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Subject: Re: [PATCH 05/11] ARM: dts: Reflect change of FSL QSPI driver and
 remove unused properties
To:     Boris Brezillon <boris.brezillon@bootlin.com>
Cc:     linux-mtd@lists.infradead.org, linux-spi@vger.kernel.org,
        dwmw2@infradead.org, computersforpeace@gmail.com,
        marek.vasut@gmail.com, richard@nod.at, miquel.raynal@bootlin.com,
        broonie@kernel.org, david.wolfe@nxp.com, fabio.estevam@nxp.com,
        prabhakar.kushwaha@nxp.com, yogeshnarayan.gaur@nxp.com,
        han.xu@nxp.com, Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Pengutronix Kernel Team <kernel@pengutronix.de>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <1527686082-15142-1-git-send-email-frieder.schrempf@exceet.de>
 <1527686082-15142-6-git-send-email-frieder.schrempf@exceet.de>
 <20180530171057.39f1a2be@bbrezillon>
From:   Frieder Schrempf <frieder.schrempf@exceet.de>
Message-ID: <d6512adf-2d48-5bdc-d793-a7c1fcabc177@exceet.de>
Date:   Fri, 1 Jun 2018 11:27:13 +0200
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Hi Boris,

On 30.05.2018 17:10, Boris Brezillon wrote:
> On Wed, 30 May 2018 15:14:34 +0200
> Frieder Schrempf <frieder.schrempf@exceet.de> wrote:
> 
>> The FSL QSPI driver was moved to the SPI framework and it now
>> acts as a SPI controller. Therefore the subnodes need to set
>> spi-[rx/tx]-bus-width = <4>, so quad mode is used just as before.
> 
> We should try to keep the current behavior even when
> spi-[rx/tx]-bus-width are not defined. How about considering
> spi-[rx/tx]-bus-width as board constraints and then let the core pick
> the best mode based on these constraints plus the SPI NOR chip
> limitations.

Ok, I'll try to adjust this, so we can leave spi-[rx/tx]-bus-width 
undefined and still get quad mode as default if possible.

> 
>>
>> Also the properties 'bus-num', 'fsl,spi-num-chipselects' and
>> 'fsl,spi-flash-chipselects' were never read by the driver and
>> can be removed.
>>
>> The 'reg' properties are adjusted to reflect the what bus and
>> chipselect the flash is connected to, as the new driver needs
>> this information.
>>
>> The property 'fsl,qspi-has-second-chip' is not needed anymore
>> and will be removed after the old driver was disabled to avoid
>> breaking ls1021a-moxa-uc-8410a.dts.
>>
>> Signed-off-by: Frieder Schrempf <frieder.schrempf@exceet.de>
>> ---
>>   arch/arm/boot/dts/imx6sx-sdb-reva.dts       | 8 ++++++--
>>   arch/arm/boot/dts/imx6sx-sdb.dts            | 8 ++++++--
>>   arch/arm/boot/dts/imx6ul-14x14-evk.dtsi     | 2 ++
>>   arch/arm/boot/dts/ls1021a-moxa-uc-8410a.dts | 5 ++---
>>   4 files changed, 16 insertions(+), 7 deletions(-)
>>
>> diff --git a/arch/arm/boot/dts/imx6sx-sdb-reva.dts b/arch/arm/boot/dts/imx6sx-sdb-reva.dts
>> index e3533e7..1a6f680 100644
>> --- a/arch/arm/boot/dts/imx6sx-sdb-reva.dts
>> +++ b/arch/arm/boot/dts/imx6sx-sdb-reva.dts
>> @@ -131,13 +131,17 @@
>>   		#size-cells = <1>;
>>   		compatible = "spansion,s25fl128s", "jedec,spi-nor";
>>   		spi-max-frequency = <66000000>;
>> +		spi-rx-bus-width = <4>;
>> +		spi-tx-bus-width = <4>;
>>   	};
>>   
>> -	flash1: s25fl128s@1 {
>> -		reg = <1>;
>> +	flash1: s25fl128s@2 {
>> +		reg = <2>;
> 
> Hm, you're breaking backward compat here. Can we try to re-use the
> old numbering scheme instead of patching all DTs?

Unfortunately in the current setup, the definitions for the reg property 
are already broken.

For example imx6sx-sdb.dts seems to have one chip connected on bus A, 
CS0 and one on bus B, CS0. It has reg set to 0 for the first and 1 for 
the second chip.

While fsl-ls208xa-qds.dtsi uses the same hw setup, but has reg set to 0 
and 2.

So either way we need to change the reg property at some place.
So the best approach in my opinion is to fix the definitions to use a 
single scheme and while at it also remove the fsl,qspi-has-second-chip 
property, that is not needed if a single consistent scheme for the reg 
properties is used.

Regards,

Frieder