[PATCH v4 2/2] iio: adc: add support for PAC194X

[<marius.cristea@microchip.com>]

From: Marius Cristea <marius.cristea@microchip.com>

This is the iio driver for Microchip PAC194X and PAC195X series of
Power Monitors with Accumulator. The PAC194X family supports 9V
Full-Scale Range and the PAC195X supports 32V Full-Scale Range.

There are two versions of the PAC194X/5X: the PAC194X/5X-1 devices
are for high-side current sensing and the PAC194X/5X-2 devices are
for low-side current sensing or floating VBUS applications. The
PAC194X/5X-1 is named shortly PAC194X/5X.

Signed-off-by: Marius Cristea <marius.cristea@microchip.com>
---
 MAINTAINERS               |    1 +
 drivers/iio/adc/Kconfig   |   12 +
 drivers/iio/adc/Makefile  |    1 +
 drivers/iio/adc/pac1944.c | 2172 +++++++++++++++++++++++++++++++++++++
 4 files changed, 2186 insertions(+)
 create mode 100644 drivers/iio/adc/pac1944.c

diff --git a/MAINTAINERS b/MAINTAINERS
index a642d095ad34..6e4221e5f446 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17390,6 +17390,7 @@ M:	Marius Cristea <marius.cristea@microchip.com>
 L:	linux-iio@vger.kernel.org
 S:	Supported
 F:	Documentation/devicetree/bindings/iio/adc/microchip,pac1944.yaml
+F:	drivers/iio/adc/pac1944.c
 
 MICROCHIP PCI1XXXX GP DRIVER
 M:	Vaibhaav Ram T.L <vaibhaavram.tl@microchip.com>
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index a9dedbb8eb46..8370b82c7b56 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -1290,6 +1290,18 @@ config PAC1934
 	  This driver can also be built as a module. If so, the module
 	  will be called pac1934.
 
+config PAC1944
+	tristate "Microchip Technology PAC1944/PAC1954 driver"
+	depends on I2C
+	help
+	  Say yes here to build support for Microchip Technology's PAC1941,
+	  PAC1941-2, PAC1942, PAC1942-2, PAC1943, PAC1944, PAC1951,
+	  PAC1951-2, PAC1952, PAC1952-2, PAC1953, PAC1954
+	  Single/Multi-Channel Power Monitor with Accumulator.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called pac1944.
+
 config PALMAS_GPADC
 	tristate "TI Palmas General Purpose ADC"
 	depends on MFD_PALMAS
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 097357d146ba..0e1cc47b68a1 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -113,6 +113,7 @@ obj-$(CONFIG_NPCM_ADC) += npcm_adc.o
 obj-$(CONFIG_NXP_SAR_ADC) += nxp-sar-adc.o
 obj-$(CONFIG_PAC1921) += pac1921.o
 obj-$(CONFIG_PAC1934) += pac1934.o
+obj-$(CONFIG_PAC1934) += pac1944.o
 obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
 obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
 obj-$(CONFIG_QCOM_SPMI_ADC5) += qcom-spmi-adc5.o
diff --git a/drivers/iio/adc/pac1944.c b/drivers/iio/adc/pac1944.c
new file mode 100644
index 000000000000..3938bbcd7e6b
--- /dev/null
+++ b/drivers/iio/adc/pac1944.c
@@ -0,0 +1,2172 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IIO driver for PAC194X and PAC195X series chips
+ *
+ * Copyright (C) 2022-2026 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Marius Cristea marius.cristea@microchip.com
+ *
+ * Datasheet for PAC1941, PAC1942, PAC1943 and PAC1944 can be found here:
+ * https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/PAC194X-Family-Data-Sheet-DS20006543.pdf
+ * Datasheet for PAC1951, PAC1952, PAC1953 and PAC1954 can be found here:
+ * https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/DataSheets/PAC195X-Family-Data-Sheet-DS20006539.pdf
+ */
+
+#include <linux/acpi.h>
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/events.h>
+#include <linux/iio/sysfs.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/unaligned.h>
+
+/*
+ * Maximum (1092 * 60 * 1000), around 1092 minutes@1024 sps
+ * We will keep the refresh lower
+ */
+#define PAC1944_MAX_RFSH_LIMIT_MS		300000
+
+/* 50msec is the timeout for validity of the cached registers */
+#define PAC1944_MIN_POLLING_TIME_MS		50
+/*
+ * 1000usec is the minimum wait time for normal conversions when sample
+ * rate doesn't change
+ */
+#define PAC1944_MIN_UPDATE_WAIT_TIME_US		1000
+
+#define PAC1944_SHUNT_UOHMS_DEFAULT		100000
+
+/* 32000mV */
+#define PAC195X_VOLTAGE_MILLIVOLTS_MAX		32000
+/* 9000mV */
+#define PAC194X_VOLTAGE_MILLIVOLTS_MAX		9000
+
+/*
+ * Voltage bits resolution when set for unsigned values and
+ * HALF FSR signed values
+ */
+#define PAC1944_VOLTAGE_16B_RES			16
+/* Voltage bits resolution when set for signed values */
+#define PAC1944_VOLTAGE_15B_RES			15
+
+/* 100mV maximum voltage drop over the sense resistors */
+#define PAC1944_VSENSE_MILLIVOLTS_MAX		100
+
+#define PAC1944_VSENSE_MICROVOLTS_MAX		100000
+#define PAC1944_VSENSE_MICROVOLTS_MIN		(-100000)
+
+/*
+ * Current bits resolution when set for unsigned values and
+ * HALF FSR signed values
+ */
+#define PAC1944_CURRENT_16B_RES			16
+
+/* Current bits resolution when set for signed values */
+#define PAC1944_CURRENT_15B_RES			15
+
+/* Power resolution is 30 bits when unsigned and HALF FSR signed values */
+#define PAC1944_POWER_30B_RES			30
+
+/* Power resolution is 29 bits when signed */
+#define PAC1944_POWER_29B_RES			29
+
+/* Accumulation register is 56 bits long for unipolar range */
+#define PAC1944_ENERGY_56B_RES			56
+
+/* Accumulation register is 56 bits long for bipolar range */
+#define PAC1944_ENERGY_55B_RES			55
+
+/* Maximum power-product value - 32 V * 0.1 V */
+#define PAC195X_PRODUCT_VOLTAGE_PV_FSR		3200000000000UL
+
+/* Maximum power-product value - 9 V * 0.1 V */
+#define PAC194X_PRODUCT_VOLTAGE_PV_FSR		900000000000UL
+
+#define PAC1944_MEAS_REG_SNAPSHOT_LEN		80
+#define PAC1944_CTRL_REG_SNAPSHOT_LEN		24
+
+#define PAC1944_DEFAULT_CHIP_SAMP_SPEED_HZ	1024
+
+/* Device register address map */
+#define PAC1944_REFRESH_REG_ADDR		0x00
+#define PAC1944_CTRL_REG_ADDR			0x01
+#define PAC1944_ACC_COUNT_REG_ADDR		0x02
+#define PAC1944_VACC_1_REG_ADDR			0x03
+#define PAC1944_VACC_2_REG_ADDR			0x04
+#define PAC1944_VACC_3_REG_ADDR			0x05
+#define PAC1944_VACC_4_REG_ADDR			0x06
+#define PAC1944_VBUS_1_ADDR			0x07
+#define PAC1944_VBUS_2_ADDR			0x08
+#define PAC1944_VBUS_3_ADDR			0x09
+#define PAC1944_VBUS_4_ADDR			0x0A
+#define PAC1944_VSENSE_1_ADDR			0x0B
+#define PAC1944_VSENSE_2_ADDR			0x0C
+#define PAC1944_VSENSE_3_ADDR			0x0D
+#define PAC1944_VSENSE_4_ADDR			0x0E
+#define PAC1944_VBUS_AVG_1_ADDR			0x0F
+#define PAC1944_VBUS_AVG_2_ADDR			0x10
+#define PAC1944_VBUS_AVG_3_ADDR			0x11
+#define PAC1944_VBUS_AVG_4_ADDR			0x12
+#define PAC1944_VSENSE_AVG_1_ADDR		0x13
+#define PAC1944_VSENSE_AVG_2_ADDR		0x14
+#define PAC1944_VSENSE_AVG_3_ADDR		0x15
+#define PAC1944_VSENSE_AVG_4_ADDR		0x16
+#define PAC1944_VPOWER_1_ADDR			0x17
+#define PAC1944_VPOWER_2_ADDR			0x18
+#define PAC1944_VPOWER_3_ADDR			0x19
+#define PAC1944_VPOWER_4_ADDR			0x1A
+
+/* Start of configurations registers */
+#define PAC1944_SMBUS_SETTINGS_REGS_ADDR	0x1C
+#define PAC1944_NEG_PWR_FSR_REG_ADDR		0x1D
+#define PAC1944_REFRESH_G_REG_ADDR		0x1E
+#define PAC1944_REFRESH_V_REG_ADDR		0x1F
+#define PAC1944_SLOW_REG_ADDR			0x20
+#define PAC1944_CTRL_ACT_REG_ADDR		0x21
+#define PAC1944_CTRL_LAT_REG_ADDR		0x23
+#define PAC1944_NEG_PWR_FSR_LAT_REG_ADDR	0x24
+#define PAC1944_ACCUM_CFG_REG_ADDR		0x25
+
+/*
+ * Registers related to alert functionality
+ */
+#define PAC1944_ALERT_STATUS_REG_ADDR		0x26
+#define PAC1944_SLOW_ALERT1_REG_ADDR		0x27
+#define PAC1944_GPIO_ALERT2_REG_ADDR		0x28
+#define PAC1944_ACC_FULLNESS_LIMITS_REG_ADDR	0x29
+#define PAC1944_OC_LIMIT_REG_ADDR		0x30
+#define PAC1944_UC_LIMIT_REG_ADDR		0x34
+#define PAC1944_OP_LIMIT_REG_ADDR		0x38
+#define PAC1944_OV_LIMIT_REG_ADDR		0x3C
