linux-kernel - Re: [PATCH] ARM: dt: tegra: ventana: define pinmux for ddc

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5088DCF2.7030000@nvidia.com>
Date:	Thu, 25 Oct 2012 14:32:18 +0800
From:	Mark Zhang <markz@...dia.com>
To:	Stephen Warren <swarren@...dotorg.org>
CC:	"linux@....linux.org.uk" <linux@....linux.org.uk>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ARM: dt: tegra: ventana: define pinmux for ddc

On 10/23/2012 01:14 AM, Stephen Warren wrote:
> On 10/22/2012 01:29 AM, Mark Zhang wrote:
>> On 10/19/2012 11:48 PM, Stephen Warren wrote:
>>> On 10/18/2012 11:58 PM, Mark Zhang wrote:
>>>> Define pinmux for DDC. The DDC pinmux in Ventana is 2 pins in I2C2.
>>>
>>>> +++ b/arch/arm/boot/dts/tegra20-ventana.dts
>>>
>>>> -            ddc {
>>>> -                nvidia,pins = "ddc", "owc", "spdi", "spdo",
>>>> -                    "uac";
>>>> -                nvidia,function = "rsvd2";
>>>> -            };
>>>
>>> So that removes the entries for 5 pin groups, yet below, entries are
>>> only added for the ddc and pta pingroups, so the other 4 pin groups
>>> become unconfigured.
>>>
>>
>> Right. So I think it should be changed to:
>>
>>          owc {
>>              nvidia,pins = "owc", "spdi", "spdo", "uac";
>>              nvidia,function = "rsvd2";
>>          };
>>
>> Is this right?
>
> Looks correct, yes.
>
>>>> +
>>>> +        state_i2cmux_ddc: pinmux_i2cmux_ddc {
>>>> +            ddc {
>>>> +                nvidia,pins = "ddc";
>>>> +                nvidia,function = "i2c2";
>>>> +            };
>>>> +            pta {
>>>> +                nvidia,pins = "pta";
>>>> +                nvidia,function = "rsvd4";
>>>> +            };
>>>
>>> Does this actually work? The pta pingroup is configured by the "hog"
>>> pinctrl state of the pinctrl node itself, so this state should fail to
>>> be applied since it attempts to touch the same pingroup.
>>
>> I know little about kernel pinctrl subsystem. After reading some docs
>> and codes, I think what you mean is, in Ventana's pinmux configuration,
>> pta pingroup has been defined as "hdmi" function and this can't be
>> changed(non-dynamic pinmuxing).
>> So I want to know why we have defined pta pingroup as hdmi function?
>> Can we remove this definition to make the i2cmux above working?
>
> I don't recall why pta was defined to be HDMI. The issue isn't that this
> patch changes the pinmux selection for the pta pingroup, but simply that
> both the pinctrl node's state definition, and the new I2C mux node's
> state definition both attempt to configure pingroup pta. The solution is
> most likely to simply remove the pta configuration from the main pinctrl
> node.
>

Understood. I tried to remove the hdmi function definition of pta 
pingroup yesterday then found HDMI can't work anymore. The EDID of HDMI 
monitor can't be fetched. After some debugging, I have found that it's 
caused by "i2c-mux-pinctrl" driver is loaded after drm driver. That 
makes drm driver can't get EDID data via this i2c mux adapter because it 
doesn't exist at that time. So I think we need to promote the load level 
of "i2c-mux-pinctrl" driver. Any other ideas?

Mark
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/