adding support for Microchip PAC193X Power Monitor

From: Marius Cristea <[email protected]>

This is the device tree schema for iio driver for Microchip PAC193X series of Power Monitors with Accumulator.

Signed-off-by Marius Cristea <[email protected]>

---
 .../bindings/iio/adc/microchip,pac193x.yaml   | 122 ++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +8 -0

new file mode 100644
index 000000000000..e4ea560991e9
@@ -0,0 +1,122 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/microchip,pac193x.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip PAC193X Power Monitors with Accumulator
+

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +8 -0

+        type: boolean
+
+    required:
+      - reg
+      - microchip,uohms-shunt-res
+      - microchip,rail-name
+
+    additionalProperties: false

Quoted 4 lines

Signed-off-by Marius Cristea <[email protected]>

---
 .../bindings/iio/adc/microchip,pac193x.yaml   | 122 ++++++++++++++++++

Quoted 17 lines

 1 file changed, 122 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +8 -0

new file mode 100644
index 000000000000..e4ea560991e9
@@ -0,0 +1,122 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/microchip,pac193x.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Microchip PAC193X Power Monitors with Accumulator
+

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 18

Quoted 10 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +10 -0

+maintainers:
+  - Marius Cristea <[email protected]>
+
+properties:
+  compatible:
+    enum:
+      - microchip,pac1934
+      - microchip,pac1933
+      - microchip,pac1932
+      - microchip,pac1931  

Maybe order these numerically (ascending)?

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 31

Quoted 13 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +13 -0

+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  microchip,samp-rate:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Sampling rate for all device's channels.  

What are the units? rate is usually in hz, which should be expressed in unit suffix (property name)]

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 35

Quoted 5 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +4 -0

+    enum: [8, 64, 256, 1024]
+    default: 1024
+
+required:  

required goes after all properties, so after patternProperties

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 43

Quoted 8 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +8 -0

+  - compatible
+  - reg
+  - microchip,samp-rate
+  - "#address-cells"
+  - "#size-cells"
+
+patternProperties:
+  "^channel([1-4])@[1-4]+$":  

Why first reg-pattern ([1-4])? For what do you need it?

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 44

Quoted 1 line

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +1 -0

+    $ref: "adc.yaml"  

Drop quotes

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 56

Quoted 12 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +12 -0

+    type: object
+    description: Represents the external channels which are connected to the ADC.
+
+    properties:
+      reg:
+        description: The channel number.
+          It can have up to 4 channels, numbered from 1 to 4.
+        items:
+          - minimum: 1
+            maximum: 4
+
+      microchip,uohms-shunt-res:  

Not a correct unit suffix. Use standard properties:
git grep shunt -- Documentation/devicetree/

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 65

Quoted 11 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +9 -0

+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: |
+          Value in micro Ohms of the shunt resistor connected between
+          the SENSE+ and SENSE- inputs, across which the current is measured. Value
+          is needed to compute the scaling of the measured current.
+
+      microchip,rail-name:
+        $ref: /schemas/types.yaml#/definitions/string
+        description: Name of the monitored power rail.  

Why do you need it? Why this is a property of DT? Aren't you now duplicating label?

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 68

Quoted 4 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +3 -0

+
+      microchip,bi-directional:
+        description: Whether the channel is bi-directional.  

Describe here what is a "bi-directional" channel for ADC... Maybe it is obvious, maybe not. For me it is not and none of other devices have it.

Quoted 8 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +8 -0

+        type: boolean
+
+    required:
+      - reg
+      - microchip,uohms-shunt-res
+      - microchip,rail-name
+
+    additionalProperties: false

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 86

Quoted 10 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +10 -0

+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        pac193x: pac193x@10 {  

Node names should be generic.
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml line 94

Quoted 8 lines

Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml new file +8 -0

+            compatible = "microchip,pac1934";
+            reg = <0x10>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+            microchip,samp-rate = <64>;
+
+            channel1@1 {  

1@1 is for sure not generic...

Best regards,
Krzysztof

Quoted 8 lines

Quoted 4 lines

+
+  microchip,samp-rate:
+    $ref: /schemas/types.yaml#/definitions/uint32 +    description: Sampling rate for all device's channels.

What are the units? rate is usually in hz, which should be expressed in
unit suffix (property name)]

It's unusual for sampling rate to be a property of the hardware and hence
suitable for DT binding. Normally we make this a userspace control instead.
If there is a reason for doing it from DT, that wants to be mentioned here.

Quoted 4 lines

Quoted 9 lines

Quoted 3 lines

+
+      microchip,bi-directional:
+        description: Whether the channel is bi-directional.

Describe here what is a "bi-directional" channel for ADC... Maybe it is
obvious, maybe not. For me it is not and none of other devices have it.

From datasheet this seems to be a novel description of whether the ADC
is measuring just positive or allows for negative voltage as well (i.e.
the current through the shut resistor is going on the other direction).
Can we relate this to a biopolar / unipolar decision on a simple voltage ADC?
For that we have standard DT bindings in iio/adc/adc.yaml

Hi Jonathan,

Thank you so much! I'm happy to contribute to IIO.

I will remove some section because I agree with the propose solution. For the rest I will comment below..

Quoted 9 lines · Jonathan Cameron

Quoted 8 lines

Quoted 4 lines

+
+  microchip,samp-rate:
+    $ref: /schemas/types.yaml#/definitions/uint32 +    description: Sampling rate for all device's channels.

What are the units? rate is usually in hz, which should be expressed in
unit suffix (property name)]

Quoted 7 lines

It's unusual for sampling rate to be a property of the hardware and hence
suitable for DT binding. Normally we make this a userspace control instead.
If there is a reason for doing it from DT, that wants to be mentioned here.

Here I could change it into the datarate (as in iio/adc/ti,ads1015.yaml). The units are samples per second. My intention was to be alingned with the datasheet.

My intention was to let the user configure the sample rate as soon as posile during the startup (the PAC device's own power consumtion will increase with the sampling rate - default the chip will start with the maximum samples per second).

Hi Jonathan,

Thank you so much! I'm happy to contribute to IIO.

I will remove some section because I agree with the propose solution. For the rest I will comment below..

Quoted 9 lines · Jonathan Cameron

Quoted 8 lines

Quoted 4 lines

+
+  microchip,samp-rate:
+    $ref: /schemas/types.yaml#/definitions/uint32 +    description: Sampling rate for all device's channels.

What are the units? rate is usually in hz, which should be expressed in
unit suffix (property name)]

Quoted 7 lines

It's unusual for sampling rate to be a property of the hardware and hence
suitable for DT binding. Normally we make this a userspace control instead.
If there is a reason for doing it from DT, that wants to be mentioned here.

Here I could change it into the datarate (as in iio/adc/ti,ads1015.yaml). The units are samples per second. My intention was to be alingned with the datasheet.

My intention was to let the user configure the sample rate as soon as posile during the startup (the PAC device's own power consumtion will increase with the sampling rate - default the chip will start with the maximum samples per second).

Quoted 15 lines

Quoted 6 lines

Quoted 9 lines

Quoted 3 lines

+
+      microchip,bi-directional:
+        description: Whether the channel is bi-directional.

Describe here what is a "bi-directional" channel for ADC... Maybe it is
obvious, maybe not. For me it is not and none of other devices have it.

Quoted 10 lines

From datasheet this seems to be a novel description of whether the ADC
is measuring just positive or allows for negative voltage as well (i.e.
the current through the shut resistor is going on the other direction).
Can we relate this to a biopolar / unipolar decision on a simple voltage ADC?
For that we have standard DT bindings in iio/adc/adc.yaml

Yes, the PAC device can measure voltages as unipolar or bipolar but also current as unidirectional or bidirectional (we are measuring the voltage across a shunt resistor). We are also reporting power and is not a "usual" thing to report power as unipolar or bipolar. Bi- directional power makes more sens if you are thinking to monitor a charge discharge cycle for a battery pack.

Thanks,
Marius

From: Marius Cristea <[email protected]>

This is the iio driver for Microchip
PAC193X series of Power Monitor with Accumulator chip family.

Signed-off-by Marius Cristea <[email protected]>

---
 MAINTAINERS               |    7 +
 drivers/iio/adc/Kconfig   |   12 +
 drivers/iio/adc/Makefile  |    1 +
 drivers/iio/adc/pac193x.c | 2072 +++++++++++++++++++++++++++++++++++++
 4 files changed, 2092 insertions(+)
 create mode 100644 drivers/iio/adc/pac193x.c

drivers/iio/adc/pac193x.c new file +12 -0

+
+#define PAC193X_NEG_PWR_CH1_BIDI(x)	((x) ? BIT(7) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDI(x)	((x) ? BIT(6) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDI(x)	((x) ? BIT(5) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDI(x)	((x) ? BIT(4) : 0)
+#define PAC193X_NEG_PWR_CH1_BIDV(x)	((x) ? BIT(3) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDV(x)	((x) ? BIT(2) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDV(x)	((x) ? BIT(1) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDV(x)	((x) ? BIT(0) : 0)
+
+/*
+ * Universal Unique Identifier (UUID),

Quoted 5 lines · On 20/02/2023 13:32, [email protected] wrote:

From: Marius Cristea <[email protected]>

This is the iio driver for Microchip
PAC193X series of Power Monitor with Accumulator chip family.

Quoted 9 lines

Signed-off-by Marius Cristea <[email protected]>

---
 MAINTAINERS               |    7 +
 drivers/iio/adc/Kconfig   |   12 +
 drivers/iio/adc/Makefile  |    1 +
 drivers/iio/adc/pac193x.c | 2072 +++++++++++++++++++++++++++++++++++++
 4 files changed, 2092 insertions(+)
 create mode 100644 drivers/iio/adc/pac193x.c

Thank you for your patch. There is something to discuss/improve.