+#define PAC1944_UV_LIMIT_REG_ADDR		0x40
+#define PAC1944_OC_LIMIT_NSAMPLES_REG_ADDR	0x44
+#define PAC1944_UC_LIMIT_NSAMPLES_REG_ADDR	0x45
+#define PAC1944_OP_LIMIT_NSAMPLES_REG_ADDR	0x46
+#define PAC1944_OV_LIMIT_NSAMPLES_REG_ADDR	0x47
+#define PAC1944_UV_LIMIT_NSAMPLES_REG_ADDR	0x48
+#define PAC1944_ALERT_ENABLE_REG_ADDR		0x49
+
+#define PAC1944_ALERT_ENABLE_REG_LEN		3
+#define PAC1944_ALERTS_REG_LEN			63
+
+#define PAC1944_PID_REG_ADDR			0xFD
+
+/* Alert Enable register */
+#define PAC1944_OC_MASK				GENMASK(23, 20)
+#define PAC1944_CH01OC_MASK			BIT(23)
+#define PAC1944_CH01OC_SET			BIT(23)
+#define PAC1944_CH02OC_MASK			BIT(22)
+#define PAC1944_CH02OC_SET			BIT(22)
+#define PAC1944_CH03OC_MASK			BIT(21)
+#define PAC1944_CH03OC_SET			BIT(21)
+#define PAC1944_CH04OC_MASK			BIT(20)
+#define PAC1944_CH04OC_SET			BIT(20)
+
+#define PAC1944_UC_MASK				GENMASK(19, 16)
+#define PAC1944_CH01UC_MASK			BIT(19)
+#define PAC1944_CH01UC_SET			BIT(19)
+#define PAC1944_CH02UC_MASK			BIT(18)
+#define PAC1944_CH02UC_SET			BIT(18)
+#define PAC1944_CH03UC_MASK			BIT(17)
+#define PAC1944_CH03UC_SET			BIT(17)
+#define PAC1944_CH04UC_MASK			BIT(16)
+#define PAC1944_CH04UC_SET			BIT(16)
+
+#define PAC1944_OV_MASK				GENMASK(15, 12)
+#define PAC1944_CH01OV_MASK			BIT(15)
+#define PAC1944_CH01OV_SET			BIT(15)
+#define PAC1944_CH02OV_MASK			BIT(14)
+#define PAC1944_CH02OV_SET			BIT(14)
+#define PAC1944_CH03OV_MASK			BIT(13)
+#define PAC1944_CH03OV_SET			BIT(13)
+#define PAC1944_CH04OV_MASK			BIT(12)
+#define PAC1944_CH04OV_SET			BIT(12)
+
+#define PAC1944_UV_MASK				GENMASK(11, 8)
+#define PAC1944_CH01UV_MASK			BIT(11)
+#define PAC1944_CH01UV_SET			BIT(11)
+#define PAC1944_CH02UV_MASK			BIT(10)
+#define PAC1944_CH02UV_SET			BIT(10)
+#define PAC1944_CH03UV_MASK			BIT(9)
+#define PAC1944_CH03UV_SET			BIT(9)
+#define PAC1944_CH04UV_MASK			BIT(8)
+#define PAC1944_CH04UV_SET			BIT(8)
+
+#define PAC1944_OP_MASK				GENMASK(7, 4)
+#define PAC1944_CH01OP_MASK			BIT(7)
+#define PAC1944_CH01OP_SET			BIT(7)
+#define PAC1944_CH02OP_MASK			BIT(6)
+#define PAC1944_CH02OP_SET			BIT(6)
+#define PAC1944_CH03OP_MASK			BIT(5)
+#define PAC1944_CH03OP_SET			BIT(5)
+#define PAC1944_CH04OP_MASK			BIT(4)
+#define PAC1944_CH04OP_SET			BIT(4)
+
+#define PAC1944_ACC_OVF_MASK			BIT(3)
+#define PAC1944_ACC_OVF_SET			BIT(3)
+
+#define PAC1944_ACC_COUNT_MASK			BIT(2)
+#define PAC1944_ACC_COUNT_SET			BIT(2)
+
+#define PAC1944_ALERT_CC1_MASK			BIT(1)
+#define PAC1944_ALERT_CC1_SET			BIT(1)
+
+#define PAC1944_ACC_REG_LEN			4
+#define PAC1944_VACC_REG_LEN			7
+#define PAC1944_VBUS_SENSE_REG_LEN		2
+#define PAC1944_VPOWER_REG_LEN			4
+#define PAC1944_CTRL_ACT_REG_LEN		2
+#define PAC1944_CTRL_LAT_REG_LEN		2
+#define PAC1944_MAX_REGISTER_LEN		6
+
+#define PAC1944_COMMON_DEVATTR			1
+#define PAC1944_ACC_DEVATTR			3
+
+#define PAC1944_MAX_CH				4
+
+/* PAC194X family */
+#define PAC_PRODUCT_ID_1941			0x68
+#define PAC_PRODUCT_ID_1942			0x69
+#define PAC_PRODUCT_ID_1943			0x6A
+#define PAC_PRODUCT_ID_1944			0x6B
+#define PAC_PRODUCT_ID_1941_2			0x6C
+#define PAC_PRODUCT_ID_1942_2			0x6D
+/* PAC195x family */
+#define PAC_PRODUCT_ID_1951			0x78
+#define PAC_PRODUCT_ID_1952			0x79
+#define PAC_PRODUCT_ID_1953			0x7A
+#define PAC_PRODUCT_ID_1954			0x7B
+#define PAC_PRODUCT_ID_1951_2			0x7C
+#define PAC_PRODUCT_ID_1952_2			0x7D
+
+#define PAC1944_ALERT				0x00
+#define PAC1944_GPIO_INPUT			0x01
+#define PAC1944_GPIO_OUTPUT			0x02
+#define PAC1944_SLOW				0x03
+
+#define PAC1944_CTRL_SAMPLE_MASK		GENMASK(15, 12)
+#define PAC1944_CTRL_GPIO_ALERT2_MASK		GENMASK(11, 10)
+#define PAC1944_CTRL_SLOW_ALERT1_MASK		GENMASK(9, 8)
+#define PAC1944_CTRL_CH_1_OFF_MASK		BIT(7)
+#define PAC1944_CTRL_CH_2_OFF_MASK		BIT(6)
+#define PAC1944_CTRL_CH_3_OFF_MASK		BIT(5)
+#define PAC1944_CTRL_CH_4_OFF_MASK		BIT(4)
+
+#define PAC1944_NEG_PWR_CFG_VS1_MASK		GENMASK(15, 14)
+#define PAC1944_NEG_PWR_CFG_VS2_MASK		GENMASK(13, 12)
+#define PAC1944_NEG_PWR_CFG_VS3_MASK		GENMASK(11, 10)
+#define PAC1944_NEG_PWR_CFG_VS4_MASK		GENMASK(9, 8)
+#define PAC1944_NEG_PWR_CFG_VB1_MASK		GENMASK(7, 6)
+#define PAC1944_NEG_PWR_CFG_VB2_MASK		GENMASK(5, 4)
+#define PAC1944_NEG_PWR_CFG_VB3_MASK		GENMASK(3, 2)
+#define PAC1944_NEG_PWR_CFG_VB4_MASK		GENMASK(1, 0)
+
+#define PAC1944_CFG_ACC4_SHIFT			0
+#define PAC1944_CFG_ACC3_SHIFT			2
+#define PAC1944_CFG_ACC2_SHIFT			4
+#define PAC1944_CFG_ACC1_SHIFT			6
+
+#define PAC1944_ACPI_GET_NAMES			1
+#define PAC1944_ACPI_GET_UOHMS_VALS		2
+#define PAC1944_ACPI_GET_BIPOLAR_SETTINGS	4
+
+#define ACCUM_REG(acc1_cfg, acc2_cfg, acc3_cfg, acc4_cfg)		   \
+			((((acc1_cfg) & 0x03) << PAC1944_CFG_ACC1_SHIFT) | \
+			 (((acc2_cfg) & 0x03) << PAC1944_CFG_ACC2_SHIFT) | \
+			 (((acc3_cfg) & 0x03) << PAC1944_CFG_ACC3_SHIFT) | \
+			 (((acc4_cfg) & 0x03) << PAC1944_CFG_ACC4_SHIFT))
+
+/*
+ * Accumulated power/energy formula (in mW-seconds):
+ * Energy = (Vacc/10^9)*[(10^9/2^30)*2^9]*3.2*10^3/Rsense
+ * Vacc - is the accumulated value per second
+ * Rsense - value of the shunt resistor in microOhms
+ *
+ * PAC195X_MAX_VPOWER_RSHIFTED_BY_29B = 3.2*((10^9)/(2^29))*10^9
+ * will be used to calculate the scale for accumulated power/energy
+ */
+#define PAC195X_MAX_VPOWER_RSHIFTED_BY_29B	5960464478UL
+
+/*
+ * PAC194X_MAX_VPOWER_RSHIFTED_BY_29B = 0.9*((10^9)/(2^29))*10^9
+ * will be used to calculate the scale for accumulated power/energy
+ */
+#define PAC194X_MAX_VPOWER_RSHIFTED_BY_29B	1676380634UL
+
+/* (100mV * 1000000) / (2^15)  used to calculate the scale for current */
+#define PAC1944_MAX_VSENSE_RSHIFTED_BY_15B	3052
+
+/*
+ * [(100mV * 1000000) / (2^15)]*10^9  used to calculate the scale
+ * for accumulated current/Coulomb counter
+ */
+#define PAC1944_MAX_VSENSE_NANO			3051757812500UL
+
+#define to_pac1944_chip_info(d) container_of(d, struct pac1944_chip_info, work_chip_rfsh)
+
+/*
+ * these indexes are exactly describing the element order within a single
+ * PAC1944/54 phys channel IIO channel descriptor; see the static const struct
+ * iio_chan_spec pac1944_single_channel[] declaration
+ */
+enum pac1944_ch_idx {
+	PAC1944_CH_POWER,
+	PAC1944_CH_VOLTAGE,
+	PAC1944_CH_CURRENT,
+	PAC1944_CH_VOLTAGE_AVERAGE,
+	PAC1944_CH_CURRENT_AVERAGE,
+};
+
+enum pac1944_acc_mode {
+	PAC1944_ACCMODE_VPOWER,
+	PAC1944_ACCMODE_VSENSE,
+};
+
+enum pac1944_vbus_fsr_cfg {
+	PAC1944_UNIPOLAR_FSR_CFG,
+	PAC1944_BIPOLAR_FSR_CFG,
+	PAC1944_BIPOLAR_HALF_FSR_CFG,
+};
+
+enum pac1944_samps {
+	PAC1944_SAMP_1024SPS,
+	PAC1944_SAMP_256SPS,
+	PAC1944_SAMP_64SPS,
+	PAC1944_SAMP_8SPS,
+};
+
+enum pac1944_adc_range {
+	PAC1944_ADC_FULL_RANGE_BIPOLAR,
+	PAC1944_ADC_HALF_RANGE_BIPOLAR,
+	PAC1944_ADC_FULL_RANGE_UNIPOLAR,
+};
+
+/*
+ * The PAC195X has a feature called Adaptive Accumulator mode (APAPT). In this
+ * mode, sampling is programmed at one of the valid sample rates and samples are
+ * accumulated. If the SLOW pin is asserted and the device begins sampling at
+ * 8 SPS, these samples are shifted by 7 bits to the left and accumulated so as
+ * to simulate sampling at the maximum sampling rate, 1024 SPS, and the
+ * accumulator count is also incremented by 128 for each sample in Slow mode
+ * (when using the Adaptive Accumulator mode) to simulate samples being
+ * accumulated at the maximum sampling rate.
+ * This offers a big reduction in host overhead and bus traffic for systems that
+ * need to use the SLOW pin for lower power operation during certain times and
+ * want to have continuous accurate energy monitoring for both the maximum
+ * sampling rate and the SLOW sampling rate.
