[PATCH v12 1/2] dt-bindings: adc: add AD7173

[PATCH v12 1/2] dt-bindings: adc: add AD7173

[Dumitru Ceclan]

The AD7173 family offer a complete integrated Sigma-Delta ADC solution
which can be used in high precision, low noise single channel applications
or higher speed multiplexed applications. The Sigma-Delta ADC is intended
primarily for measurement of signals close to DC but also delivers
outstanding performance with input bandwidths out to ~10kHz.

Signed-off-by: Dumitru Ceclan <mitrutzceclan@gmail.com>
---

V11->V12
 - Drop "binding", describe hardware in binding description
 - Rename refin and refin2 to vref and vref2
 - Add better description to external references to better show that the voltage
    value that needs to be specified is the difference between the positive and
    negative reference pins
 - Add optional clocks properties
 - Add optional adi,clock-select property
 - Add option for second interrupt, error
 - Add description to interrupts
V10->V11
 - Fix example warning: '#gpio-cells' is a dependency of 'gpio-controller'
 - Add description to #gpio-cells property
V9->V10
 - Fix dt_binding_check type warning from adi,reference-select
V8->v9
 - Add gpio-controller and "#gpio-cells" properties
 - Add missing avdd2 and iovdd supplies
 - Add string type to reference-select
V7->V8
 - include missing fix from V6
V6->V7 <no changes>
V5->V6
 - Moved global required property to proper placement
V4 -> V5
 - Use string enum instead of integers for "adi,reference-select"
 - Fix conditional checking in regards to compatible
V3 -> V4
 - include supply attributes
 - add channel attribute for selecting conversion reference
V2 -> V3
 - remove redundant descriptions
 - use referenced 'bipolar' property
 - remove newlines from example
V1 -> V2 <no changes>

 .../bindings/iio/adc/adi,ad7173.yaml          | 242 ++++++++++++++++++
 1 file changed, 242 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
new file mode 100644
index 000000000000..4d0870cc014c
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
@@ -0,0 +1,242 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2023 Analog Devices Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/adi,ad7173.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD7173 ADC
+
+maintainers:
+  - Ceclan Dumitru <dumitru.ceclan@analog.com>
+
+description: |
+  Analog Devices AD717x ADC's:
+  The AD717x family offer a complete integrated Sigma-Delta ADC solution which
+  can be used in high precision, low noise single channel applications
+  (Life Science measurements) or higher speed multiplexed applications
+  (Factory Automation PLC Input modules). The Sigma-Delta ADC is intended
+  primarily for measurement of signals close to DC but also delivers
+  outstanding performance with input bandwidths out to ~10kHz.
+
+  Datasheets for supported chips:
+    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7172-2.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7173-8.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7175-2.pdf
+    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7176-2.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,ad7172-2
+      - adi,ad7173-8
+      - adi,ad7175-2
+      - adi,ad7176-2
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    minItems: 1
+    description: |
+      Ready interrupt: multiplexed with SPI data out. While SPI CS is low,
+      can be used to indicate the completion of a conversion.
+
+      Error: The three error bits in the status register (ADC_ERROR, CRC_ERROR,
+      and REG_ERROR) are OR'ed, inverted, and mapped to the ERROR pin. Therefore,
+      the ERROR pin indicates that an error has occurred.
+
+  interrupt-names:
+    minItems: 1
+    items:
+      - const: rdy
+      - const: err
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+  spi-max-frequency:
+    maximum: 20000000
+
+  gpio-controller:
+    description: Marks the device node as a GPIO controller.
+
+  "#gpio-cells":
+    const: 2
+    description:
+      The first cell is the GPIO number and the second cell specifies
+      GPIO flags, as defined in <dt-bindings/gpio/gpio.h>.
+
+  vref-supply:
+    description: |
+      Differential external reference supply used for conversion. The reference
+      voltage (Vref) specified here must be the voltage difference between the
+      REF+ and REF- pins: Vref = (REF+) - (REF-).
+
+  vref2-supply:
+    description: |
+      Differential external reference supply used for conversion. The reference
+      voltage (Vref2) specified here must be the voltage difference between the
+      REF2+ and REF2- pins: Vref2 = (REF2+) - (REF2-).
+
+  avdd-supply:
+    description: avdd supply, can be used as reference for conversion.
+
+  avdd2-supply:
+    description: avdd2 supply, used as the input to the internal voltage regulator.
+
+  iovdd-supply:
+    description: iovdd supply, used for the chip digital interface.
+
+  clocks:
+    maxItems: 1
+    description: |
+      Optional external clock source. Can include one clock source: external
+      clock or external crystal.
+
+  clock-names:
+    enum:
+      - ext-clk
+      - xtal
+
+  adi,clock-select:
+    description: |
+      Select the ADC clock source. Valid values are:
+      int         : Internal oscillator
+      int-out     : Internal oscillator with output on XTAL2 pin
+      ext-clk     : External clock input on XTAL2 pin
+      xtal        : External crystal on XTAL1 and XTAL2 pins
+
+    $ref: /schemas/types.yaml#/definitions/string
+    enum:
+      - int
+      - int-out
+      - ext-clk
+      - xtal
+    default: int
+
+patternProperties:
+  "^channel@[0-9a-f]$":
+    type: object
+    $ref: adc.yaml
+    unevaluatedProperties: false
+
+    properties:
+      reg:
+        minimum: 0
+        maximum: 15
+
+      diff-channels:
+        items:
+          minimum: 0
+          maximum: 31
+
+      adi,reference-select:
+        description: |
+          Select the reference source to use when converting on
+          the specific channel. Valid values are:
+          vref       : REF+  /REF−
+          vref2      : REF2+ /REF2−
+          refout-avss: REFOUT/AVSS (Internal reference)
+          avdd       : AVDD
+
+          External reference ref2 only available on ad7173-8.
+          If not specified, internal reference used.
+        $ref: /schemas/types.yaml#/definitions/string
+        enum:
+          - vref
+          - vref2
+          - refout-avss
+          - avdd
+        default: refout-avss
+
+    required:
+      - reg
+      - diff-channels
+
+required:
+  - compatible
+  - reg
+
+allOf:
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+  - if:
+      properties:
+        compatible:
+          not:
+            contains:
+              const: adi,ad7173-8
+    then:
+      properties:
+        vref2-supply: false
+      patternProperties:
+        "^channel@[0-9a-f]$":
+          properties:
+            adi,reference-select:
+              enum:
+                - vref
+                - refout-avss
+                - avdd
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      adc@0 {
+        compatible = "adi,ad7173-8";
+        reg = <0>;
+
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
+        interrupt-names = "rdy";
+        interrupt-parent = <&gpio>;
+        spi-max-frequency = <5000000>;
+        gpio-controller;
+        #gpio-cells = <2>;
+
+        vref-supply = <&dummy_regulator>;
+
+        channel@0 {
+          reg = <0>;
+          bipolar;
+          diff-channels = <0 1>;
+          adi,reference-select = "vref";
+        };
+
+        channel@1 {
+          reg = <1>;
+          diff-channels = <2 3>;
+        };
+
+        channel@2 {
+          reg = <2>;
+          bipolar;
+          diff-channels = <4 5>;
+        };
+
+        channel@3 {
+          reg = <3>;
+          bipolar;
+          diff-channels = <6 7>;
+        };
+
+        channel@4 {
+          reg = <4>;
+          diff-channels = <8 9>;
+          adi,reference-select = "avdd";
+        };
+      };
+    };
-- 
2.42.0

[PATCH v12 2/2] iio: adc: ad7173: add AD7173 driver

[Dumitru Ceclan]

The AD7173 family offer a complete integrated Sigma-Delta ADC solution
which can be used in high precision, low noise single channel
applications or higher speed multiplexed applications. The Sigma-Delta
ADC is intended primarily for measurement of signals close to DC but also
delivers outstanding performance with input bandwidths out to ~10kHz.

Reviewed-by: Andy Shevchenko <andy@kernel.org>
Reviewed-by: Michael Walle <michael@walle.cc> # for gpio-regmap
Signed-off-by: Dumitru Ceclan <mitrutzceclan@gmail.com>
---