Quoted 16 lines

drivers/iio/adc/pac193x.c new file +16 -0

+
+#define PAC193X_NEG_PWR_CH1_BIDI(x)	((x) ? BIT(7) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDI(x)	((x) ? BIT(6) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDI(x)	((x) ? BIT(5) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDI(x)	((x) ? BIT(4) : 0)
+#define PAC193X_NEG_PWR_CH1_BIDV(x)	((x) ? BIT(3) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDV(x)	((x) ? BIT(2) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDV(x)	((x) ? BIT(1) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDV(x)	((x) ? BIT(0) : 0)
+
+/*
+ * Universal Unique Identifier (UUID),
+ * 033771E0-1705-47B4-9535-D1BBE14D9A09, is
+ * reserved to Microchip for the PAC193X and must not be changed
+ */
+#define PAC193X_DSM_UUID		"033771E0-1705-47B4-9535-D1BBE14D9A09"

drivers/iio/adc/pac193x.c line 261

Quoted 6 lines

drivers/iio/adc/pac193x.c new file +6 -0

+
+enum pac193x_ids {
+	pac1934,
+	pac1933,
+	pac1932,
+	pac1931  

Enums are usually uppercase.

Best regards,
Krzysztof

Quoted 35 lines · On Tue, 21 Feb 2023 14:46:08 +0100 Krzysztof Kozlowski <[email protected]> wrote:

Quoted 5 lines · On 20/02/2023 13:32, [email protected] wrote:

From: Marius Cristea <[email protected]>

This is the iio driver for Microchip
PAC193X series of Power Monitor with Accumulator chip family.

Quoted 9 lines

Signed-off-by Marius Cristea <[email protected]>

---
 MAINTAINERS               |    7 +
 drivers/iio/adc/Kconfig   |   12 +
 drivers/iio/adc/Makefile  |    1 +
 drivers/iio/adc/pac193x.c | 2072 +++++++++++++++++++++++++++++++++++++
 4 files changed, 2092 insertions(+)
 create mode 100644 drivers/iio/adc/pac193x.c

Thank you for your patch. There is something to discuss/improve.

Quoted 16 lines

drivers/iio/adc/pac193x.c new file +16 -0

+
+#define PAC193X_NEG_PWR_CH1_BIDI(x)	((x) ? BIT(7) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDI(x)	((x) ? BIT(6) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDI(x)	((x) ? BIT(5) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDI(x)	((x) ? BIT(4) : 0)
+#define PAC193X_NEG_PWR_CH1_BIDV(x)	((x) ? BIT(3) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDV(x)	((x) ? BIT(2) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDV(x)	((x) ? BIT(1) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDV(x)	((x) ? BIT(0) : 0)
+
+/*
+ * Universal Unique Identifier (UUID),
+ * 033771E0-1705-47B4-9535-D1BBE14D9A09, is
+ * reserved to Microchip for the PAC193X and must not be changed
+ */
+#define PAC193X_DSM_UUID		"033771E0-1705-47B4-9535-D1BBE14D9A09"

Quoted 8 lines

drivers/iio/adc/pac193x.c line 261

Quoted 6 lines

drivers/iio/adc/pac193x.c new file +6 -0

+
+enum pac193x_ids {
+	pac1934,
+	pac1933,
+	pac1932,
+	pac1931    

Enums are usually uppercase.

I'm not sure there is anything in coding standard around that and a grep finds a mixture of the two when it comes to ones used for IDs. Mind you uppercase is fine :)

Quoted 8 lines

Best regards,
Krzysztof

EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe

Quoted 50 lines · On Sat, 25 Feb 2023 17:19:54 +0000 Jonathan Cameron <[email protected]> wrote:

Quoted 38 lines · On Tue, 21 Feb 2023 14:46:08 +0100 Krzysztof Kozlowski <[email protected]> wrote:

Quoted 6 lines · On 20/02/2023 13:32, [email protected] wrote:

From: Marius Cristea <[email protected]>

This is the iio driver for Microchip
PAC193X series of Power Monitor with Accumulator chip family.

Signed-off-by Marius Cristea <[email protected]>

Quoted 9 lines

---
 MAINTAINERS               |    7 +
 drivers/iio/adc/Kconfig   |   12 +
 drivers/iio/adc/Makefile  |    1 +
 drivers/iio/adc/pac193x.c | 2072
+++++++++++++++++++++++++++++++++++++

 4 files changed, 2092 insertions(+)

 create mode 100644 drivers/iio/adc/pac193x.c

Thank you for your patch. There is something to discuss/improve.

Quoted 18 lines

drivers/iio/adc/pac193x.c new file +14 -0

+
+#define PAC193X_NEG_PWR_CH1_BIDI(x)      ((x) ? BIT(7) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDI(x)      ((x) ? BIT(6) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDI(x)      ((x) ? BIT(5) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDI(x)      ((x) ? BIT(4) : 0)
+#define PAC193X_NEG_PWR_CH1_BIDV(x)      ((x) ? BIT(3) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDV(x)      ((x) ? BIT(2) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDV(x)      ((x) ? BIT(1) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDV(x)      ((x) ? BIT(0) : 0)
+
+/*
+ * Universal Unique Identifier (UUID),
+ * 033771E0-1705-47B4-9535-D1BBE14D9A09, is
+ * reserved to Microchip for the PAC193X and must not be

changed
+ */
+#define PAC193X_DSM_UUID         "033771E0-1705-47B4-9535- D1BBE14D9A09"

Quoted 8 lines

drivers/iio/adc/pac193x.c line 261

Quoted 6 lines

drivers/iio/adc/pac193x.c new file +6 -0

+
+enum pac193x_ids {
+ pac1934,
+ pac1933,
+ pac1932,
+ pac1931

Enums are usually uppercase.

Quoted 5 lines

I'm not sure there is anything in coding standard around that and a grep finds
a mixture of the two when it comes to ones used for IDs.  Mind you uppercase
is fine :)

I take it back. Is indeed in coding style doc.  Glad checkpatch doesn't check for
this though as we'd get 1000s of 'fixes' if it did and in most cases it doesn't
hurt readability.  I'll try and be more consistent on this in review going forwards!

Thanks!

Jonathan

Quoted 9 lines

Quoted 8 lines

Best regards,
Krzysztof

From: Marius Cristea <[email protected]>

This is the iio driver for Microchip
PAC193X series of Power Monitor with Accumulator chip family.

Signed-off-by Marius Cristea <[email protected]>

---
 MAINTAINERS               |    7 +
 drivers/iio/adc/Kconfig   |   12 +
 drivers/iio/adc/Makefile  |    1 +
 drivers/iio/adc/pac193x.c | 2072 +++++++++++++++++++++++++++++++++++++
 4 files changed, 2092 insertions(+)
 create mode 100644 drivers/iio/adc/pac193x.c

MAINTAINERS +7 -0

index c81bbb771678..6675dc1b6b19 100644
@@ -8187,6 +8187,13 @@ S:	Maintained
 F:	Documentation/ABI/testing/sysfs-driver-intel-m10-bmc-sec-update
 F:	drivers/fpga/intel-m10-bmc-sec-update.c
 
+MICROCHIP PAC193X POWER/ENERGY MONITOR DRIVER
+M:	Marius Cristea <marius.cristea@@microchip.com>
+L:	[email protected]
+S:	Supported
+F:	Documentation/devicetree/bindings/iio/adc/microchip,pac193x.yaml
+F:	drivers/iio/adc/pac193x.c
+
 MICROCHIP POLARFIRE FPGA DRIVERS
 M:	Conor Dooley <[email protected]>
 R:	Ivan Bornyakov <[email protected]>

drivers/iio/adc/Kconfig +0 -0

index 4a95c843a91b..ae4f60e290c4 100644
@@ -867,6 +867,18 @@ config NPCM_ADC
 	  This driver can also be built as a module. If so, the module

drivers/iio/adc/Kconfig +4 -0

+
+	  This driver can also be built as a module. If so, the module
+	  will be called pac193x.
+
 config PALMAS_GPADC
 	tristate "TI Palmas General Purpose ADC"
 	depends on MFD_PALMAS

drivers/iio/adc/Makefile +1 -0

index 36c18177322a..81824128c6cd 100644
@@ -80,6 +80,7 @@ obj-$(CONFIG_MP2629_ADC) += mp2629_adc.o
 obj-$(CONFIG_MXS_LRADC_ADC) += mxs-lradc-adc.o
 obj-$(CONFIG_NAU7802) += nau7802.o
 obj-$(CONFIG_NPCM_ADC) += npcm_adc.o
+obj-$(CONFIG_PAC193X) += pac193x.o
 obj-$(CONFIG_PALMAS_GPADC) += palmas_gpadc.o
 obj-$(CONFIG_QCOM_SPMI_ADC5) += qcom-spmi-adc5.o
 obj-$(CONFIG_QCOM_SPMI_IADC) += qcom-spmi-iadc.o

drivers/iio/adc/pac193x.c new file +16 -0

new file mode 100644
index 000000000000..ece6bf028fe2
@@ -0,0 +1,2072 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IIO driver for PAC193X Multi-Channel DC Power/Energy Monitor
+ *
+ * Copyright (C) 2017-2023 Microchip Technology Inc. and its subsidiaries
+ *
+ * Author: Bogdan Bolocan <[email protected]>
+ * Author: Victor Tudose
+ * Author: Marius Cristea <[email protected]>
+ *
+ * Datasheet for PAC1931, PAC1932, PAC1933 and PAC1934 can be found here:
+ * https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/PAC1931-Family-Data-Sheet-DS20005850E.pdf
+ *
+ */
+
+#include <linux/acpi.h>