+ */
+static const unsigned int pac1944_samp_rate_map_tbl[] = {
+	[PAC1944_SAMP_1024SPS] = 1024,
+	[PAC1944_SAMP_256SPS] = 256,
+	[PAC1944_SAMP_64SPS] = 64,
+	[PAC1944_SAMP_8SPS] = 8,
+};
+
+static const unsigned int shift_map_tbl[] = {
+	[PAC1944_SAMP_1024SPS] = 10,
+	[PAC1944_SAMP_256SPS] = 8,
+	[PAC1944_SAMP_64SPS] = 6,
+	[PAC1944_SAMP_8SPS] = 3,
+};
+
+/* Available Sample Modes */
+static const char * const pac1944_frequency_avail[] = {
+	"1024",
+	"256",
+	"64",
+	"8",
+};
+
+static const int pac1944_adc_range_tbl[][2] = {
+	[PAC1944_ADC_FULL_RANGE_BIPOLAR] = {-9000000, 9000000},
+	[PAC1944_ADC_HALF_RANGE_BIPOLAR] = {-4500000, 4500000},
+	[PAC1944_ADC_FULL_RANGE_UNIPOLAR] = {0, 9000000},
+};
+
+static const int pac1954_adc_range_tbl[][2] = {
+	[PAC1944_ADC_FULL_RANGE_BIPOLAR] = {-32000000, 32000000},
+	[PAC1944_ADC_HALF_RANGE_BIPOLAR] = {-16000000, 16000000},
+	[PAC1944_ADC_FULL_RANGE_UNIPOLAR] = {0, 32000000},
+};
+
+static const int pac1944_adc_vsense_range_tbl[][2] = {
+	[PAC1944_ADC_FULL_RANGE_BIPOLAR] = {-100000, 100000},
+	[PAC1944_ADC_HALF_RANGE_BIPOLAR] = {-50000, 50000},
+	[PAC1944_ADC_FULL_RANGE_UNIPOLAR] = {0, 100000},
+};
+
+/**
+ * struct reg_data - data from the registers
+ * @vsense_mode:array of values, Full Scale Range (FSR) mode for V Sense
+ * @vbus_mode: array of values, Full Scale Range (FSR) mode for V Bus
+ * @accumulation_mode: array of values, accumulation mode for hardware accumulator
+ * @meas_regs: snapshot of raw measurements registers
+ * @ctrl_act_reg: snapshot of the ctrl_act register
+ * @ctrl_lat_reg: snapshot of the ctrl_lat register
+ * @acc_count: snapshot of the acc_count register
+ * @acc_val: accumulated values per second
+ * @vacc: accumulated vpower values
+ * @vpower: snapshot of vpower registers
+ * @vbus: snapshot of vbus registers
+ * @vbus_avg: averages of vbus registers
+ * @vsense: snapshot of vsense registers
+ * @vsense_avg: averages of vsense registers
+ * @jiffies_tstamp: chip's uptime
+ */
+struct reg_data {
+	u8	vbus_mode[PAC1944_MAX_CH];
+	u8	vsense_mode[PAC1944_MAX_CH];
+	u8	accumulation_mode[PAC1944_MAX_CH];
+	u8	meas_regs[PAC1944_MEAS_REG_SNAPSHOT_LEN];
+	u16	ctrl_act_reg;
+	u16	ctrl_lat_reg;
+	u32	acc_count;
+	s64	acc_val[PAC1944_MAX_CH];
+	s64	vacc[PAC1944_MAX_CH];
+	s32	vpower[PAC1944_MAX_CH];
+	s32	vbus[PAC1944_MAX_CH];
+	s32	vbus_avg[PAC1944_MAX_CH];
+	s32	vsense[PAC1944_MAX_CH];
+	s32	vsense_avg[PAC1944_MAX_CH];
+	unsigned long jiffies_tstamp;
+};
+
+/**
+ * struct pac1944_chip_info - chip configuration
+ * @channels: array of values, true means that channel is active
+ * @iio_info: pointer to iio_info structure
+ * @client: a pointer to the i2c client associated with the device
+ * @lock: lock to prevent concurrent reads/writes
+ * @work_chip_rfsh: chip refresh workqueue implementation
+ * @active_channels_mask: active channels
+ * @phys_channels: number of physical channels for the device
+ * @shunts: array of values, shunt resistor values
+ * @chip_reg_data: pointer to structure, containing data from the device registers
+ * @labels: array of string, name of each channel
+ * @is_pac195x_family: true if device is part of the PAC195x family
+ * @sampling_mode: sampling mode used by the device
+ * @num_enabled_channels: count of how many chip channels are currently enabled
+ * @enable_acc: array of values, true means that accumulation channel is measured
+ */
+struct pac1944_chip_info {
+	const struct iio_chan_spec  *channels;
+	struct iio_info		iio_info;
+	struct i2c_client	*client;
+	struct mutex		lock; /* lock to prevent concurrent reads/writes */
+	struct delayed_work	work_chip_rfsh;
+	unsigned long	active_channels_mask;
+	u8		phys_channels;
+	u32		shunts[PAC1944_MAX_CH];
+	struct reg_data chip_reg_data;
+	char		*labels[PAC1944_MAX_CH];
+	bool		is_pac195x_family;
+	u8		sampling_mode;
+	u8		num_enabled_channels;
+	bool		enable_acc[PAC1944_MAX_CH];
+};
+
+/**
+ * struct pac1944_features - features of a pac194x instance
+ * @phys_channels:	number of physical channels supported by the chip
+ * @prod_id:		hardware ID
+ * @name:		chip's name
+ */
+struct pac1944_features {
+	u8 phys_channels;
+	u8 prod_id;
+	const char *name;
+};
+
+/* PAC194X Family */
+static const struct pac1944_features pac1941_chip_config = {
+	.phys_channels = 1,
+	.prod_id = PAC_PRODUCT_ID_1941,
+	.name = "pac1941",
+};
+
+static const struct pac1944_features pac1942_chip_config = {
+	.phys_channels = 2,
+	.prod_id = PAC_PRODUCT_ID_1942,
+	.name = "pac1942",
+};
+
+static const struct pac1944_features pac1943_chip_config = {
+	.phys_channels = 3,
+	.prod_id = PAC_PRODUCT_ID_1943,
+	.name = "pac1943",
+};
+
+static const struct pac1944_features pac1944_chip_config = {
+	.phys_channels = 4,
+	.prod_id = PAC_PRODUCT_ID_1944,
+	.name = "pac1944",
+};
+
+static const struct pac1944_features pac1941_2_chip_config = {
+	.phys_channels = 1,
+	.prod_id = PAC_PRODUCT_ID_1941_2,
+	.name = "pac1941_2",
+};
+
+static const struct pac1944_features pac1942_2_chip_config = {
+	.phys_channels = 2,
+	.prod_id = PAC_PRODUCT_ID_1942_2,
+	.name = "pac1942_2",
+};
+
+/* PAC195X Family */
+static const struct pac1944_features pac1951_chip_config = {
+	.phys_channels = 1,
+	.prod_id = PAC_PRODUCT_ID_1951,
+	.name = "pac1951",
+};
+
+static const struct pac1944_features pac1952_chip_config = {
+	.phys_channels = 2,
+	.prod_id = PAC_PRODUCT_ID_1952,
+	.name = "pac1952",
+};
+
+static const struct pac1944_features pac1953_chip_config = {
+	.phys_channels = 3,
+	.prod_id = PAC_PRODUCT_ID_1953,
+	.name = "pac1953",
+};
+
+static const struct pac1944_features pac1954_chip_config = {
+	.phys_channels = 4,
+	.prod_id = PAC_PRODUCT_ID_1954,
+	.name = "pac1954",
+};
+
+static const struct pac1944_features pac1951_2_chip_config = {
+	.phys_channels = 1,
+	.prod_id = PAC_PRODUCT_ID_1951_2,
+	.name = "pac1951_2",
+};
+
+static const struct pac1944_features pac1952_2_chip_config = {
+	.phys_channels = 2,
+	.prod_id = PAC_PRODUCT_ID_1952_2,
+	.name = "pac1952_2",
+};
+
+static inline u64 pac1944_get_unaligned_be56(const u8 *p)
+{
+	return (u64)p[0] << 48 | (u64)p[1] << 40 | (u64)p[2] << 32 |
+		(u64)p[3] << 24 | (u64)p[4] << 16 | (u64)p[5] << 8 | (u64)p[6];
+}
+
+/* Low-level I2c functions used to transfer more then 32 bytes at once */
+static int pac1944_i2c_read(struct i2c_client *client, u8 reg_addr,
+			    void *databuf, u8 len)
+{
+	struct i2c_msg msgs[2] = {
+		{
+		 .addr = client->addr,
+		 .len = 1,
+		 .buf = (u8 *)&reg_addr,
+		 .flags = 0
+		},
+		{
+		 .addr = client->addr,
+		 .len = len,
+		 .buf = databuf,
+		 .flags = I2C_M_RD
+		}
+	};
+
+	return i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+}
+
+/* Custom IIO Device Attributes */
+static ssize_t pac1944_shunt_value_show(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+
+	return sysfs_emit(buf, "%u\n", info->shunts[this_attr->address]);
+}
+
+static ssize_t pac1944_shunt_value_store(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t count)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	int sh_val;
+
+	if (kstrtouint(buf, 10, &sh_val)) {
+		dev_err(dev, "Shunt value is not valid\n");
+		return -EINVAL;
+	}
+
+	scoped_guard(mutex, &info->lock)
+		info->shunts[this_attr->address] = sh_val;
+
+	return count;
+}
+
+static IIO_DEVICE_ATTR(in_current1_shunt_resistor, 0644,
+		       pac1944_shunt_value_show, pac1944_shunt_value_store, 0);
+static IIO_DEVICE_ATTR(in_current2_shunt_resistor, 0644,
+		       pac1944_shunt_value_show, pac1944_shunt_value_store, 1);
+static IIO_DEVICE_ATTR(in_current3_shunt_resistor, 0644,
+		       pac1944_shunt_value_show, pac1944_shunt_value_store, 2);
+static IIO_DEVICE_ATTR(in_current4_shunt_resistor, 0644,
+		       pac1944_shunt_value_show, pac1944_shunt_value_store, 3);
+
+static struct attribute *pac1944_all_attrs[] = {
+	&iio_dev_attr_in_current1_shunt_resistor.dev_attr.attr,
+	&iio_dev_attr_in_current2_shunt_resistor.dev_attr.attr,
+	&iio_dev_attr_in_current3_shunt_resistor.dev_attr.attr,
+	&iio_dev_attr_in_current4_shunt_resistor.dev_attr.attr,
+	NULL
+};
+
+#define PAC1944_VBUS_CHANNEL(_index, _address) {		\
+	.type = IIO_VOLTAGE,					\
+	.address = (_address),					\
+	.indexed = 1,						\
+	.channel = (_index) + 1,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+			      BIT(IIO_CHAN_INFO_SCALE),		\
+	.ext_info = pac1944_ext_info				\
+}
+
+#define PAC1944_VBUS_AVG_CHANNEL(_index, _address) {		\
+	.type = IIO_VOLTAGE,					\
+	.address = (_address),					\
+	.indexed = 1,						\
+	.channel = (_index) + 1,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_AVERAGE_RAW) |	\
+			      BIT(IIO_CHAN_INFO_SCALE),		\
+	.ext_info = pac1944_ext_info				\
+}
+
+#define PAC1944_VSENSE_CHANNEL(_index, _address) {		\
+	.type = IIO_CURRENT,					\
+	.address = (_address),					\
+	.indexed = 1,						\
+	.channel = (_index) + 1,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+			      BIT(IIO_CHAN_INFO_SCALE),		\
+	.ext_info = pac1944_ext_info				\
+}
+
+#define PAC1944_VSENSE_AVG_CHANNEL(_index, _address) {		\
+	.type = IIO_CURRENT,					\
+	.address = (_address),					\
+	.indexed = 1,						\
+	.channel = (_index) + 1,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_AVERAGE_RAW) |	\
+			      BIT(IIO_CHAN_INFO_SCALE),		\
+	.ext_info = pac1944_ext_info				\
+}
+
+#define PAC1944_VPOWER_CHANNEL(_index, _address) {		\
+	.type = IIO_POWER,					\
+	.address = (_address),					\
+	.indexed = 1,						\
+	.channel = (_index) + 1,				\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
+			      BIT(IIO_CHAN_INFO_SCALE),		\
+	.ext_info = pac1944_ext_info				\
+}
+
+static int pac1944_send_refresh(struct pac1944_chip_info *info, u8 refresh_addr,
+				u32 wait_time)
+{
+	struct i2c_client *client = info->client;
+	int ret;
+
+	/* Writing a REFRESH or a REFRESH_V command. */
+	ret = i2c_smbus_write_byte(client, refresh_addr);
+	if (ret) {
+		dev_err(&client->dev, "%s - cannot send Refresh cmd (0x%02X) to PAC1944\n",
+			__func__, refresh_addr);
+		return ret;
+	}
+
+	/* Register data retrieval timestamp. */
+	info->chip_reg_data.jiffies_tstamp = jiffies;
+	/* Wait till the data is available. */
+	usleep_range(wait_time, wait_time + 100);
+
+	return 0;
+}
+
+static int pac1944_reg_snapshot(struct pac1944_chip_info *info, bool do_refresh,
+				u8 refresh_addr, u32 wait_time)
+{
+	struct i2c_client *client = info->client;
+	struct device *dev = &client->dev;
+	s64 stored_value, tmp_s64;
+	u8 *offset_reg_data_p;
+	bool is_unipolar;
+	u16 smpl_mode;
+	int cnt, ret;
+	s64 inc = 0;
+	u8 shift;
+
+	guard(mutex)(&info->lock);
+
+	if (do_refresh) {
+		ret = pac1944_send_refresh(info, refresh_addr, wait_time);
+		if (ret < 0) {
+			dev_err(dev, "cannot send refresh towards PAC1944\n");
+			return ret;
+		}
+	}
+
+	/* Read the ctrl/status registers for this snapshot. */
+	ret = i2c_smbus_read_word_swapped(client, PAC1944_CTRL_ACT_REG_ADDR);
+	if (ret < 0) {
+		dev_err(dev, "cannot read PAC1944 regs from 0x%02X\n", PAC1944_CTRL_ACT_REG_ADDR);
+		return ret;
+	}
+
+	info->chip_reg_data.ctrl_act_reg = ret;
+
+	ret = i2c_smbus_read_word_swapped(client, PAC1944_CTRL_LAT_REG_ADDR);
+	if (ret < 0) {
+		dev_err(dev, "cannot read PAC1944 regs from 0x%02X\n", PAC1944_CTRL_LAT_REG_ADDR);
+		return ret;
+	}
+
+	info->chip_reg_data.ctrl_lat_reg = ret;
+
+	/* Read the data registers. */
+	ret = pac1944_i2c_read(client, PAC1944_ACC_COUNT_REG_ADDR,
+			       (u8 *)info->chip_reg_data.meas_regs,
+			       PAC1944_MEAS_REG_SNAPSHOT_LEN);
+	if (ret < 0) {
+		dev_err(dev, "cannot read PAC1944 regs from 0x%02X\n", PAC1944_ACC_COUNT_REG_ADDR);
+		return ret;
+	}
+
+	offset_reg_data_p = &info->chip_reg_data.meas_regs[0];
+
+	info->chip_reg_data.acc_count = get_unaligned_be32(offset_reg_data_p);
+
+	offset_reg_data_p += PAC1944_ACC_REG_LEN;
+
+	/*
+	 * Check if the channel is active (within the data read from the chip),
+	 * skip all fields if disabled.
