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Date:   Wed, 26 Jul 2023 11:33:15 +0200
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Subject: Re: [PATCH 4/4] ARM: multi_v7_defconfig: Add SCMI regulator support
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        <p.paillet@foss.st.com>, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Maxime Coquelin <mcoquelin.stm32@gmail.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        Russell King <linux@armlinux.org.uk>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        Claudiu Beznea <claudiu.beznea@microchip.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Fabrice Gasnier <fabrice.gasnier@foss.st.com>,
        Alexander Stein <alexander.stein@ew.tq-group.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        <devicetree@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>
CC:     Etienne Carriere <etienne.carriere@foss.st.com>
References: <20230712142432.1885162-1-p.paillet@foss.st.com>
 <20230712142432.1885162-5-p.paillet@foss.st.com>
 <aa05bcd6-140d-d951-2c7f-c09abf7f49f7@linaro.org>
From:   Patrick DELAUNAY <patrick.delaunay@foss.st.com>
In-Reply-To: <aa05bcd6-140d-d951-2c7f-c09abf7f49f7@linaro.org>
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Hi,

On 7/12/23 21:25, Krzysztof Kozlowski wrote:
> On 12/07/2023 16:24, p.paillet@foss.st.com wrote:
>> From: Pascal Paillet <p.paillet@foss.st.com>
>>
>> Enable ARM SCMI regulator support.
>>
> This we see from the diff. Please explain why, e.g. which boards use it.
>
> Best regards,
> Krzysztof


The STM32MP platforms rely on OP-TEE to boot: Clocks and regulators are 
handled in
the secure world by OP-TEE and exported to the non secure world (LINUX)
thanks to ARM SCMI protocol.

Today it is used in the ARMv7 STMicrolectronics stm32mp boards:
- for STM32MP13: stm32mp135f-dk
- the STM32MP15 boards with SCMI variant, introduced by commit 5b7e58313a77
   ("ARM: dts: stm32: Add SCMI version of STM32 boards (DK1/DK2/ED1/EV1)")
   * stm32mp157c-ev1-scmi
   * stm32mp157c-ed1-scmi
   * stm32mp157c-dk2-scmi
   * stm32mp157a-dk1-scmi

This SCMI server provide access to "secured" resources protected in SoC
(for example with RCC_SECFGR); the resources need to be available early
for these board and the  SCMI server is associated with OP-TEE, already
activated by the commit 24c159793238  ("ARM: multi_v7_defconfig: Add
OPTEE support").

Regards

Patrick

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