drivers/iio/adc/pac193x.c new file +60 -0

+ * till PAC193X register stars to saturate
+ */
+#define PAC193X_MAX_RFSH_LIMIT_MS		60000
+
+/* 50msec is the timeout for validity of the cached registers */
+#define PAC193X_MIN_POLLING_TIME_MS		50
+
+#define SHUNT_UOHMS_DEFAULT			100000
+/* 32000mV */
+#define PAC193X_VOLTAGE_MILLIVOLTS_MAX		32000
+/* voltage bits resolution when set for unsigned values */
+#define PAC193X_VOLTAGE_U_RES			16
+/* voltage bits resolution when set for signed values */
+#define PAC193X_VOLTAGE_S_RES			15
+/* 100mV maximum for current shunts */
+#define PAC193X_VSENSE_MILLIVOLTS_MAX		100
+/* voltage bits resolution when set for unsigned values */
+#define PAC193X_CURRENT_U_RES			16
+/* voltage bits resolution when set for signed values */
+#define PAC193X_CURRENT_S_RES			15
+
+/* power resolution is 28 bits when unsigned */
+#define PAC193X_POWER_U_RES			 28
+/* power resolution is 27 bits when signed */
+#define PAC193X_POWER_S_RES			27
+
+/* energy accumulation is 48 bits long */
+#define PAC193X_ENERGY_U_RES			48
+
+#define PAC193X_ENERGY_S_RES			47
+#define PAC193X_ENERGY_SHIFT_MAIN_VAL		32
+
+#define BIT_INDEX_31				31
+
+/*
+ * max signed value that can be stored on 32 bits and 8 digits fractional value
+ * (2^31 - 1) * 10^8 + 99999999
+ */
+#define PAC_193X_MAX_POWER_ACC			214748364799999999LL
+/*
+ * min signed value that can be stored on 32 bits and 8 digits fractional value
+ * -(2^31) * 10^8 - 99999999
+ */
+#define PAC_193X_MIN_POWER_ACC			-214748364899999999LL
+
+/* maximum value that device can measure - 32 V * 0.1 V */
+#define PAC193X_PRODUCT_VOLTAGE_PV_FSR		3200000000000UL
+
+#define PAC193X_MAX_NUM_CHANNELS		4
+#define PAC1931_NUM_CHANNELS			1
+#define PAC1932_NUM_CHANNELS			2
+#define PAC1933_NUM_CHANNELS			3
+#define PAC1934_NUM_CHANNELS			4
+#define PAC193X_CH_1				0
+#define PAC193X_CH_2				1
+#define PAC193X_CH_3				2
+#define PAC193X_CH_4				3
+#define PAC193X_MEAS_REG_LEN			76
+#define PAC193X_CTRL_REG_LEN			12
+

drivers/iio/adc/pac193x.c new file +126 -0

+#define PAC193X_CTRL_REG			0x01
+#define PAC193X_REFRESH_V_REG			0x1F
+#define PAC193X_ACC_COUNT_REG			0x02
+#define PAC193X_CTRL_STAT_REGS_ADDR		0x1C
+#define PAC193X_PID_REG_ADDR			0xFD
+#define PAC193X_MID_REG_ADDR			0xFE
+#define PAC193X_RID_REG_ADDR			0xFF
+
+/* PRODUCT ID REGISTER + MANUFACTURER ID REGISTER + REVISION ID REGISTER */
+#define PAC193X_ID_REG_LEN			0x03
+#define PAC193X_PID_IDX				0
+#define PAC193X_MID_IDX				1
+#define PAC193X_RID_IDX				2
+
+#define PAC193X_ACPI_ARG_COUNT			4
+#define PAC193X_ACPI_GET_NAMES_AND_MOHMS_VALS	1
+#define PAC193X_ACPI_GET_UOHMS_VALS		2
+#define PAC193X_ACPI_GET_BIPOLAR_SETTINGS	4
+#define PAC193X_ACPI_GET_SAMP			5
+
+#define PAC193X_VPOWER_ACC_1_ADDR		0x03
+#define PAC193X_VPOWER_ACC_2_ADDR		0x04
+#define PAC193X_VPOWER_ACC_3_ADDR		0x05
+#define PAC193X_VPOWER_ACC_4_ADDR		0x06
+#define PAC193X_VBUS_1_ADDR			0x07
+#define PAC193X_VBUS_2_ADDR			0x08
+#define PAC193X_VBUS_3_ADDR			0x09
+#define PAC193X_VBUS_4_ADDR			0x0A
+#define PAC193X_VSENSE_1_ADDR			0x0B
+#define PAC193X_VSENSE_2_ADDR			0x0C
+#define PAC193X_VSENSE_3_ADDR			0x0D
+#define PAC193X_VSENSE_4_ADDR			0x0E
+#define PAC193X_VBUS_AVG_1_ADDR			0x0F
+#define PAC193X_VBUS_AVG_2_ADDR			0x10
+#define PAC193X_VBUS_AVG_3_ADDR			0x11
+#define PAC193X_VBUS_AVG_4_ADDR			0x12
+#define PAC193X_VSENSE_AVG_1_ADDR		0x13
+#define PAC193X_VSENSE_AVG_2_ADDR		0x14
+#define PAC193X_VSENSE_AVG_3_ADDR		0x15
+#define PAC193X_VSENSE_AVG_4_ADDR		0x16
+#define PAC193X_VPOWER_1_ADDR			0x17
+#define PAC193X_VPOWER_2_ADDR			0x18
+#define PAC193X_VPOWER_3_ADDR			0x19
+#define PAC193X_VPOWER_4_ADDR			0x1A
+
+#define PAC193X_SAMPLE_RATE_SHIFT		6
+
+/*
+ * these indexes are exactly describing the element order within a single
+ * PAC193X phys channel IIO channel descriptor; see the static const struct
+ * iio_chan_spec pac193x_single_channel[] declaration
+ */
+#define IIO_EN					0
+#define IIO_POW					1
+#define IIO_VOLT				2
+#define IIO_CRT					3
+#define IIO_VOLTAVG				4
+#define IIO_CRTAVG				5
+
+#define PAC193X_VBUS_SENSE_REG_LEN		2
+#define PAC193X_ACC_REG_LEN			3
+#define PAC193X_VPOWER_REG_LEN			4
+#define PAC193X_VPOWER_ACC_REG_LEN		6
+#define PAC193X_MAX_REGISTER_LENGTH		6
+
+#define PAC193X_CUSTOM_ATTR_FOR_CHANNEL		2
+#define PAC193X_SHARED_DEVATTRS_COUNT		1
+
+/*
+ * relative offsets when using multi-byte reads/writes even though these
+ * bytes are read one after the other, they are not at adjacent memory
+ * locations within the I2C memory map. The chip can skip some addresses
+ */
+#define PAC193X_CHANNEL_DIS_REG_OFF		0
+#define PAC193X_NEG_PWR_REG_OFF			1
+
+/*
+ * when reading/writing multiple bytes from offset PAC193X_CHANNEL_DIS_REG_OFF,
+ * the chip jumps over the 0x1E (REFRESH_G) and 0x1F (REFRESH_V) offsets
+ */
+#define PAC193X_SLOW_REG_OFF			2
+#define PAC193X_CTRL_ACT_REG_OFF		3
+#define PAC193X_CHANNEL_DIS_ACT_REG_OFF		4
+#define PAC193X_NEG_PWR_ACT_REG_OFF		5
+#define PAC193X_CTRL_LAT_REG_OFF		6
+#define PAC193X_CHANNEL_DIS_LAT_REG_OFF		7
+#define PAC193X_NEG_PWR_LAT_REG_OFF		8
+#define PAC193X_PID_REG_OFF			9
+#define PAC193X_MID_REG_OFF			10
+#define PAC193X_REV_REG_OFF			11
+#define PAC193X_CTRL_STATUS_INFO_LEN		12
+
+#define PAC193X_MID				0x5D
+#define PAC1934_PID				0x5B
+#define PAC1933_PID				0x5A
+#define PAC1932_PID				0x59
+#define PAC1931_PID				0x58
+
+/* Scale constant = (10^8 / 2^28) * 3.2 * 10^9 */
+#define PAC193X_SCALE_CONSTANT			1192092895UL
+
+#define PAC193X_MAX_VPOWER_RSHIFTED_BY_28B	11921
+#define PAC193X_MAX_VSENSE_RSHIFTED_BY_16B	1525
+
+#define PAC193X_DEV_ATTR(name) (&iio_dev_attr_##name.dev_attr.attr)
+
+#define PAC193X_CRTL_SAMPLE_RATE_MASK	GENMASK(7, 6)
+#define PAC193X_CRTL_SAMPLE_RATE_SET(x)	((u8)FIELD_PREP(PAC193X_CRTL_SAMPLE_RATE_MASK, (x)))
+#define PAC193X_CHAN_SLEEP_MASK		BIT(5)
+#define PAC193X_CHAN_SLEEP_SET		BIT(5)
+#define PAC193X_CHAN_SINLE_MASK		BIT(4)
+#define PAC193X_CHAN_SINLE_SHOT_SET	BIT(4)
+#define PAC193X_CHAN_ALERT_MASK		BIT(3)
+#define PAC193X_CHAN_ALERT_EN		BIT(3)
+#define PAC193X_CHAN_ALERT_CC_MASK	BIT(2)
+#define PAC193X_CHAN_ALERT_CC_EN	BIT(2)
+#define PAC193X_CHAN_OVF_ALERT_MASK	BIT(1)
+#define PAC193X_CHAN_OVF_ALERT_EN	BIT(1)
+#define PAC193X_CHAN_OVF_MASK		BIT(0)
+
+#define PAC193X_CHAN_DIS_CH1_OFF_MASK	BIT(7)
+#define PAC193X_CHAN_DIS_CH1_OFF(x)	((u8)FIELD_PREP(PAC193X_CHAN_DIS_CH1_OFF_MASK, !(x)))
+#define PAC193X_CHAN_DIS_CH2_OFF_MASK	BIT(6)
+#define PAC193X_CHAN_DIS_CH2_OFF(x)	((u8)FIELD_PREP(PAC193X_CHAN_DIS_CH2_OFF_MASK, !(x)))
+#define PAC193X_CHAN_DIS_CH3_OFF_MASK	BIT(5)
+#define PAC193X_CHAN_DIS_CH3_OFF(x)	((u8)FIELD_PREP(PAC193X_CHAN_DIS_CH3_OFF_MASK, !(x)))