V11-> V12
 - rename refin, refin2 to vref, vref2
V10-> V11 <no changes>
V9 -> V10 <no changes>
V8 -> V9
 - Add '(x)' to some macro's definition to reduce NO of checks
 - Use reg 0 constant definition in debug_reg_access()
 - Rename  channels_st_priv_arr to chans_st_arr
 - Remove unnecessary u32 cast from read_raw()
 - Compute read_raw() offset instead of constant
 - Add offset comments to data rate arrays
 - Removed redundant newline in _parse_channel_config()
V7 -> V8
 - remove Kconfig commas
 - reorder include <...gpio/regmap.h>
 - GPO12_DATA(x)  from BIT(x) -> BIT(x+0)
 - use the same pointer to dev in ad7173_setup()
 - rewrite temp channel read_raw scale for better readability
 - add comment to explain temp channel offset
 - follow multi-line comment style
 - change ref_sel type to signed int
 - use fwnode_property_match_property_string()
V6 -> V7
 - format Kconfig supported models using '-'
 - include types.h instead of stddef.h
 - change device_info->num_gpios type to u8
 - reorder fields in ad7173_state, place ad_sigma_delta
 - reorder fields in ad7173_device_info, group by type
 - add default case in read_raw()
 - rename ad7173_debug() to ad7173_debug_reg_access()
 - remove explicit u8 cast
 - remove return 0; for offset in read_raw()
 - add '\n' to error messages
 - reorder probe variables -> reversed xmas tree
 - remove redundant inner commas in of_match and id_table
 - simplify selected reference code by setting default value and ignoring
   fwnode_property_read_string() error
 - use match_string() for finding selected reference
 - err on no channels specified
 - add missing fwnode_handle_put(child) on err return branches
 - remove spi_set_drvdata() from probe
 - remove offset variable from find_live_config(), not used
 - add comment showing a generic LRU implementation might be used if one
   will exist
 - MISC:  add blank line to chanel_config struct, trailing comma ref_sel_str[],
   remove blank line in update_scan_mode(), add spaces around '/'
V5->V6 <no changes>
V4 -> V5
 - List Kconfig supported models one per line
 - Include <array_size.h> and <container_of.h>
 - Remove bits.h and kernel.h include
 - Add spaces before '\' on multi-line definitions
 - Change constant definition name from "..._MICROV" to "..._uV"
 - Change ad7173_channel_config attributes order for grouping by type
 - Remove redundant {} in ad7173_gpio_init()
 - Add array with reference select strings
 - Change parsing of device tree adi,reference-select from integer to string
 - Change indentation  for ad7173_find_live_config() header
 - Use struct_group() in config struct
 - Use offsetofend() and sizeof_field() in ad7173_find_live_config()
 - Split line on logic operator in ad7173_find_live_config() at configs comparison
 - Use IDA for config slots allocation
 - Reverse xmas tree order for probe local variables
 - Use BIT() for computing bipolar channels offset
 - Change (MICRO/MILLI) to MILLI in read_raw for integer part of sampling frequency
 - MISC: remove blank line, use 0 value dirrectly, one line statement devm_kcalloc()
V3 -> V4
 - cleaned up includes
 - add ad7173_gpio_disable(), include to devm actions
 - remove iio_device_claim_direct_mode() from update_scan_mode()
 - always set differential iio_chan attribute to true, retain bipolar info only in private struct
 - store multiple regulators in state for voltage references
 - compute read_raw offset depending on channel used reference
 - configure channel setup using selected reference
 - add ad7173_get_ref_voltage_milli() 
 - clean up ad7173_fw_sparse_channel_config() changing array access of channel structs to pointers
 - retain chip name in st->info structure
 - use spi_device_get_match_data() in probe
V2 -> V3
 - change Kconfig GPIO_REGMAP and REGMAP_SPI to be conditioned by GPIOLIB
 - cast chip info to (kernel_ulong_t) to suppress warnings
 - adjust copyright year to reflect the out-of-tree history
 - remove unused sysfs and trigger header files
 - clean up defined macros by using FIELD_PREP( ) inline
 - use DECLARE_BITMAP( ) for defiining cfg_slots_status
 - use clear/set _bit instead of assign_bit
 - rename state field regmap to reg_gpiocon_regmap to better represent usage
 - replace container_of( ) usages to ad_sigma_delta_to_ad7173( )
 - improve readability of sampling frequency conversion in write_raw( )
				specifying conversion from Micro to Milli
 - use iio_device_claim_direct_mode( ) correctly in write_raw( )
 - flip logic in write_raw( ) to reduce line length
 - pass only state struct to gpio_init function
 - remove else branch at end of probe
 - remove comma after list terminator for of_match and id_table arrays
 - clarify write_raw( ) realbits 32 bit size check in a comment
 - change parsed fw property 'adi,bipolar' to 'bipolar' to matched referenced adc.yaml 
 - use reg_set_base for gpio regmap xlate 
V1 -> V2
 - keep original out-of-tree AD7173 naming
 - remove gpio_cleanup
 - handle 32bit realbits offset case
 - use iio_device_claim_direct_mode, drop own mutex
 - use dev_err_probe
 - cleanup headers include
 - use GENMASK() and FIELD_PREP()
 - use HZ_PER_MHZ
 - change #ifdef GPIOLIB to if( IS_ENABLED(CONFIG_GPIOLIB)) 
 - use gpio-regmap
 - change boolean flag in info struct to number of gpios
 - NIH memset64
 - use struct pointers for config comparison
 - use spi_write_then_read for ADC reset
 - use stack allocated buffer for reset
 - define constant for reset sequence size
 - use kcalloc instead of kzalloc
 - change of naming to fw of dt parse function
 - change de-referencing chain to local variable dev in multiple locations
 - drop write_raw_get_fmt
 - add driver private data to spi_device_id table
 - use fsleep() instead of usleep_range()
 - put config value inline
 - align read/write raw arguments
 - remove zeroed values from channel templates structure
 - define constants for temperature sensor positive and negative inputs
 - always enable temperature channel
 - configure spi clock phase and polarity from driver
 misc changes (test bit, return disable all, indentation fix, change statements to single line)

 drivers/iio/adc/Kconfig  |  17 +
 drivers/iio/adc/Makefile |   1 +
 drivers/iio/adc/ad7173.c | 974 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 992 insertions(+)
 create mode 100644 drivers/iio/adc/ad7173.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 3b73c509bd68..c32054afdfc4 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -70,6 +70,23 @@ config AD7124
 	  To compile this driver as a module, choose M here: the module will be
 	  called ad7124.
 
