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Subject: Re: [PATCH v3 6/8] ARM: dts: rtd1195: Add reset nodes
To:     James Tai <james.tai@realtek.com>
Cc:     "linux-realtek-soc@lists.infradead.org" 
        <linux-realtek-soc@lists.infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        Philipp Zabel <p.zabel@pengutronix.de>
References: <20191117072109.20402-1-afaerber@suse.de>
 <20191117072109.20402-7-afaerber@suse.de>
 <20b3d0956bed4338a540216df07f16e5@realtek.com>
From:   =?UTF-8?Q?Andreas_F=c3=a4rber?= <afaerber@suse.de>
Organization: SUSE Software Solutions Germany GmbH
Message-ID: <ed7c483d-b518-c74f-f66d-a812d0858f4c@suse.de>
Date:   Tue, 19 Nov 2019 09:34:46 +0100
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Hi James,

Adding Philipp.

Am 18.11.19 um 10:22 schrieb James Tai:
>> +			reset1: reset-controller@0 {
>> +				compatible = "snps,dw-low-reset";
>> +				reg = <0x0 0x4>;
>> +				#reset-cells = <1>;
>> +			};
>> +
>> +			reset2: reset-controller@4 {
>> +				compatible = "snps,dw-low-reset";
>> +				reg = <0x4 0x4>;
>> +				#reset-cells = <1>;
>> +			};
>> +
>> +			reset3: reset-controller@8 {
>> +				compatible = "snps,dw-low-reset";
>> +				reg = <0x8 0x4>;
>> +				#reset-cells = <1>;
>> +			};
>> +
>> +			iso_reset: reset-controller@7088 {
>> +				compatible = "snps,dw-low-reset";
>> +				reg = <0x7088 0x4>;
>> +				#reset-cells = <1>;
>> +			};
>> +
> 
> We don't use the DesignWare IP for the reset controller.

Thanks for reviewing.

We already merged the equivalent nodes for RTD129x into arm-soc.git.
No Realtek review was received back when it was posted [1], sadly.

How does your reset controller differ from DesignWare, and how would you
prefer to handle it?

a) Do you want to send patches for a new Realtek-specific dt-binding [2]
and extend reset-simple driver to cover it as a copy&paste of the
DesignWare of_device_id?

b) Do you believe you need to submit a completely new reset driver?

An issue I had raised twice [4, 1] was that reset-simple only allows for
contiguous registers and thus couldn't handle the gap between reset3 and
reset4 on RTD1295, forcing me to use per-register nodes for consistency.
I am against modeling RTD1195 differently from RTD1295+, assuming
they're the equivalent IP, so we need a solution that works for both.
Philipp did indicate in [4] we could extend reset-simple for this gap
"if the implementation could be kept reasonably simple".

With v5.4-rc8 already tagged, please hurry if you want a different
binding in v5.5.

Regards,
Andreas

[1] https://patchwork.kernel.org/cover/11206255/
[2] https://patchwork.kernel.org/patch/9902665/
[3] https://patchwork.kernel.org/patch/9902673/
[4] https://patchwork.kernel.org/patch/9902675/
[5] https://patchwork.kernel.org/patch/9902671/
[6] https://patchwork.kernel.org/patch/9902663/

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