From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
To: Alban <albeu@free.fr>
Cc: linux-kernel@vger.kernel.org, Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
David Woodhouse <dwmw2@infradead.org>,
Brian Norris <computersforpeace@gmail.com>,
Boris Brezillon <boris.brezillon@free-electrons.com>,
Marek Vasut <marek.vasut@gmail.com>,
Richard Weinberger <richard@nod.at>,
Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
devicetree@vger.kernel.org, linux-mtd@lists.infradead.org
Subject: Re: [PATCH v3 1/3] nvmem: Update the OF binding to use a subnode for the cells list
Date: Wed, 18 Apr 2018 13:12:48 +0100 [thread overview]
Message-ID: <9f7d2987-b33e-79b5-ae58-2985fd7334e4@linaro.org> (raw)
In-Reply-To: <20180418134119.2e587621@avionic-0020>
On 18/04/18 12:41, Alban wrote:
> On Tue, 17 Apr 2018 18:00:40 +0200
> Alban <albeu@free.fr> wrote:
>
>> On Tue, 17 Apr 2018 16:44:01 +0100
>> Srinivas Kandagatla <srinivas.kandagatla@linaro.org> wrote:
>>
>>> Thanks for explaining,
>>>
>>> On 17/04/18 15:54, Alban wrote:
>>>> This will not only allow reading the calibration data from nvmem, but
>>>> will also create a partition on the MTD device, which is not acceptable.
>>>> With my proposed binding this would become:
>>>>
>>>> flash@0 {
>>>> #address-cells = <1>;
>>>> #size-cells = <1>;
>>>> compatible = "s25sl064a";
>>>> reg = <0>;
>>>>
>>>> nvmem-cells {
>>>> compatible = "nvmem-cells";
>>>> #address-cells = <1>;
>>>> #address-cells = <1>;
>>>>
>>>> calibration: calib@404 {
>>>> reg = <0x404 0x10>;
>>>> };
>>>> };
>>>
>>> Why can't we make nvmem-cells node a nvmem provider in this case?
>>> Which should work!
>>
>> TBH I just copied what have been done to fix the same problem with the
>> MTD partitions. But yes we could also just extend the current binding
>> to require a compatible string on each nvmem-cell, which would not
>> require any code change to support.
>
> However this scheme will not work if the device node binding already
> have subnodes with addresses. The addressing, as specified by
> #address-cells and #size-cells, might be incompatible or might overlap.
> Using the nvmem-cells subnode solve this problem.
>
I was also suggesting you to use nvmem-cell subnode, but make it a
proper nvmem provider device, rather than reusing its parent device.
You would end up some thing like this in dt.
flash@0 {
#address-cells = <1>;
#size-cells = <1>;
compatible = "s25sl064a";
reg = <0>;
nvmem-cells {
compatible = "mtd-nvmem";
#address-cells = <1>;
#size-cells = <1>;
calibration: calib@404 {
reg = <0x404 0x10>;
};
};
};
--srini
> Alban
>
next prev parent reply other threads:[~2018-04-18 12:12 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-24 23:24 [PATCH v3 0/3] mtd: Add support for reading MTD devices via the nvmem API Alban Bedel
2018-03-24 23:24 ` [PATCH v3 1/3] nvmem: Update the OF binding to use a subnode for the cells list Alban Bedel
2018-04-16 21:04 ` Rob Herring
2018-04-17 12:31 ` Alban
2018-04-17 12:54 ` Srinivas Kandagatla
2018-04-17 14:54 ` Alban
2018-04-17 15:44 ` Srinivas Kandagatla
2018-04-17 16:00 ` Alban
2018-04-18 11:41 ` Alban
2018-04-18 12:12 ` Srinivas Kandagatla [this message]
2018-04-18 12:32 ` Alban
2018-04-18 12:53 ` Srinivas Kandagatla
2018-04-18 13:34 ` Alban
2018-05-01 16:49 ` Srinivas Kandagatla
2018-06-07 16:41 ` Alban
2018-06-07 17:03 ` Srinivas Kandagatla
2018-06-08 10:59 ` Alban
2018-06-08 11:34 ` Srinivas Kandagatla
2018-06-08 17:07 ` Alban
2018-06-10 10:32 ` Srinivas Kandagatla
2018-06-10 11:36 ` Alban
2018-06-10 13:28 ` Srinivas Kandagatla
2018-03-24 23:24 ` [PATCH v3 2/3] doc: bindings: Add bindings documentation for mtd nvmem Alban Bedel
2018-04-16 21:08 ` Rob Herring
2018-04-17 12:44 ` Alban
2018-03-24 23:24 ` [PATCH v3 3/3] mtd: Add support for reading MTD devices via the nvmem API Alban Bedel
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