[RFC,1/4] Documentation: mmc: add description for new caps
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Message ID 1465374021-2526-1-git-send-email-shawn.lin@rock-chips.com
State New
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Commit Message

Shawn Lin June 8, 2016, 8:20 a.m. UTC
Let's add some basic description for cap-no-sdio,
cap-no-sd and cap-no-mmc.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

---

 Documentation/devicetree/bindings/mmc/mmc.txt | 3 +++
 1 file changed, 3 insertions(+)

Comments

Rob Herring June 8, 2016, 8:48 p.m. UTC | #1
On Wed, Jun 08, 2016 at 04:20:21PM +0800, Shawn Lin wrote:
> Let's add some basic description for cap-no-sdio,
> cap-no-sd and cap-no-mmc.

This doesn't say why.

If you know what is there, then there's a better way to do this. Look at 
the child nodes because chances are if you have something soldered down 
like SDIO or eMMC, then you have a child node already for resets, 
regulators, etc.

Rob
Ulf Hansson June 22, 2016, 12:30 p.m. UTC | #2
On 8 June 2016 at 22:48, Rob Herring <robh@kernel.org> wrote:
> On Wed, Jun 08, 2016 at 04:20:21PM +0800, Shawn Lin wrote:
>> Let's add some basic description for cap-no-sdio,
>> cap-no-sd and cap-no-mmc.
>
> This doesn't say why.
>
> If you know what is there, then there's a better way to do this. Look at
> the child nodes because chances are if you have something soldered down
> like SDIO or eMMC, then you have a child node already for resets,
> regulators, etc.
>

According to patch4, this is a description of the mmc controller,
perhaps together with some limitations as per SoC/platform and thus
has nothing to do with the card.

I have seen several drivers, which needs to validate every single
piece of command to avoid execute those it cannot support.

So, I personally thinks these new DT bindings would be nice to add.

Kind regards
Uffe
Doug Anderson June 22, 2016, 3:06 p.m. UTC | #3
Hi,

On Wed, Jun 8, 2016 at 1:20 AM, Shawn Lin <shawn.lin@rock-chips.com> wrote:
> Let's add some basic description for cap-no-sdio,
> cap-no-sd and cap-no-mmc.
>
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>
> ---
>
>  Documentation/devicetree/bindings/mmc/mmc.txt | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
> index ecc007a..e16d42b 100644
> --- a/Documentation/devicetree/bindings/mmc/mmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
> @@ -39,6 +39,9 @@ Optional properties:
>  - cap-power-off-card: powering off the card is safe
>  - cap-mmc-hw-reset: eMMC hardware reset is supported
>  - cap-sdio-irq: enable SDIO IRQ signalling on this interface
> +- cap-no-sdio: skip sending sdio cmd during initialization
> +- cap-no-sd: skip sending sd cmd during initialization
> +- cap-no-mmc: skip sending mmc cmd during initialization

In the past it has been determined that the "cap-" prefix is
unnecessary.  Some properties still have "cap-" because of backward
compatibility reasons, but as I understand it new properties shouldn't
start with "cap-".

See <https://lists.ozlabs.org/pipermail/devicetree-discuss/2013-June/034664.html>
for reference.

