Subject: Re: [PATCH v2] ARM: zynq: Add #io-channel-cells to (x)adc node for
 iio-hwmon
To: Moritz Fischer <moritz.fischer.private@gmail.com>,
        Michal Simek <michal.simek@xilinx.com>
References: <1489003884-2489-1-git-send-email-mdf@kernel.org>
 <e6da3f38-7039-66e5-5b9d-a44ff42aa9c9@xilinx.com>
 <CAJYdmeNc48=OOvRiUjqPBJhz9RCbzeaRGu1Tfm=hrvzkJrSsag@mail.gmail.com>
CC: linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        =?UTF-8?Q?S=c3=b6ren_Brinkmann?= <soren.brinkmann@xilinx.com>,
        "Julia Cartwright" <julia@ni.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Devicetree List <devicetree@vger.kernel.org>
From: Michal Simek <michal.simek@xilinx.com>
Message-ID: <7e4fbe16-8686-5399-748d-af222c630338@xilinx.com>
Date: Thu, 16 Mar 2017 17:45:57 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Thunderbird/45.7.0
MIME-Version: 1.0
In-Reply-To: <CAJYdmeNc48=OOvRiUjqPBJhz9RCbzeaRGu1Tfm=hrvzkJrSsag@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
SpamDiagnosticOutput: 1:99
SpamDiagnosticMetadata: NSPM
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Mar 2017 16:46:09.1164
 (UTC)
X-MS-Exchange-CrossTenant-Id: 657af505-d5df-48d0-8300-c31994686c5c
X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=657af505-d5df-48d0-8300-c31994686c5c;Ip=[149.199.60.83];Helo=[xsj-pvapsmtpgw01]
X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem
X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY1PR02MB1382
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 1997
Lines: 67

On 16.3.2017 17:39, Moritz Fischer wrote:
> On Thu, Mar 16, 2017 at 9:16 AM, Michal Simek <michal.simek@xilinx.com> wrote:
>> Hi,
>>
>> On 8.3.2017 21:11, Moritz Fischer wrote:
>>> Fix
>>>
>>> OF: /iio_hwmon: could not get #io-channel-cells for
>>> /amba/adc@f8007100
>>> OF: /iio_hwmon: could not get #io-channel-cells for
>>> /amba/adc@f8007100
>>> OF: /iio_hwmon: could not get #io-channel-cells for
>>> /amba/adc@f8007100
>>>
>>> by adding the #io-channel-cells property.
>>>
>>> Signed-off-by: Moritz Fischer <mdf@kernel.org>
>>> Cc: Michal Simek <michal.simek@xilinx.com>
>>> Cc: Sören Brinkmann <soren.brinkmann@xilinx.com>
>>> Cc: Julia Cartwright <julia@ni.com>
>>> Cc: linux-kernel@vger.kernel.org
>>> Cc: devicetree@vger.kernel.org
>>> ---
>>>
>>> Changes from v1:
>>> - fix messed up commit message
>>> ---
>>>  arch/arm/boot/dts/zynq-7000.dtsi | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/arch/arm/boot/dts/zynq-7000.dtsi b/arch/arm/boot/dts/zynq-7000.dtsi
>>> index f3ac9bf..98233a8 100644
>>> --- a/arch/arm/boot/dts/zynq-7000.dtsi
>>> +++ b/arch/arm/boot/dts/zynq-7000.dtsi
>>> @@ -72,6 +72,7 @@
>>>                       interrupts = <0 7 4>;
>>>                       interrupt-parent = <&intc>;
>>>                       clocks = <&clkc 12>;
>>> +                     #io-channel-cells = <1>;
>>>               };
>>>
>>>               can0: can@e0008000 {
>>>
>>
>> I think it will be good to the next step too.
>> It means also add iio-hwmon node too.
>>
>> What do you think?
> 
> I hadn't put it in there since dts is supposed to describe hw,
> but obviously putting the actual hwmon in there makes it more useful.

I had one discussion about this with Grant in past and it is common
mistake. It is simplification of purpose of dts.

> 
> I can resubmit with the hwmon node in there.

If you grep kernel tree you will see that others are using it too.
Also there is accepted binding for that that's why I can't see big
problem with it.

Thanks,
Michal