drivers/iio/adc/pac193x.c new file +44 -0

+#define PAC193X_NEG_PWR_CH2_BIDI(x)	((x) ? BIT(6) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDI(x)	((x) ? BIT(5) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDI(x)	((x) ? BIT(4) : 0)
+#define PAC193X_NEG_PWR_CH1_BIDV(x)	((x) ? BIT(3) : 0)
+#define PAC193X_NEG_PWR_CH2_BIDV(x)	((x) ? BIT(2) : 0)
+#define PAC193X_NEG_PWR_CH3_BIDV(x)	((x) ? BIT(1) : 0)
+#define PAC193X_NEG_PWR_CH4_BIDV(x)	((x) ? BIT(0) : 0)
+
+/*
+ * Universal Unique Identifier (UUID),
+ * 033771E0-1705-47B4-9535-D1BBE14D9A09, is
+ * reserved to Microchip for the PAC193X and must not be changed
+ */
+#define PAC193X_DSM_UUID		"033771E0-1705-47B4-9535-D1BBE14D9A09"
+
+enum pac193x_ids {
+	pac1934,
+	pac1933,
+	pac1932,
+	pac1931
+};
+
+enum pac193x_samps {
+	pac193X_samp_1024sps,
+	pac193X_samp_256sps,
+	pac193X_samp_64sps,
+	pac193X_samp_8sps
+};
+
+/**
+ * struct pac193x_features - features of a pac193x instance
+ * @phys_channels: number of physical channels supported by the chip
+ * @prod_id: product ID
+ */
+struct pac193x_features {
+	u8 phys_channels;
+	u8 prod_id;
+};
+
+struct samp_rate_mapping {
+	u16 samp_rate;
+	u8 shift2value;
+};
+

drivers/iio/adc/pac193x.c new file +51 -0

+	    .prod_id = PAC1934_PID,
+	},
+	[pac1933] = {
+	    .phys_channels = PAC193X_MAX_NUM_CHANNELS - 1,
+	    .prod_id = PAC1933_PID,
+	},
+	[pac1932] = {
+	    .phys_channels = PAC193X_MAX_NUM_CHANNELS - 2,
+	    .prod_id = PAC1932_PID,
+	},
+	[pac1931] = {
+	    .phys_channels = PAC193X_MAX_NUM_CHANNELS - 3,
+	    .prod_id = PAC1931_PID,
+	},
+};
+
+/**
+ * struct reg_data - data from the registers
+ * @meas_regs: snapshot of raw measurements registers
+ * @ctrl_regs: snapshot of control registers
+ * @energy_sec_acc: snapshot of energy values
+ * @vpower_acc: 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
+ * @num_enabled_channels: count of how many chip channels are currently enabled
+ */
+struct reg_data {
+	u8	meas_regs[PAC193X_MEAS_REG_LEN];
+	u8	ctrl_regs[PAC193X_CTRL_REG_LEN];
+	s64	energy_sec_acc[PAC193X_MAX_NUM_CHANNELS];
+	s64	vpower_acc[PAC193X_MAX_NUM_CHANNELS];
+	s32	vpower[PAC193X_MAX_NUM_CHANNELS];
+	s32	vbus[PAC193X_MAX_NUM_CHANNELS];
+	s32	vbus_avg[PAC193X_MAX_NUM_CHANNELS];
+	s32	vsense[PAC193X_MAX_NUM_CHANNELS];
+	s32	vsense_avg[PAC193X_MAX_NUM_CHANNELS];
+	u8	num_enabled_channels;
+};
+
+/**
+ * struct pac193x_chip_info - information about the chip
+ * @client: the i2c-client attached to the device
+ * @lock: lock used by the chip's mutex
+ * @tmr_forced_update: timers used
+ * @wq_chip: queued work used for refresh commands
+ * @work_chip_rfsh: work used for refresh commands
+ * @phys_channels: phys channels count
+ * @active_channels: array of values, true means that channel is active

drivers/iio/adc/pac193x.c new file +12 -0

+ */
+struct pac193x_chip_info {
+	struct i2c_client	*client;
+	struct mutex		lock; /*lock to prevent concurent reads/writes */
+	struct timer_list	tmr_forced_update;
+	struct workqueue_struct *wq_chip;
+	struct work_struct	work_chip_rfsh;
+	u8			phys_channels;
+	bool			active_channels[PAC193X_MAX_NUM_CHANNELS];
+	bool			bi_dir[PAC193X_MAX_NUM_CHANNELS];
+	u8			chip_variant;
+	u8			chip_revision;

drivers/iio/adc/pac193x.c new file +80 -0

+
+#define PAC193X_VPOWER_ACC_CHANNEL(_index, _si, _address) {			\
+	.type = IIO_ENERGY,							\
+	.address = (_address),							\
+	.indexed = 1,								\
+	.channel = (_index),							\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW)	|			\
+				BIT(IIO_CHAN_INFO_SCALE),			\
+	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),		\
+	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
+	.scan_index = (_si),							\
+	.scan_type = {								\
+		.sign = 'u',							\
+		.realbits = PAC193X_ENERGY_U_RES,				\
+		.storagebits = PAC193X_ENERGY_U_RES,				\
+		.shift = 0,							\
+		.endianness = IIO_CPU,						\
+	}									\
+}
+
+#define PAC193X_VBUS_CHANNEL(_index, _si, _address) {				\
+	.type = IIO_VOLTAGE,							\
+	.address = (_address),							\
+	.indexed = 1,								\
+	.channel = (_index),							\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),				\
+	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),		\
+	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
+	.scan_index = (_si),							\
+	.scan_type = {								\
+		.sign = 'u',							\
+		.realbits = PAC193X_VOLTAGE_U_RES,				\
+		.storagebits = PAC193X_VOLTAGE_U_RES,				\
+		.shift = 0,							\
+		.endianness = IIO_CPU,						\
+	}									\
+}
+
+#define PAC193X_VBUS_AVG_CHANNEL(_index, _si, _address) {			\
+	.type = IIO_VOLTAGE,							\
+	.address = (_address),							\
+	.indexed = 1,								\
+	.channel = (_index),							\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_AVERAGE_RAW)			\
+				| BIT(IIO_CHAN_INFO_SCALE),			\
+	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),		\
+	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
+	.scan_index = (_si),							\
+	.scan_type = {								\
+		.sign = 'u',							\
+		.realbits = PAC193X_VOLTAGE_U_RES,				\
+		.storagebits = PAC193X_VOLTAGE_U_RES,				\
+		.shift = 0,							\
+		.endianness = IIO_CPU,						\
+	}									\
+}
+
+#define PAC193X_VSENSE_CHANNEL(_index, _si, _address) {				\
+	.type = IIO_CURRENT,							\
+	.address = (_address),							\
+	.indexed = 1,								\
+	.channel = (_index),							\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),				\
+	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),		\
+	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
+	.scan_index = (_si),							\
+	.scan_type = {								\
+		.sign = 'u',							\
+		.realbits = PAC193X_CURRENT_U_RES,				\
+		.storagebits = PAC193X_CURRENT_U_RES,				\
+		.shift = 0,							\
+		.endianness = IIO_CPU,						\
+	}									\
+}
+
+#define PAC193X_VSENSE_AVG_CHANNEL(_index, _si, _address) {			\
+	.type = IIO_CURRENT,							\
+	.address = (_address),							\
+	.indexed = 1,								\
+	.channel = (_index),							\

drivers/iio/adc/pac193x.c new file +16 -0

+		.endianness = IIO_CPU,						\
+	}									\
+}
+
+#define PAC193X_VPOWER_CHANNEL(_index, _si, _address) {				\
+	.type = IIO_POWER,							\
+	.address = (_address),							\
+	.indexed = 1,								\
+	.channel = (_index),							\
+	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |				\
+			BIT(IIO_CHAN_INFO_SCALE),				\
+	.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),		\
+	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
+	.scan_index = (_si),							\
+	.scan_type = {								\
+		.sign = 'u',							\

drivers/iio/adc/pac193x.c new file +14 -0

+	.scan_index = (_index),							\
+}
+
+static const struct iio_chan_spec pac193x_single_channel[] = {
+	PAC193X_VPOWER_ACC_CHANNEL(0, 0, PAC193X_VPOWER_ACC_1_ADDR),
+	PAC193X_VPOWER_CHANNEL(0, 0, PAC193X_VPOWER_1_ADDR),
+	PAC193X_VBUS_CHANNEL(0, 0, PAC193X_VBUS_1_ADDR),
+	PAC193X_VSENSE_CHANNEL(0, 0, PAC193X_VSENSE_1_ADDR),
+	PAC193X_VBUS_AVG_CHANNEL(0, 0, PAC193X_VBUS_AVG_1_ADDR),
+	PAC193X_VSENSE_AVG_CHANNEL(0, 0, PAC193X_VSENSE_AVG_1_ADDR),
+};
+
+static const struct iio_chan_spec pac193x_ts[] = {
+	PAC193X_SOFT_TIMESTAMP(0),

drivers/iio/adc/pac193x.c new file +33 -0

+
+	return tmp;
+}
+
+/* Low-level I2c functions */
+static int pac193x_i2c_read(struct i2c_client *client, u8 reg_addr, void *databuf, u8 len)
+{
+	int ret;
+	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
+		}
+	};
+
+	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int pac193x_i2c_write_byte(struct i2c_client *client, u8 reg_addr, u8 val)
+{
+	int ret;
+	u8 buf[2];
+	struct i2c_msg msg = {

drivers/iio/adc/pac193x.c new file +12 -0

+	if (ret < 0) {
+		dev_err(&client->dev,
+			"failed writing register 0x%02X\n", reg_addr);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int pac193x_i2c_send_byte(struct i2c_client *client, u8 reg_addr)
+{
+	int ret;

drivers/iio/adc/pac193x.c new file +11 -0

+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int pac193x_i2c_write(struct i2c_client *client, u8 reg_addr, u8 *data, int len)
+{
+	int ret;
+	u8 send[PAC193X_MAX_REGISTER_LENGTH + 1];
+	struct i2c_msg msg = {