+	 */
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		/* skip if the energy accumulation is disabled */
+		if (!info->enable_acc[cnt]) {
+			offset_reg_data_p += PAC1944_VACC_REG_LEN;
+			continue;
+		}
+
+		stored_value = info->chip_reg_data.acc_val[cnt];
+
+		info->chip_reg_data.vacc[cnt] = pac1944_get_unaligned_be56(offset_reg_data_p);
+
+		is_unipolar = true;
+		switch (info->chip_reg_data.accumulation_mode[cnt]) {
+		case PAC1944_ACCMODE_VPOWER:
+			if (info->chip_reg_data.vbus_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG ||
+			    info->chip_reg_data.vsense_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+				is_unipolar = false;
+			break;
+		case PAC1944_ACCMODE_VSENSE:
+			if (info->chip_reg_data.vsense_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+				is_unipolar = false;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		if (!is_unipolar)
+			info->chip_reg_data.vacc[cnt] =
+				sign_extend64(info->chip_reg_data.vacc[cnt], 55);
+
+		/*
+		 * Integrate the accumulated power or current over the elapsed
+		 * interval.
+		 */
+		smpl_mode = FIELD_GET(PAC1944_CTRL_SAMPLE_MASK, info->chip_reg_data.ctrl_lat_reg);
+
+		if (smpl_mode <= PAC1944_SAMP_8SPS) {
+			tmp_s64 = info->chip_reg_data.vacc[cnt];
+			/*
+			 * Find how much shift is required by the sample rate.
+			 * The chip's sampling rate is 2^shift samples/sec.
+			 */
+			shift = shift_map_tbl[smpl_mode];
+			inc = tmp_s64 >> shift;
+		} else {
+			dev_err(dev, "Invalid sample rate index: %d!\n", smpl_mode);
+			return -EINVAL;
+		}
+
+		if (check_add_overflow(stored_value, inc, &stored_value)) {
+			if (stored_value < 0)
+				info->chip_reg_data.acc_val[cnt] = S64_MIN;
+			else
+				info->chip_reg_data.acc_val[cnt] = S64_MAX;
+
+			dev_err(dev, "Overflow detected on channel [%d]!\n", cnt + 1);
+		} else {
+			info->chip_reg_data.acc_val[cnt] = stored_value;
+		}
+
+		offset_reg_data_p += PAC1944_VACC_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vbus[cnt] = get_unaligned_be16(offset_reg_data_p);
+
+		if (info->chip_reg_data.vbus_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vbus[cnt] =
+				sign_extend32(info->chip_reg_data.vbus[cnt], 15);
+
+		offset_reg_data_p += PAC1944_VBUS_SENSE_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vsense[cnt] = get_unaligned_be16(offset_reg_data_p);
+
+		if (info->chip_reg_data.vsense_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vsense[cnt] =
+				sign_extend32(info->chip_reg_data.vsense[cnt], 15);
+
+		offset_reg_data_p += PAC1944_VBUS_SENSE_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vbus_avg[cnt] = get_unaligned_be16(offset_reg_data_p);
+
+		if (info->chip_reg_data.vbus_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vbus_avg[cnt] =
+				sign_extend32(info->chip_reg_data.vbus_avg[cnt], 15);
+
+		offset_reg_data_p += PAC1944_VBUS_SENSE_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vsense_avg[cnt] = get_unaligned_be16(offset_reg_data_p);
+
+		if (info->chip_reg_data.vsense_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vsense_avg[cnt] =
+				sign_extend32(info->chip_reg_data.vsense_avg[cnt], 15);
+
+		offset_reg_data_p += PAC1944_VBUS_SENSE_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vpower[cnt] = get_unaligned_be32(offset_reg_data_p) >> 2;
+
+		if (info->chip_reg_data.vbus_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG ||
+		    info->chip_reg_data.vsense_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vpower[cnt] =
+				sign_extend32(info->chip_reg_data.vpower[cnt], 29);
+
+		offset_reg_data_p += PAC1944_VPOWER_REG_LEN;
+	}
+
+	return 0;
+}
+
+static int pac1944_retrieve_data(struct pac1944_chip_info *info, u32 wait_time)
+{
+	int ret;
+
+	/*
+	 * Check if the minimal elapsed time has passed and if so,
+	 * re-read the chip, otherwise the cached info is just fine.
+	 */
+	if (!time_after(jiffies, info->chip_reg_data.jiffies_tstamp +
+		       msecs_to_jiffies(PAC1944_MIN_POLLING_TIME_MS)))
+		return 0;
+
+	/* We need to re-read the chip values */
+	ret = pac1944_reg_snapshot(info, true, PAC1944_REFRESH_REG_ADDR, wait_time);
+
+	/*
+	 * Re-schedule the work for the read registers timeout
+	 * (to prevent chip regs saturation)
+	 */
+	mod_delayed_work(system_percpu_wq, &info->work_chip_rfsh,
+			 msecs_to_jiffies(PAC1944_MAX_RFSH_LIMIT_MS));
+
+	return ret;
+}
+
+static ssize_t pac1944_in_power_acc_raw_show(struct device *dev,
+					     struct device_attribute *attr,
+					     char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	s64 curr_energy, int_part;
+	int ret;
+	int rem;
+
+	ret = pac1944_retrieve_data(info, PAC1944_MIN_UPDATE_WAIT_TIME_US);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Expresses the 64 bit energy value as a
+	 * 64 bit integer and a 32 bit nano value
+	 */
+	curr_energy = info->chip_reg_data.acc_val[this_attr->address];
+	int_part = div_s64_rem(curr_energy, 1000000000, &rem);
+
+	if (rem < 0)
+		return sysfs_emit(buf, "-%lld.%09u\n", abs(int_part), -rem);
+	else
+		return sysfs_emit(buf, "%lld.%09u\n", int_part, abs(rem));
+}
+
+static ssize_t pac1944_in_power_acc_scale_show(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	unsigned int shunt, rem;
+	u64 tmp, ref;
+
+	if (info->is_pac195x_family)
+		ref = PAC195X_MAX_VPOWER_RSHIFTED_BY_29B;
+	else
+		ref = PAC194X_MAX_VPOWER_RSHIFTED_BY_29B;
+
+	if ((info->chip_reg_data.vbus_mode[this_attr->address] == PAC1944_UNIPOLAR_FSR_CFG &&
+	     info->chip_reg_data.vsense_mode[this_attr->address] == PAC1944_UNIPOLAR_FSR_CFG) ||
+	    info->chip_reg_data.vbus_mode[this_attr->address] == PAC1944_BIPOLAR_HALF_FSR_CFG ||
+	    info->chip_reg_data.vsense_mode[this_attr->address] == PAC1944_BIPOLAR_HALF_FSR_CFG)
+		ref = ref >> 1;
+
+	shunt = info->shunts[this_attr->address];
+
+	tmp = div_u64(ref * 1000000000LL, shunt);
+	rem = do_div(tmp, 1000000000LL);
+
+	return sysfs_emit(buf, "%lld.%09u\n", tmp, rem);
+}
+
+static ssize_t pac1944_in_enable_acc_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+
+	return sysfs_emit(buf, "%d\n", info->enable_acc[this_attr->address]);
+}
+
+static ssize_t pac1944_in_enable_acc_store(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t count)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	bool val;
+
+	if (kstrtobool(buf, &val)) {
+		dev_err(dev, "Value is not valid\n");
+		return -EINVAL;
+	}
+
+	scoped_guard(mutex, &info->lock) {
+		info->enable_acc[this_attr->address] = val ? true : false;
+		if (val)
+			info->chip_reg_data.acc_val[this_attr->address] = 0;
+	}
+
+	return count;
+}
+
+static ssize_t pac1944_in_current_acc_raw_show(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	int ret;
+
+	ret = pac1944_retrieve_data(info, PAC1944_MIN_UPDATE_WAIT_TIME_US);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%lld\n", info->chip_reg_data.acc_val[this_attr->address]);
+}
+
+static ssize_t pac1944_in_current_acc_scale_show(struct device *dev,
+						 struct device_attribute *attr,
+						 char *buf)
+{
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	u64 tmp_u64, ref;
+	int shunt, rem;
+
+	/*
+	 * Currents - scale for mA - depends on the channel's shunt value
+	 * (100mV * 1000000) / (2^16 * shunt(uOhm))
+	 */
+	ref = PAC1944_MAX_VSENSE_NANO;
+
+	switch (info->chip_reg_data.vsense_mode[this_attr->address]) {
+	case PAC1944_UNIPOLAR_FSR_CFG:
+	case PAC1944_BIPOLAR_HALF_FSR_CFG:
+		shunt = info->shunts[this_attr->address];
+		break;
+	case PAC1944_BIPOLAR_FSR_CFG:
+		ref = ref << 1;
+		shunt = info->shunts[this_attr->address];
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/*
+	 * Increasing precision
+	 * (100mV * 1000000 * 1000000000) / 2^16 )
+	 */
+	tmp_u64 = div_u64(ref, shunt);
+	rem = do_div(tmp_u64, 1000000000LL);
+
+	return sysfs_emit(buf, "%lld.%09u\n", tmp_u64, rem);
