linux-kernel - Re: [PATCH v2 04/15] dt-bindings: mfd: ROHM BD72720

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Message-ID: <c28bbb75-36b0-4776-b81c-c5dc2dd5ae28@gmail.com>
Date: Wed, 29 Oct 2025 14:22:30 +0200
From: Matti Vaittinen <mazziesaccount@...il.com>
To: Rob Herring <robh@...nel.org>
Cc: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>,
 Lee Jones <lee@...nel.org>, Pavel Machek <pavel@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Sebastian Reichel <sre@...nel.org>,
 Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>,
 Michael Turquette <mturquette@...libre.com>, Stephen Boyd
 <sboyd@...nel.org>, Linus Walleij <linus.walleij@...aro.org>,
 Bartosz Golaszewski <brgl@...ev.pl>, Andreas Kemnade <andreas@...nade.info>,
 Alexandre Belloni <alexandre.belloni@...tlin.com>,
 linux-leds@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
 linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
 linux-rtc@...r.kernel.org
Subject: Re: [PATCH v2 04/15] dt-bindings: mfd: ROHM BD72720

On 27/10/2025 23:13, Rob Herring wrote:
> On Mon, Oct 27, 2025 at 01:45:46PM +0200, Matti Vaittinen wrote:
>> The ROHM BD72720 is a power management IC integrating regulators, GPIOs,
>> charger, LEDs, RTC and a clock gate.
>>
>> Add dt-binding doc for ROHM BD72720.
>>
>> Signed-off-by: Matti Vaittinen <mazziesaccount@...il.com>
>>
>> ---
>> Revision history:
>>   RFCv1 => v2:
>>   - Typofixes
>> ---
>>   .../bindings/mfd/rohm,bd72720-pmic.yaml       | 269 ++++++++++++++++++
>>   1 file changed, 269 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/mfd/rohm,bd72720-pmic.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/mfd/rohm,bd72720-pmic.yaml b/Documentation/devicetree/bindings/mfd/rohm,bd72720-pmic.yaml
>> new file mode 100644
>> index 000000000000..b0d4bc01d199
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mfd/rohm,bd72720-pmic.yaml
>> @@ -0,0 +1,269 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/mfd/rohm,bd72720-pmic.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: ROHM BD72720 Power Management Integrated Circuit
>> +
>> +maintainers:
>> +  - Matti Vaittinen <mazziesaccount@...il.com>
>> +
>> +description: |
>> +  BD72720 is a single-chip power management IC for battery-powered portable
>> +  devices. The BD72720 integrates 10 bucks and 11 LDOs, and a 3000 mA
>> +  switching charger. The IC also includes a Coulomb counter, a real-time
>> +  clock (RTC), GPIOs and a 32.768 kHz clock gate.
>> +
>> +# In addition to the properties found from the charger node, the ROHM BD72720
>> +# uses properties from a static battery node. Please see the:
>> +# Documentation/devicetree/bindings/power/supply/rohm,vdr-battery.yaml
> 
> Why is all of this a comment?

Hi Rob,

Thanks for (all the) reviews! Much appreciated.

I added these as comments because they aren't meant to be in the BD72720 
charger-node (which is described by this driver), but in a static 
battery node. The battery node does not belong in the charger node.

My idea was still to document (for integrator) the battery properties 
this charger uses from a static battery node when present. Only thing we 
include directly to this node is the:
monitored-battery = <&battery>; - reference.

> 
>> +#
>> +# Following properties are used
>> +# when present:
>> +#
>> +# charge-full-design-microamp-hours: Battry capacity in mAh
>> +# voltage-max-design-microvolt:      Maximum voltage
>> +# voltage-min-design-microvolt:      Minimum voltage system is still operating.
>> +# degrade-cycle-microamp-hours:      Capacity lost due to aging at each full
>> +#                                    charge cycle.
>> +# ocv-capacity-celsius:              Array of OCV table temperatures. 1/table.
>> +# ocv-capacity-table-<N>:            Table of OCV voltage/SOC pairs. Corresponds
>> +#                                    N.th temperature in ocv-capacity-celsius
>> +#
>> +# ROHM specific properties:
>> +# rohm,voltage-vdr-thresh-microvolt: Threshold for starting the VDR correction
>> +# rohm,volt-drop-soc:                Table of capacity values matching the
>> +#                                    values in VDR tables.
>> +# rohm,volt-drop-high-temp-microvolt: VDR table for high temperature
>> +# rohm,volt-drop-normal-temp-microvolt: VDR table for normal temperature
>> +# rohm,volt-drop-low-temp-microvolt:  VDR table for low temperature
>> +# rohm,volt-drop-very-low-temp-microvolt: VDR table for very low temperature
>> +#
>> +# VDR tables are (usually) determined for a specific battery by ROHM.
>> +# The battery node would then be referred from the charger node:
>> +#
>> +# monitored-battery = <&battery>;
>> +
>> +properties:
>> +  compatible:
>> +    const: rohm,bd72720
>> +
>> +  reg:
>> +    description:
>> +      I2C slave address.
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
>> +  gpio-controller: true
>> +
>> +  "#gpio-cells":
>> +    const: 2
>> +    description: |

// snip

>> +
>> +  rohm,pin-dvs0:
>> +    $ref: /schemas/types.yaml#/definitions/string
>> +    description:
>> +      BD72720 has 4 different OTP options to determine the use of dvs0-pin.
>> +      OTP0 - regulator RUN state control.
>> +      OTP1 - GPI.
>> +      OTP2 - GPO.
>> +      OTP3 - Power sequencer output.
>> +      This property specifies the use of the pin.
>> +    enum:
>> +      - dvs-input
>> +      - gpi
>> +      - gpo
>> +
>> +  rohm,pin-dvs1:
>> +    $ref: /schemas/types.yaml#/definitions/string
>> +    description:
>> +      see rohm,pin-dvs0
>> +    enum:
>> +      - dvs-input
>> +      - gpi
>> +      - gpo
> 
> These 2 could be combined into a single entry in patternProperties.
> 
>> +
>> +  rohm,pin-exten0:
>> +    $ref: /schemas/types.yaml#/definitions/string
>> +    description: BD72720 has an OTP option to use exten0-pin for different
>> +      purposes. Set this property accordingly.
>> +    const: gpo
>> +
>> +  rohm,pin-exten1:
>> +    $ref: /schemas/types.yaml#/definitions/string
>> +    description: BD72720 has an OTP option to use exten1-pin for different
>> +      purposes. Set this property accordingly.
>> +    const: gpo
> 
> And these 2 also.
> 
>> +
>> +  rohm,pin-fault_b:
>> +    $ref: /schemas/types.yaml#/definitions/string
>> +    description: BD72720 has an OTP option to use fault_b-pin for different
>> +      purposes. Set this property accordingly.
>> +    const: gpo
> 
> Seems like different purposes would have more than 1 option.

They do. I only omitted them because I don't think knowing those 
use-cases is relevant for the software. OTOH, maybe they some day can be 
so I will revise the other uses and make more complete list. Thanks.

> 
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - interrupts
>> +  - clocks
>> +  - "#clock-cells"
>> +  - regulators
>> +  - gpio-controller
>> +  - "#gpio-cells"
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/interrupt-controller/irq.h>
>> +    #include <dt-bindings/leds/common.h>
>> +    i2c {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +        pmic: pmic@4b {
>> +            compatible = "rohm,bd71828";
>> +            reg = <0x4b>;
> 
> Just 1 complete example in the mfd schema and drop this example.

Hmm? This is the MFD schema, right? :)

Yours,
	-- Matti