drivers/iio/adc/pac193x.c new file +7 -0

+	if (ret < 0) {
+		dev_err(&client->dev,
+			"failed writing data from register 0x%02X\n", reg_addr);
+		return ret;
+	}
+
+	return 0;

drivers/iio/adc/pac193x.c new file +11 -0

+
+	if (cnt == ARRAY_SIZE(samp_rate_map_tbl))
+		/* not a valid sample rate value */
+		return -EINVAL;
+
+	return 0;
+}
+
+static ssize_t shunt_value_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);

drivers/iio/adc/pac193x.c new file +4 -0

+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);

drivers/iio/adc/pac193x.c new file +20 -0

+				 struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac193x_chip_info *chip_info = iio_priv(indio_dev);
+	int sh_val, target;
+
+	target = (int)(attr->attr.name[strlen(attr->attr.name) - 1] - '0') - 1;
+	if (kstrtouint(buf, 10, &sh_val)) {
+		dev_err(dev, "Shunt value is not valid\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&chip_info->lock);
+	chip_info->shunts[target] = sh_val;
+	mutex_unlock(&chip_info->lock);
+
+	return count;
+}
+

drivers/iio/adc/pac193x.c new file +59 -0

+		 * see: PAC193X Family Data Sheet Errata DS80000836A.pdf
+		 */
+		revision_bug = true;
+
+		bidir_reg = PAC193X_NEG_PWR_CH1_BIDI(chip_info->bi_dir[PAC193X_CH_1]) |
+			PAC193X_NEG_PWR_CH2_BIDI(chip_info->bi_dir[PAC193X_CH_2]) |
+			PAC193X_NEG_PWR_CH3_BIDI(chip_info->bi_dir[PAC193X_CH_3]) |
+			PAC193X_NEG_PWR_CH4_BIDI(chip_info->bi_dir[PAC193X_CH_4]) |
+			PAC193X_NEG_PWR_CH1_BIDV(chip_info->bi_dir[PAC193X_CH_1]) |
+			PAC193X_NEG_PWR_CH2_BIDV(chip_info->bi_dir[PAC193X_CH_2]) |
+			PAC193X_NEG_PWR_CH3_BIDV(chip_info->bi_dir[PAC193X_CH_3]) |
+			PAC193X_NEG_PWR_CH4_BIDV(chip_info->bi_dir[PAC193X_CH_4]);
+
+		/* write the updated registers back */
+		ret = pac193x_i2c_write_byte(client,
+					     PAC193X_CTRL_STAT_REGS_ADDR +
+					     PAC193X_NEG_PWR_REG_OFF,
+					     bidir_reg);
+		if (ret)
+			return ret;
+	}
+
+	/*
+	 * if refresh_v is not false, send REFRESH_V instead of REFRESH
+	 * (doesn't reset the accumulators)
+	 */
+	if (refresh_v)
+		refresh_cmd = PAC193X_REFRESH_V_REG;
+	else
+		refresh_cmd = PAC193X_REFRESH_REG;
+
+	ret = pac193x_i2c_send_byte(client, refresh_cmd);
+	if (ret) {
+		dev_err(&client->dev, "%s - cannot send 0x%02X\n",
+			__func__, refresh_cmd);
+		return ret;
+	}
+
+	if (revision_bug) {
+		/*
+		 * chip rev 2 and 3 bug workaround - write again the same register
+		 * write the updated registers back
+		 */
+		ret = pac193x_i2c_write_byte(client,
+					     PAC193X_CTRL_STAT_REGS_ADDR +
+					     PAC193X_NEG_PWR_REG_OFF, bidir_reg);
+		if (ret)
+			return ret;
+	}
+
+	/* register data retrieval timestamp */
+	chip_info->jiffies_tstamp = jiffies;
+
+	/* wait till the data is available */
+	usleep_range(wait_time, wait_time + 100);
+
+	return ret;
+}
+

+ */

drivers/iio/adc/pac193x.c new file +50 -0

+static int pac193x_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, int *val,
+			    int *val2, long mask)
+{
+	struct pac193x_chip_info *chip_info = iio_priv(indio_dev);
+	s64 curr_energy, int_part;
+	int rem, ret, channel = chan->channel - 1;
+
+	ret = pac193x_retrieve_data(chip_info, PAC193X_MIN_UPDATE_WAIT_TIME_MS);
+	if (ret < 0)
+		return ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			switch (chan->address) {
+			case PAC193X_VBUS_1_ADDR:
+			case PAC193X_VBUS_2_ADDR:
+			case PAC193X_VBUS_3_ADDR:
+			case PAC193X_VBUS_4_ADDR:
+				*val = chip_info->chip_reg_data.vbus[channel];
+				return IIO_VAL_INT;
+			default:
+				return -EINVAL;
+			}
+			break;
+		case IIO_CURRENT:
+			switch (chan->address) {
+			case PAC193X_VSENSE_1_ADDR:
+			case PAC193X_VSENSE_2_ADDR:
+			case PAC193X_VSENSE_3_ADDR:
+			case PAC193X_VSENSE_4_ADDR:
+				*val = chip_info->chip_reg_data.vsense[channel];
+				return IIO_VAL_INT;
+			default:
+				return -EINVAL;
+			}
+			break;
+		case IIO_POWER:
+			switch (chan->address) {
+			case PAC193X_VPOWER_1_ADDR:
+			case PAC193X_VPOWER_2_ADDR:
+			case PAC193X_VPOWER_3_ADDR:
+			case PAC193X_VPOWER_4_ADDR:
+				*val = chip_info->chip_reg_data.vpower[channel];
+				return IIO_VAL_INT;
+			default:
+				return -EINVAL;
+			}

drivers/iio/adc/pac193x.c new file +9 -0

+				 */
+				curr_energy = chip_info->chip_reg_data.energy_sec_acc[channel];
+				int_part = div_s64_rem(curr_energy, 100000000, &rem);
+
+				/* rescale reminder to be printed as "nano" value */
+				rem = rem * 10;
+
+				*val = int_part;
+				*val2 = rem;

drivers/iio/adc/pac193x.c new file +115 -0

+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			switch (chan->address) {
+			case PAC193X_VBUS_AVG_1_ADDR:
+			case PAC193X_VBUS_AVG_2_ADDR:
+			case PAC193X_VBUS_AVG_3_ADDR:
+			case PAC193X_VBUS_AVG_4_ADDR:
+				*val = chip_info->chip_reg_data.vbus_avg[channel];
+				return IIO_VAL_INT;
+
+			default:
+				return -EINVAL;
+			}
+			break;
+		case IIO_CURRENT:
+			switch (chan->address) {
+			case PAC193X_VSENSE_AVG_1_ADDR:
+			case PAC193X_VSENSE_AVG_2_ADDR:
+			case PAC193X_VSENSE_AVG_3_ADDR:
+			case PAC193X_VSENSE_AVG_4_ADDR:
+				*val = chip_info->chip_reg_data.vsense_avg[channel];
+				return IIO_VAL_INT;
+
+			default:
+				return -EINVAL;
+			}
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->address) {
+		/* Voltages - scale for millivolts */
+		case PAC193X_VBUS_1_ADDR:
+		case PAC193X_VBUS_2_ADDR:
+		case PAC193X_VBUS_3_ADDR:
+		case PAC193X_VBUS_4_ADDR:
+		case PAC193X_VBUS_AVG_1_ADDR:
+		case PAC193X_VBUS_AVG_2_ADDR:
+		case PAC193X_VBUS_AVG_3_ADDR:
+		case PAC193X_VBUS_AVG_4_ADDR:
+			*val = PAC193X_VOLTAGE_MILLIVOLTS_MAX;
+			if (chan->scan_type.sign == 'u')
+				*val2 = PAC193X_VOLTAGE_U_RES;
+			else
+				*val2 = PAC193X_VOLTAGE_S_RES;
+			return IIO_VAL_FRACTIONAL_LOG2;
+
+		/*
+		 * Currents - scale for mA - depends on the
+		 * channel's shunt value
+		 * (100mV * 1000000) / (2^16 * shunt(uohm))
+		 */
+		case PAC193X_VSENSE_1_ADDR:
+		case PAC193X_VSENSE_2_ADDR:
+		case PAC193X_VSENSE_3_ADDR:
+		case PAC193X_VSENSE_4_ADDR:
+		case PAC193X_VSENSE_AVG_1_ADDR:
+		case PAC193X_VSENSE_AVG_2_ADDR:
+		case PAC193X_VSENSE_AVG_3_ADDR:
+		case PAC193X_VSENSE_AVG_4_ADDR:
+			*val = PAC193X_MAX_VSENSE_RSHIFTED_BY_16B;
+			if (chan->scan_type.sign == 'u')
+				*val2 = chip_info->shunts[channel];
+			else
+				*val2 = chip_info->shunts[channel] >> 1;
+			return IIO_VAL_FRACTIONAL;
+
+		/*
+		 * Power - mW - it will use the combined scale
+		 * for current and voltage
+		 * current(mA) * voltage(mV) = power (uW)
+		 */
+		case PAC193X_VPOWER_1_ADDR:
+		case PAC193X_VPOWER_2_ADDR:
+		case PAC193X_VPOWER_3_ADDR:
+		case PAC193X_VPOWER_4_ADDR:
+			*val = PAC193X_MAX_VPOWER_RSHIFTED_BY_28B;
+			if (chan->scan_type.sign == 'u')
+				*val2 = chip_info->shunts[channel];
+			else
+				*val2 = chip_info->shunts[channel] >> 1;
+			return IIO_VAL_FRACTIONAL;
+		case PAC193X_VPOWER_ACC_1_ADDR:
+		case PAC193X_VPOWER_ACC_2_ADDR:
+		case PAC193X_VPOWER_ACC_3_ADDR:
+		case PAC193X_VPOWER_ACC_4_ADDR:
+
+			/*
+			 * expresses the 32 bit scale value
+			 * here compute the scale for energy (Watt-second or Joule)
+			 */
+			*val = PAC193X_SCALE_CONSTANT;
+
+			if (chan->scan_type.sign == 'u')
+				*val2 = chip_info->shunts[channel];
+			else
+				*val2 = chip_info->shunts[channel] >> 1;
+			return IIO_VAL_FRACTIONAL;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = chip_info->sample_rate_value;
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+
+	return -EINVAL;
+}
+
+/*