+}
+
+static IIO_DEVICE_ATTR(in_energy1_raw, 0444, pac1944_in_power_acc_raw_show, NULL, 0);
+static IIO_DEVICE_ATTR(in_energy2_raw, 0444, pac1944_in_power_acc_raw_show, NULL, 1);
+static IIO_DEVICE_ATTR(in_energy3_raw, 0444, pac1944_in_power_acc_raw_show, NULL, 2);
+static IIO_DEVICE_ATTR(in_energy4_raw, 0444, pac1944_in_power_acc_raw_show, NULL, 3);
+
+static IIO_DEVICE_ATTR(in_energy1_scale, 0444, pac1944_in_power_acc_scale_show, NULL, 0);
+static IIO_DEVICE_ATTR(in_energy2_scale, 0444, pac1944_in_power_acc_scale_show, NULL, 1);
+static IIO_DEVICE_ATTR(in_energy3_scale, 0444, pac1944_in_power_acc_scale_show, NULL, 2);
+static IIO_DEVICE_ATTR(in_energy4_scale, 0444, pac1944_in_power_acc_scale_show, NULL, 3);
+
+static IIO_DEVICE_ATTR(in_energy1_en, 0644, pac1944_in_enable_acc_show,
+		       pac1944_in_enable_acc_store, 0);
+static IIO_DEVICE_ATTR(in_energy2_en, 0644, pac1944_in_enable_acc_show,
+		       pac1944_in_enable_acc_store, 1);
+static IIO_DEVICE_ATTR(in_energy3_en, 0644, pac1944_in_enable_acc_show,
+		       pac1944_in_enable_acc_store, 2);
+static IIO_DEVICE_ATTR(in_energy4_en, 0644, pac1944_in_enable_acc_show,
+		       pac1944_in_enable_acc_store, 3);
+
+static IIO_DEVICE_ATTR(in_current_acc1_raw, 0444, pac1944_in_current_acc_raw_show, NULL, 0);
+static IIO_DEVICE_ATTR(in_current_acc2_raw, 0444, pac1944_in_current_acc_raw_show, NULL, 1);
+static IIO_DEVICE_ATTR(in_current_acc3_raw, 0444, pac1944_in_current_acc_raw_show, NULL, 2);
+static IIO_DEVICE_ATTR(in_current_acc4_raw, 0444, pac1944_in_current_acc_raw_show, NULL, 3);
+
+static IIO_DEVICE_ATTR(in_current_acc1_scale, 0444, pac1944_in_current_acc_scale_show, NULL, 0);
+static IIO_DEVICE_ATTR(in_current_acc2_scale, 0444, pac1944_in_current_acc_scale_show, NULL, 1);
+static IIO_DEVICE_ATTR(in_current_acc3_scale, 0444, pac1944_in_current_acc_scale_show, NULL, 2);
+static IIO_DEVICE_ATTR(in_current_acc4_scale, 0444, pac1944_in_current_acc_scale_show, NULL, 3);
+
+static IIO_DEVICE_ATTR(in_current_acc1_en, 0644, pac1944_in_enable_acc_show,
+		       pac1944_in_enable_acc_store, 0);
+static IIO_DEVICE_ATTR(in_current_acc2_en, 0644, pac1944_in_enable_acc_show,
+		       pac1944_in_enable_acc_store, 1);
+static IIO_DEVICE_ATTR(in_current_acc3_en, 0644, pac1944_in_enable_acc_show,
+		       pac1944_in_enable_acc_store, 2);
+static IIO_DEVICE_ATTR(in_current_acc4_en, 0644, pac1944_in_enable_acc_show,
+		       pac1944_in_enable_acc_store, 3);
+
+static struct attribute *pac1944_power_acc_attr[] = {
+	&iio_dev_attr_in_energy1_raw.dev_attr.attr,
+	&iio_dev_attr_in_energy2_raw.dev_attr.attr,
+	&iio_dev_attr_in_energy3_raw.dev_attr.attr,
+	&iio_dev_attr_in_energy4_raw.dev_attr.attr,
+	&iio_dev_attr_in_energy1_scale.dev_attr.attr,
+	&iio_dev_attr_in_energy2_scale.dev_attr.attr,
+	&iio_dev_attr_in_energy3_scale.dev_attr.attr,
+	&iio_dev_attr_in_energy4_scale.dev_attr.attr,
+	&iio_dev_attr_in_energy1_en.dev_attr.attr,
+	&iio_dev_attr_in_energy2_en.dev_attr.attr,
+	&iio_dev_attr_in_energy3_en.dev_attr.attr,
+	&iio_dev_attr_in_energy4_en.dev_attr.attr,
+	NULL
+};
+
+static struct attribute *pac1944_current_acc_attr[] = {
+	&iio_dev_attr_in_current_acc1_raw.dev_attr.attr,
+	&iio_dev_attr_in_current_acc2_raw.dev_attr.attr,
+	&iio_dev_attr_in_current_acc3_raw.dev_attr.attr,
+	&iio_dev_attr_in_current_acc4_raw.dev_attr.attr,
+	&iio_dev_attr_in_current_acc1_scale.dev_attr.attr,
+	&iio_dev_attr_in_current_acc2_scale.dev_attr.attr,
+	&iio_dev_attr_in_current_acc3_scale.dev_attr.attr,
+	&iio_dev_attr_in_current_acc4_scale.dev_attr.attr,
+	&iio_dev_attr_in_current_acc1_en.dev_attr.attr,
+	&iio_dev_attr_in_current_acc2_en.dev_attr.attr,
+	&iio_dev_attr_in_current_acc3_en.dev_attr.attr,
+	&iio_dev_attr_in_current_acc4_en.dev_attr.attr,
+	NULL
+};
+
+static int pac1944_prep_custom_attributes(struct pac1944_chip_info *info,
+					  struct iio_dev *indio_dev)
+{
+	struct attribute **pac1944_custom_attrs, **tmp_attr;
+	struct i2c_client *client = info->client;
+	struct attribute_group *pac1944_group;
+	int active_channels_count = 0;
+	int custom_attr_cnt;
+	int ch, i, j;
+
+	active_channels_count = info->num_enabled_channels;
+
+	pac1944_group = devm_kzalloc(&client->dev, sizeof(*pac1944_group), GFP_KERNEL);
+	if (!pac1944_group)
+		return -ENOMEM;
+
+	/*
+	 * Attributes for channel X:
+	 *	- in_shunt_value_X
+	 *	- one of attributes:
+	 *		- in_power_accX_raw,in_power_accX_scale and in_power_accX_en
+	 *		- in_current_accX_raw, in_current_accX_scale and in_current_accX_en
+	 */
+	custom_attr_cnt = PAC1944_COMMON_DEVATTR * active_channels_count;
+	custom_attr_cnt += PAC1944_ACC_DEVATTR * active_channels_count;
+
+	pac1944_custom_attrs = devm_kcalloc(&client->dev, custom_attr_cnt + 1,
+					    sizeof(*pac1944_custom_attrs), GFP_KERNEL);
+	if (!pac1944_custom_attrs)
+		return -ENOMEM;
+
+	j = 0;
+
+	for_each_set_bit(ch, &info->active_channels_mask, info->phys_channels) {
+		for (i = 0; i < PAC1944_COMMON_DEVATTR; i++)
+			pac1944_custom_attrs[j++] =
+				pac1944_all_attrs[PAC1944_COMMON_DEVATTR * ch + i];
+
+		switch (info->chip_reg_data.accumulation_mode[ch]) {
+		case PAC1944_ACCMODE_VPOWER:
+			tmp_attr = pac1944_power_acc_attr;
+			break;
+		case PAC1944_ACCMODE_VSENSE:
+			tmp_attr = pac1944_current_acc_attr;
+			break;
+		default:
+			return -EINVAL;
+		}
+
+		pac1944_custom_attrs[j++] = tmp_attr[ch];
+		pac1944_custom_attrs[j++] = tmp_attr[PAC1944_MAX_CH + ch];
+		pac1944_custom_attrs[j++] = tmp_attr[2 * PAC1944_MAX_CH + ch];
+	}
+
+	pac1944_group->attrs = pac1944_custom_attrs;
+	info->iio_info.attrs = pac1944_group;
+
+	return 0;
+}
+
+static int pac1944_frequency_set(struct iio_dev *indio_dev,
+				 const struct iio_chan_spec *chan,
+				 unsigned int mode)
+{
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	struct i2c_client *client = info->client;
+	u16 tmp_u16;
+	int ret;
+
+	ret = i2c_smbus_read_word_swapped(client, PAC1944_CTRL_ACT_REG_ADDR);
+	if (ret < 0) {
+		dev_err(&client->dev, "cannot read PAC1944 regs from 0x%02X\n",
+			PAC1944_CTRL_ACT_REG_ADDR);
+		return ret;
+	}
+
+	tmp_u16 = ret;
+	tmp_u16 &= ~PAC1944_CTRL_SAMPLE_MASK;
+	tmp_u16 |= FIELD_PREP(PAC1944_CTRL_SAMPLE_MASK, mode);
+
+	scoped_guard(mutex, &info->lock) {
+		ret = i2c_smbus_write_word_swapped(client, PAC1944_CTRL_REG_ADDR, tmp_u16);
+		if (ret < 0) {
+			dev_err(&client->dev, "Failed to configure sampling mode\n");
+			return ret;
+		}
+
+		info->sampling_mode = mode;
+		info->chip_reg_data.ctrl_act_reg = tmp_u16;
+	}
+
+	return pac1944_retrieve_data(info, PAC1944_MIN_UPDATE_WAIT_TIME_US);
+}
+
+static int pac1944_frequency_get(struct iio_dev *indio_dev,
+				 const struct iio_chan_spec *chan)
+{
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+
+	return info->sampling_mode;
+}
+
+static const struct iio_enum sampling_mode_enum = {
+	.items = pac1944_frequency_avail,
+	.num_items = ARRAY_SIZE(pac1944_frequency_avail),
+	.set = pac1944_frequency_set,
+	.get = pac1944_frequency_get,
+};
+
+static const struct iio_chan_spec_ext_info pac1944_ext_info[] = {
+	IIO_ENUM("sampling_frequency", IIO_SHARED_BY_ALL, &sampling_mode_enum),
+	{
+		.name = "sampling_frequency_available",
+		.shared = IIO_SHARED_BY_ALL,
+		.read = iio_enum_available_read,
+		.private = (uintptr_t)&sampling_mode_enum,
+	},
+	{ }
+};
+
+static int pac1944_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	int ret, idx;
+	u64 tmp;
+
+	ret = pac1944_retrieve_data(info, PAC1944_MIN_UPDATE_WAIT_TIME_US);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * In the datasheet channels are referred to as 1 to 4. For AVG the index
+	 * should be between 5 to 8. To calculate PAC1944_CH_VOLTAGE_AVERAGE and
+	 * PAC1944_CH_CURRENT_AVERAGE real index, we need to remove the added
+	 * offset (PAC1944_MAX_CH).