+config AD7173
+	tristate "Analog Devices AD7173 driver"
+	depends on SPI_MASTER
+	select AD_SIGMA_DELTA
+	select GPIO_REGMAP if GPIOLIB
+	select REGMAP_SPI if GPIOLIB
+	help
+	  Say yes here to build support for Analog Devices AD7173 and similar ADC
+	  Currently supported models:
+	   - AD7172-2
+	   - AD7173-8
+	   - AD7175-2
+	   - AD7176-2
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ad7173.
+
 config AD7192
 	tristate "Analog Devices AD7190 AD7192 AD7193 AD7195 ADC driver"
 	depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index d2fda54a3259..dd4210a3634f 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_AD7091R) += ad7091r-base.o
 obj-$(CONFIG_AD7091R5) += ad7091r5.o
 obj-$(CONFIG_AD7091R8) += ad7091r8.o
 obj-$(CONFIG_AD7124) += ad7124.o
+obj-$(CONFIG_AD7173) += ad7173.o
 obj-$(CONFIG_AD7192) += ad7192.o
 obj-$(CONFIG_AD7266) += ad7266.o
 obj-$(CONFIG_AD7280) += ad7280a.o
diff --git a/drivers/iio/adc/ad7173.c b/drivers/iio/adc/ad7173.c
new file mode 100644
index 000000000000..6d3e04423969
--- /dev/null
+++ b/drivers/iio/adc/ad7173.c
@@ -0,0 +1,974 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * AD7172-2/AD7173-8/AD7175-2/AD7176-2 SPI ADC driver
+ * Copyright (C) 2015, 2023 Analog Devices, Inc.
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitfield.h>
+#include <linux/bitmap.h>
+#include <linux/container_of.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/driver.h>
+#include <linux/gpio/regmap.h>
+#include <linux/idr.h>
+#include <linux/interrupt.h>
+#include <linux/math64.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+#include <linux/types.h>
+#include <linux/units.h>
+
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#include <linux/iio/adc/ad_sigma_delta.h>
+
+#define AD7173_REG_COMMS		0x00
+#define AD7173_REG_ADC_MODE		0x01
+#define AD7173_REG_INTERFACE_MODE	0x02
+#define AD7173_REG_CRC			0x03
+#define AD7173_REG_DATA			0x04
+#define AD7173_REG_GPIO			0x06
+#define AD7173_REG_ID			0x07
+#define AD7173_REG_CH(x)		(0x10 + (x))
+#define AD7173_REG_SETUP(x)		(0x20 + (x))
+#define AD7173_REG_FILTER(x)		(0x28 + (x))
+#define AD7173_REG_OFFSET(x)		(0x30 + (x))
+#define AD7173_REG_GAIN(x)		(0x38 + (x))
+
+#define AD7173_RESET_LENGTH		BITS_TO_BYTES(64)
+
+#define AD7173_CH_ENABLE		BIT(15)
+#define AD7173_CH_SETUP_SEL_MASK	GENMASK(14, 12)
+#define AD7173_CH_SETUP_AINPOS_MASK	GENMASK(9, 5)
+#define AD7173_CH_SETUP_AINNEG_MASK	GENMASK(4, 0)
+
+#define AD7173_CH_ADDRESS(pos, neg) \
+	(FIELD_PREP(AD7173_CH_SETUP_AINPOS_MASK, pos) | \
+	 FIELD_PREP(AD7173_CH_SETUP_AINNEG_MASK, neg))
+#define AD7173_AIN_TEMP_POS	17
+#define AD7173_AIN_TEMP_NEG	18
+
+#define AD7172_ID			0x00d0
+#define AD7173_ID			0x30d0
+#define AD7175_ID			0x0cd0
+#define AD7176_ID			0x0c90
+#define AD7173_ID_MASK			GENMASK(15, 4)
+
+#define AD7173_ADC_MODE_REF_EN		BIT(15)
+#define AD7173_ADC_MODE_SING_CYC	BIT(13)
+#define AD7173_ADC_MODE_MODE_MASK	GENMASK(6, 4)
+#define AD7173_ADC_MODE_CLOCKSEL_MASK	GENMASK(3, 2)
+
+#define AD7173_GPIO_PDSW	BIT(14)
+#define AD7173_GPIO_OP_EN2_3	BIT(13)
+#define AD7173_GPIO_MUX_IO	BIT(12)
+#define AD7173_GPIO_SYNC_EN	BIT(11)
+#define AD7173_GPIO_ERR_EN	BIT(10)
+#define AD7173_GPIO_ERR_DAT	BIT(9)
+#define AD7173_GPIO_GP_DATA3	BIT(7)
+#define AD7173_GPIO_GP_DATA2	BIT(6)
+#define AD7173_GPIO_IP_EN1	BIT(5)
+#define AD7173_GPIO_IP_EN0	BIT(4)
+#define AD7173_GPIO_OP_EN1	BIT(3)
+#define AD7173_GPIO_OP_EN0	BIT(2)
+#define AD7173_GPIO_GP_DATA1	BIT(1)
+#define AD7173_GPIO_GP_DATA0	BIT(0)
+
+#define AD7173_GPO12_DATA(x)	BIT((x) + 0)
+#define AD7173_GPO23_DATA(x)	BIT((x) + 4)
+#define AD7173_GPO_DATA(x)	((x) < 2 ? AD7173_GPO12_DATA(x) : AD7173_GPO23_DATA(x))
+
+#define AD7173_INTERFACE_DATA_STAT	BIT(6)
+#define AD7173_INTERFACE_DATA_STAT_EN(x) \
+	FIELD_PREP(AD7173_INTERFACE_DATA_STAT, x)
+
+#define AD7173_SETUP_BIPOLAR		BIT(12)
+#define AD7173_SETUP_AREF_BUF_MASK	GENMASK(11, 10)
+#define AD7173_SETUP_AIN_BUF_MASK	GENMASK(9, 8)
+
+#define AD7173_SETUP_REF_SEL_MASK	GENMASK(5, 4)
+#define AD7173_SETUP_REF_SEL_AVDD1_AVSS	0x3
+#define AD7173_SETUP_REF_SEL_INT_REF	0x2
+#define AD7173_SETUP_REF_SEL_EXT_REF2	0x1
+#define AD7173_SETUP_REF_SEL_EXT_REF	0x0
+#define AD7173_VOLTAGE_INT_REF_uV	2500000
+#define AD7173_TEMP_SENSIIVITY_uV_per_C	477
+
+#define AD7173_FILTER_ODR0_MASK		GENMASK(5, 0)
+#define AD7173_MAX_CONFIGS		8
+
+enum ad7173_ids {
+	ID_AD7172_2,
+	ID_AD7173_8,
+	ID_AD7175_2,
+	ID_AD7176_2,
+};
+
+struct ad7173_device_info {
+	const unsigned int *sinc5_data_rates;
+	unsigned int num_sinc5_data_rates;
+	unsigned int num_channels;
+	unsigned int num_configs;
+	unsigned int num_inputs;
+	unsigned int clock;
+	unsigned int id;
+	char *name;
+	bool has_temp;
+	u8 num_gpios;
+};
+
+struct ad7173_channel_config {
+	u8 cfg_slot;
+	bool live;
+
+	/* Following fields are used to compare equality. */
+	struct_group(config_props,
+		bool bipolar;
+		bool input_buf;
+		u8 odr;
+		u8 ref_sel;
+	);
+};
+
+struct ad7173_channel {
+	unsigned int chan_reg;
+	unsigned int ain;
+	struct ad7173_channel_config cfg;
+};
+
+struct ad7173_state {
+	struct ad_sigma_delta sd;
+	const struct ad7173_device_info *info;
+	struct ad7173_channel *channels;
+	struct regulator_bulk_data regulators[3];
+	unsigned int adc_mode;
+	unsigned int interface_mode;
+	unsigned int num_channels;
+	struct ida cfg_slots_status;
+	unsigned long long config_usage_counter;
+	unsigned long long *config_cnts;
+#if IS_ENABLED(CONFIG_GPIOLIB)
+	struct regmap *reg_gpiocon_regmap;
+	struct gpio_regmap *gpio_regmap;
+#endif
+};
+
+static const unsigned int ad7173_sinc5_data_rates[] = {
+	6211000, 6211000, 6211000, 6211000, 6211000, 6211000, 5181000, 4444000,	/*  0-7  */
+	3115000, 2597000, 1007000, 503800,  381000,  200300,  100500,  59520,	/*  8-15 */
+	49680,	 20010,	  16333,   10000,   5000,    2500,    1250,		/* 16-22 */
+};
+
+static const unsigned int ad7175_sinc5_data_rates[] = {
+	50000000, 41667000, 31250000, 27778000,	/*  0-3  */
+	20833000, 17857000, 12500000, 10000000,	/*  4-7  */
+	5000000,  2500000,  1000000,  500000,	/*  8-11 */
+	397500,   200000,   100000,   59920,	/* 12-15 */
+	49960,    20000,    16666,    10000,	/* 16-19 */
+	5000,					/* 20    */
+};
+
+static const struct ad7173_device_info ad7173_device_info[] = {
+	[ID_AD7172_2] = {
+		.name = "ad7172-2",
+		.id = AD7172_ID,
+		.num_inputs = 5,
+		.num_channels = 4,
+		.num_configs = 4,
+		.num_gpios = 2,
+		.has_temp = true,
+		.clock = 2 * HZ_PER_MHZ,
+		.sinc5_data_rates = ad7173_sinc5_data_rates,
+		.num_sinc5_data_rates = ARRAY_SIZE(ad7173_sinc5_data_rates),
+	},
+	[ID_AD7173_8] = {
+		.name = "ad7173-8",
+		.id = AD7173_ID,
+		.num_inputs = 17,
+		.num_channels = 16,
+		.num_configs = 8,
+		.num_gpios = 4,
+		.has_temp = true,
+		.clock = 2 * HZ_PER_MHZ,
+		.sinc5_data_rates = ad7173_sinc5_data_rates,
+		.num_sinc5_data_rates = ARRAY_SIZE(ad7173_sinc5_data_rates),
+	},
+	[ID_AD7175_2] = {
+		.name = "ad7175-2",
+		.id = AD7175_ID,
+		.num_inputs = 5,
+		.num_channels = 4,
+		.num_configs = 4,
+		.num_gpios = 2,
+		.has_temp = true,
+		.clock = 16 * HZ_PER_MHZ,
+		.sinc5_data_rates = ad7175_sinc5_data_rates,
+		.num_sinc5_data_rates = ARRAY_SIZE(ad7175_sinc5_data_rates),
+	},
+	[ID_AD7176_2] = {
+		.name = "ad7176-2",
+		.id = AD7176_ID,
+		.num_inputs = 5,
+		.num_channels = 4,
+		.num_configs = 4,
+		.num_gpios = 2,
+		.has_temp = false,
+		.clock = 16 * HZ_PER_MHZ,
+		.sinc5_data_rates = ad7175_sinc5_data_rates,
+		.num_sinc5_data_rates = ARRAY_SIZE(ad7175_sinc5_data_rates),
+	},
+};
+
+static const char *const ad7173_ref_sel_str[] = {
+	[AD7173_SETUP_REF_SEL_EXT_REF]    = "vref",
+	[AD7173_SETUP_REF_SEL_EXT_REF2]   = "vref2",
+	[AD7173_SETUP_REF_SEL_INT_REF]    = "refout-avss",
+	[AD7173_SETUP_REF_SEL_AVDD1_AVSS] = "avdd",
+};
+
+#if IS_ENABLED(CONFIG_GPIOLIB)
+
+static const struct regmap_range ad7173_range_gpio[] = {
+	regmap_reg_range(AD7173_REG_GPIO, AD7173_REG_GPIO),
+};
+
+static const struct regmap_access_table ad7173_access_table = {
+	.yes_ranges = ad7173_range_gpio,
+	.n_yes_ranges = ARRAY_SIZE(ad7173_range_gpio),
+};
+
+static const struct regmap_config ad7173_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.rd_table = &ad7173_access_table,
+	.wr_table = &ad7173_access_table,
+	.read_flag_mask = BIT(6),
+};
+
+static int ad7173_mask_xlate(struct gpio_regmap *gpio, unsigned int base,
+			     unsigned int offset, unsigned int *reg,
+			     unsigned int *mask)
+{
+	*mask = AD7173_GPO_DATA(offset);
+	*reg = base;
+	return 0;
+}
+
+static void ad7173_gpio_disable(void *data)
+{
+	struct ad7173_state *st = data;
+	unsigned int mask;
+
+	mask = AD7173_GPIO_OP_EN0 | AD7173_GPIO_OP_EN1 | AD7173_GPIO_OP_EN2_3;
+	regmap_update_bits(st->reg_gpiocon_regmap, AD7173_REG_GPIO, mask, ~mask);
+}
+
+static int ad7173_gpio_init(struct ad7173_state *st)
+{
+	struct gpio_regmap_config gpio_regmap = {};
+	struct device *dev = &st->sd.spi->dev;
+	unsigned int mask;
+	int ret;
+
+	st->reg_gpiocon_regmap = devm_regmap_init_spi(st->sd.spi, &ad7173_regmap_config);
+	ret = PTR_ERR_OR_ZERO(st->reg_gpiocon_regmap);
+	if (ret)
+		return dev_err_probe(dev, ret, "Unable to init regmap\n");
+
+	mask = AD7173_GPIO_OP_EN0 | AD7173_GPIO_OP_EN1 | AD7173_GPIO_OP_EN2_3;
+	regmap_update_bits(st->reg_gpiocon_regmap, AD7173_REG_GPIO, mask, mask);
