Re: [PATCH v3 2/3] dt-bindings: iio: adc: Add support for QCOM PMIC5 Gen3 ADC

From: Dmitry Baryshkov
Date: Sun Dec 31 2023 - 12:41:51 EST

On Sun, 31 Dec 2023 at 19:13, Jishnu Prakash <quic_jprakash@xxxxxxxxxxx> wrote:
>
> For the PMIC5-Gen3 type PMICs, ADC peripheral is present in HW for the
> following PMICs: PMK8550, PM8550, PM8550B and PM8550VX PMICs.
>
> It is similar to PMIC5-Gen2, with SW communication to ADCs on all PMICs
> going through PBS(Programmable Boot Sequence) firmware through a single
> register interface. This interface is implemented on an SDAM (Shared
> Direct Access Memory) peripheral on the master PMIC PMK8550 rather
> than a dedicated ADC peripheral.
>
> Add documentation for PMIC5 Gen3 ADC and macro definitions for ADC
> channels and virtual channels (combination of ADC channel number and
> PMIC SID number) per PMIC, to be used by clients of this device.
>
> Changes since v2:
> - Moved ADC5 Gen3 documentation into a separate new file.
>
> Changes since v1:
> - Updated properties separately for all compatibles to clarify usage
> of new properties and updates in usage of old properties for ADC5 Gen3.
> - Avoided updating 'adc7' name to 'adc5 gen2' and just left a comment
> mentioning this convention.
> - Used predefined channel IDs in individual PMIC channel definitions
> instead of numeric IDs.
> - Addressed other comments from reviewers.
>
> Co-developed-by: Anjelique Melendez <quic_amelende@xxxxxxxxxxx>
> Signed-off-by: Anjelique Melendez <quic_amelende@xxxxxxxxxxx>
> Signed-off-by: Jishnu Prakash <quic_jprakash@xxxxxxxxxxx>
> ---
> .../bindings/iio/adc/qcom,spmi-adc5-gen3.yaml | 212 ++++++++++++++++++
> .../iio/adc/qcom,spmi-adc5-gen3-pm8550.h | 50 +++++
> .../iio/adc/qcom,spmi-adc5-gen3-pm8550b.h | 89 ++++++++
> .../iio/adc/qcom,spmi-adc5-gen3-pm8550vx.h | 22 ++
> .../iio/adc/qcom,spmi-adc5-gen3-pmk8550.h | 56 +++++
> .../iio/adc/qcom,spmi-adc7-pmr735b.h | 2 +-
> .../iio/adc/qcom,spmi-adc7-smb139x.h | 2 +-
> include/dt-bindings/iio/adc/qcom,spmi-vadc.h | 81 +++++++
> 8 files changed, 512 insertions(+), 2 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,spmi-adc5-gen3.yaml
> create mode 100644 include/dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550.h
> create mode 100644 include/dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550b.h
> create mode 100644 include/dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550vx.h
> create mode 100644 include/dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pmk8550.h
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-adc5-gen3.yaml b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-adc5-gen3.yaml
> new file mode 100644
> index 000000000000..ed5bb53e7628
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-adc5-gen3.yaml
> @@ -0,0 +1,212 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/qcom,spmi-adc5-gen3.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm's SPMI PMIC ADC5 Gen3
> +
> +maintainers:
> + - Jishnu Prakash <quic_jprakash@xxxxxxxxxxx>
> +
> +description: |
> + SPMI PMIC5 Gen3 voltage ADC (ADC) provides interface to
> + clients to read voltage. It is a 16-bit sigma-delta ADC.
> + It also performs the same thermal monitoring function as
> + the existing ADC_TM devices.
> +
> +properties:
> + compatible:
> + const: qcom,spmi-adc5-gen3
> +
> + reg:
> + description: |
> + - Each reg corresponds to an SDAM peripheral base address that is being used for ADC.
> +
> + '#address-cells':
> + const: 1
> +
> + '#size-cells':
> + const: 0
> +
> + "#thermal-sensor-cells":
> + const: 1
> + description:
> + Number of cells required to uniquely identify the thermal sensors. Since
> + we have multiple sensors this is set to 1. This property is required for
> + ADC devices with channels used for TM (thermal monitoring) functionality.
> +
> + '#io-channel-cells':
> + const: 1
> +
> + interrupts:
> + description: |
> + End of conversion interrupt. Interrupts are defined for each SDAM being used.
> +
> + interrupt-names:
> + minItems: 1
> + maxItems: 10
> + items:
> + pattern: "^adc-sdam[0-9]+$"
> + description: |
> + Names should be defined as "adc-sdam<N>" where <N> represents the SDAM index.
> +
> +required:
> + - compatible
> + - reg
> + - '#address-cells'
> + - '#size-cells'
> + - '#io-channel-cells'
> + - interrupts
> + - interrupt-names
> +
> +patternProperties:
> + "^channel@[0-9a-f]+$":
> + type: object
> + additionalProperties: false
> + description: |
> + Represents the external channels which are connected to the ADC.
> +
> + properties:
> + reg:
> + maxItems: 1
> + description: |
> + ADC channel number.
> + See include/dt-bindings/iio/adc/qcom,spmi-vadc.h
> + For PMIC5 Gen3 ADC, the channel numbers are specified separately
> + per PMIC in the PMIC-specific files in include/dt-bindings/iio/adc.
> +
> + label:
> + $ref: /schemas/types.yaml#/definitions/string
> + description: |
> + ADC input of the platform as seen in the schematics.