drivers/iio/adc/pac193x.c new file +41 -0

+			return ret;
+		}
+
+		/*
+		 * unlock the access towards the chip - register
+		 * snapshot includes its own access lock
+		 */
+		mutex_unlock(&chip_info->lock);
+
+		/*
+		 * now, force a snapshot with refresh - call retrieve
+		 * data in order to update the refresh timer
+		 * alter the timestamp in order to force trigger a
+		 * register snapshot and a timestamp update
+		 */
+		chip_info->jiffies_tstamp -=
+			msecs_to_jiffies(PAC193X_MIN_POLLING_TIME_MS);
+		ret = pac193x_retrieve_data(chip_info, (1024 / old_samp_rate) * 1000);
+		if (ret < 0) {
+			dev_err(&client->dev,
+				"%s - cannot snapshot ctrl and measurement regs\n",
+				__func__);
+			return ret;
+		}
+
+		ret = 0;
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+static void pac193x_work_periodic_rfsh(struct work_struct *work)
+{
+	struct pac193x_chip_info *chip_info = to_pac193x_chip_info(work);
+
+	/* do a REFRESH, then read */
+	pac193x_reg_snapshot(chip_info, true, false, PAC193X_MIN_UPDATE_WAIT_TIME_MS);
+}

drivers/iio/adc/pac193x.c new file +9 -0

+	 * read the chip ID values
+	 */
+	ret = pac193x_i2c_read(client, PAC193X_PID_REG_ADDR, buf, PAC193X_ID_REG_LEN);
+	if (ret) {
+		dev_err(&client->dev, "cannot read revision\n");
+		return ret;
+	}
+
+	return 0;

drivers/iio/adc/pac193x.c new file +14 -0

+	if (ret) {
+		dev_err(&client->dev, "cannot read revision\n");
+		return ret;
+	}
+
+	if (rev_info[PAC193X_PID_IDX] != pac193x_chip_config[chip_info->chip_variant].prod_id) {
+		dev_err(&client->dev,
+			"chip's product ID doesn't match the exact one for this part\n");
+		return -EINVAL;
+	}
+
+	dev_dbg(&client->dev, "Chip revision: 0x%02X\n", rev_info[PAC193X_RID_IDX]);
+	chip_info->chip_revision = rev_info[PAC193X_RID_IDX];
+

drivers/iio/adc/pac193x.c new file +12 -0

+			chip_info->phys_channels = PAC1934_NUM_CHANNELS;
+			break;
+		case PAC1933_PID:
+			chip_info->phys_channels = PAC1933_NUM_CHANNELS;
+			break;
+		case PAC1932_PID:
+			chip_info->phys_channels = PAC1932_NUM_CHANNELS;
+			break;
+		case PAC1931_PID:
+			chip_info->phys_channels = PAC1931_NUM_CHANNELS;
+			break;
+		default:

drivers/iio/adc/pac193x.c new file +57 -0

+
+	/* register the timer */
+	mod_timer(&chip_info->tmr_forced_update,
+		  jiffies + msecs_to_jiffies(PAC193X_MAX_RFSH_LIMIT_MS));
+
+	return 0;
+}
+
+static union acpi_object *pac193x_acpi_eval_function(acpi_handle handle,
+						     int revision,
+						     int function)
+{
+	acpi_status status;
+	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
+	union acpi_object args[PAC193X_ACPI_ARG_COUNT];
+	struct acpi_object_list args_list;
+	uuid_t uuid;
+
+	uuid_parse(PAC193X_DSM_UUID, &uuid);
+
+	args[0].type = ACPI_TYPE_BUFFER;
+	args[0].buffer.length = sizeof(struct pac193x_uuid_format);
+	args[0].buffer.pointer = (u8 *)&uuid;
+
+	args[1].type = ACPI_TYPE_INTEGER;
+	args[1].integer.value = revision;
+
+	args[2].type = ACPI_TYPE_INTEGER;
+	args[2].integer.value = function;
+
+	args[3].type = ACPI_TYPE_PACKAGE;
+	args[3].package.count = 0;
+
+	args_list.count = PAC193X_ACPI_ARG_COUNT;
+	args_list.pointer = &args[0];
+
+	status = acpi_evaluate_object(handle, "_DSM", &args_list, &buffer);
+
+	if (ACPI_FAILURE(status)) {
+		kfree(buffer.pointer);
+		return NULL;
+	}
+
+	return buffer.pointer;
+}
+
+static char *pac193x_acpi_get_acpi_match_entry(acpi_handle handle)
+{
+	acpi_status status;
+	union acpi_object *name_object;
+	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
+
+	status = acpi_evaluate_object(handle, "_HID", NULL, &buffer);
+	name_object = buffer.pointer;
+
+	return name_object->string.pointer;
+}

drivers/iio/adc/pac193x.c new file +54 -0

+	if (!name)
+		return NULL;
+
+	rez = pac193x_acpi_eval_function(handle, 0, PAC193X_ACPI_GET_NAMES_AND_MOHMS_VALS);
+
+	if (!rez)
+		return NULL;
+
+	for (i = 0; i < rez->package.count; i += 2) {
+		idx = i / 2;
+		chip_info->channel_names[idx] =
+			devm_kmemdup(&client->dev, rez->package.elements[i].string.pointer,
+				     (size_t)rez->package.elements[i].string.length + 1,
+				     GFP_KERNEL);
+		chip_info->channel_names[idx][rez->package.elements[i].string.length] = '\0';
+		chip_info->shunts[idx] =
+			rez->package.elements[i + 1].integer.value * 1000;
+		chip_info->active_channels[idx] = (chip_info->shunts[idx] != 0);
+	}
+
+	kfree(rez);
+
+	rez = pac193x_acpi_eval_function(handle, 1, PAC193X_ACPI_GET_UOHMS_VALS);
+	if (!rez) {
+		/*
+		 * initialising with default values
+		 * we assume all channels are unidectional(the mask is zero)
+		 * and assign the default sampling rate
+		 */
+		chip_info->sample_rate_value = PAC193X_DEFAULT_CHIP_SAMP_SPEED;
+		return name;
+	}
+
+	for (i = 0; i < rez->package.count; i++) {
+		idx = i;
+		chip_info->shunts[idx] = rez->package.elements[i].integer.value;
+		chip_info->active_channels[idx] = (chip_info->shunts[idx] != 0);
+	}
+
+	kfree(rez);
+
+	rez = pac193x_acpi_eval_function(handle, 1, PAC193X_ACPI_GET_BIPOLAR_SETTINGS);
+	if (!rez)
+		return NULL;
+	bi_dir_mask = rez->package.elements[0].integer.value;
+	chip_info->bi_dir[0] = (bi_dir_mask & (1 << 0)) << 0;
+	chip_info->bi_dir[0] = (bi_dir_mask & (1 << 1)) << 1;
+	chip_info->bi_dir[0] = (bi_dir_mask & (1 << 2)) << 2;
+	chip_info->bi_dir[0] = (bi_dir_mask & (1 << 3)) << 3;
+	kfree(rez);
+
+	rez = pac193x_acpi_eval_function(handle, 1, PAC193X_ACPI_GET_SAMP);
+	if (!rez)
+		return NULL;

drivers/iio/adc/pac193x.c new file +76 -0

+	}
+
+	ret = pac193x_match_samp_rate(chip_info, chip_info->sample_rate_value);
+	if (ret) {
+		dev_err(&client->dev,
+			"The given sample rate value is not supported: %d\n",
+			chip_info->sample_rate_value);
+		goto err_of_node_put;
+	}
+
+	current_channel = 1;
+	for_each_child_of_node(client->dev.of_node, node) {
+		ret = of_property_read_u32(node, "reg", &idx);
+		if (ret) {
+			dev_err(&client->dev,
+				"invalid channel_index, error: %d\n",
+				ret);
+			goto err_of_node_put;
+		}
+		/* adjust idx to match channel index (1 to 4) from the datasheet */
+		idx--;
+		if (current_channel >= (chip_info->phys_channels + 1) ||
+		    idx >= chip_info->phys_channels || idx < 0) {
+			dev_err(&client->dev,
+				"invalid channel_index %d value on %s\n",
+				(idx + 1), node->full_name);
+			goto err_of_node_put;
+		}
+
+		/* enable channel */
+		chip_info->active_channels[idx] = true;
+
+		ret = of_property_read_u32(node, "microchip,uohms-shunt-res",
+					   &chip_info->shunts[idx]);
+		if (ret) {
+			dev_err(&client->dev,
+				"%s: invalid shunt-resistor value: %d\n",
+				node->full_name, ret);
+			goto err_of_node_put;
+		}
+
+		ret = of_property_read_string(node, "microchip,rail-name",
+					      (const char **)&chip_info->channel_names[idx]);
+		if (ret) {
+			dev_err(&client->dev,
+				"%s: invalid rail-name value: %d\n",
+				node->full_name, ret);
+			goto err_of_node_put;
+		}
+
+		chip_info->bi_dir[idx] =
+			of_property_read_bool(node, "microchip,bi-directional");
+
+		current_channel++;
+	}
+
+	return 0;
+
+err_of_node_put:
+	of_node_put(node);
+	return ret;
+}
+
+static int pac193x_chip_configure(struct pac193x_chip_info *chip_info)
+{
+	int cnt, ret;
+	struct i2c_client *client = chip_info->client;
+	u8 regs[PAC193X_CTRL_STATUS_INFO_LEN], idx, ctrl_reg;
+	u32 wait_time;
+
+	/*
+	 * count how many channels are enabled and store
+	 * this information within the driver data
+	 */
+	cnt = 0;
+	chip_info->chip_reg_data.num_enabled_channels = 0;

