From: Lars Povlsen <lars.povlsen@microchip.com>
To: Rob Herring <robh@kernel.org>
Cc: Lars Povlsen <lars.povlsen@microchip.com>,
Sebastian Reichel <sre@kernel.org>, SoC Team <soc@kernel.org>,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
Microchip Linux Driver Support <UNGLinuxDriver@microchip.com>,
<linux-pm@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 3/5] dt-bindings: reset: ocelot: Add documentation for 'microchip,reset-switch-core' property
Date: Tue, 2 Jun 2020 11:49:08 +0200 [thread overview]
Message-ID: <87wo4piyqz.fsf@soft-dev15.microsemi.net> (raw)
In-Reply-To: <20200528022502.GA3234572@bogus>
Rob Herring writes:
> On Wed, May 13, 2020 at 03:08:40PM +0200, Lars Povlsen wrote:
>> This documents the 'microchip,reset-switch-core' property in the
>> ocelot-reset driver.
>>
>> Signed-off-by: Lars Povlsen <lars.povlsen@microchip.com>
>> ---
>> .../devicetree/bindings/power/reset/ocelot-reset.txt | 6 ++++++
>> 1 file changed, 6 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/power/reset/ocelot-reset.txt b/Documentation/devicetree/bindings/power/reset/ocelot-reset.txt
>> index 4d530d8154848..20fff03753ad2 100644
>> --- a/Documentation/devicetree/bindings/power/reset/ocelot-reset.txt
>> +++ b/Documentation/devicetree/bindings/power/reset/ocelot-reset.txt
>> @@ -9,9 +9,15 @@ microchip Sparx5 armv8 SoC's.
>> Required Properties:
>> - compatible: "mscc,ocelot-chip-reset" or "microchip,sparx5-chip-reset"
>>
>> +Optional properties:
>> +- microchip,reset-switch-core : Perform a switch core reset at the
>> + time of driver load. This is may be used to initialize the switch
>> + core to a known state (before other drivers are loaded).
>
> How do you know when other drivers are loaded? This could be a module
> perhaps. Doesn't seem like something that belongs in DT.
>
The reset driver is loaded at postcore_initcall() time, which ensures it
is loaded before other drivers using the switch core. I noticed other
drivers do the same to do low-level system reset and initialization at
early boot time.
> Can this behavior be implied with "microchip,sparx5-chip-reset"?
Since we need to cater for both modus operandi, I would need two driver
compatible strings per platform, which scales worse than a single
property.
The "microchip,reset-switch-core" is a device configuration property
which tells the system (driver) how the hw should be handled. Since you
do not *always* want to reset the switch core (f.ex. when implementing
systems with warm reboot), I think it makes perfect sense - but I may be
biased off course :-)
Thank you for (all) of your comments, by the way!
---Lars
>
> Rob
--
Lars Povlsen,
Microchip
next prev parent reply other threads:[~2020-06-02 9:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 13:08 [PATCH 0/5] power: Adding support for Microchip Sparx5 SoC Lars Povlsen
2020-05-13 13:08 ` [PATCH 1/5] dt-bindings: reset: ocelot: Add Sparx5 support Lars Povlsen
2020-05-13 13:08 ` [PATCH 2/5] power: reset: ocelot: Add support for Sparx5 Lars Povlsen
2020-05-13 13:08 ` [PATCH 3/5] dt-bindings: reset: ocelot: Add documentation for 'microchip,reset-switch-core' property Lars Povlsen
2020-05-28 2:25 ` Rob Herring
2020-06-02 9:49 ` Lars Povlsen [this message]
[not found] ` <20200828163916.g6vbk3anfyijl7sx@earth.universe>
2020-08-31 8:19 ` Lars Povlsen
2020-09-16 8:00 ` Lars Povlsen
2020-09-29 22:04 ` Sebastian Reichel
2020-05-13 13:08 ` [PATCH 4/5] power: reset: ocelot: Add support for reset switch on load time Lars Povlsen
2020-05-13 13:08 ` [PATCH 5/5] arm64: dts: sparx5: Add reset support Lars Povlsen
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