+
+	ret = devm_add_action_or_reset(dev, ad7173_gpio_disable, st);
+	if (ret)
+		return ret;
+
+	gpio_regmap.parent = dev;
+	gpio_regmap.regmap = st->reg_gpiocon_regmap;
+	gpio_regmap.ngpio = st->info->num_gpios;
+	gpio_regmap.reg_set_base = AD7173_REG_GPIO;
+	gpio_regmap.reg_mask_xlate = ad7173_mask_xlate;
+
+	st->gpio_regmap = devm_gpio_regmap_register(dev, &gpio_regmap);
+	ret = PTR_ERR_OR_ZERO(st->gpio_regmap);
+	if (ret)
+		return dev_err_probe(dev, ret, "Unable to init gpio-regmap\n");
+
+	return 0;
+}
+
+#endif /* CONFIG_GPIOLIB */
+
+static struct ad7173_state *ad_sigma_delta_to_ad7173(struct ad_sigma_delta *sd)
+{
+	return container_of(sd, struct ad7173_state, sd);
+}
+
+static void ad7173_ida_destroy(void *data)
+{
+	struct ad7173_state *st = data;
+
+	ida_destroy(&st->cfg_slots_status);
+}
+
+static void ad7173_reset_usage_cnts(struct ad7173_state *st)
+{
+	memset64(st->config_cnts, 0, st->info->num_configs);
+	st->config_usage_counter = 0;
+}
+
+static struct ad7173_channel_config *
+ad7173_find_live_config(struct ad7173_state *st, struct ad7173_channel_config *cfg)
+{
+	struct ad7173_channel_config *cfg_aux;
+	ptrdiff_t cmp_size;
+	int i;
+
+	cmp_size = sizeof_field(struct ad7173_channel_config, config_props);
+	for (i = 0; i < st->num_channels; i++) {
+		cfg_aux = &st->channels[i].cfg;
+
+		if (cfg_aux->live &&
+		    !memcmp(&cfg->config_props, &cfg_aux->config_props, cmp_size))
+			return cfg_aux;
+	}
+	return NULL;
+}
+
+/* Could be replaced with a generic LRU implementation */
+static int ad7173_free_config_slot_lru(struct ad7173_state *st)
+{
+	int i, lru_position = 0;
+
+	for (i = 1; i < st->info->num_configs; i++)
+		if (st->config_cnts[i] < st->config_cnts[lru_position])
+			lru_position = i;
+
+	for (i = 0; i < st->num_channels; i++)
+		if (st->channels[i].cfg.cfg_slot == lru_position)
+			st->channels[i].cfg.live = false;
+
+	ida_free(&st->cfg_slots_status, lru_position);
+	return ida_alloc(&st->cfg_slots_status, GFP_KERNEL);
+}
+
+/* Could be replaced with a generic LRU implementation */
+static int ad7173_load_config(struct ad7173_state *st,
+			      struct ad7173_channel_config *cfg)
+{
+	unsigned int config;
+	int free_cfg_slot, ret;
+
+	free_cfg_slot = ida_alloc_range(&st->cfg_slots_status, 0,
+					st->info->num_configs - 1, GFP_KERNEL);
+	if (free_cfg_slot < 0)
+		free_cfg_slot = ad7173_free_config_slot_lru(st);
+
+	cfg->cfg_slot = free_cfg_slot;
+	config = FIELD_PREP(AD7173_SETUP_REF_SEL_MASK, cfg->ref_sel);
+
+	if (cfg->bipolar)
+		config |= AD7173_SETUP_BIPOLAR;
+
+	if (cfg->input_buf)
+		config |= AD7173_SETUP_AIN_BUF_MASK;
+
+	ret = ad_sd_write_reg(&st->sd, AD7173_REG_SETUP(free_cfg_slot), 2, config);
+	if (ret)
+		return ret;
+
+	return ad_sd_write_reg(&st->sd, AD7173_REG_FILTER(free_cfg_slot), 2,
+			       AD7173_FILTER_ODR0_MASK & cfg->odr);
+}
+
+static int ad7173_config_channel(struct ad7173_state *st, int addr)
+{
+	struct ad7173_channel_config *cfg = &st->channels[addr].cfg;
+	struct ad7173_channel_config *live_cfg;
+	int ret;
+
+	if (!cfg->live) {
+		live_cfg = ad7173_find_live_config(st, cfg);
+		if (live_cfg) {
+			cfg->cfg_slot = live_cfg->cfg_slot;
+		} else {
+			ret = ad7173_load_config(st, cfg);
+			if (ret)
+				return ret;
+			cfg->live = true;
+		}
+	}
+
+	if (st->config_usage_counter == U64_MAX)
+		ad7173_reset_usage_cnts(st);
+
+	st->config_usage_counter++;
+	st->config_cnts[cfg->cfg_slot] = st->config_usage_counter;
+
+	return 0;
+}
+
+static int ad7173_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
+{
+	struct ad7173_state *st = ad_sigma_delta_to_ad7173(sd);
+	unsigned int val;
+	int ret;
+
+	ret = ad7173_config_channel(st, channel);
+	if (ret)
+		return ret;
+
+	val = AD7173_CH_ENABLE |
+	      FIELD_PREP(AD7173_CH_SETUP_SEL_MASK, st->channels[channel].cfg.cfg_slot) |
+	      st->channels[channel].ain;
+
+	return ad_sd_write_reg(&st->sd, AD7173_REG_CH(channel), 2, val);
+}
+
+static int ad7173_set_mode(struct ad_sigma_delta *sd,
+			   enum ad_sigma_delta_mode mode)
+{
+	struct ad7173_state *st = ad_sigma_delta_to_ad7173(sd);
+
+	st->adc_mode &= ~AD7173_ADC_MODE_MODE_MASK;
+	st->adc_mode |= FIELD_PREP(AD7173_ADC_MODE_MODE_MASK, mode);
+
+	return ad_sd_write_reg(&st->sd, AD7173_REG_ADC_MODE, 2, st->adc_mode);
+}
+
+static int ad7173_append_status(struct ad_sigma_delta *sd, bool append)
+{
+	struct ad7173_state *st = ad_sigma_delta_to_ad7173(sd);
+	unsigned int interface_mode = st->interface_mode;
+	int ret;
+
+	interface_mode |= AD7173_INTERFACE_DATA_STAT_EN(append);
+	ret = ad_sd_write_reg(&st->sd, AD7173_REG_INTERFACE_MODE, 2, interface_mode);
+	if (ret)
+		return ret;
+
+	st->interface_mode = interface_mode;
+
+	return 0;
+}
+
+static int ad7173_disable_all(struct ad_sigma_delta *sd)
+{
+	struct ad7173_state *st = ad_sigma_delta_to_ad7173(sd);
+	int ret;
+	int i;
+
+	for (i = 0; i < st->num_channels; i++) {
+		ret = ad_sd_write_reg(sd, AD7173_REG_CH(i), 2, 0);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static struct ad_sigma_delta_info ad7173_sigma_delta_info = {
+	.set_channel = ad7173_set_channel,
+	.append_status = ad7173_append_status,
+	.disable_all = ad7173_disable_all,
+	.set_mode = ad7173_set_mode,
+	.has_registers = true,
+	.addr_shift = 0,
+	.read_mask = BIT(6),
+	.status_ch_mask = GENMASK(3, 0),
+	.data_reg = AD7173_REG_DATA,
+	.irq_flags = IRQF_TRIGGER_FALLING,
+};
+
+static int ad7173_setup(struct iio_dev *indio_dev)
+{
+	struct ad7173_state *st = iio_priv(indio_dev);
+	u8 buf[AD7173_RESET_LENGTH];
+	unsigned int id;
+	int ret;
+
+	/* reset the serial interface */
+	memset(buf, 0xff, AD7173_RESET_LENGTH);
+	ret = spi_write_then_read(st->sd.spi, buf, sizeof(buf), NULL, 0);
+	if (ret < 0)
+		return ret;
+
+	/* datasheet recommends a delay of at least 500us after reset */
+	fsleep(500);
+
+	ret = ad_sd_read_reg(&st->sd, AD7173_REG_ID, 2, &id);
+	if (ret)
+		return ret;
+
+	id &= AD7173_ID_MASK;
+	if (id != st->info->id)
+		dev_warn(&st->sd.spi->dev,
+			 "Unexpected device id: 0x%04X, expected: 0x%04X\n",
+			 id, st->info->id);
+
+	st->adc_mode |= AD7173_ADC_MODE_SING_CYC;
+	st->interface_mode = 0x0;
+
+	st->config_usage_counter = 0;
+	st->config_cnts = devm_kcalloc(&st->sd.spi->dev, st->info->num_configs,
+				       sizeof(u64), GFP_KERNEL);
+	if (!st->config_cnts)
+		return -ENOMEM;
+
+	/* All channels are enabled by default after a reset */
+	return ad7173_disable_all(&st->sd);
+}
+
+static unsigned int ad7173_get_ref_voltage_milli(struct ad7173_state *st,
+						 u8 reference_select)
+{
+	int vref;
+
+	switch (reference_select) {
+	case AD7173_SETUP_REF_SEL_EXT_REF:
+		vref = regulator_get_voltage(st->regulators[0].consumer);
+		break;
+
+	case AD7173_SETUP_REF_SEL_EXT_REF2:
+		vref = regulator_get_voltage(st->regulators[1].consumer);
+		break;
+
+	case AD7173_SETUP_REF_SEL_INT_REF:
+		vref = AD7173_VOLTAGE_INT_REF_uV;
+		break;
+
+	case AD7173_SETUP_REF_SEL_AVDD1_AVSS:
+		vref = regulator_get_voltage(st->regulators[2].consumer);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	if (vref < 0)
+		return vref;
+
+	return vref / (MICRO / MILLI);
+}
+
+static int ad7173_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long info)
+{
+	struct ad7173_state *st = iio_priv(indio_dev);
+	struct ad7173_channel *ch = &st->channels[chan->address];
+	unsigned int reg;
+	u64 temp;
+	int ret;
+
+	switch (info) {
+	case IIO_CHAN_INFO_RAW:
+		ret = ad_sigma_delta_single_conversion(indio_dev, chan, val);
+		if (ret < 0)
+			return ret;
+
+		/* disable channel after single conversion */
+		ret = ad_sd_write_reg(&st->sd, AD7173_REG_CH(chan->address), 2, 0);
+		if (ret < 0)
+			return ret;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->type == IIO_TEMP) {
+			temp = AD7173_VOLTAGE_INT_REF_uV * MILLI;
+			temp /= AD7173_TEMP_SENSIIVITY_uV_per_C;
+			*val = temp;
+			*val2 = chan->scan_type.realbits;
+		} else {
+			*val = ad7173_get_ref_voltage_milli(st, ch->cfg.ref_sel);
+			*val2 = chan->scan_type.realbits - !!(ch->cfg.bipolar);
+		}
+		return IIO_VAL_FRACTIONAL_LOG2;
+	case IIO_CHAN_INFO_OFFSET:
+		if (chan->type == IIO_TEMP) {
+			/* 0 Kelvin -> raw sample */
+			temp   = -ABSOLUTE_ZERO_MILLICELSIUS;
+			temp  *= AD7173_TEMP_SENSIIVITY_uV_per_C;
+			temp <<= chan->scan_type.realbits;
+			temp   = DIV_U64_ROUND_CLOSEST(temp,
+						       AD7173_VOLTAGE_INT_REF_uV *
+						       MILLI);
+			*val   = -temp;
+		} else {
+			*val = -BIT(chan->scan_type.realbits - 1);
+		}
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		reg = st->channels[chan->address].cfg.odr;
+
+		*val = st->info->sinc5_data_rates[reg] / MILLI;
+		*val2 = (st->info->sinc5_data_rates[reg] % MILLI) * (MICRO / MILLI);
+
+		return IIO_VAL_INT_PLUS_MICRO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int ad7173_write_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val, int val2, long info)
+{
+	struct ad7173_state *st = iio_priv(indio_dev);
+	struct ad7173_channel_config *cfg;
+	unsigned int freq, i, reg;
+	int ret;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
+
+	switch (info) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		freq = val * MILLI + val2 / MILLI;
+		for (i = 0; i < st->info->num_sinc5_data_rates - 1; i++)
+			if (freq >= st->info->sinc5_data_rates[i])