+	 */
+	idx = (chan->channel - 1) % PAC1944_MAX_CH;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			*val = info->chip_reg_data.vbus[idx];
+			return IIO_VAL_INT;
+		case IIO_CURRENT:
+			*val = info->chip_reg_data.vsense[idx];
+			return IIO_VAL_INT;
+		case IIO_POWER:
+			*val = info->chip_reg_data.vpower[idx];
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_AVERAGE_RAW:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			*val = info->chip_reg_data.vbus_avg[idx];
+			return IIO_VAL_INT;
+		case IIO_CURRENT:
+			*val = info->chip_reg_data.vsense_avg[idx];
+			return IIO_VAL_INT;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->address) {
+		case PAC1944_VBUS_1_ADDR:
+		case PAC1944_VBUS_2_ADDR:
+		case PAC1944_VBUS_3_ADDR:
+		case PAC1944_VBUS_4_ADDR:
+		case PAC1944_VBUS_AVG_1_ADDR:
+		case PAC1944_VBUS_AVG_2_ADDR:
+		case PAC1944_VBUS_AVG_3_ADDR:
+		case PAC1944_VBUS_AVG_4_ADDR:
+			if (info->is_pac195x_family)
+				*val = PAC195X_VOLTAGE_MILLIVOLTS_MAX;
+			else
+				*val = PAC194X_VOLTAGE_MILLIVOLTS_MAX;
+
+			switch (info->chip_reg_data.vbus_mode[idx]) {
+			case PAC1944_UNIPOLAR_FSR_CFG:
+			case PAC1944_BIPOLAR_HALF_FSR_CFG:
+				*val2 = PAC1944_VOLTAGE_16B_RES;
+				break;
+			case PAC1944_BIPOLAR_FSR_CFG:
+				*val2 = PAC1944_VOLTAGE_15B_RES;
+				break;
+			default:
+				return -EINVAL;
+			}
+			return IIO_VAL_FRACTIONAL_LOG2;
+		/*
+		 * Currents - scale for mA - depends on the
+		 * channel's shunt value
+		 * (100mV * 1000000) / (2^16 * shunt(microOhm))
+		 */
+		case PAC1944_VSENSE_1_ADDR:
+		case PAC1944_VSENSE_2_ADDR:
+		case PAC1944_VSENSE_3_ADDR:
+		case PAC1944_VSENSE_4_ADDR:
+		case PAC1944_VSENSE_AVG_1_ADDR:
+		case PAC1944_VSENSE_AVG_2_ADDR:
+		case PAC1944_VSENSE_AVG_3_ADDR:
+		case PAC1944_VSENSE_AVG_4_ADDR:
+			*val = PAC1944_MAX_VSENSE_RSHIFTED_BY_15B;
+			switch (info->chip_reg_data.vsense_mode[idx]) {
+			case PAC1944_UNIPOLAR_FSR_CFG:
+			case PAC1944_BIPOLAR_HALF_FSR_CFG:
+				*val = *val >> 1;
+				*val2 = info->shunts[idx];
+				break;
+			case PAC1944_BIPOLAR_FSR_CFG:
+				*val2 = info->shunts[idx];
+				break;
+			default:
+				return -EINVAL;
+			}
+			return IIO_VAL_FRACTIONAL;
+		/*
+		 * Power - mW - it will use the combined scale
+		 * for current and voltage
+		 * current(mA) * voltage(mV) = power (uW)
+		 */
+		case PAC1944_VPOWER_1_ADDR:
+		case PAC1944_VPOWER_2_ADDR:
+		case PAC1944_VPOWER_3_ADDR:
+		case PAC1944_VPOWER_4_ADDR:
+			if (info->is_pac195x_family)
+				tmp = PAC195X_PRODUCT_VOLTAGE_PV_FSR;
+			else
+				tmp = PAC194X_PRODUCT_VOLTAGE_PV_FSR;
+
+			do_div(tmp, info->shunts[idx]);
+			*val = (int)tmp;
+			if ((info->chip_reg_data.vbus_mode[idx] == PAC1944_UNIPOLAR_FSR_CFG &&
+			     info->chip_reg_data.vsense_mode[idx] == PAC1944_UNIPOLAR_FSR_CFG) ||
+			    info->chip_reg_data.vbus_mode[idx] == PAC1944_BIPOLAR_HALF_FSR_CFG ||
+			    info->chip_reg_data.vsense_mode[idx] == PAC1944_BIPOLAR_HALF_FSR_CFG)
+				*val2 = PAC1944_POWER_30B_RES;
+			else
+				*val2 = PAC1944_POWER_29B_RES;
+
+			return IIO_VAL_FRACTIONAL_LOG2;
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
+static int pac1944_read_label(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan, char *label)
+{
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	int idx;
+
+	/*
+	 * In the datasheet channels are referred to as 1 to 4. For AVG the index
+	 * should be between 5 to 8. To calculate PAC1944_CH_VOLTAGE_AVERAGE and
+	 * PAC1944_CH_CURRENT_AVERAGE real index, we need to remove the added
+	 * offset (PAC1944_MAX_CH).
+	 */
+	idx = (chan->channel - 1) % PAC1944_MAX_CH;
+
+	switch (chan->address) {
+	case PAC1944_VBUS_1_ADDR:
+	case PAC1944_VBUS_2_ADDR:
+	case PAC1944_VBUS_3_ADDR:
+	case PAC1944_VBUS_4_ADDR:
+		if (info->labels[idx])
+			return sysfs_emit(label, "%s_VBUS_%d\n", info->labels[idx], idx + 1);
+
+		return sysfs_emit(label, "VBUS_%d\n", idx + 1);
+	case PAC1944_VBUS_AVG_1_ADDR:
+	case PAC1944_VBUS_AVG_2_ADDR:
+	case PAC1944_VBUS_AVG_3_ADDR:
+	case PAC1944_VBUS_AVG_4_ADDR:
+		if (info->labels[idx])
+			return sysfs_emit(label, "%s_VBUS_AVG_%d\n", info->labels[idx], idx + 1);
+
+		return sysfs_emit(label, "VBUS_AVG_%d\n", idx + 1);
+	case PAC1944_VSENSE_1_ADDR:
+	case PAC1944_VSENSE_2_ADDR:
+	case PAC1944_VSENSE_3_ADDR:
+	case PAC1944_VSENSE_4_ADDR:
+		if (info->labels[idx])
+			return sysfs_emit(label, "%s_IBUS_%d\n", info->labels[idx], idx + 1);
+
+		return sysfs_emit(label, "IBUS_%d\n", idx + 1);
+	case PAC1944_VSENSE_AVG_1_ADDR:
+	case PAC1944_VSENSE_AVG_2_ADDR:
+	case PAC1944_VSENSE_AVG_3_ADDR:
+	case PAC1944_VSENSE_AVG_4_ADDR:
+		if (info->labels[idx])
+			return sysfs_emit(label, "%s_IBUS_AVG_%d\n", info->labels[idx], idx + 1);
+
+		return sysfs_emit(label, "IBUS_AVG_%d\n", idx + 1);
+	case PAC1944_VPOWER_1_ADDR:
+	case PAC1944_VPOWER_2_ADDR:
+	case PAC1944_VPOWER_3_ADDR:
+	case PAC1944_VPOWER_4_ADDR:
+		if (info->labels[idx])
+			return sysfs_emit(label, "%s_POWER_%d\n", info->labels[idx], idx + 1);
+
+		return sysfs_emit(label, "POWER_%d\n", idx + 1);
+	}
+
+	return 0;
+}
+
+static void pac1944_work_periodic_rfsh(struct work_struct *work)
+{
+	struct pac1944_chip_info *info = to_pac1944_chip_info(to_delayed_work(work));
+	struct i2c_client *client = info->client;
+
+	dev_dbg(&client->dev, "Periodic refresh\n");
+
+	pac1944_reg_snapshot(info, true, PAC1944_REFRESH_REG_ADDR,
+			     PAC1944_MIN_UPDATE_WAIT_TIME_US);
+
+	mod_delayed_work(system_percpu_wq, &info->work_chip_rfsh,
+			 msecs_to_jiffies(PAC1944_MAX_RFSH_LIMIT_MS));
+}
+
+/*
+ * Universal Unique Identifier (UUID),
+ * 721F1534-5D27-4B60-9DF4-41A3C4B7DA3A,
+ * is reserved to Microchip for the PAC194x and PAC195x.
+ */
+#define PAC1944_DSM_UUID       "721F1534-5D27-4B60-9DF4-41A3C4B7DA3A"
+
+/*
+ * documentation related to the ACPI device definition
+ * https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/UserGuides/PAC194X_5X-UEFI-BIOS-Integration-and-Microsoft-Windows-10-and-Windows-11-Energy-Meter-Interface-Device-Driver-Users-Guide-DS50003155.pdf
+ */
+static int pac1944_acpi_parse_channel_config(struct i2c_client *client,
+					     struct pac1944_chip_info *info)
+{
+	struct device *dev = &client->dev;
+	const struct acpi_device_id *id;
+	unsigned short bi_dir_mask;
+	union acpi_object *rez;
+	acpi_handle handle;
+	guid_t guid;
+	int i;
+
+	handle = ACPI_HANDLE(dev);
+
+	id = acpi_match_device(dev->driver->acpi_match_table, dev);
+	if (!id)
+		return -ENODEV;
+
+	guid_parse(PAC1944_DSM_UUID, &guid);
+
+	rez = acpi_evaluate_dsm(handle, &guid, 0, PAC1944_ACPI_GET_NAMES, NULL);
+	if (!rez)
+		return -EINVAL;
+
+	if (rez->package.count > PAC1944_MAX_CH) {
+		ACPI_FREE(rez);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < rez->package.count; i++) {
+		if (rez->package.elements[i].type != ACPI_TYPE_STRING) {
+			ACPI_FREE(rez);
+			return -EINVAL;
+		}
+
+		info->labels[i] = devm_kmemdup(dev, rez->package.elements[i].string.pointer,
+					       (size_t)rez->package.elements[i].string.length + 1,
+					       GFP_KERNEL);
+		if (!info->labels[i]) {
+			ACPI_FREE(rez);
+			return -ENOMEM;
+		}
+
+		info->labels[i][rez->package.elements[i].string.length] = '\0';
+	}
+
+	ACPI_FREE(rez);
+
+	rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1944_ACPI_GET_UOHMS_VALS, NULL);
+	if (!rez)
+		return -EINVAL;
+
+	if (rez->package.count > PAC1944_MAX_CH) {
+		ACPI_FREE(rez);
+		return -EINVAL;
+	}
+
+	for (i = 0; i < rez->package.count; i++) {
+		if (rez->package.elements[i].type != ACPI_TYPE_INTEGER) {
+			ACPI_FREE(rez);
+			return -EINVAL;
+		}
+
+		info->shunts[i] = rez->package.elements[i].integer.value;
+		if (info->shunts[i])
+			set_bit(i, &info->active_channels_mask);
+	}
+
+	ACPI_FREE(rez);
+
+	rez = acpi_evaluate_dsm(handle, &guid, 1, PAC1944_ACPI_GET_BIPOLAR_SETTINGS, NULL);
+	if (!rez)
+		return -EINVAL;
+
+	if (rez->package.count != 2 * PAC1944_MAX_CH) {
+		ACPI_FREE(rez);
+		return -EINVAL;
+	}
+
+	for_each_set_bit(i, &info->active_channels_mask, info->phys_channels) {
+		if (rez->package.elements[i].type != ACPI_TYPE_INTEGER) {
+			ACPI_FREE(rez);
+			return -EINVAL;
+		}
+
+		bi_dir_mask = rez->package.elements[i].integer.value;
+
+		if (bi_dir_mask == PAC1944_UNIPOLAR_FSR_CFG ||
+		    bi_dir_mask == PAC1944_BIPOLAR_FSR_CFG  ||
+		    bi_dir_mask == PAC1944_BIPOLAR_HALF_FSR_CFG) {
+			dev_dbg(dev, "VBUS{%d} mode set to: %d\n", i, bi_dir_mask);
+			info->chip_reg_data.vbus_mode[i] = bi_dir_mask;
+		} else {
+			return dev_err_probe(dev, -EINVAL, "invalid vbus-mode value on %i\n", i);
+		}
+