-Doug
Shawn Lin June 23, 2016, 1:29 a.m. UTC | #4
在 2016/6/22 23:06, Doug Anderson 写道:
> Hi,
>
> On Wed, Jun 8, 2016 at 1:20 AM, Shawn Lin <shawn.lin@rock-chips.com> wrote:
>> Let's add some basic description for cap-no-sdio,
>> cap-no-sd and cap-no-mmc.
>>
>> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>>
>> ---
>>
>>  Documentation/devicetree/bindings/mmc/mmc.txt | 3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
>> index ecc007a..e16d42b 100644
>> --- a/Documentation/devicetree/bindings/mmc/mmc.txt
>> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
>> @@ -39,6 +39,9 @@ Optional properties:
>>  - cap-power-off-card: powering off the card is safe
>>  - cap-mmc-hw-reset: eMMC hardware reset is supported
>>  - cap-sdio-irq: enable SDIO IRQ signalling on this interface
>> +- cap-no-sdio: skip sending sdio cmd during initialization
>> +- cap-no-sd: skip sending sd cmd during initialization
>> +- cap-no-mmc: skip sending mmc cmd during initialization
>
> In the past it has been determined that the "cap-" prefix is
> unnecessary.  Some properties still have "cap-" because of backward
> compatibility reasons, but as I understand it new properties shouldn't
> start with "cap-".
>
> See <https://lists.ozlabs.org/pipermail/devicetree-discuss/2013-June/034664.html>
> for reference.
>

Really?  was that the final decision? I just see Olof complained it but
don't see other comments from dt maintainer or from mmc
maintainer(Chris Ball)?

Hi Ulf and Rob,

What is your opinion?


> -Doug
>
>
>
Doug Anderson June 23, 2016, 4:33 a.m. UTC | #5
Hi,

On Wed, Jun 22, 2016 at 6:29 PM, Shawn Lin <shawn.lin@rock-chips.com> wrote:
> 在 2016/6/22 23:06, Doug Anderson 写道:
>>
>> Hi,
>>
>> On Wed, Jun 8, 2016 at 1:20 AM, Shawn Lin <shawn.lin@rock-chips.com>
>> wrote:
>>>
>>> Let's add some basic description for cap-no-sdio,
>>> cap-no-sd and cap-no-mmc.
>>>
>>> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
>>>
>>> ---
>>>
>>>  Documentation/devicetree/bindings/mmc/mmc.txt | 3 +++
>>>  1 file changed, 3 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt
>>> b/Documentation/devicetree/bindings/mmc/mmc.txt
>>> index ecc007a..e16d42b 100644
>>> --- a/Documentation/devicetree/bindings/mmc/mmc.txt
>>> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
>>> @@ -39,6 +39,9 @@ Optional properties:
>>>  - cap-power-off-card: powering off the card is safe
>>>  - cap-mmc-hw-reset: eMMC hardware reset is supported
>>>  - cap-sdio-irq: enable SDIO IRQ signalling on this interface
>>> +- cap-no-sdio: skip sending sdio cmd during initialization
>>> +- cap-no-sd: skip sending sd cmd during initialization
>>> +- cap-no-mmc: skip sending mmc cmd during initialization
>>
>>
>> In the past it has been determined that the "cap-" prefix is
>> unnecessary.  Some properties still have "cap-" because of backward
>> compatibility reasons, but as I understand it new properties shouldn't
>> start with "cap-".
>>
>> See
>> <https://lists.ozlabs.org/pipermail/devicetree-discuss/2013-June/034664.html>
>> for reference.
>>
>
> Really?  was that the final decision? I just see Olof complained it but
> don't see other comments from dt maintainer or from mmc
> maintainer(Chris Ball)?
>
> Hi Ulf and Rob,
>
> What is your opinion?

Notice that most things added later (like mmc-hs200-1_8v) don't have "cap-"

Patch
diff mbox

diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index ecc007a..e16d42b 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -39,6 +39,9 @@  Optional properties:
 - cap-power-off-card: powering off the card is safe
 - cap-mmc-hw-reset: eMMC hardware reset is supported
 - cap-sdio-irq: enable SDIO IRQ signalling on this interface
+- cap-no-sdio: skip sending sdio cmd during initialization
+- cap-no-sd: skip sending sd cmd during initialization
+- cap-no-mmc: skip sending mmc cmd during initialization
 - full-pwr-cycle: full power cycle of the card is supported
 - mmc-ddr-1_8v: eMMC high-speed DDR mode(1.8V I/O) is supported
 - mmc-ddr-1_2v: eMMC high-speed DDR mode(1.2V I/O) is supported