linux-kernel - Re: [PATCH v2] ARM: dts: da850: add the mstpri and ddrctl nodes

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Date:   Thu, 24 Nov 2016 09:48:41 +0100
From:   Bartosz Golaszewski <bgolaszewski@...libre.com>
To:     Sekhar Nori <nsekhar@...com>
Cc:     David Lechner <david@...hnology.com>,
        Kevin Hilman <khilman@...libre.com>,
        Michael Turquette <mturquette@...libre.com>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Rowand <frowand.list@...il.com>,
        Mark Rutland <mark.rutland@....com>,
        Peter Ujfalusi <peter.ujfalusi@...com>,
        Russell King <linux@...linux.org.uk>,
        linux-devicetree <devicetree@...r.kernel.org>,
        David Airlie <airlied@...ux.ie>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-drm <dri-devel@...ts.freedesktop.org>,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        Jyri Sarha <jsarha@...com>,
        arm-soc <linux-arm-kernel@...ts.infradead.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Subject: Re: [PATCH v2] ARM: dts: da850: add the mstpri and ddrctl nodes

2016-11-24 6:03 GMT+01:00 Sekhar Nori <nsekhar@...com>:
> On Thursday 24 November 2016 04:18 AM, David Lechner wrote:
>> On 11/23/2016 04:32 PM, Kevin Hilman wrote:
>>> David Lechner <david@...hnology.com> writes:
>>>
>>>> On 11/23/2016 04:27 AM, Bartosz Golaszewski wrote:
>>>>> 2016-11-22 23:23 GMT+01:00 David Lechner <david@...hnology.com>:
>>>>>> On 11/15/2016 05:00 AM, Bartosz Golaszewski wrote:
>>>>>>>
>>>>>>> Add the nodes for the MSTPRI configuration and DDR2/mDDR memory
>>>>>>> controller drivers to da850.dtsi.
>>>>>>>
>>>>>>> Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
>>>>>>> ---
>>>>>>> v1 -> v2:
>>>>>>> - moved the priority controller node above the cfgchip node
>>>>>>> - renamed added nodes to better reflect their purpose
>>>>>>>
>>>>>>>  arch/arm/boot/dts/da850.dtsi | 8 ++++++++
>>>>>>>  1 file changed, 8 insertions(+)
>>>>>>>
>>>>>>> diff --git a/arch/arm/boot/dts/da850.dtsi
>>>>>>> b/arch/arm/boot/dts/da850.dtsi
>>>>>>> index 1bb1f6d..412eec6 100644
>>>>>>> --- a/arch/arm/boot/dts/da850.dtsi
>>>>>>> +++ b/arch/arm/boot/dts/da850.dtsi
>>>>>>> @@ -210,6 +210,10 @@
>>>>>>>                         };
>>>>>>>
>>>>>>>                 };
>>>>>>> +               prictrl: priority-controller@...10 {
>>>>>>> +                       compatible = "ti,da850-mstpri";
>>>>>>> +                       reg = <0x14110 0x0c>;
>>>>>>
>>>>>>
>>>>>> I think we should add status = "disabled"; here and let boards opt in.
>>>>>>
>>>>>>> +               };
>>>>>>>                 cfgchip: chip-controller@...7c {
>>>>>>>                         compatible = "ti,da830-cfgchip", "syscon",
>>>>>>> "simple-mfd";
>>>>>>>                         reg = <0x1417c 0x14>;
>>>>>>> @@ -451,4 +455,8 @@
>>>>>>>                           1 0 0x68000000 0x00008000>;
>>>>>>>                 status = "disabled";
>>>>>>>         };
>>>>>>> +       memctrl: memory-controller@...00000 {
>>>>>>> +               compatible = "ti,da850-ddr-controller";
>>>>>>> +               reg = <0xb0000000 0xe8>;
>>>>>>
>>>>>>
>>>>>> same here. status = "disabled";
>>>>>>
>>>>>>> +       };
>>>>>>>  };
>>>>>>>
>>>>>
>>>>> Hi David,
>>>>>
>>>>> I did that initially[1][2] and it was rejected by Kevin[3] and
>>>>> Laurent[4].
>>>>>
>>>>> FYI this patch has already been queued by Sekhar.
>>>>
>>>> Thanks. I did not see those threads.
>>>>
>>>> FYI to maintainers, having these enabled by default causes error
>>>> messages in the kernel log for other boards that are not supported by
>>>> the drivers.
>>>
>>> Then the driver is too noisy and should be cleaned up.
>>>
>>>> Since there is only one board that is supported and soon
>>>> to be 2 that are not, I would rather have this disabled by default to
>>>> avoid the error messages.
>>>
>>> IMO, what exactly are the error messages? Sounds like the driver is
>>> being too verbose, and calling things errors that are not really errors.
>>
>> It is just one line per driver.
>>
>>     dev_err(dev, "no master priorities defined for this board\n");
>>
>> and
>>
>>     dev_err(dev, "no settings defined for this board\n");
>>
>>
>> Since "ti,da850-lcdk" is the only board supported in these drivers, all
>> other boards will see these error messages.
>
> Thats pretty bad. Sorry about that. The original justification for
> keeping them enabled all the time was that they are in-SoC modules with
> no external dependencies (like IO lines or voltage rails) so they can be
> enabled on all boards that use DA850. While that remains true, the
> configuration itself is board specific.
>
> I think the error messages are still useful, so instead of silencing
> them, I think we should go back to keeping these nodes disabled by
> default and enabling only on boards which have support for it in the driver.
>
> Thanks,
> Sekhar

I'll send a patch.

Thanks,
Bartosz