> + For thermistor inputs connected to generic AMUX or GPIO inputs
> + these can vary across platform for the same pins. Hence select
> + the platform schematics name for this channel.
> +
> + qcom,decimation:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: |
> + This parameter is used to decrease ADC sampling rate.
> + Quicker measurements can be made by reducing decimation ratio.
> + enum: [ 85, 340, 1360 ]
> + default: 1360
> +
> + qcom,pre-scaling:
> + description: |
> + Used for scaling the channel input signal before the signal is
> + fed to VADC. The configuration for this node is to know the
> + pre-determined ratio and use it for post scaling. It is a pair of
> + integers, denoting the numerator and denominator of the fraction by which
> + input signal is multiplied. For example, <1 3> indicates the signal is scaled
> + down to 1/3 of its value before ADC measurement.
> + If property is not found default value depending on chip will be used.
> + $ref: /schemas/types.yaml#/definitions/uint32-array
> + items:
> + - const: 1
> + - enum: [ 1, 3, 6, 16 ]
> +
> + qcom,ratiometric:
> + description: |
> + Channel calibration type.
> + - If this property is specified VADC will use the VDD reference (1.875V)
> + and GND for channel calibration. If property is not found, channel will be
> + calibrated with 0V and 1.25V reference channels, also known as
> + absolute calibration.
> + type: boolean
> +
> + qcom,hw-settle-time:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: |
> + Time between AMUX getting configured and the ADC starting
> + conversion. The 'hw_settle_time' is an index used from valid values
> + and programmed in hardware to achieve the hardware settling delay.
> + enum: [ 15, 100, 200, 300, 400, 500, 600, 700, 1000, 2000, 4000,
> + 8000, 16000, 32000, 64000, 128000 ]
> + default: 15
> +
> + qcom,avg-samples:
> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: |
> + Number of samples to be used for measurement.
> + Averaging provides the option to obtain a single measurement
> + from the ADC that is an average of multiple samples. The value
> + selected is 2^(value).
> + enum: [ 1, 2, 4, 8, 16 ]
> + default: 1
> +
> + qcom,adc-tm:
> + description: |
> + Indicates if ADC_TM monitoring is done on this channel.
> + Defined for compatible property "qcom,spmi-adc5-gen3".
> + This is the same functionality as in the existing QCOM ADC_TM
> + device, documented at devicetree/bindings/thermal/qcom-spmi-adc-tm5.yaml.
> + type: boolean
> +
> + required:
> + - reg
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pmk8550.h>
> + #include <dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550.h>
> + #include <dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550b.h>
> + #include <dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550vx.h>
> + #include <dt-bindings/interrupt-controller/irq.h>
> +
> + pmic {
> + #address-cells = <1>;
> + #size-cells = <0>;
> +
> + /* VADC node */
> + pmk8550_vadc: vadc@9000 {
> + compatible = "qcom,spmi-adc5-gen3";
> + reg = <0x9000>, <0x9100>;
> + interrupts = <0x0 0x90 0x1 IRQ_TYPE_EDGE_RISING>,
> + <0x0 0x91 0x1 IRQ_TYPE_EDGE_RISING>;
> + interrupt-names = "adc-sdam0", "adc-sdam1";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + #io-channel-cells = <1>;
> + #thermal-sensor-cells = <1>;
> +
> + /* PMK8550 Channel nodes */
> + channel@3 {
> + reg = <PMK8550_ADC5_GEN3_DIE_TEMP>;
> + label = "pmk8550_die_temp";
> + qcom,pre-scaling = <1 1>;
> + };
> +
> + channel@44 {
> + reg = <PMK8550_ADC5_GEN3_AMUX_THM1_XO_THERM_100K_PU>;
> + label = "pmk8550_xo_therm";
> + qcom,pre-scaling = <1 1>;
> + qcom,ratiometric;
> + qcom,hw-settle-time = <200>;
> + qcom,adc-tm;
> + };
> +
> + /* PM8550 Channel nodes */
> + channel@103 {
> + reg = <PM8550_ADC5_GEN3_DIE_TEMP>;
> + label = "pm8550_die_temp";
> + qcom,pre-scaling = <1 1>;
> + };
> +
> + /* PM8550B Channel nodes */
> + channel@78f {
> + reg = <PM8550B_ADC5_GEN3_VBAT_SNS_QBG>;
> + label = "pm8550b_vbat_sns_qbg";
> + qcom,pre-scaling = <1 3>;
> + };
> +
> + /* PM8550VS_C Channel nodes */
> + channel@203 {
> + reg = <PM8550VS_ADC5_GEN3_DIE_TEMP(2)>;
> + label = "pm8550vs_c_die_temp";
> + qcom,pre-scaling = <1 1>;
> + };
> + };
> + };
> diff --git a/include/dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550.h b/include/dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550.h
> new file mode 100644
> index 000000000000..0f25ef87ed5c
> --- /dev/null
> +++ b/include/dt-bindings/iio/adc/qcom,spmi-adc5-gen3-pm8550.h
> @@ -0,0 +1,50 @@
> +/* SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) */
> +/*
> + * Copyright (c) 2023, Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#ifndef _DT_BINDINGS_QCOM_SPMI_VADC_PM8550_H
> +#define _DT_BINDINGS_QCOM_SPMI_VADC_PM8550_H
> +
> +#ifndef PM8550_SID
> +#define PM8550_SID 1
> +#endif

Please drop these defaults.
We should drop them from the existing binding files too...

> +
> +#include <dt-bindings/iio/adc/qcom,spmi-vadc.h>
>

--
With best wishes
Dmitry