+		if (rez->package.elements[i + PAC1944_MAX_CH].type != ACPI_TYPE_INTEGER) {
+			ACPI_FREE(rez);
+			return -EINVAL;
+		}
+
+		bi_dir_mask = rez->package.elements[i + PAC1944_MAX_CH].integer.value;
+
+		if (bi_dir_mask == PAC1944_UNIPOLAR_FSR_CFG ||
+		    bi_dir_mask == PAC1944_BIPOLAR_FSR_CFG  ||
+		    bi_dir_mask == PAC1944_BIPOLAR_HALF_FSR_CFG) {
+			dev_dbg(dev, "VSENSE{%d} mode set to: %d\n", i, bi_dir_mask);
+			info->chip_reg_data.vsense_mode[i] = bi_dir_mask;
+		} else {
+			return dev_err_probe(dev, -EINVAL, "invalid vsense-mode value on %i\n", i);
+		}
+	}
+
+	ACPI_FREE(rez);
+
+	return 0;
+}
+
+static int pac1944_check_range(s32 *vals, const int ranges[][2], int num_ranges)
+{
+	int i;
+
+	for (i = 0; i < num_ranges; i++) {
+		if (vals[0] == ranges[i][0] && vals[1] == ranges[i][1])
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int pac1944_setup_adc_vbus_range(const struct fwnode_handle *child,
+					struct pac1944_chip_info *info, int idx)
+{
+	const char *prop_name = "microchip,vbus-input-range-microvolt";
+	struct i2c_client *client = info->client;
+	struct device *dev = &client->dev;
+	bool is_bipolar, is_half_fsr;
+	unsigned int tbl_len;
+	s32 vals[2];
+	int ret;
+
+	/* default value is unipolar and Full Scale Range */
+	is_bipolar = false;
+	is_half_fsr = false;
+
+	ret = fwnode_property_read_u32_array(child, prop_name, vals, 2);
+	if (!ret) {
+		if (info->is_pac195x_family) {
+			tbl_len = ARRAY_SIZE(pac1954_adc_range_tbl);
+			ret = pac1944_check_range(vals, pac1954_adc_range_tbl, tbl_len);
+		} else {
+			tbl_len = ARRAY_SIZE(pac1944_adc_range_tbl);
+			ret = pac1944_check_range(vals, pac1944_adc_range_tbl, tbl_len);
+		}
+		if (ret < 0) {
+			return dev_err_probe(dev, -EINVAL,
+					     "Invalid value %d, %d for prop %s\n",
+					     vals[0], vals[1], prop_name);
+		}
+
+		if (ret != PAC1944_ADC_FULL_RANGE_UNIPOLAR)
+			is_bipolar = true;
+		if (ret == PAC1944_ADC_HALF_RANGE_BIPOLAR)
+			is_half_fsr = true;
+	}
+
+	info->chip_reg_data.vbus_mode[idx] = PAC1944_UNIPOLAR_FSR_CFG;
+	if (is_half_fsr)
+		info->chip_reg_data.vbus_mode[idx] = PAC1944_BIPOLAR_HALF_FSR_CFG;
+	else if (is_bipolar)
+		info->chip_reg_data.vbus_mode[idx] = PAC1944_BIPOLAR_FSR_CFG;
+
+	return 0;
+}
+
+static int pac1944_setup_adc_vsense_range(const struct fwnode_handle *child,
+					  struct pac1944_chip_info *info, int idx)
+{
+	const char *prop_name = "microchip,vsense-input-range-microvolt";
+	struct i2c_client *client = info->client;
+	struct device *dev = &client->dev;
+	bool is_bipolar, is_half_fsr;
+	unsigned int tbl_len;
+	s32 vals[2];
+	int ret;
+
+	/* default value is unipolar and Full Scale Range */
+	is_bipolar = false;
+	is_half_fsr = false;
+
+	ret = fwnode_property_read_u32_array(child, prop_name, vals, 2);
+	if (!ret) {
+		tbl_len = ARRAY_SIZE(pac1944_adc_vsense_range_tbl);
+		ret = pac1944_check_range(vals, pac1944_adc_vsense_range_tbl, tbl_len);
+		if (ret < 0) {
+			return dev_err_probe(dev, -EINVAL,
+					     "Invalid value %d, %d for prop %s\n",
+					     vals[0], vals[1], prop_name);
+		}
+
+		if (ret != PAC1944_ADC_FULL_RANGE_UNIPOLAR)
+			is_bipolar = true;
+		if (ret == PAC1944_ADC_HALF_RANGE_BIPOLAR)
+			is_half_fsr = true;
+	}
+
+	info->chip_reg_data.vsense_mode[idx] = PAC1944_UNIPOLAR_FSR_CFG;
+	if (is_half_fsr)
+		info->chip_reg_data.vsense_mode[idx] = PAC1944_BIPOLAR_HALF_FSR_CFG;
+	else if (is_bipolar)
+		info->chip_reg_data.vsense_mode[idx] = PAC1944_BIPOLAR_FSR_CFG;
+
+	return 0;
+}
+
+static int pac1944_of_parse_channel_config(struct i2c_client *client,
+					   struct pac1944_chip_info *info)
+{
+	struct device *dev = &client->dev;
+	unsigned int current_channel;
+	int ret, acc_mode;
+	u32 idx;
+
+	current_channel = 1;
+
+	device_for_each_child_node_scoped(dev, child) {
+		ret = fwnode_property_read_u32(child, "reg", &idx);
+		if (ret)
+			return dev_err_probe(dev, ret, "reading invalid channel index\n");
+
+		if (current_channel > info->phys_channels || idx > info->phys_channels || idx == 0)
+			return dev_err_probe(dev, -EINVAL, "invalid channel index %d value\n", idx);
+
+		/* adjust idx to match channel index (1 to 4) from the datasheet */
+		idx--;
+
+		if (test_and_set_bit(idx, &info->active_channels_mask))
+			return dev_err_probe(dev, -EINVAL, "duplicate reg value %u\n", idx + 1);
+
+		ret = fwnode_property_read_u32(child, "shunt-resistor-micro-ohms",
+					       &info->shunts[idx]);
+		if (ret)
+			return dev_err_probe(dev, ret, "%s: invalid shunt-resistor value\n",
+					     fwnode_get_name(child));
+
+		fwnode_property_read_string(child, "label", (const char **)&info->labels[idx]);
+
+		ret = pac1944_setup_adc_vbus_range(child, info, idx);
+		if (ret)
+			return ret;
+
+		ret = pac1944_setup_adc_vsense_range(child, info, idx);
+		if (ret)
+			return ret;
+
+		ret = fwnode_property_read_u32(child, "microchip,accumulation-mode", &acc_mode);
+		if (ret)
+			return dev_err_probe(dev, ret, "invalid accumulation-mode value on %s\n",
+					     fwnode_get_name(child));
+		if (acc_mode == PAC1944_ACCMODE_VPOWER ||
+		    acc_mode == PAC1944_ACCMODE_VSENSE) {
+			dev_dbg(dev, "Accumulation{%d} mode set to: %d\n", idx, acc_mode);
+			info->chip_reg_data.accumulation_mode[idx] = acc_mode;
+		} else {
+			return dev_err_probe(dev, -EINVAL,
+					     "invalid mode for accumulator value on %s\n",
+					     fwnode_get_name(child));
+		}
+		current_channel++;
+	}
+
+	return 0;
+}
+
+static void pac1944_cancel_delayed_work(void *dwork)
+{
+	cancel_delayed_work_sync(dwork);
+}
+
+static int pac1944_chip_identify(struct iio_dev *indio_dev, struct pac1944_chip_info *info)
+{
+	struct i2c_client *client = info->client;
+	u8 chip_rev[3];
+	int ret;
+
+	ret = i2c_smbus_read_i2c_block_data(client, PAC1944_PID_REG_ADDR,
+					    sizeof(chip_rev),
+					    chip_rev);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret, "cannot read revision\n");
+
+	dev_info(&client->dev, "Chip revision: 0x%02X\n", chip_rev[2]);
+
+	if (chip_rev[0] >= PAC_PRODUCT_ID_1941 && chip_rev[0] <= PAC_PRODUCT_ID_1942_2) {
+		info->is_pac195x_family = false;
+	} else if (chip_rev[0] >= PAC_PRODUCT_ID_1951 && chip_rev[0] <= PAC_PRODUCT_ID_1952_2) {
+		info->is_pac195x_family = true;
+	} else {
+		dev_err(&client->dev,
+			"product ID (0x%02X, 0x%02X, 0x%02X) for this part doesn't match\n",
+			chip_rev[0], chip_rev[1], chip_rev[2]);
+		return -EINVAL;
+	}
+
+	switch (chip_rev[0]) {
+	case PAC_PRODUCT_ID_1941:
+		info->phys_channels = pac1941_chip_config.phys_channels;
+		indio_dev->name = pac1941_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1942:
+		info->phys_channels = pac1942_chip_config.phys_channels;
+		indio_dev->name = pac1942_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1943:
+		info->phys_channels = pac1943_chip_config.phys_channels;
+		indio_dev->name = pac1943_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1944:
+		info->phys_channels = pac1944_chip_config.phys_channels;
+		indio_dev->name = pac1944_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1941_2:
+		info->phys_channels = pac1941_2_chip_config.phys_channels;
+		indio_dev->name = pac1941_2_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1942_2:
+		info->phys_channels = pac1942_2_chip_config.phys_channels;
+		indio_dev->name = pac1942_2_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1951:
+		info->phys_channels = pac1951_chip_config.phys_channels;
+		indio_dev->name = pac1951_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1952:
+		info->phys_channels = pac1952_chip_config.phys_channels;
+		indio_dev->name = pac1952_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1953:
+		info->phys_channels = pac1953_chip_config.phys_channels;
+		indio_dev->name = pac1953_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1954:
+		info->phys_channels = pac1954_chip_config.phys_channels;
+		indio_dev->name = pac1954_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1951_2:
+		info->phys_channels = pac1951_2_chip_config.phys_channels;
+		indio_dev->name = pac1951_2_chip_config.name;
+		break;
+	case PAC_PRODUCT_ID_1952_2:
+		info->phys_channels = pac1952_2_chip_config.phys_channels;
+		indio_dev->name = pac1952_2_chip_config.name;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int pac1944_chip_configure(struct pac1944_chip_info *info)
+{
+	struct i2c_client *client = info->client;
+	u32 wait_time;
+	u16 cfg = 0;
+	u8 acc_cfg;
+	int ret, i;
+
+	/*
+	 * Count how many channels are enabled and store this information within
+	 * the driver data.
