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Subject: Re: [Linux-stm32] [PATCH 3/3] ARM: dts: stm32: update stm32mp151 for
 remote proc synchronisation support
To:     Ahmad Fatoum <a.fatoum@pengutronix.de>,
        Rob Herring <robh@kernel.org>,
        Alexandre TORGUE <alexandre.torgue@st.com>
CC:     Ohad Ben-Cohen <ohad@wizery.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        "linux-remoteproc@vger.kernel.org" <linux-remoteproc@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Fabien DESSENNE <fabien.dessenne@st.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        "linux-stm32@st-md-mailman.stormreply.com" 
        <linux-stm32@st-md-mailman.stormreply.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
References: <20200827072101.26588-1-arnaud.pouliquen@st.com>
 <20200827072101.26588-4-arnaud.pouliquen@st.com>
 <be888a4b-b931-521b-42c7-fd4e60afd945@pengutronix.de>
From:   Arnaud POULIQUEN <arnaud.pouliquen@st.com>
Message-ID: <c8fbe2df-a648-913a-d9f9-19e2202f1687@st.com>
Date:   Thu, 24 Sep 2020 10:02:42 +0200
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Hi Ahmad,

On 9/24/20 7:45 AM, Ahmad Fatoum wrote:
> Hello Arnaud,
> 
> On 8/27/20 9:21 AM, Arnaud Pouliquen wrote:
>> Two backup registers are used to store the Cortex-M4 state and the resource
>> table address.
>> Declare the tamp node and add associated properties in m4_rproc node
>> to allow Linux to attach to a firmware loaded by the first boot stages.
>>
>> Associated driver implementation is available in commit 9276536f455b3
>> ("remoteproc: stm32: Parse syscon that will manage M4 synchronisation").
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
>> ---
>>  arch/arm/boot/dts/stm32mp151.dtsi | 7 +++++++
>>  1 file changed, 7 insertions(+)
>>
>> diff --git a/arch/arm/boot/dts/stm32mp151.dtsi b/arch/arm/boot/dts/stm32mp151.dtsi
>> index bfe29023fbd5..842ecffae73a 100644
>> --- a/arch/arm/boot/dts/stm32mp151.dtsi
>> +++ b/arch/arm/boot/dts/stm32mp151.dtsi
>> @@ -1541,6 +1541,11 @@
>>  			status = "disabled";
>>  		};
>>  
>> +		tamp: tamp@5c00a000 {
>> +			compatible = "st,stm32-tamp", "syscon";
>> +			reg = <0x5c00a000 0x400>;
>> +		};
>> +
> 
> Just saw this now. I have a pending patch adding this node as well:
> https://lore.kernel.org/patchwork/patch/1306971/
> 
> For my use case, I need a "simple-mfd" compatible to allow child
> nodes to be probed.
> 
> Could you CC me when you send out your v2, so I can rebase?
> (Or if you don't mind, just add the "simple-mfd" into the compatible
> list yourself :-)

I prefer that you propose the "simple-mfd" compatibility. I do not master the
consequence of adding it...
I will add you in cc of my v2 , but as your patch could trig some discussions
I would suggest to send in advance a patchset including this patch and your patch
on top of, just add a reference to this series in the cover letter and explain
potential impact (or non impact) on the legacy.

Regards,
Arnaud
 
> 
> Cheers
> Ahmad
> 
>>  		/*
>>  		 * Break node order to solve dependency probe issue between
>>  		 * pinctrl and exti.
>> @@ -1717,6 +1722,8 @@
>>  			st,syscfg-holdboot = <&rcc 0x10C 0x1>;
>>  			st,syscfg-tz = <&rcc 0x000 0x1>;
>>  			st,syscfg-pdds = <&pwr_mcu 0x0 0x1>;
>> +			st,syscfg-rsc-tbl = <&tamp 0x144 0xFFFFFFFF>;
>> +			st,syscfg-m4-state = <&tamp 0x148 0xFFFFFFFF>;
>>  			status = "disabled";
>>  		};
>>  	};
>>
>