+	int default_pga_mode;
+	int pgia_mode2pin_offset;
+	bool has_pga;
+	bool has_variable_aaf;
+	bool has_vcm_regulator;
 };
 
 struct ad7768_state {
@@ -234,14 +296,19 @@ struct ad7768_state {
 	unsigned int samp_freq;
 	unsigned int samp_freq_avail[ARRAY_SIZE(ad7768_mclk_div_rates)];
 	unsigned int samp_freq_avail_len;
+	unsigned int pga_gain_mode;
+	unsigned int aaf_gain;
+	int scale_tbl[ADAQ776X_MAX_GAIN_MODES][2];
 	struct completion completion;
 	struct iio_trigger *trig;
+	struct gpio_descs *pga_gpios;
 	struct gpio_desc *gpio_sync_in;
 	struct gpio_desc *gpio_reset;
 	const char *labels[AD7768_MAX_CHANNELS];
 	struct gpio_chip gpiochip;
 	const struct ad7768_chip_info *chip;
 	bool en_spi_sync;
+	struct mutex pga_lock; /* protect device internal state (PGA) */
 	/*
 	 * DMA (thus cache coherency maintenance) may require the
 	 * transfer buffers to live in their own cache lines.
@@ -464,6 +531,42 @@ static int ad7768_reg_access(struct iio_dev *indio_dev,
 	return ret;
 }
 
+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 u32_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) {
+			fract.numerator *= ad7768_aaf_gains_bp[st->aaf_gain];
+			fract.denominator *= BASIS_POINTS;
+		}
+
+		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 = ((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 */
+	}
+}
+
 static int ad7768_set_sinc3_dec_rate(struct ad7768_state *st,
 				     unsigned int dec_rate)
 {
@@ -565,12 +668,72 @@ static int ad7768_configure_dig_fil(struct iio_dev *dev,
 		st->oversampling_ratio = ad7768_dec_rate_values[dec_rate_idx];
 	}
 
+	/* Update scale table: scale values vary according to the precision */
+	ad7768_fill_scale_tbl(dev);
+
 	ad7768_fill_samp_freq_tbl(st);
 
 	/* A sync-in pulse is required after every configuration change */
 	return ad7768_send_sync_pulse(st);
 }
 
+/*
+ * FIXME: Using GPIOs from the device's own controller causes the device
+ * to get stuck when claiming direct mode in the ad7768_gpio_get() function.
+ * This happens because the direct mode remains locked by the
+ * ad7768_write_raw() function.
+ */
+static int ad7768_setup_pga(struct device *dev, struct ad7768_state *st)
+{
+	st->pga_gpios = devm_gpiod_get_array(dev, "pga", GPIOD_OUT_LOW);
+	if (IS_ERR(st->pga_gpios))
+		return dev_err_probe(dev, PTR_ERR(st->pga_gpios),
+				     "Failed to get PGA gpios.\n");
+
+	if (st->pga_gpios->ndescs != ADAQ7768_PGA_PINS)
+		return dev_err_probe(dev, -EINVAL,
+				     "Expected %d GPIOs for PGA control.\n",
+				     ADAQ7768_PGA_PINS);
+	return 0;
+}
+
+static int ad7768_calc_pga_gain(struct ad7768_state *st, int gain_int,
+				int gain_fract, int precision)
+{
+	u64 gain_nano;
+	u32 tmp;
+
+	gain_nano = gain_int * NANO + gain_fract;
+	gain_nano = clamp(gain_nano, 0, ADAQ776X_GAIN_MAX_NANO);
+	tmp = DIV_ROUND_CLOSEST_ULL(gain_nano << precision, NANO);
+	gain_nano = DIV_ROUND_CLOSEST(st->vref_uv, tmp);
+	if (st->chip->has_variable_aaf)
+		gain_nano = DIV_ROUND_CLOSEST_ULL(gain_nano * BASIS_POINTS,
+						  ad7768_aaf_gains_bp[st->aaf_gain]);
+
+	return find_closest(gain_nano, st->chip->pga_gains,
+			    (int)st->chip->num_pga_modes);
+}
+
+static int ad7768_set_pga_gain(struct ad7768_state *st,
+			       int gain_mode)
+{
+	int pgia_pins_value = abs(gain_mode - st->chip->pgia_mode2pin_offset);
+	DECLARE_BITMAP(bitmap, ADAQ7768_PGA_PINS) = { };
+	int ret;
+
+	guard(mutex)(&st->pga_lock);
+
+	bitmap_write(bitmap, pgia_pins_value, 0, ADAQ7768_PGA_PINS);
+	ret = gpiod_multi_set_value_cansleep(st->pga_gpios, bitmap);
+	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);
@@ -779,6 +942,10 @@ 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)
@@ -806,7 +973,19 @@ 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) {
+			guard(mutex)(&st->pga_lock);
+
+			*val = st->scale_tbl[st->pga_gain_mode][0];
+			*val2 = st->scale_tbl[st->pga_gain_mode][1];
+			return IIO_VAL_INT_PLUS_NANO;
+		}
+
+		temp = (st->vref_uv * 2) / 1000;
+		if (st->chip->has_variable_aaf)
+			temp = (temp * BASIS_POINTS) / ad7768_aaf_gains_bp[st->aaf_gain];
+
+		*val = temp;
 		*val2 = scan_type->realbits;
 