+	 */
+	info->num_enabled_channels = hweight_long(info->active_channels_mask);
+
+	/* get sampling rate from PAC */
+	ret = i2c_smbus_read_word_swapped(client, PAC1944_CTRL_REG_ADDR);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret, "cannot read CTRL reg\n");
+
+	info->sampling_mode = FIELD_GET(PAC1944_CTRL_SAMPLE_MASK, ret);
+
+	if (info->sampling_mode > PAC1944_SAMP_8SPS)
+		return dev_err_probe(&client->dev, -EINVAL, "Unsupported sample mode\n");
+
+	/*
+	 * The current/voltage can be measured unidirectional, bidirectional or half FSR
+	 * no SLOW triggered REFRESH, clear POR
+	 */
+	for_each_set_bit(i, &info->active_channels_mask, PAC1944_MAX_CH)
+		cfg |= (info->chip_reg_data.vbus_mode[i] << (6 - 2 * i)) |
+			info->chip_reg_data.vsense_mode[i] << (14 - 2 * i);
+
+	ret = i2c_smbus_write_word_swapped(client, PAC1944_NEG_PWR_FSR_REG_ADDR, cfg);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "cannot write NEG_PWR_FSR reg\n");
+
+	ret = i2c_smbus_write_word_data(client, PAC1944_SLOW_REG_ADDR, 0);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "cannot write SLOW reg\n");
+
+	/* Write the CHANNEL_N_OFF from CTRL REGISTER */
+	cfg = FIELD_PREP(PAC1944_CTRL_SAMPLE_MASK, info->sampling_mode) |
+		FIELD_PREP(PAC1944_CTRL_GPIO_ALERT2_MASK, 0) |
+		FIELD_PREP(PAC1944_CTRL_SLOW_ALERT1_MASK, 0) |
+		FIELD_PREP(PAC1944_CTRL_CH_1_OFF_MASK, !test_bit(0, &info->active_channels_mask)) |
+		FIELD_PREP(PAC1944_CTRL_CH_2_OFF_MASK, !test_bit(1, &info->active_channels_mask)) |
+		FIELD_PREP(PAC1944_CTRL_CH_3_OFF_MASK, !test_bit(2, &info->active_channels_mask)) |
+		FIELD_PREP(PAC1944_CTRL_CH_4_OFF_MASK, !test_bit(3, &info->active_channels_mask));
+
+	ret = i2c_smbus_write_word_swapped(client, PAC1944_CTRL_REG_ADDR, cfg);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "cannot write CTRL reg\n");
+
+	acc_cfg = ACCUM_REG(info->chip_reg_data.accumulation_mode[0],
+			    info->chip_reg_data.accumulation_mode[1],
+			    info->chip_reg_data.accumulation_mode[2],
+			    info->chip_reg_data.accumulation_mode[3]);
+
+	ret = i2c_smbus_write_byte_data(client, PAC1944_ACCUM_CFG_REG_ADDR, acc_cfg);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "cannot write ACCUM_CFG reg\n");
+
+	/*
+	 * Sending a REFRESH to the chip, so the new settings take place
+	 * as well as resetting the accumulators
+	 */
+	ret = i2c_smbus_write_byte(client, PAC1944_REFRESH_REG_ADDR);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "cannot write REFRESH reg\n");
+
+	/*
+	 * Get the current (in the chip) sampling speed and compute the
+	 * required timeout based on its value the timeout is 1/sampling_speed
+	 * wait the maximum amount of time to be on the safe side - the
+	 * maximum wait time is for 8sps
+	 */
+	wait_time = (1024 / pac1944_samp_rate_map_tbl[info->sampling_mode]) * 1000;
+	usleep_range(wait_time, wait_time + 100);
+
+	INIT_DELAYED_WORK(&info->work_chip_rfsh, pac1944_work_periodic_rfsh);
+	/* Setup the latest moment for reading the regs before saturation */
+	mod_delayed_work(system_percpu_wq, &info->work_chip_rfsh,
+			 msecs_to_jiffies(PAC1944_MAX_RFSH_LIMIT_MS));
+
+	return devm_add_action_or_reset(&client->dev, pac1944_cancel_delayed_work,
+					&info->work_chip_rfsh);
+}
+
+static const struct iio_chan_spec pac1944_single_channel[] = {
+	PAC1944_VPOWER_CHANNEL(0, PAC1944_VPOWER_1_ADDR),
+	PAC1944_VBUS_CHANNEL(0, PAC1944_VBUS_1_ADDR),
+	PAC1944_VSENSE_CHANNEL(0, PAC1944_VSENSE_1_ADDR),
+	PAC1944_VBUS_AVG_CHANNEL(0, PAC1944_VBUS_AVG_1_ADDR),
+	PAC1944_VSENSE_AVG_CHANNEL(0, PAC1944_VSENSE_AVG_1_ADDR),
+};
+
+static int pac1944_prep_iio_channels(struct pac1944_chip_info *info,
+				     struct iio_dev *indio_dev)
+{
+	struct device *dev = &info->client->dev;
+	int channel_size, attribute_count, cnt;
+	struct iio_chan_spec *ch_sp;
+
+	/* Finding out dynamically how many IIO channels we need */
+	attribute_count = 0;
+	channel_size = 0;
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		/* add the size of the properties of one chip physical channel */
+		channel_size += sizeof(pac1944_single_channel);
+		/* count how many enabled channels we have */
+		attribute_count += ARRAY_SIZE(pac1944_single_channel);
+		dev_dbg(dev, ":%s: Channel %d active\n", __func__, cnt + 1);
+	}
+
+	ch_sp = devm_kzalloc(dev, channel_size, GFP_KERNEL);
+	if (!ch_sp)
+		return -ENOMEM;
+
+	/*
+	 * Send the updated dynamic channel structure information towards IIO
+	 * prepare the required field for IIO class registration
+	 */
+	indio_dev->num_channels = attribute_count;
+	indio_dev->channels = ch_sp;
+
+	/* Populate the dynamic channels and make all the adjustments */
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		memcpy(ch_sp, pac1944_single_channel, sizeof(pac1944_single_channel));
+		/*
+		 * In the datasheet channels are referred to as 1 to 4, so we will
+		 * adjust the channel to match channel index (1 to 4) from the
+		 * datasheet.
+		 */
+		ch_sp[PAC1944_CH_POWER].channel = cnt + 1;
+		ch_sp[PAC1944_CH_POWER].address = cnt + PAC1944_VPOWER_1_ADDR;
+		ch_sp[PAC1944_CH_VOLTAGE].channel = cnt + 1;
+		ch_sp[PAC1944_CH_VOLTAGE].address = cnt + PAC1944_VBUS_1_ADDR;
+		ch_sp[PAC1944_CH_CURRENT].channel = cnt + 1;
+		ch_sp[PAC1944_CH_CURRENT].address = cnt + PAC1944_VSENSE_1_ADDR;
+		/*
+		 * In order to be able to use labels for PAC1944_CH_VOLTAGE and
+		 * PAC1944_CH_VOLTAGE_AVERAGE, respectively PAC1944_CH_CURRENT
+		 * and PAC1944_CH_CURRENT_AVERAGE we need to use different channel numbers.
+		 * We will add  +5 (+1 to maximum PAC channels).
+		 */
+		ch_sp[PAC1944_CH_VOLTAGE_AVERAGE].channel = cnt + PAC1944_MAX_CH + 1;
+		ch_sp[PAC1944_CH_VOLTAGE_AVERAGE].address = cnt + PAC1944_VBUS_AVG_1_ADDR;
+		ch_sp[PAC1944_CH_CURRENT_AVERAGE].channel = cnt + PAC1944_MAX_CH + 1;
+		ch_sp[PAC1944_CH_CURRENT_AVERAGE].address = cnt + PAC1944_VSENSE_AVG_1_ADDR;
+
+		/* advance the pointer */
+		ch_sp += ARRAY_SIZE(pac1944_single_channel);
+	}
+
+	return 0;
+}
+
+static const struct iio_info pac1944_info = {
+	.read_raw = pac1944_read_raw,
+	.read_label = pac1944_read_label,
+};
+
+static int pac1944_probe(struct i2c_client *client)
+{
+	const struct pac1944_features *chip;
+	struct device *dev = &client->dev;
+	struct pac1944_chip_info *info;
+	struct iio_dev *indio_dev;
+	int cnt, ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*info));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	info = iio_priv(indio_dev);
+	info->client = client;
+
+	ret = pac1944_chip_identify(indio_dev, info);
+	if (ret < 0) {
+		dev_dbg(dev, "Failed to identify the device based on HW ID\n");
+		/*
+		 * If failed to identify the hardware based on internal registers,
+		 * try using fallback compatible in device tree to deal with
+		 * some newer part number.
+		 */
+		chip = i2c_get_match_data(client);
+		if (!chip)
+			return -EINVAL;
+
+		info->phys_channels = chip->phys_channels;
+		indio_dev->name = chip->name;
+
+		switch (chip->prod_id) {
+		case PAC_PRODUCT_ID_1941:
+		case PAC_PRODUCT_ID_1942:
+		case PAC_PRODUCT_ID_1943:
+		case PAC_PRODUCT_ID_1944:
+		case PAC_PRODUCT_ID_1941_2:
+		case PAC_PRODUCT_ID_1942_2:
+			info->is_pac195x_family = false;
+			break;
+		case PAC_PRODUCT_ID_1951:
+		case PAC_PRODUCT_ID_1952:
+		case PAC_PRODUCT_ID_1953:
+		case PAC_PRODUCT_ID_1954:
+		case PAC_PRODUCT_ID_1951_2:
+		case PAC_PRODUCT_ID_1952_2:
+			info->is_pac195x_family = true;
+			break;
+		default:
+			dev_err(&client->dev,
+				"Unknown product ID (0x%02X)\n", chip->prod_id);
+			return -EINVAL;
+		}
+	}
+
+	for (cnt = 0; cnt < info->phys_channels; cnt++) {
+		/* always start with accumulation channels enabled */
+		info->enable_acc[cnt] = true;
+	}
+
+	if (ACPI_HANDLE(dev))
+		ret = pac1944_acpi_parse_channel_config(client, info);
+	else
+		ret = pac1944_of_parse_channel_config(client, info);
+
+	if (ret)
+		return dev_err_probe(dev, ret, "parameter parsing returned an error\n");
+
+	ret = devm_mutex_init(dev, &info->lock);
+	if (ret < 0)
+		return ret;
+
+	ret = pac1944_chip_configure(info);
+	if (ret < 0)
+		return ret;
+
+	ret = pac1944_prep_iio_channels(info, indio_dev);
+	if (ret < 0)
+		return ret;
+
+	info->iio_info = pac1944_info;
+	indio_dev->info = &info->iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = pac1944_prep_custom_attributes(info, indio_dev);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Can't configure custom attributes for device\n");
+
+	ret = pac1944_reg_snapshot(info, true, PAC1944_REFRESH_REG_ADDR,
+				   PAC1944_MIN_UPDATE_WAIT_TIME_US);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_iio_device_register(dev, indio_dev);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Can't register IIO device\n");
+
+	return 0;
+}
+
+static const struct i2c_device_id pac1944_id[] = {
+	{ .name = "pac1941", .driver_data = (kernel_ulong_t)&pac1941_chip_config },
+	{ .name = "pac1941-2", .driver_data = (kernel_ulong_t)&pac1941_2_chip_config },
+	{ .name = "pac1942", .driver_data = (kernel_ulong_t)&pac1942_chip_config },
+	{ .name = "pac1942-2", .driver_data = (kernel_ulong_t)&pac1942_2_chip_config },
+	{ .name = "pac1943", .driver_data = (kernel_ulong_t)&pac1943_chip_config },
+	{ .name = "pac1944", .driver_data = (kernel_ulong_t)&pac1944_chip_config },
+	{ .name = "pac1951", .driver_data = (kernel_ulong_t)&pac1951_chip_config },
+	{ .name = "pac1951-2", .driver_data = (kernel_ulong_t)&pac1951_2_chip_config },
+	{ .name = "pac1952", .driver_data = (kernel_ulong_t)&pac1952_chip_config },
+	{ .name = "pac1952-2", .driver_data = (kernel_ulong_t)&pac1952_2_chip_config },
+	{ .name = "pac1953", .driver_data = (kernel_ulong_t)&pac1953_chip_config },
+	{ .name = "pac1954", .driver_data = (kernel_ulong_t)&pac1954_chip_config },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, pac1944_id);
+
+static const struct of_device_id pac1944_of_match[] = {
+	{
+		.compatible = "microchip,pac1941",
+		.data = &pac1941_chip_config
+	},
+	{
+		.compatible = "microchip,pac1941-2",
+		.data = &pac1941_2_chip_config
+	},
+	{
+		.compatible = "microchip,pac1942",
+		.data = &pac1942_chip_config
+	},
+	{
+		.compatible = "microchip,pac1942-2",
+		.data = &pac1942_2_chip_config
+	},
+	{
+		.compatible = "microchip,pac1943",
+		.data = &pac1943_chip_config
+	},
+	{
+		.compatible = "microchip,pac1944",
+		.data = &pac1944_chip_config
+	},
+	{
+		.compatible = "microchip,pac1951",
+		.data = &pac1951_chip_config
+	},
+	{
+		.compatible = "microchip,pac1951-2",
+		.data = &pac1951_2_chip_config
+	},
+	{
+		.compatible = "microchip,pac1952",
+		.data = &pac1952_chip_config
+	},
+	{
+		.compatible = "microchip,pac1952-2",
+		.data = &pac1952_2_chip_config
+	},
+	{
+		.compatible = "microchip,pac1953",
+		.data = &pac1953_chip_config
+	},
+	{
+		.compatible = "microchip,pac1954",
+		.data = &pac1954_chip_config
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pac1944_of_match);
+
+static const struct acpi_device_id pac1944_acpi_match[] = {
+	{ "MCHP1940", .driver_data = (kernel_ulong_t)&pac1944_chip_config },
+	{ }
+};
+MODULE_DEVICE_TABLE(acpi, pac1944_acpi_match);
+
+static struct i2c_driver pac1944_driver = {
+	.driver = {
+		.name = "pac1944",
+		.of_match_table = pac1944_of_match,
+		.acpi_match_table = pac1944_acpi_match
+	},
+	.probe = pac1944_probe,
+	.id_table = pac1944_id,
+};
+module_i2c_driver(pac1944_driver);
+
+MODULE_AUTHOR("Marius Cristea <marius.cristea@microchip.com>");
+MODULE_DESCRIPTION("Microchip PAC194X and PAC195X Power Monitor");
+MODULE_LICENSE("GPL");
-- 
2.51.0