Add Richtek RTQ6056 support

From: ChiYuan Huang <[email protected]>

This patch series is to enable Richtek RTQ6056 support.

The RTQ6056 is a high accuracy current-sense monitor with I2C interface, and the device provides full information for system by reading out the load current and power.

Since v6
- Remove specific rtq6056 ABI document.
- Update integration time description in general ABI document.
- Remove the redundant blank line.
- To prevent the race condition for attribute wrtie and shunt resistor write, use 'iio_device_claim_direct_mode' API.
- Refine the order for 'action_reset' and 'pm_runtime'.
- Fix text typo in comment like as ohm to Ohm and timea to time.

Since v5
- Fix kernel version text for ABI.

Since v4
- Add '__aligned(8)' for timestamp member.
- Declare timestamp from 'int64_t' to more unified 's64'.

Since v3
- change the node name to be generic 'adc' in binding example.
- Refine pm_runtime API calling order in 'read_channel' API.
- Fix vshunt wrong scale for divider.
- Refine the comment text.
- Use 'devm_add_action_or_reset' to decrease the code usage in probe function.
- Use RUNTIME_PM_OPS to replace SET_RUNTIME_PM_OPS.
- minor fix for the comma.
- Use pm_ptr to replace the direct assigned pm_ops.

Since v2
- Change the resistor property name to be generic 'shunt-resistor-micro-ohms'.
- Rename file from 'rtq6056-adc' to 'rtq6056'.
- Refine the ABI, if generic already defined it, remove it and check the channel report unit.
- Add copyright text.
- include the correct header.
- change the property parsing name.
- To use iio_chan_spec address field.
- Refine each channel separate and shared_by_all.
- Use pm_runtime and pm_runtime_autosuspend.
- Remove the shutdown callback. From the HW suggestion, it's not recommended to use battery as the power supply.
- Check all scale unit (voltage->mV, current->mA, power->milliWatt).
- Use the read_avail to provide the interface for attribute value list.
- Add comma for the last element in the const integer array.
- Refine each ADC label text.
- In read_label callback, replace snprintf to sysfs_emit.

ChiYuan Huang (3):
dt-bindings: iio: adc: Add rtq6056 adc support
iio: adc: Add rtq6056 support
Documentation: ABI: testing: rtq6056: Update ABI docs

 Documentation/ABI/testing/sysfs-bus-iio            |  10 +
 .../bindings/iio/adc/richtek,rtq6056.yaml          |  56 ++
 drivers/iio/adc/Kconfig                            |  15 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/rtq6056.c                          | 664 +++++++++++++++++++++
 5 files changed, 746 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/richtek,rtq6056.yaml
 create mode 100644 drivers/iio/adc/rtq6056.c

2.7.4

From: ChiYuan Huang <[email protected]>

Add the documentation for Richtek rtq6056.

---
Since v3
- change the node name to be generic 'adc' in binding example.

Since v2
- Change the resistor property name to be generic 'shunt-resistor-micro-ohms'.

---
 .../bindings/iio/adc/richtek,rtq6056.yaml          | 56 ++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/richtek,rtq6056.yaml

new file mode 100644
index 00000000..88e0086
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/richtek,rtq6056.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RTQ6056 Bi-Directional Current and Power Monitor with 16-bit ADC
+
+maintainers:
+  - ChiYuan Huang <[email protected]>
+
+description: |
+  The RTQ6056 is a high accuracy current-sense monitor with I2C and SMBus
+  interface, and the device provides full information for system by reading
+  out the loading current and power.
+
+  The device monitors both of the drops across sense resistor and the BUS
+  voltage, converts into the current in amperes, and power in watts through
+  internal analog-to-digital converter ADC. The programmable calibration,
+  adjustable conversion time, and averaging function are also built in for
+  more design flexibility.
+
+  Datasheet is available at
+  https://www.richtek.com/assets/product_file/RTQ6056/DSQ6056-00.pdf
+
+properties:
+  compatible:
+    const: richtek,rtq6056
+
+  reg:
+    maxItems: 1
+
+  "#io-channel-cells":
+    const: 1
+
+  shunt-resistor-micro-ohms:
+    description: Shunt IN+/IN- sensing node resistor
+
+required:
+  - compatible
+  - reg
+  - "#io-channel-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      adc@40 {
+        compatible = "richtek,rtq6056";
+        reg = <0x40>;
+        #io-channel-cells = <1>;
+      };
+    };

2.7.4

From: ChiYuan Huang <[email protected]>

Add Richtek rtq6056 supporting.