 		return IIO_VAL_FRACTIONAL_LOG2;
@@ -862,18 +1041,39 @@ static int ad7768_read_avail(struct iio_dev *indio_dev,
 		*length = st->samp_freq_avail_len;
 		*type = IIO_VAL_INT;
 		return IIO_AVAIL_LIST;
+	case IIO_CHAN_INFO_SCALE:
+		*vals = (int *)st->scale_tbl;
+		*length = st->chip->num_pga_modes * 2;
+		*type = IIO_VAL_INT_PLUS_NANO;
+		return IIO_AVAIL_LIST;
 	default:
 		return -EINVAL;
 	}
 }
 
+static int ad7768_write_raw_get_fmt(struct iio_dev *indio_dev,
+				    struct iio_chan_spec const *chan, long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		return IIO_VAL_INT_PLUS_NANO;
+	default:
+		return IIO_VAL_INT_PLUS_MICRO;
+	}
+}
+
 static int __ad7768_write_raw(struct iio_dev *indio_dev,
 			      struct iio_chan_spec const *chan,
 			      int val, int val2, long info)
 {
 	struct ad7768_state *st = iio_priv(indio_dev);
+	const struct iio_scan_type *scan_type;
 	int ret;
 
+	scan_type = iio_get_current_scan_type(indio_dev, chan);
+	if (IS_ERR(scan_type))
+		return PTR_ERR(scan_type);
+
 	switch (info) {
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		return ad7768_set_freq(st, val);
@@ -885,6 +1085,21 @@ static int __ad7768_write_raw(struct iio_dev *indio_dev,
 
 		/* Update sampling frequency */
 		return ad7768_set_freq(st, st->samp_freq);
+	case IIO_CHAN_INFO_SCALE: {
+		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);
+	}
 	default:
 		return -EINVAL;
 	}
@@ -926,6 +1141,7 @@ static const struct iio_info ad7768_info = {
 	.read_raw = &ad7768_read_raw,
 	.read_avail = &ad7768_read_avail,
 	.write_raw = &ad7768_write_raw,
+	.write_raw_get_fmt = &ad7768_write_raw_get_fmt,
 	.read_label = ad7768_read_label,
 	.get_current_scan_type = &ad7768_get_current_scan_type,
 	.debugfs_reg_access = &ad7768_reg_access,
@@ -1309,8 +1525,9 @@ static const struct regulator_desc vcm_desc = {
 	.owner = THIS_MODULE,
 };
 
-static int ad7768_register_regulators(struct device *dev, struct ad7768_state *st,
-				      struct iio_dev *indio_dev)
+static int ad7768_register_vcm_regulator(struct device *dev,
+					 struct ad7768_state *st,
+					 struct iio_dev *indio_dev)
 {
 	struct regulator_config config = {
 		.dev = dev,
@@ -1332,10 +1549,82 @@ static int ad7768_register_regulators(struct device *dev, struct ad7768_state *s
 	return 0;
 }
 