+				break;
+
+		cfg = &st->channels[chan->address].cfg;
+		cfg->odr = i;
+
+		if (!cfg->live)
+			break;
+
+		ret = ad_sd_read_reg(&st->sd, AD7173_REG_FILTER(cfg->cfg_slot), 2, &reg);
+		if (ret)
+			break;
+		reg &= ~AD7173_FILTER_ODR0_MASK;
+		reg |= FIELD_PREP(AD7173_FILTER_ODR0_MASK, i);
+		ret = ad_sd_write_reg(&st->sd, AD7173_REG_FILTER(cfg->cfg_slot), 2, reg);
+		break;
+
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	iio_device_release_direct_mode(indio_dev);
+	return ret;
+}
+
+static int ad7173_update_scan_mode(struct iio_dev *indio_dev,
+				   const unsigned long *scan_mask)
+{
+	struct ad7173_state *st = iio_priv(indio_dev);
+	int i, ret;
+
+	for (i = 0; i < indio_dev->num_channels; i++) {
+		if (test_bit(i, scan_mask))
+			ret = ad7173_set_channel(&st->sd, i);
+		else
+			ret = ad_sd_write_reg(&st->sd, AD7173_REG_CH(i), 2, 0);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int ad7173_debug_reg_access(struct iio_dev *indio_dev, unsigned int reg,
+				   unsigned int writeval, unsigned int *readval)
+{
+	struct ad7173_state *st = iio_priv(indio_dev);
+	u8 reg_size;
+
+	if (reg == AD7173_REG_COMMS)
+		reg_size = 1;
+	else if (reg == AD7173_REG_CRC || reg == AD7173_REG_DATA ||
+		 reg >= AD7173_REG_OFFSET(0))
+		reg_size = 3;
+	else
+		reg_size = 2;
+
+	if (readval)
+		return ad_sd_read_reg(&st->sd, reg, reg_size, readval);
+
+	return ad_sd_write_reg(&st->sd, reg, reg_size, writeval);
+}
+
+static const struct iio_info ad7173_info = {
+	.read_raw = &ad7173_read_raw,
+	.write_raw = &ad7173_write_raw,
+	.debugfs_reg_access = &ad7173_debug_reg_access,
+	.validate_trigger = ad_sd_validate_trigger,
+	.update_scan_mode = ad7173_update_scan_mode,
+};
+
+static const struct iio_chan_spec ad7173_channel_template = {
+	.type = IIO_VOLTAGE,
+	.indexed = 1,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_SCALE),
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.scan_type = {
+		.sign = 'u',
+		.realbits = 24,
+		.storagebits = 32,
+		.endianness = IIO_BE,
+	},
+};
+
+static const struct iio_chan_spec ad7173_temp_iio_channel_template = {
+	.type = IIO_TEMP,
+	.indexed = 1,
+	.channel = AD7173_AIN_TEMP_POS,
+	.channel2 = AD7173_AIN_TEMP_NEG,
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET),
+	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	.scan_type = {
+		.sign = 'u',
+		.realbits = 24,
+		.storagebits = 32,
+		.endianness = IIO_BE,
+	},
+};
+
+static void ad7173_disable_regulators(void *data)
+{
+	struct ad7173_state *st = data;
+
+	regulator_bulk_disable(ARRAY_SIZE(st->regulators), st->regulators);
+}
+
+static int ad7173_fw_parse_channel_config(struct iio_dev *indio_dev)
+{
+	struct ad7173_channel *chans_st_arr, *chan_st_priv;
+	struct ad7173_state *st = iio_priv(indio_dev);
+	struct device *dev = indio_dev->dev.parent;
+	struct iio_chan_spec *chan_arr, *chan;
+	struct fwnode_handle *child;
+	unsigned int ain[2], chan_index = 0;
+	unsigned int num_channels;
+	int ref_sel;
+	int ret;
+
+	st->regulators[0].supply = ad7173_ref_sel_str[AD7173_SETUP_REF_SEL_EXT_REF];
+	st->regulators[1].supply = ad7173_ref_sel_str[AD7173_SETUP_REF_SEL_EXT_REF2];
+	st->regulators[2].supply = ad7173_ref_sel_str[AD7173_SETUP_REF_SEL_AVDD1_AVSS];
+
+	/*
+	 * If a regulator is not available, it will be set to a dummy regulator.
+	 * Each channel reference is checked with regulator_get_voltage() before
+	 * setting attributes so if any channel uses a dummy supply the driver
+	 * probe will fail.
+	 */
+	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(st->regulators),
+				      st->regulators);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get regulators\n");
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(st->regulators), st->regulators);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable regulators\n");
+
+	ret = devm_add_action_or_reset(dev, ad7173_disable_regulators, st);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to add regulators disable action\n");
+
+	num_channels = device_get_child_node_count(dev);
+
+	if (st->info->has_temp)
+		num_channels++;
+
+	if (num_channels == 0)
+		return dev_err_probe(dev, -EINVAL, "No channels specified\n");
+	st->num_channels = num_channels;
+
+	chan_arr = devm_kcalloc(dev, sizeof(*chan_arr), num_channels, GFP_KERNEL);
+	if (!chan_arr)
+		return -ENOMEM;
+
+	chans_st_arr = devm_kcalloc(dev, num_channels, sizeof(*chans_st_arr),
+				    GFP_KERNEL);
+	if (!chans_st_arr)
+		return -ENOMEM;
+
+	indio_dev->channels = chan_arr;
+	indio_dev->num_channels = num_channels;
+	st->channels = chans_st_arr;
+
+	if (st->info->has_temp) {
+		chan_arr[chan_index] = ad7173_temp_iio_channel_template;
+		chan_st_priv = &chans_st_arr[chan_index];
+		chan_st_priv->ain =
+			AD7173_CH_ADDRESS(chan_arr[chan_index].channel, chan_arr[chan_index].channel2);
+		chan_st_priv->cfg.bipolar = false;
+		chan_st_priv->cfg.input_buf = true;
+		chan_st_priv->cfg.ref_sel = AD7173_SETUP_REF_SEL_INT_REF;
+		st->adc_mode |= AD7173_ADC_MODE_REF_EN;
+
+		chan_index++;
+	}
+
+	device_for_each_child_node(dev, child) {
+		chan = &chan_arr[chan_index];
+		chan_st_priv = &chans_st_arr[chan_index];
+		ret = fwnode_property_read_u32_array(child, "diff-channels",
+						     ain, ARRAY_SIZE(ain));
+		if (ret) {
+			fwnode_handle_put(child);
+			return ret;
+		}
+
+		if (ain[0] >= st->info->num_inputs ||
+		    ain[1] >= st->info->num_inputs) {
+			fwnode_handle_put(child);
+			return dev_err_probe(dev, -EINVAL,
+					     "Input pin number out of range for pair (%d %d).\n",
+					     ain[0], ain[1]);
+		}
+
+		ret = fwnode_property_match_property_string(child,
+							    "adi,reference-select",
+							    ad7173_ref_sel_str,
+							    ARRAY_SIZE(ad7173_ref_sel_str));
+		if (ret < 0)
+			ref_sel = AD7173_SETUP_REF_SEL_INT_REF;
+		else
+			ref_sel = ret;
+
+		if (ref_sel == AD7173_SETUP_REF_SEL_EXT_REF2 &&
+		    st->info->id != AD7173_ID) {
+			fwnode_handle_put(child);
+			return dev_err_probe(dev, -EINVAL, "External reference 2 is only available on ad7173-8\n");
+		}
+
+		ret = ad7173_get_ref_voltage_milli(st, ref_sel);
+		if (ret < 0) {
+			fwnode_handle_put(child);
+			return dev_err_probe(dev, ret,
+					     "Cannot use reference %u\n", ref_sel);
+		}
+		if (ref_sel == AD7173_SETUP_REF_SEL_INT_REF)
+			st->adc_mode |= AD7173_ADC_MODE_REF_EN;
+		chan_st_priv->cfg.ref_sel = ref_sel;
+
+		*chan = ad7173_channel_template;
+		chan->address = chan_index;
+		chan->scan_index = chan_index;
+		chan->channel = ain[0];
+		chan->channel2 = ain[1];
+		chan->differential = true;
+
+		chan_st_priv->ain = AD7173_CH_ADDRESS(ain[0], ain[1]);
+		chan_st_priv->chan_reg = chan_index;
+		chan_st_priv->cfg.input_buf = true;
+		chan_st_priv->cfg.odr = 0;
+
+		chan_st_priv->cfg.bipolar = fwnode_property_read_bool(child, "bipolar");
+		if (chan_st_priv->cfg.bipolar)
+			chan->info_mask_separate |= BIT(IIO_CHAN_INFO_OFFSET);
+
+		chan_index++;
+	}
+
+	return 0;
+}
+
+static int ad7173_probe(struct spi_device *spi)
+{
+	struct device *dev = &spi->dev;
+	struct ad7173_state *st;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+	st->info = spi_get_device_match_data(spi);
+	if (!st->info)
+		return -ENODEV;
+
+	ida_init(&st->cfg_slots_status);
+	ret = devm_add_action_or_reset(dev, ad7173_ida_destroy, st);
+	if (ret)
+		return ret;
+
+	indio_dev->name = st->info->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &ad7173_info;
+
+	spi->mode = SPI_MODE_3;
+
+	ad7173_sigma_delta_info.num_slots = st->info->num_configs;
+	ret = ad_sd_init(&st->sd, indio_dev, spi, &ad7173_sigma_delta_info);
+	if (ret)
+		return ret;
+
+	ret = ad7173_fw_parse_channel_config(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_ad_sd_setup_buffer_and_trigger(dev, indio_dev);
+	if (ret)
+		return ret;
+
+	ret = ad7173_setup(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret)
+		return ret;
+
+	if (IS_ENABLED(CONFIG_GPIOLIB))
+		return ad7173_gpio_init(st);
+
+	return 0;
+}
+
+static const struct of_device_id ad7173_of_match[] = {
+	{ .compatible = "adi,ad7172-2",
+	  .data = &ad7173_device_info[ID_AD7172_2]},
+	{ .compatible = "adi,ad7173-8",
+	  .data = &ad7173_device_info[ID_AD7173_8]},
+	{ .compatible = "adi,ad7175-2",
+	  .data = &ad7173_device_info[ID_AD7175_2]},
+	{ .compatible = "adi,ad7176-2",
+	  .data = &ad7173_device_info[ID_AD7176_2]},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ad7173_of_match);
+
+static const struct spi_device_id ad7173_id_table[] = {
+	{ "ad7172-2", (kernel_ulong_t)&ad7173_device_info[ID_AD7172_2]},
+	{ "ad7173-8", (kernel_ulong_t)&ad7173_device_info[ID_AD7173_8]},
+	{ "ad7175-2", (kernel_ulong_t)&ad7173_device_info[ID_AD7175_2]},
+	{ "ad7176-2", (kernel_ulong_t)&ad7173_device_info[ID_AD7176_2]},
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ad7173_id_table);
+
+static struct spi_driver ad7173_driver = {
+	.driver = {
+		.name	= "ad7173",
+		.of_match_table = ad7173_of_match,
+	},
+	.probe		= ad7173_probe,
+	.id_table	= ad7173_id_table,
+};
+module_spi_driver(ad7173_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafo.de>");
+MODULE_AUTHOR("Dumitru Ceclan <dumitru.ceclan@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD7172/AD7173/AD7175/AD7176 ADC driver");
+MODULE_LICENSE("GPL");
-- 
2.42.0

