Date:   Wed, 13 Feb 2019 15:38:40 -0800
From:   Angus Ainslie <angus@...ea.ca>
To:     Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
Cc:     mazziesaccount@...il.com, Lee Jones <lee.jones@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, heikki.haikola@...rohmeurope.com,
        mikko.mutanen@...rohmeurope.com,
        Robin Gong ‎ <yibin.gong@....com>,
        Elven Wang ‎ 
        <elven.wang@....com>,
        Anson Huang ‎ 
        <anson.huang@....com>, linux-kernel-owner@...r.kernel.org
Subject: Re: [PATCH v2 1/3] devicetree: bindings: bd718x7: document HW state  related ROHM specific properties

Hi Matti,

On 2019-02-13 01:50, Matti Vaittinen wrote:
> Add ROHM BD71837 / BD71847 specific device tree bindings for
> controlling the PMIC shutdown/reset states and voltages for
> different HW states. The PMIC was designed to be used with NXP
> i.MX8 SoC and it supports SNVS low power state which seems to
> be typical for NXP i.MX SoCs. However, when SNVS is used we must
> not allow SW to control enabling/disabling those regulators which
> are crucial for system to boot as there is a HW limitation which
> causes SW controlled regulators to be kept shut down after SNVS
> reset.
> 
> Allow setting the SNVS to be used as reset target state and allow
> marking those regulators which are critical for boot.
> 
> Signed-off-by: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>
> ---
>  .../devicetree/bindings/mfd/rohm,bd71837-pmic.txt  | 15 +++++++++++
>  .../bindings/regulator/rohm,bd71837-regulator.txt  | 30 
> ++++++++++++++++++++++
>  2 files changed, 45 insertions(+)
> 
> diff --git
> a/Documentation/devicetree/bindings/mfd/rohm,bd71837-pmic.txt
> b/Documentation/devicetree/bindings/mfd/rohm,bd71837-pmic.txt
> index a4b056761eaa..f07c32975315 100644
> --- a/Documentation/devicetree/bindings/mfd/rohm,bd71837-pmic.txt
> +++ b/Documentation/devicetree/bindings/mfd/rohm,bd71837-pmic.txt
> @@ -23,6 +23,21 @@ Required properties:
> 
>  Optional properties:
>  - clock-output-names	: Should contain name for output clock.
> +- rohm,reset-snvs-powered : Transfer BD718x7 to SNVS state at reset.
> +
> +The BD718x7 supports two different HW states as reset target states. 
> States
> +are called as SNVS and READY. At READY state all the PMIC power 
> outputs go
> +down and OTP is reload. At the SNVS state all other logic and external
> +devices apart from the SNVS power domain are shut off. Please refer to 
> NXP
> +i.MX8 documentation for further information regarding SNVS state. When 
> a
> +reset is done via SNVS state the PMIC OTP data is not reload. This 
> cause
> +

It looks like there is some text missing here.

> +There is a HW quirk in BD718x7 which causes power outputs that have 
> been
> +under SW control to stay down when reset has switched power state to 
> SNVS.
> +If reset is done via READY state the power outputs will be set to HW 
> control
> +by OTP loading. Thus the reset target state is set to READY by 
> default. If
> +SNVS state is used the boot crucial regulators must have the
> +regulator-always-on and regulator-boot-on properties set in regulator 
> node.
> 
>  Example:
> 
> diff --git
> a/Documentation/devicetree/bindings/regulator/rohm,bd71837-regulator.txt
> b/Documentation/devicetree/bindings/regulator/rohm,bd71837-regulator.txt
> index 4b98ca26e61a..4a05cbf915ee 100644
> --- 
> a/Documentation/devicetree/bindings/regulator/rohm,bd71837-regulator.txt
> +++ 
> b/Documentation/devicetree/bindings/regulator/rohm,bd71837-regulator.txt
> @@ -27,8 +27,38 @@ BUCK1, BUCK2, BUCK3, BUCK4, BUCK5, BUCK6
>  LDO1, LDO2, LDO3, LDO4, LDO5, LDO6
> 
>  Optional properties:
> +- rohm,dvs-run-voltage		: PMIC default "RUN" state voltage in uV.
> +				  See below table for bucks which support this.
> +- rohm,dvs-idle-voltage		: PMIC default "IDLE" state voltage in uV.
> +				  See below table for bucks which support this.
> +- rohm,dvs-suspend-voltage	: PMIC default "SUSPEND" state voltage in 
> uV.
> +				  See below table for bucks which support this.
>  - Any optional property defined in bindings/regulator/regulator.txt
> 
> +Supported default DVS states:
> +
> +BD71837:
> +buck	| dvs-run-voltage	| dvs-idle-voltage	| dvs-suspend-voltage
> +-----------------------------------------------------------------------------
> +1	| supported		| supported		| supported
> +----------------------------------------------------------------------------
> +2	| supported		| supported		| not supported
> +----------------------------------------------------------------------------
> +3	| supported		| not supported		| not supported
> +----------------------------------------------------------------------------
> +4	| supported		| not supported		| not supported
> +----------------------------------------------------------------------------
> +rest	| not supported		| not supported		| not supported
> +
> +BD71847:
> +buck	| dvs-run-voltage	| dvs-idle-voltage	| dvs-suspend-voltage
> +-----------------------------------------------------------------------------
> +1	| supported		| supported		| supported
> +----------------------------------------------------------------------------
> +2	| supported		| supported		| not supported
> +----------------------------------------------------------------------------
> +rest	| not supported		| not supported		| not supported
> +
>  Example:

Could you add an example of the optional properties ?

Thanks
Angus

>  regulators {
>  	buck1: BUCK1 {
> --
> 2.14.3

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