drivers/iio/adc/pac193x.c new file +26 -0

+		return ret;
+	}
+
+	/* write the CHANNEL_DIS and the NEG_PWR registers */
+	regs[PAC193X_CHANNEL_DIS_REG_OFF] =
+		PAC193X_CHAN_DIS_CH1_OFF(chip_info->active_channels[PAC193X_CH_1]) |
+		PAC193X_CHAN_DIS_CH2_OFF(chip_info->active_channels[PAC193X_CH_2]) |
+		PAC193X_CHAN_DIS_CH3_OFF(chip_info->active_channels[PAC193X_CH_3]) |
+		PAC193X_CHAN_DIS_CH4_OFF(chip_info->active_channels[PAC193X_CH_4]) |
+		PAC193X_SMBUS_TIMEOUT_EN(0) |
+		PAC193X_SMBUS_BYTECOUNT_EN(0) |
+		PAC193X_SMBUS_NO_SKIP_EN(0);
+
+	regs[PAC193X_NEG_PWR_REG_OFF] =
+		PAC193X_NEG_PWR_CH1_BIDI(chip_info->bi_dir[PAC193X_CH_1]) |
+		PAC193X_NEG_PWR_CH2_BIDI(chip_info->bi_dir[PAC193X_CH_2]) |
+		PAC193X_NEG_PWR_CH3_BIDI(chip_info->bi_dir[PAC193X_CH_3]) |
+		PAC193X_NEG_PWR_CH4_BIDI(chip_info->bi_dir[PAC193X_CH_4]) |
+		PAC193X_NEG_PWR_CH1_BIDV(chip_info->bi_dir[PAC193X_CH_1]) |
+		PAC193X_NEG_PWR_CH2_BIDV(chip_info->bi_dir[PAC193X_CH_2]) |
+		PAC193X_NEG_PWR_CH3_BIDV(chip_info->bi_dir[PAC193X_CH_3]) |
+		PAC193X_NEG_PWR_CH4_BIDV(chip_info->bi_dir[PAC193X_CH_4]);
+
+	/*
+	 * the current can be measured uni or bi-dir, but voltages are set only
+	 * for uni-directional operation

drivers/iio/adc/pac193x.c new file +12 -0

+	if (ret) {
+		dev_err(&client->dev,
+			"%s - cannot send 0x%02X\n",
+			__func__, PAC193X_REFRESH_REG);
+		return ret;
+	}
+
+	/*
+	 * get the current(in the chip) sampling speed and compute the
+	 * required timeout based on its value
+	 * the timeout is 1/sampling_speed
+	 */

drivers/iio/adc/pac193x.c new file +132 -0

+
+	return ret;
+}
+
+static int pac193x_prep_iio_channels(struct pac193x_chip_info *chip_info, struct iio_dev *indio_dev)
+{
+	struct i2c_client *client;
+	struct iio_chan_spec *ch_sp;
+	int channel_size, channel_attribute_count, attribute_count, cnt;
+	void *dyn_ch_struct, *tmp_data;
+
+	client = chip_info->client;
+
+	/* find out dynamically how many IIO channels we need */
+	channel_attribute_count = 0;
+	channel_size = 0;
+	for (cnt = 0; cnt < chip_info->phys_channels; cnt++) {
+		if (chip_info->active_channels[cnt]) {
+			/* add the size of the properties of one chip physical channel */
+			channel_size += sizeof(pac193x_single_channel);
+			/* count how many enabled channels we have */
+			channel_attribute_count += ARRAY_SIZE(pac193x_single_channel);
+			dev_info(&client->dev, ":%s: Channel %d active\n", __func__, cnt + 1);
+		}
+	}
+
+	/* now add the timestamp channel size */
+	channel_size += sizeof(pac193x_ts);
+
+	/* add one more channel which is the timestamp */
+	attribute_count = channel_attribute_count + 1;
+
+	dyn_ch_struct = kzalloc(channel_size, GFP_KERNEL);
+	if (!dyn_ch_struct)
+		return -EINVAL;
+
+	tmp_data = dyn_ch_struct;
+
+	/* populate the dynamic channels and make all the adjustments */
+	for (cnt = 0; cnt < chip_info->phys_channels; cnt++) {
+		if (chip_info->active_channels[cnt]) {
+			memcpy(tmp_data, pac193x_single_channel, sizeof(pac193x_single_channel));
+			ch_sp = (struct iio_chan_spec *)tmp_data;
+			ch_sp[IIO_EN].channel = cnt  + 1;
+			ch_sp[IIO_EN].scan_index = cnt;
+			ch_sp[IIO_EN].address = cnt + PAC193X_VPOWER_ACC_1_ADDR;
+			ch_sp[IIO_POW].channel = cnt  + 1;
+			ch_sp[IIO_POW].scan_index = cnt;
+			ch_sp[IIO_POW].address = cnt + PAC193X_VPOWER_1_ADDR;
+			ch_sp[IIO_VOLT].channel = cnt  + 1;
+			ch_sp[IIO_VOLT].scan_index = cnt;
+			ch_sp[IIO_VOLT].address = cnt + PAC193X_VBUS_1_ADDR;
+			ch_sp[IIO_CRT].channel = cnt  + 1;
+			ch_sp[IIO_CRT].scan_index = cnt;
+			ch_sp[IIO_CRT].address = cnt + PAC193X_VSENSE_1_ADDR;
+			ch_sp[IIO_VOLTAVG].channel = cnt  + 1;
+			ch_sp[IIO_VOLTAVG].scan_index = cnt;
+			ch_sp[IIO_VOLTAVG].address = cnt + PAC193X_VBUS_AVG_1_ADDR;
+			ch_sp[IIO_CRTAVG].channel = cnt  + 1;
+			ch_sp[IIO_CRTAVG].scan_index = cnt;
+			ch_sp[IIO_CRTAVG].address = cnt + PAC193X_VSENSE_AVG_1_ADDR;
+
+			/*
+			 * now modify the parameters in all channels if the
+			 * whole chip rail(channel) is bi-directional
+			 */
+			if (chip_info->bi_dir[cnt]) {
+				ch_sp[IIO_EN].scan_type.sign = 's';
+				ch_sp[IIO_EN].scan_type.realbits = PAC193X_ENERGY_S_RES;
+				ch_sp[IIO_POW].scan_type.sign = 's';
+				ch_sp[IIO_POW].scan_type.realbits = PAC193X_POWER_S_RES;
+				ch_sp[IIO_VOLT].scan_type.sign = 's';
+				ch_sp[IIO_VOLT].scan_type.realbits = PAC193X_VOLTAGE_S_RES;
+				ch_sp[IIO_CRT].scan_type.sign = 's';
+				ch_sp[IIO_CRT].scan_type.realbits = PAC193X_CURRENT_S_RES;
+				ch_sp[IIO_VOLTAVG].scan_type.sign = 's';
+				ch_sp[IIO_VOLTAVG].scan_type.realbits = PAC193X_VOLTAGE_S_RES;
+				ch_sp[IIO_CRTAVG].scan_type.sign = 's';
+				ch_sp[IIO_CRTAVG].scan_type.realbits = PAC193X_CURRENT_S_RES;
+			}
+			tmp_data += sizeof(pac193x_single_channel);
+		}
+	}
+
+	/* now copy the timestamp channel */
+	memcpy(tmp_data, pac193x_ts, sizeof(pac193x_ts));
+	ch_sp = (struct iio_chan_spec *)tmp_data;
+	ch_sp[0].scan_index = attribute_count - 1;
+
+	/*
+	 * 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 = devm_kmemdup(&client->dev,
+					   (const struct iio_chan_spec *)dyn_ch_struct,
+					   channel_size, GFP_KERNEL);
+
+	kfree(dyn_ch_struct);
+
+	if (!indio_dev->channels)
+		return -EINVAL;
+
+	return 0;
+}
+
+static ssize_t reset_accumulators_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac193x_chip_info *chip_info = iio_priv(indio_dev);
+	int ret, i;
+	u8 refresh_cmd = PAC193X_REFRESH_REG;
+
+	ret = pac193x_i2c_send_byte(chip_info->client, refresh_cmd);
+	if (ret) {
+		dev_err(&indio_dev->dev,
+			"%s - cannot send 0x%02X\n",
+			__func__, refresh_cmd);
+	}
+
+	for (i = 0 ; i < chip_info->phys_channels; i++)
+		chip_info->chip_reg_data.energy_sec_acc[i] = 0;
+
+	return count;
+}
+
+static IIO_DEVICE_ATTR(shunt_value_1, 0644, shunt_value_show, shunt_value_store, 0);
+static IIO_DEVICE_ATTR(shunt_value_2, 0644, shunt_value_show, shunt_value_store, 0);
+static IIO_DEVICE_ATTR(shunt_value_3, 0644, shunt_value_show, shunt_value_store, 0);
+static IIO_DEVICE_ATTR(shunt_value_4, 0644, shunt_value_show, shunt_value_store, 0);