+static int ad7768_parse_aaf_gain(struct device *dev, struct ad7768_state *st)
+{
+	bool aaf_gain_provided;
+	u32 val;
+	int ret;
+
+	ret = device_property_read_u32(dev, "adi,aaf-gain-bp", &val);
+	if (ret == -EINVAL)
+		aaf_gain_provided = false;
+	else if (ret)
+		return dev_err_probe(dev, ret, "Failed to get AAF gain value\n");
+	else
+		aaf_gain_provided = true;
+
+	if (!aaf_gain_provided) {
+		if (st->chip->has_variable_aaf)
+			st->aaf_gain = AD7768_AAF_IN1;
+		return 0;
+	}
+
+	if (aaf_gain_provided && !st->chip->has_variable_aaf)
+		return dev_err_probe(dev, -EOPNOTSUPP,
+				     "AAF gain not supported for %s\n", st->chip->name);
+
+	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;
+}
+
 static const struct ad7768_chip_info ad7768_chip_info = {
 	.name = "ad7768-1",
 	.channel_spec = ad7768_channels,
 	.num_channels = ARRAY_SIZE(ad7768_channels),
+	.has_vcm_regulator = true,
+};
+
+static const struct ad7768_chip_info adaq7767_chip_info = {
+	.name = "adaq7767-1",
+	.channel_spec = ad7768_channels,
+	.num_channels = ARRAY_SIZE(ad7768_channels),
+	.has_variable_aaf = true,
+};
+
+static const struct ad7768_chip_info adaq7768_chip_info = {
+	.name = "adaq7768-1",
+	.channel_spec = adaq776x_channels,
+	.num_channels = ARRAY_SIZE(adaq776x_channels),
+	.pga_gains = adaq7768_gains,
+	.default_pga_mode = AD7768_PGA_GAIN_2,
+	.num_pga_modes = ARRAY_SIZE(adaq7768_gains),
+	.pgia_mode2pin_offset = 6,
+	.has_pga = true,
+};
+
+static const struct ad7768_chip_info adaq7769_chip_info = {
+	.name = "adaq7769-1",
+	.channel_spec = adaq776x_channels,
+	.num_channels = ARRAY_SIZE(adaq776x_channels),
+	.pga_gains = adaq7769_gains,
+	.default_pga_mode = AD7768_PGA_GAIN_0,
+	.num_pga_modes = ARRAY_SIZE(adaq7769_gains),
+	.pgia_mode2pin_offset = 0,
+	.has_pga = true,
+	.has_variable_aaf = true,
 };
 
 static int ad7768_probe(struct spi_device *spi)
@@ -1396,7 +1685,13 @@ static int ad7768_probe(struct spi_device *spi)
 	indio_dev->modes = INDIO_DIRECT_MODE;
 
 	/* Register VCM output regulator */
-	ret = ad7768_register_regulators(&spi->dev, st, indio_dev);
+	if (st->chip->has_vcm_regulator) {
+		ret = ad7768_register_vcm_regulator(&spi->dev, st, indio_dev);
+		if (ret)
+			return ret;
+	}
+
+	ret = ad7768_parse_aaf_gain(&spi->dev, st);
 	if (ret)
 		return ret;
 
@@ -1407,6 +1702,19 @@ static int ad7768_probe(struct spi_device *spi)
 	}
 
 	init_completion(&st->completion);
+	ret = devm_mutex_init(&spi->dev, &st->pga_lock);
+	if (ret)
+		return ret;
+
+	if (st->chip->has_pga) {
+		ret = ad7768_setup_pga(&spi->dev, st);
+		if (ret)
+			return ret;
+
+		ret = ad7768_set_pga_gain(st, st->chip->default_pga_mode);
+		if (ret)
+			return ret;
+	}
 
 	ret = ad7768_set_channel_label(indio_dev, st->chip->num_channels);
 	if (ret)
@@ -1428,12 +1736,18 @@ static int ad7768_probe(struct spi_device *spi)
 
 static const struct spi_device_id ad7768_id_table[] = {
 	{ "ad7768-1", (kernel_ulong_t)&ad7768_chip_info },
+	{ "adaq7767-1", (kernel_ulong_t)&adaq7767_chip_info },
+	{ "adaq7768-1", (kernel_ulong_t)&adaq7768_chip_info },
+	{ "adaq7769-1", (kernel_ulong_t)&adaq7769_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(spi, ad7768_id_table);
 
 static const struct of_device_id ad7768_of_match[] = {
 	{ .compatible = "adi,ad7768-1", .data = &ad7768_chip_info },
+	{ .compatible = "adi,adaq7767-1", .data = &adaq7767_chip_info },
+	{ .compatible = "adi,adaq7768-1", .data = &adaq7768_chip_info },
+	{ .compatible = "adi,adaq7769-1", .data = &adaq7769_chip_info },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, ad7768_of_match);
-- 
2.34.1

Re: [PATCH v4 3/4] units: add BASIS_POINTS macro

[Andy Shevchenko]

On Wed, Nov 26, 2025 at 06:56:26PM -0300, Jonathan Santos wrote:
> Add macro for basis points unit, defined as a 1/100th of a percent.