It can be used for the system to monitor load current and power with 16-bit resolution.

---
Since v6
- Remove specific rtq6056 ABI document.
- Remove the redundant blank line.
- To prevent the race condition for attribute wrtie and shunt resistor write, use 'iio_device_claim_direct_mode' API.
- Refine the order for 'action_reset' and 'pm_runtime'.
- Fix text typo in comment like as ohm to Ohm and timea to time.

Since v5
- Fix kernel version text for ABI.

Since v4
- Add '__aligned(8)' for timestamp member in buffer_trigger_handler function.
- Declare timestamp from 'int64_t' to more unified 's64'.

Since v3
- Refine pm_runtime API calling order in 'read_channel' API.
- Fix vshunt wrong scale for divider.
- Refine the comment text.
- Use 'devm_add_action_or_reset' to decrease the code usage in probe function.
- Use RUNTIME_PM_OPS to replace SET_RUNTIME_PM_OPS.
- minor fix for the comma.
- Use pm_ptr to replace the direct assigned pm_ops.

Since v2
- Rename file from 'rtq6056-adc' to 'rtq6056'.
- Refine the ABI, if generic already defined it, remove it and check the channel report unit.
- Add copyright text.
- include the correct header.
- change the property parsing name.
- To use iio_chan_spec address field.
- Refine each channel separate and shared_by_all.
- Use pm_runtime and pm_runtime_autosuspend.
- Remove the shutdown callback. From the HW suggestion, it's not recommended to use battery as the power supply.
- Check all scale unit (voltage->mV, current->mA, power->milliWatt).
- Use the read_avail to provide the interface for attribute value list.
- Add comma for the last element in the const integer array.
- Refine each ADC label text.
- In read_label callback, replace snprintf to sysfs_emit.

---
 drivers/iio/adc/Kconfig   |  15 ++
 drivers/iio/adc/Makefile  |   1 +
 drivers/iio/adc/rtq6056.c | 664 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 680 insertions(+)
 create mode 100644 drivers/iio/adc/rtq6056.c

index 48ace74..caebd1a 100644
@@ -908,6 +908,21 @@ config ROCKCHIP_SARADC
 	  To compile this driver as a module, choose M here: the
 	  module will be called rockchip_saradc.
 
+config RICHTEK_RTQ6056
+	tristate "Richtek RTQ6056 Current and Power Monitor ADC"
+	depends on I2C
+	select REGMAP_I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say yes here to enable RQT6056 ADC support.
+	  RTQ6056 is a high accuracy current-sense monitor with I2C and SMBus
+	  compatible interface, and the device provides full information for
+	  system by reading out the load current and power.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called rtq6056.
+
 config RZG2L_ADC
 	tristate "Renesas RZ/G2L ADC driver"
 	depends on ARCH_RZG2L || COMPILE_TEST

index 39d806f..cda7580 100644
@@ -84,6 +84,7 @@ obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
 obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
 obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_RICHTEK_RTQ6056) += rtq6056.o
 obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
 obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
 obj-$(CONFIG_SPEAR_ADC) += spear_adc.o

2.7.4

From: ChiYuan Huang <[email protected]>

Add documentation for the usage of voltage channel integration time.

---
 Documentation/ABI/testing/sysfs-bus-iio | 10 ++++++++++
 1 file changed, 10 insertions(+)

index d4ccc68..1f7d327 100644
@@ -2030,3 +2030,13 @@ Description:
 		Available range for the forced calibration value, expressed as:
 
 		- a range specified as "[min step max]"
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_integration_time
+KernelVersion:	5.20
+Contact:	[email protected]
+Description:
+		For voltage sensing hardware, there may be different time between
+		channel conversion and sample update. 'Integration time' is used to
+		specify the channel internal conversion time. And sample update
+		interval is equal to average sample count multiple integration time.
+		Unit as microsecond.

2.7.4