Re: [PATCH v12 1/2] dt-bindings: adc: add AD7173

[Conor Dooley]

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On Thu, Jan 18, 2024 at 02:49:22PM +0200, Dumitru Ceclan wrote:
> The AD7173 family offer a complete integrated Sigma-Delta ADC solution
> which can be used in high precision, low noise single channel applications
> or higher speed multiplexed applications. The Sigma-Delta ADC is intended
> primarily for measurement of signals close to DC but also delivers
> outstanding performance with input bandwidths out to ~10kHz.
> 
> Signed-off-by: Dumitru Ceclan <mitrutzceclan@gmail.com>
> ---
> 
> V11->V12
>  - Drop "binding", describe hardware in binding description
>  - Rename refin and refin2 to vref and vref2
>  - Add better description to external references to better show that the voltage
>     value that needs to be specified is the difference between the positive and
>     negative reference pins
>  - Add optional clocks properties
>  - Add optional adi,clock-select property
>  - Add option for second interrupt, error
>  - Add description to interrupts
> V10->V11
>  - Fix example warning: '#gpio-cells' is a dependency of 'gpio-controller'
>  - Add description to #gpio-cells property
> V9->V10
>  - Fix dt_binding_check type warning from adi,reference-select
> V8->v9
>  - Add gpio-controller and "#gpio-cells" properties
>  - Add missing avdd2 and iovdd supplies
>  - Add string type to reference-select
> V7->V8
>  - include missing fix from V6
> V6->V7 <no changes>
> V5->V6
>  - Moved global required property to proper placement
> V4 -> V5
>  - Use string enum instead of integers for "adi,reference-select"
>  - Fix conditional checking in regards to compatible
> V3 -> V4
>  - include supply attributes
>  - add channel attribute for selecting conversion reference
> V2 -> V3
>  - remove redundant descriptions
>  - use referenced 'bipolar' property
>  - remove newlines from example
> V1 -> V2 <no changes>
> 
>  .../bindings/iio/adc/adi,ad7173.yaml          | 242 ++++++++++++++++++
>  1 file changed, 242 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
> new file mode 100644
> index 000000000000..4d0870cc014c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
> @@ -0,0 +1,242 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2023 Analog Devices Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/adi,ad7173.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices AD7173 ADC
> +
> +maintainers:
> +  - Ceclan Dumitru <dumitru.ceclan@analog.com>
> +
> +description: |
> +  Analog Devices AD717x ADC's:
> +  The AD717x family offer a complete integrated Sigma-Delta ADC solution which
> +  can be used in high precision, low noise single channel applications
> +  (Life Science measurements) or higher speed multiplexed applications
> +  (Factory Automation PLC Input modules). The Sigma-Delta ADC is intended
> +  primarily for measurement of signals close to DC but also delivers
> +  outstanding performance with input bandwidths out to ~10kHz.
> +
> +  Datasheets for supported chips:
> +    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7172-2.pdf
> +    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7173-8.pdf
> +    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7175-2.pdf
> +    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7176-2.pdf
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,ad7172-2
> +      - adi,ad7173-8
> +      - adi,ad7175-2
> +      - adi,ad7176-2
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    minItems: 1
> +    description: |
> +      Ready interrupt: multiplexed with SPI data out. While SPI CS is low,
> +      can be used to indicate the completion of a conversion.
> +
> +      Error: The three error bits in the status register (ADC_ERROR, CRC_ERROR,
> +      and REG_ERROR) are OR'ed, inverted, and mapped to the ERROR pin. Therefore,
> +      the ERROR pin indicates that an error has occurred.

Instead of having a single description like this, you can create an
items list with two descriptions, one for each interrupt.

> +
> +  interrupt-names:
> +    minItems: 1
> +    items:
> +      - const: rdy
> +      - const: err

> +  clocks:
> +    maxItems: 1
> +    description: |
> +      Optional external clock source. Can include one clock source: external
> +      clock or external crystal.
> +
> +  clock-names:
> +    enum:
> +      - ext-clk
> +      - xtal
> +
> +  adi,clock-select:
> +    description: |
> +      Select the ADC clock source. Valid values are:
> +      int         : Internal oscillator
> +      int-out     : Internal oscillator with output on XTAL2 pin
> +      ext-clk     : External clock input on XTAL2 pin
> +      xtal        : External crystal on XTAL1 and XTAL2 pins
> +
> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum:
> +      - int
> +      - int-out
> +      - ext-clk
> +      - xtal
> +    default: int

I am not a fan of properties like this one, that in my view reimplement
things that are supported by the regular clocks properties. I've got
some questions for you so I can understand whether or not this custom
property is required.

Whether or not the ext-clk or xtal is used is known based on
clock-names - why is the custom property required to determine that?
If neither of those clocks are present, then the internal clock would be
used. Choosing to use the internal clock if an external one is provided
sounds to me like a software policy decision made by the operating
system.

Finally, if the ADC has a clock output, why can that not be represented
by making the ADC a clock-controller?

Cheers,
Conor.

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Re: [PATCH v12 1/2] dt-bindings: adc: add AD7173

[Ceclan Dumitru]

On 1/18/24 17:23, Conor Dooley wrote:
> On Thu, Jan 18, 2024 at 02:49:22PM +0200, Dumitru Ceclan wrote:

...

>> +  adi,clock-select:
>> +    description: |
>> +      Select the ADC clock source. Valid values are:
>> +      int         : Internal oscillator
>> +      int-out     : Internal oscillator with output on XTAL2 pin
>> +      ext-clk     : External clock input on XTAL2 pin
>> +      xtal        : External crystal on XTAL1 and XTAL2 pins
>> +
>> +    $ref: /schemas/types.yaml#/definitions/string
>> +    enum:
>> +      - int
>> +      - int-out
>> +      - ext-clk
>> +      - xtal
>> +    default: int
> I am not a fan of properties like this one, that in my view reimplement
> things that are supported by the regular clocks properties. I've got
> some questions for you so I can understand whether or not this custom
> property is required.
> 
> Whether or not the ext-clk or xtal is used is known based on
> clock-names - why is the custom property required to determine that?
> If neither of those clocks are present, then the internal clock would be
> used. Choosing to use the internal clock if an external one is provided
> sounds to me like a software policy decision made by the operating
> system.

If there was no int-out, sure. I considered that the choice between int
and int-out could be made here. So better for driver to choose int/int-out?

> 
> Finally, if the ADC has a clock output, why can that not be represented
> by making the ADC a clock-controller?
> 

Was not familiar with this/did not cross my mind. So if xtal/ext-clk is
present, the driver should detect it and disable the option for clock
output? (Common pin XTAL2)

Re: [PATCH v12 1/2] dt-bindings: adc: add AD7173

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 2776 bytes --]

On Thu, Jan 18, 2024 at 05:51:20PM +0200, Ceclan Dumitru wrote:
> 
> 
> On 1/18/24 17:23, Conor Dooley wrote:
> > On Thu, Jan 18, 2024 at 02:49:22PM +0200, Dumitru Ceclan wrote:
> 
> ...
> 
> >> +  adi,clock-select:
> >> +    description: |
> >> +      Select the ADC clock source. Valid values are:
> >> +      int         : Internal oscillator
> >> +      int-out     : Internal oscillator with output on XTAL2 pin
> >> +      ext-clk     : External clock input on XTAL2 pin
> >> +      xtal        : External crystal on XTAL1 and XTAL2 pins
> >> +
> >> +    $ref: /schemas/types.yaml#/definitions/string
> >> +    enum:
> >> +      - int
> >> +      - int-out
> >> +      - ext-clk
> >> +      - xtal
> >> +    default: int
> > I am not a fan of properties like this one, that in my view reimplement
> > things that are supported by the regular clocks properties. I've got
> > some questions for you so I can understand whether or not this custom
> > property is required.
> > 
> > Whether or not the ext-clk or xtal is used is known based on
> > clock-names - why is the custom property required to determine that?

> > If neither of those clocks are present, then the internal clock would be
> > used. Choosing to use the internal clock if an external one is provided
> > sounds to me like a software policy decision made by the operating
> > system.
> 
> If there was no int-out, sure. I considered that the choice between int
> and int-out could be made here. So better for driver to choose int/int-out?

This part of my comments was specifically about choosing between use of
the internal clock when ext-clk or xtal are provided, which I think
excludes the possibility of using int-out, since the XTAL2 pin is an
input.

There's 3 situations:
- no external clock provided
- ext-clk provided
- xtal provided

For the former, you know you're in that state when no "clocks" property
is present. The latter two you can differentiate based on "clock-names".

Choosing to use the internal clock if an external clock is provided
seems to be a software policy decision, unless I am mistaken.

> > 
> > Finally, if the ADC has a clock output, why can that not be represented
> > by making the ADC a clock-controller?
> > 
> 
> Was not familiar with this/did not cross my mind. So if xtal/ext-clk is
> present, the driver should detect it and disable the option for clock
> output? (Common pin XTAL2)

Yeah, if those clocks are provided you would not register as a clock
controller. If there is a user of the output clock, it should have its
own "clocks" property that references the ADC's output.

Your dt-binding could also make clocks/clock-names & clock-controller
mutually exclusive.

Cheers,
Conor.