Fine, but why? Can you elaborate more on use cases?

...


Perhaps you also want to add a PERCENT to understand the relationship
between two?

> +#define BASIS_POINTS 10000UL

And this needs a comment with an example (something like I asked above
for the commit message).


-- 
With Best Regards,
Andy Shevchenko

Re: [PATCH v4 1/4] dt-bindings: iio: adc: ad7768-1: add new supported parts

[Krzysztof Kozlowski]

On Wed, Nov 26, 2025 at 06:56:02PM -0300, Jonathan Santos wrote:
> 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, and for PGA gain, supported by ADAQ7768-1
> and ADAQ7769-1:
> 	adi,aaf-gain-bp
> 	pga-gpios
> 
> Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

Best regards,
Krzysztof

Re: [PATCH v4 4/4] iio: adc: ad7768-1: add support for ADAQ776x-1 ADC Family

[Jonathan Cameron]

On Wed, 26 Nov 2025 18:56:35 -0300
Jonathan Santos <Jonathan.Santos@analog.com> wrote:

> 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 controlled by GPIOs provided in
> the device tree.
> 
> The AAF gain is defined by hardware connections and should be specified
> in the device tree.
> 
> Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
> ---
> v4 Changes:
> * replaced shift_right() with '>>' operator in the ad7768_fill_scale_tbl()
>   function.
> * Refactored ad7768_parse_aaf_gain () as requested.
> * renamed ad7768_register_regulators() to ad7768_register_vcm_regulator()
>   to better reflect its purpose (not sure if this is ok to do).
> * Replaced u64_fract with u32_fract -> after reviewing the numbers again, I
>   realized that u32_fract is sufficient for these calculations.
> * addressed minor suggestions.
> * Adopted a new approach to manage the PGA GPIOs, using pga-gpios property.
>   This avoids possible conflicts when the internal gpio controller is used
>   externally (and also allows hardwiring, as soon as the gpio interface 
>   supports it). However, using GPIOs from the device's own controller causes
>   a deadlock when claiming direct mode in the ad7768_gpio_get() function.
>   This happens because the direct mode remains locked by the ad7768_write_raw()
>   function. I have kept this approach for now to discuss a way around this
>   problem. It would be good to have the flexibility provided by pga-gpios 
>   property.

See below. I 'think' this is easy enough to resolve by relaxing the need
to claim direct mode for scale changes - if it were an external gpio that
should be safe anyway and if it is internal, then the inner direct mode
claim should do the job.

Other than that, to me this code looks nice and clean so hopefully we can
merge it once that fix is in place.

Thanks,

Jonathan




> @@ -464,6 +531,42 @@ static int ad7768_reg_access(struct iio_dev *indio_dev,
>  	return ret;
>  }

>  
> +/*
> + * FIXME: Using GPIOs from the device's own controller causes the device
> + * to get stuck when claiming direct mode in the ad7768_gpio_get() function.
> + * This happens because the direct mode remains locked by the
> + * ad7768_write_raw() function.

Ouch. I'm not spotting why we need to claim direct mode for this particular
use of write_raw().  Seems safe enough to modify the gain whilst in buffered
mode.  Bit confusing perhaps if a user does this, but not a functional problem.
Sometimes we over protect in that path because userspace rarely uses write_raw
with the buffer mode enabled as it doesn't work on many devices.

So I'd squash the __ad7768_write_raw() back into ad7768_write_raw()
and claim and release direct mode only in the switch legs that need it
(oversampling and sampling frequency probably).  That should resolve
the deadlock.


> + */
> +static int ad7768_setup_pga(struct device *dev, struct ad7768_state *st)
> +{
> +	st->pga_gpios = devm_gpiod_get_array(dev, "pga", GPIOD_OUT_LOW);
> +	if (IS_ERR(st->pga_gpios))
> +		return dev_err_probe(dev, PTR_ERR(st->pga_gpios),
> +				     "Failed to get PGA gpios.\n");
> +
> +	if (st->pga_gpios->ndescs != ADAQ7768_PGA_PINS)
> +		return dev_err_probe(dev, -EINVAL,
> +				     "Expected %d GPIOs for PGA control.\n",
> +				     ADAQ7768_PGA_PINS);
> +	return 0;
> +}