drivers/iio/adc/pac193x.c new file +82 -0

+	PAC193X_DEV_ATTR(channel_name_1),
+	PAC193X_DEV_ATTR(shunt_value_2),
+	PAC193X_DEV_ATTR(channel_name_2),
+	PAC193X_DEV_ATTR(shunt_value_3),
+	PAC193X_DEV_ATTR(channel_name_3),
+	PAC193X_DEV_ATTR(shunt_value_4),
+	PAC193X_DEV_ATTR(channel_name_4),
+	PAC193X_DEV_ATTR(reset_accumulators),
+	NULL
+};
+
+static int pac193x_prep_custom_attributes(struct pac193x_chip_info *chip_info,
+					  struct iio_dev *indio_dev)
+{
+	int i, j, active_channels_count = 0;
+	struct attribute **pac193x_custom_attributes;
+	struct attribute_group *pac193x_group;
+	struct i2c_client *client = chip_info->client;
+
+	for (i = 0 ; i < chip_info->phys_channels; i++)
+		if (chip_info->active_channels[i])
+			active_channels_count++;
+
+	pac193x_group = devm_kzalloc(&client->dev, sizeof(*pac193x_group), GFP_KERNEL);
+
+	pac193x_custom_attributes = devm_kzalloc(&client->dev,
+						 (PAC193X_CUSTOM_ATTR_FOR_CHANNEL *
+						 active_channels_count +
+						 PAC193X_SHARED_DEVATTRS_COUNT)
+						 * sizeof(*pac193x_group) + 1,
+						 GFP_KERNEL);
+	j = 0;
+
+	for (i = 0 ; i < chip_info->phys_channels; i++) {
+		if (chip_info->active_channels[i]) {
+			pac193x_custom_attributes[PAC193X_CUSTOM_ATTR_FOR_CHANNEL * j] =
+			pac193x_all_attributes[PAC193X_CUSTOM_ATTR_FOR_CHANNEL * i];
+			pac193x_custom_attributes[PAC193X_CUSTOM_ATTR_FOR_CHANNEL * j + 1] =
+			pac193x_all_attributes[PAC193X_CUSTOM_ATTR_FOR_CHANNEL * i + 1];
+			j++;
+		}
+	}
+
+	for (i = 0; i < PAC193X_SHARED_DEVATTRS_COUNT; i++)
+		pac193x_custom_attributes[PAC193X_CUSTOM_ATTR_FOR_CHANNEL *
+			active_channels_count + i] =
+			pac193x_all_attributes[PAC193X_CUSTOM_ATTR_FOR_CHANNEL *
+			chip_info->phys_channels + i];
+
+	pac193x_group->attrs = pac193x_custom_attributes;
+	chip_info->pac193x_info.attrs = pac193x_group;
+
+	return 0;
+}
+
+static void pac193x_remove(struct i2c_client *client)
+{
+	int ret;
+	struct iio_dev *indio_dev = dev_get_drvdata(&client->dev);
+	struct pac193x_chip_info *chip_info = iio_priv(indio_dev);
+
+	ret = try_to_del_timer_sync(&chip_info->tmr_forced_update);
+	if (ret < 0)
+		dev_err(&client->dev,
+			"%s - cannot delete the forced readout timer\n",
+			__func__);
+
+	if (chip_info->wq_chip) {
+		cancel_work_sync(&chip_info->work_chip_rfsh);
+		flush_workqueue(chip_info->wq_chip);
+		destroy_workqueue(chip_info->wq_chip);
+	}
+}
+
+static int pac193x_probe(struct i2c_client *client, const struct i2c_device_id *id)
+{
+	struct pac193x_chip_info *chip_info;
+	struct iio_dev *indio_dev;
+	const char *name = NULL;
+	const struct of_device_id *match;
+	int cnt, ret, dev_id = 0;
+

drivers/iio/adc/pac193x.c new file +4 -0

+			break;
+		case PAC1933_PID:
+			client->dev.init_name = "pac1933";
+			break;

drivers/iio/adc/pac193x.c new file +9 -0

+		}
+	}
+
+	if (!name) {
+		dev_err_probe(&indio_dev->dev, PTR_ERR(indio_dev),
+			      "parameter parsing returned an error\n");
+		return -EINVAL;
+	}
+

drivers/iio/adc/pac193x.c new file +10 -0

+
+	/* prepare the channel information */
+	ret = pac193x_prep_iio_channels(chip_info, indio_dev);
+	if (ret < 0)
+		goto free_chan_attr_mem;
+
+	ret = pac193x_prep_custom_attributes(chip_info, indio_dev);
+	if (ret < 0) {
+		dev_err_probe(&indio_dev->dev, ret,
+			      "Can't configure custom attributes for PAC193X device\n");

drivers/iio/adc/pac193x.c new file +11 -0

+	.remove = pac193x_remove,
+	.id_table = pac193x_id,
+};
+
+module_i2c_driver(pac193x_driver);
+
+MODULE_AUTHOR("Bogdan Bolocan <[email protected]>");
+MODULE_AUTHOR("Victor Tudose");
+MODULE_AUTHOR("Marius Cristea <[email protected]>");
+MODULE_DESCRIPTION("IIO driver for PAC193X Multi-Channel DC Power/Energy Monitor");
+MODULE_LICENSE("GPL");

a representative part from the list - if no other basis to chose go with the
lowest number currently supported.

The custom ABI in here needs documentation before we can review it properly.

Comments inline.

It's a big driver, so I'm sure more stuff will come up next round just due to
mental exhaustion reviewing it in one go!

Quoted 20 lines

BIT(IIO_CHAN_INFO_SAMP_FREQ),      \
+     .scan_index =
(_si),                                                    \
+     .scan_type =
{                                                          \
+             .sign =
'u',                                                    \
+             .realbits =
PAC193X_POWER_U_RES,                                \
+             .storagebits =
32,                                              \
+             .shift =
4,                                                     \
+             .endianness =
IIO_CPU,                                          \
+
}
     \

(quoted diff) +2 -0

+}
+

Quoted 6 lines

+#define PAC193X_SOFT_TIMESTAMP(_index)
{                                     \
+     .type =
IIO_TIMESTAMP,                                                  \
+     .channel = -
1,                                                          \

What is this for?

drivers/iio/adc/pac193x.c line 672

Quoted 10 lines

drivers/iio/adc/pac193x.c new file +7 -0

+
+     len += sprintf(buf, "%u\n", chip_info->shunts[target]);
+
+     return len;
+}
+
+static ssize_t channel_name_show(struct device *dev,

Looks like per channel label support provided by the read_label iio_info callback.

Quoted 11 lines

+                              struct device_attribute *attr, +                              char *buf)
+{
+     struct iio_dev *indio_dev = dev_to_iio_dev(dev); +     struct pac193x_chip_info *chip_info = iio_priv(indio_dev); +     int len = 0;
+     int target = (int)(attr->attr.name[strlen(attr->attr.name) - 1] - '0') - 1;
+
+     len += sprintf(buf, "%s\n", chip_info-

Quoted 1 line

channel_names[target]);

drivers/iio/adc/pac193x.c line 686

Quoted 5 lines

drivers/iio/adc/pac193x.c new file +5 -0

+
+     return len;
+}
+
+static ssize_t shunt_value_store(struct device *dev,

Shunt values aren't normally dynamic.  Why do you need to write it from
userspace? I'd expect that to come from firmware.

If it's needed the ext_info framework might be a better fit than direct implementation of the attribute.

Quoted 4 lines

+                     case PAC193X_VPOWER_4_ADDR:
+                             *val = chip_info-

Quoted 1 line

chip_reg_data.vpower[channel];

Quoted 16 lines

+                             return IIO_VAL_INT;
+                     default:
+                             return -EINVAL;
+                     }
+                     break;
+             case IIO_ENERGY:
+                     switch (chan->address) {
+                     case PAC193X_VPOWER_ACC_1_ADDR:
+                     case PAC193X_VPOWER_ACC_2_ADDR:
+                     case PAC193X_VPOWER_ACC_3_ADDR:
+                     case PAC193X_VPOWER_ACC_4_ADDR:
+                             /*
+                              * expresses the 64 bit energy value as a 32 bit integer part and
+                              * 32 bits (representing 8 digits) fractional value

I'm lost.  So it's a 64 bit value?
We have IIO_VAL_INT_64. Does that not work here?

Quoted 14 lines

+                              */
+                             curr_energy = chip_info-

Quoted 1 line

chip_reg_data.energy_sec_acc[channel];

+                             int_part = div_s64_rem(curr_energy, 100000000, &rem);
+
+                             /* rescale reminder to be printed as "nano" value */
+                             rem = rem * 10;
+
+                             *val = int_part;
+                             *val2 = rem;
+                             return IIO_VAL_INT_PLUS_NANO; +                     default:

Quoted 8 lines

+                             return -EINVAL;
+                     }
+                     break;
+             default:
+                     return -EINVAL;
+             }
+             break;
+     case IIO_CHAN_INFO_AVERAGE_RAW:

I'd forgotten we had this ABI and had to look up the docs.   Hmm. It's a bit clunky but I guess
still useful in this case.  Longer term we should think about how to describe that and how it
is different from oversampling. The problem with oversampling is it affects the main channel
so we can't easily associate both an averaged value  and a raw one like you have here.

Given lots of other changes requested and early in this kernel cycle, perhaps it will make sense to revisit
this question at a later version of this patch (or maybe just leave it alone as too hard
to do better!)

Quoted 6 lines

+             ctrl_reg = PAC193X_CRTL_SAMPLE_RATE_SET(chip_info-

Quoted 1 line

crt_samp_spd_bitfield) |

Quoted 8 lines

+                     PAC193X_CHAN_ALERT_EN;
+             ret = pac193x_i2c_write_byte(client, PAC193X_CTRL_REG, ctrl_reg);
+             if (ret) {
+                     dev_err(&client->dev, "%s - can't update sample rate\n", __func__);
+                     chip_info->sample_rate_value = old_samp_rate; +                     mutex_unlock(&chip_info->lock);

Fun thing about i2c bus write failures. You have no idea what failed. The value might be
the old value or the new one after the failed write... So normally we don't bother too much if our values are
out of sync. and that leads to easier unwinding.  However, if you want to keep this as it
is then that's fine.

Quoted 15 lines

drivers/iio/adc/pac193x.c new file +3 -0

+static void pac193x_work_periodic_rfsh(struct work_struct *work)
+{
+     struct pac193x_chip_info *chip_info =

to_pac193x_chip_info(work);
+
+     /* do a REFRESH, then read */
+     pac193x_reg_snapshot(chip_info, true, false, PAC193X_MIN_UPDATE_WAIT_TIME_MS);

drivers/iio/adc/pac193x.c new file +5 -0

+}
+
+static void pac193x_read_reg_timeout(struct timer_list *t)
+{
+     struct pac193x_chip_info *chip_info = from_timer(chip_info,

t, tmr_forced_update);
+