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Re: [PATCH v12 1/2] dt-bindings: adc: add AD7173

[David Lechner]

On Thu, Jan 18, 2024 at 6:50 AM Dumitru Ceclan <mitrutzceclan@gmail.com> wrote:
>
> The AD7173 family offer a complete integrated Sigma-Delta ADC solution
> which can be used in high precision, low noise single channel applications
> or higher speed multiplexed applications. The Sigma-Delta ADC is intended
> primarily for measurement of signals close to DC but also delivers
> outstanding performance with input bandwidths out to ~10kHz.
>
> Signed-off-by: Dumitru Ceclan <mitrutzceclan@gmail.com>
> ---
>
> V11->V12
>  - Drop "binding", describe hardware in binding description
>  - Rename refin and refin2 to vref and vref2
>  - Add better description to external references to better show that the voltage
>     value that needs to be specified is the difference between the positive and
>     negative reference pins
>  - Add optional clocks properties
>  - Add optional adi,clock-select property
>  - Add option for second interrupt, error
>  - Add description to interrupts
> V10->V11
>  - Fix example warning: '#gpio-cells' is a dependency of 'gpio-controller'
>  - Add description to #gpio-cells property
> V9->V10
>  - Fix dt_binding_check type warning from adi,reference-select
> V8->v9
>  - Add gpio-controller and "#gpio-cells" properties
>  - Add missing avdd2 and iovdd supplies
>  - Add string type to reference-select
> V7->V8
>  - include missing fix from V6
> V6->V7 <no changes>
> V5->V6
>  - Moved global required property to proper placement
> V4 -> V5
>  - Use string enum instead of integers for "adi,reference-select"
>  - Fix conditional checking in regards to compatible
> V3 -> V4
>  - include supply attributes
>  - add channel attribute for selecting conversion reference
> V2 -> V3
>  - remove redundant descriptions
>  - use referenced 'bipolar' property
>  - remove newlines from example
> V1 -> V2 <no changes>
>
>  .../bindings/iio/adc/adi,ad7173.yaml          | 242 ++++++++++++++++++
>  1 file changed, 242 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
> new file mode 100644
> index 000000000000..4d0870cc014c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7173.yaml
> @@ -0,0 +1,242 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2023 Analog Devices Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/adi,ad7173.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices AD7173 ADC
> +
> +maintainers:
> +  - Ceclan Dumitru <dumitru.ceclan@analog.com>
> +
> +description: |
> +  Analog Devices AD717x ADC's:
> +  The AD717x family offer a complete integrated Sigma-Delta ADC solution which
> +  can be used in high precision, low noise single channel applications
> +  (Life Science measurements) or higher speed multiplexed applications
> +  (Factory Automation PLC Input modules). The Sigma-Delta ADC is intended
> +  primarily for measurement of signals close to DC but also delivers
> +  outstanding performance with input bandwidths out to ~10kHz.
> +
> +  Datasheets for supported chips:
> +    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7172-2.pdf
> +    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7173-8.pdf
> +    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7175-2.pdf
> +    https://www.analog.com/media/en/technical-documentation/data-sheets/AD7176-2.pdf
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,ad7172-2
> +      - adi,ad7173-8
> +      - adi,ad7175-2
> +      - adi,ad7176-2
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    minItems: 1
> +    description: |
> +      Ready interrupt: multiplexed with SPI data out. While SPI CS is low,
> +      can be used to indicate the completion of a conversion.
> +
> +      Error: The three error bits in the status register (ADC_ERROR, CRC_ERROR,
> +      and REG_ERROR) are OR'ed, inverted, and mapped to the ERROR pin. Therefore,
> +      the ERROR pin indicates that an error has occurred.
> +
> +  interrupt-names:
> +    minItems: 1
> +    items:
> +      - const: rdy
> +      - const: err
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +  spi-max-frequency:
> +    maximum: 20000000
> +
> +  gpio-controller:
> +    description: Marks the device node as a GPIO controller.
> +
> +  "#gpio-cells":
> +    const: 2
> +    description:
> +      The first cell is the GPIO number and the second cell specifies
> +      GPIO flags, as defined in <dt-bindings/gpio/gpio.h>.
> +
> +  vref-supply:
> +    description: |
> +      Differential external reference supply used for conversion. The reference
> +      voltage (Vref) specified here must be the voltage difference between the
> +      REF+ and REF- pins: Vref = (REF+) - (REF-).
> +
> +  vref2-supply:
> +    description: |
> +      Differential external reference supply used for conversion. The reference
> +      voltage (Vref2) specified here must be the voltage difference between the
> +      REF2+ and REF2- pins: Vref2 = (REF2+) - (REF2-).
> +
> +  avdd-supply:
> +    description: avdd supply, can be used as reference for conversion.

I think it would be helpful to have a description similar to
vref-supply here. This is the voltage between AVDD and AVSS. So in
both cases AVDD=5V, AVSS=0V and AVDD=+2.5V, AVSS=-2.5V, this supply
should report 5V.

> +
> +  avdd2-supply:
> +    description: avdd2 supply, used as the input to the internal voltage regulator.

This supply is also referenced to AVSS.

> +
> +  iovdd-supply:
> +    description: iovdd supply, used for the chip digital interface.
> +
> +  clocks:
> +    maxItems: 1
> +    description: |
> +      Optional external clock source. Can include one clock source: external
> +      clock or external crystal.
> +
> +  clock-names:
> +    enum:
> +      - ext-clk
> +      - xtal
> +
> +  adi,clock-select:
> +    description: |
> +      Select the ADC clock source. Valid values are:
> +      int         : Internal oscillator
> +      int-out     : Internal oscillator with output on XTAL2 pin
> +      ext-clk     : External clock input on XTAL2 pin
> +      xtal        : External crystal on XTAL1 and XTAL2 pins
> +
> +    $ref: /schemas/types.yaml#/definitions/string
> +    enum:
> +      - int
> +      - int-out
> +      - ext-clk
> +      - xtal
> +    default: int
> +
> +patternProperties:
> +  "^channel@[0-9a-f]$":
> +    type: object
> +    $ref: adc.yaml
> +    unevaluatedProperties: false
> +
> +    properties:
> +      reg:
> +        minimum: 0
> +        maximum: 15
> +
> +      diff-channels:
> +        items:
> +          minimum: 0
> +          maximum: 31
> +
> +      adi,reference-select:
> +        description: |
> +          Select the reference source to use when converting on
> +          the specific channel. Valid values are:
> +          vref       : REF+  /REF−
> +          vref2      : REF2+ /REF2−
> +          refout-avss: REFOUT/AVSS (Internal reference)
> +          avdd       : AVDD

Could write this as AVDD/AVSS to be consistent with the other 3 options.

(Or if this is really AVDD to 0V, we may need to reconsider some of
our other decisions.)

> +
> +          External reference ref2 only available on ad7173-8.
> +          If not specified, internal reference used.
> +        $ref: /schemas/types.yaml#/definitions/string
> +        enum:
> +          - vref
> +          - vref2
> +          - refout-avss
> +          - avdd
> +        default: refout-avss
> +
> +    required:
> +      - reg
> +      - diff-channels
> +
> +required:
> +  - compatible
> +  - reg
> +
> +allOf:
> +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
> +
> +  - if:
> +      properties:
> +        compatible:
> +          not:
> +            contains:
> +              const: adi,ad7173-8
> +    then:
> +      properties:
> +        vref2-supply: false
> +      patternProperties:
> +        "^channel@[0-9a-f]$":
> +          properties:
> +            adi,reference-select:
> +              enum:
> +                - vref
> +                - refout-avss
> +                - avdd
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    spi {
> +      #address-cells = <1>;
> +      #size-cells = <0>;
> +
> +      adc@0 {
> +        compatible = "adi,ad7173-8";
> +        reg = <0>;
> +
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        interrupts = <25 IRQ_TYPE_EDGE_FALLING>;
> +        interrupt-names = "rdy";
> +        interrupt-parent = <&gpio>;
> +        spi-max-frequency = <5000000>;
> +        gpio-controller;
> +        #gpio-cells = <2>;
> +
> +        vref-supply = <&dummy_regulator>;
> +
> +        channel@0 {
> +          reg = <0>;
> +          bipolar;
> +          diff-channels = <0 1>;
> +          adi,reference-select = "vref";
> +        };
> +
> +        channel@1 {
> +          reg = <1>;
> +          diff-channels = <2 3>;
> +        };
> +
> +        channel@2 {
> +          reg = <2>;
> +          bipolar;
> +          diff-channels = <4 5>;
> +        };
> +
> +        channel@3 {
> +          reg = <3>;
> +          bipolar;
> +          diff-channels = <6 7>;
> +        };
> +
> +        channel@4 {
> +          reg = <4>;
> +          diff-channels = <8 9>;
> +          adi,reference-select = "avdd";
> +        };
> +      };
> +    };
> --
> 2.42.0
>

Re: [PATCH v12 1/2] dt-bindings: adc: add AD7173

[Jonathan Cameron]

On Thu, 18 Jan 2024 16:06:29 +0000
Conor Dooley <conor@kernel.org> wrote:

> On Thu, Jan 18, 2024 at 05:51:20PM +0200, Ceclan Dumitru wrote:
> > 
> > 
> > On 1/18/24 17:23, Conor Dooley wrote:  
> > > On Thu, Jan 18, 2024 at 02:49:22PM +0200, Dumitru Ceclan wrote:  
> > 
> > ...
> >   
> > >> +  adi,clock-select:
> > >> +    description: |
> > >> +      Select the ADC clock source. Valid values are:
> > >> +      int         : Internal oscillator
> > >> +      int-out     : Internal oscillator with output on XTAL2 pin
> > >> +      ext-clk     : External clock input on XTAL2 pin
> > >> +      xtal        : External crystal on XTAL1 and XTAL2 pins
> > >> +
> > >> +    $ref: /schemas/types.yaml#/definitions/string
> > >> +    enum:
> > >> +      - int
> > >> +      - int-out
> > >> +      - ext-clk
> > >> +      - xtal
> > >> +    default: int  
> > > I am not a fan of properties like this one, that in my view reimplement
> > > things that are supported by the regular clocks properties. I've got
> > > some questions for you so I can understand whether or not this custom
> > > property is required.
> > > 
> > > Whether or not the ext-clk or xtal is used is known based on
> > > clock-names - why is the custom property required to determine that?  
> 
> > > If neither of those clocks are present, then the internal clock would be
> > > used. Choosing to use the internal clock if an external one is provided
> > > sounds to me like a software policy decision made by the operating
> > > system.  
> > 
> > If there was no int-out, sure. I considered that the choice between int
> > and int-out could be made here. So better for driver to choose int/int-out?  
> 
> This part of my comments was specifically about choosing between use of
> the internal clock when ext-clk or xtal are provided, which I think
> excludes the possibility of using int-out, since the XTAL2 pin is an
> input.
> 
> There's 3 situations:
> - no external clock provided
> - ext-clk provided
> - xtal provided
> 
> For the former, you know you're in that state when no "clocks" property
> is present. The latter two you can differentiate based on "clock-names".
> 
> Choosing to use the internal clock if an external clock is provided
> seems to be a software policy decision, unless I am mistaken.

Agreed, though it rarely makes sense as if someone put down a precision
clock they normally wanted you to use it!

So as a general rule we don't both providing policy controls beyond if
there is extra hardware (external clock source) then use that.

If someone has a good reason to want to do something else then we can
probably figure out a reasonable way to control it.


> 
> > > 
> > > Finally, if the ADC has a clock output, why can that not be represented
> > > by making the ADC a clock-controller?
> > >   
> > 
> > Was not familiar with this/did not cross my mind. So if xtal/ext-clk is
> > present, the driver should detect it and disable the option for clock
> > output? (Common pin XTAL2)  
> 
> Yeah, if those clocks are provided you would not register as a clock
> controller. If there is a user of the output clock, it should have its
> own "clocks" property that references the ADC's output.
> 
> Your dt-binding could also make clocks/clock-names & clock-controller
> mutually exclusive.

That would indeed be the nicest solution.  How this has been done
in drivers has somewhat 'evolved' over time, but this is the nicest
option from point of view of standard bindings and clarity over what
is going on.

> 
> Cheers,
> Conor.

Re: [PATCH v12 2/2] iio: adc: ad7173: add AD7173 driver

[Jonathan Cameron]

On Thu, 18 Jan 2024 14:49:23 +0200
Dumitru Ceclan <mitrutzceclan@gmail.com> wrote:

> The AD7173 family offer a complete integrated Sigma-Delta ADC solution
> which can be used in high precision, low noise single channel
> applications or higher speed multiplexed applications. The Sigma-Delta
> ADC is intended primarily for measurement of signals close to DC but also
> delivers outstanding performance with input bandwidths out to ~10kHz.
> 
> Reviewed-by: Andy Shevchenko <andy@kernel.org>
> Reviewed-by: Michael Walle <michael@walle.cc> # for gpio-regmap
> Signed-off-by: Dumitru Ceclan <mitrutzceclan@gmail.com>

One comment following through from adding the named irq support to the
binding.  The driver needs to check that it has the right one
as perhaps only the error one is wired, or it is the first one specified
in the binding.


> +static int ad7173_probe(struct spi_device *spi)
> +{
> +	struct device *dev = &spi->dev;
> +	struct ad7173_state *st;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +	st->info = spi_get_device_match_data(spi);
> +	if (!st->info)
> +		return -ENODEV;
> +
> +	ida_init(&st->cfg_slots_status);
> +	ret = devm_add_action_or_reset(dev, ad7173_ida_destroy, st);
> +	if (ret)
> +		return ret;
> +
> +	indio_dev->name = st->info->name;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &ad7173_info;
> +
> +	spi->mode = SPI_MODE_3;
> +
> +	ad7173_sigma_delta_info.num_slots = st->info->num_configs;
> +	ret = ad_sd_init(&st->sd, indio_dev, spi, &ad7173_sigma_delta_info);
> +	if (ret)
> +		return ret;
> +
> +	ret = ad7173_fw_parse_channel_config(indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_ad_sd_setup_buffer_and_trigger(dev, indio_dev);

If the error interrupt is provided either first, or as the only interrupt
this is going to use the wrong one.

Probably need to have a variant of that which takes an explicit irq so that
figuring out which irq is relevant becomes a driver problem rather than the
library having a go based on spi->irq.


> +	if (ret)
> +		return ret;
> +
> +	ret = ad7173_setup(indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_iio_device_register(dev, indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	if (IS_ENABLED(CONFIG_GPIOLIB))
> +		return ad7173_gpio_init(st);
> +
> +	return 0;
> +}

Re: [PATCH v12 2/2] iio: adc: ad7173: add AD7173 driver

[Ceclan Dumitru]

On 1/21/24 17:50, Jonathan Cameron wrote:
>> +	ret = devm_ad_sd_setup_buffer_and_trigger(dev, indio_dev);
> If the error interrupt is provided either first, or as the only interrupt
> this is going to use the wrong one.
> 
> Probably need to have a variant of that which takes an explicit irq so that
> figuring out which irq is relevant becomes a driver problem rather than the
> library having a go based on spi->irq.

Would it be acceptable to check if spi->irq interrupt number is equal to
fwnode_irq_get_byname(dev_fwnode(dev), "rdy")?

If not, a message could be passed that specifies either that "rdy" is
needed or that it must be placed first.


Another alternative would be adding irq to ad_sigma_delta_info so a
driver could specify the desired interrupt to be used for conversions.

Re: [PATCH v12 2/2] iio: adc: ad7173: add AD7173 driver

[Jonathan Cameron]

On Mon, 22 Jan 2024 12:02:35 +0200
Ceclan Dumitru <mitrutzceclan@gmail.com> wrote:

> On 1/21/24 17:50, Jonathan Cameron wrote:
> >> +	ret = devm_ad_sd_setup_buffer_and_trigger(dev, indio_dev);  
> > If the error interrupt is provided either first, or as the only interrupt
> > this is going to use the wrong one.
> > 
> > Probably need to have a variant of that which takes an explicit irq so that
> > figuring out which irq is relevant becomes a driver problem rather than the
> > library having a go based on spi->irq.  
> 
> Would it be acceptable to check if spi->irq interrupt number is equal to
> fwnode_irq_get_byname(dev_fwnode(dev), "rdy")?

That would be a good start and probably cover most cases.
> 
> If not, a message could be passed that specifies either that "rdy" is
> needed or that it must be placed first.

If you are mandating the order, that should possibly be reflected in the binding.
If this was hard to fix, I'd be fine with leaving for when someone runs into
a case where they have it ordered the other way around, but given it seems simple
to fix up probably better to just do it and avoid having to remember anything
about it later.

> 
> 
> Another alternative would be adding irq to ad_sigma_delta_info so a
> driver could specify the desired interrupt to be used for conversions.
> 

That works.  Make it optional so if value is 0 use spi->irq as before so
that you don't need to modify the other drivers.


Jonathan

Re: [PATCH v12 1/2] dt-bindings: adc: add AD7173

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 4199 bytes --]

On Sun, Jan 21, 2024 at 03:41:18PM +0000, Jonathan Cameron wrote:
> On Thu, 18 Jan 2024 16:06:29 +0000
> Conor Dooley <conor@kernel.org> wrote:
> > On Thu, Jan 18, 2024 at 05:51:20PM +0200, Ceclan Dumitru wrote:
> > > On 1/18/24 17:23, Conor Dooley wrote:  
> > > > On Thu, Jan 18, 2024 at 02:49:22PM +0200, Dumitru Ceclan wrote:  
> > > >> +  adi,clock-select:
> > > >> +    description: |
> > > >> +      Select the ADC clock source. Valid values are:
> > > >> +      int         : Internal oscillator
> > > >> +      int-out     : Internal oscillator with output on XTAL2 pin
> > > >> +      ext-clk     : External clock input on XTAL2 pin
> > > >> +      xtal        : External crystal on XTAL1 and XTAL2 pins
> > > >> +
> > > >> +    $ref: /schemas/types.yaml#/definitions/string
> > > >> +    enum:
> > > >> +      - int
> > > >> +      - int-out
> > > >> +      - ext-clk
> > > >> +      - xtal
> > > >> +    default: int  
> > > > I am not a fan of properties like this one, that in my view reimplement
> > > > things that are supported by the regular clocks properties. I've got
> > > > some questions for you so I can understand whether or not this custom
> > > > property is required.
> > > > 
> > > > Whether or not the ext-clk or xtal is used is known based on
> > > > clock-names - why is the custom property required to determine that?  
> > 
> > > > If neither of those clocks are present, then the internal clock would be
> > > > used. Choosing to use the internal clock if an external one is provided
> > > > sounds to me like a software policy decision made by the operating
> > > > system.  
> > > 
> > > If there was no int-out, sure. I considered that the choice between int
> > > and int-out could be made here. So better for driver to choose int/int-out?  
> > 
> > This part of my comments was specifically about choosing between use of
> > the internal clock when ext-clk or xtal are provided, which I think
> > excludes the possibility of using int-out, since the XTAL2 pin is an
> > input.
> > 
> > There's 3 situations:
> > - no external clock provided
> > - ext-clk provided
> > - xtal provided
> > 
> > For the former, you know you're in that state when no "clocks" property
> > is present. The latter two you can differentiate based on "clock-names".
> > 
> > Choosing to use the internal clock if an external clock is provided
> > seems to be a software policy decision, unless I am mistaken.
> 
> Agreed, though it rarely makes sense as if someone put down a precision
> clock they normally wanted you to use it!
> 
> So as a general rule we don't both providing policy controls beyond if
> there is extra hardware (external clock source) then use that.
> 
> If someone has a good reason to want to do something else then we can
> probably figure out a reasonable way to control it.

Yah, I figured there'd be few situations, outside of maybe debugging
hardware issues, where that internal clock is more desirable to use.

> > > > Finally, if the ADC has a clock output, why can that not be represented
> > > > by making the ADC a clock-controller?
> > > >   
> > > 
> > > Was not familiar with this/did not cross my mind. So if xtal/ext-clk is
> > > present, the driver should detect it and disable the option for clock
> > > output? (Common pin XTAL2)  
> > 
> > Yeah, if those clocks are provided you would not register as a clock
> > controller. If there is a user of the output clock, it should have its
> > own "clocks" property that references the ADC's output.
> > 
> > Your dt-binding could also make clocks/clock-names & clock-controller
> > mutually exclusive.
> 
> That would indeed be the nicest solution.  How this has been done
> in drivers has somewhat 'evolved' over time, but this is the nicest
> option from point of view of standard bindings and clarity over what
> is going on.

Yeah, I know that this has not really been normal thing to do in some
corners of the kernel (ethernet PHYs in particular I think have been
rolling their own clock controller stuff) and I've been trying to push
back on these kinds of things for new devices.

Thanks,
Conor.

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