From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH V2 1/3] ARM: dts: tegra: add clock source for PMC
Date: Wed, 20 Mar 2013 09:54:16 -0600 [thread overview]
Message-ID: <5149DBA8.4030308@wwwdotorg.org> (raw)
In-Reply-To: <1363774325.5697.19.camel@jlo-ubuntu-64.nvidia.com>
On 03/20/2013 04:12 AM, Joseph Lo wrote:
> On Wed, 2013-03-20 at 00:42 +0800, Stephen Warren wrote:
>> On 03/18/2013 02:09 AM, Joseph Lo wrote:
>>> The clock source of PMC is PCLK. Adding it into DTS for Tegra20 and Tegra30.
>>
>>> diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi
>>
>>> pmc {
>>> compatible = "nvidia,tegra20-pmc";
>>> reg = <0x7000e400 0x400>;
>>> + clocks = <&tegra_car 110>;
>>> };
>>
>> The DT binding documentation needs to list the set of clocks that must
>> be present.
>>
>> Doesn't the PMC also receive a "clk32k_in" from the PMIC, or is that
>> routed into the CAR, and then into the PMC? Either way, the PMC module
>> receives that clock somehow. Since there are multiple clocks, that also
>> means that a clock-names property is required.
>
> Do you mean the DTS below and add it into binding document?
>
> / SoC dts including file
> pmc {
> compatible = "nvidia,tegra20-pmc";
> reg = <0x7000e400 0x400>;
> clocks = <&tegra_car 110>, <&clk32k_in>;
> clock-names= "pclk", "clk32k_in";
> };
Yes, that's what should technically be present.
> / Tegra board dts file
>
> pmic {
> ...
> clocks {
> compatible = "simple-bus";
> #address-cells = <1>;
> #size-cells = <0>;
>
> clk32k_in: clock at 0 {
> compatible = "fixed-clock";
> reg=<0>;
> #clock-cells = <0>;
> clock-frequency = <32768>;
> };
> };
> };
That won't work; the PMIC drivers don't enumerate sub-nodes as busss, so
that clocks node won't ever be processed. Also, the PMIC drivers aren't
clock providers in most cases. It's not quite a correct representation
of the HW, but I would suggest simply creating a top-level "clock" node
for that fixed clock. If we ever have more top-level clocks, we can move
them into a top-level "clocks" node at that time.
Note: If there aren't already any other top-level clock nodes (which I
think is the case), the node can be named just "clock" rather than
"clock at 0", since there are no naming conflicts.
next prev parent reply other threads:[~2013-03-20 15:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-18 8:09 [PATCH V2 0/3] ARM: tegra: add clock source for PMC Joseph Lo
2013-03-18 8:09 ` [PATCH V2 1/3] ARM: dts: " Joseph Lo
2013-03-19 16:42 ` Stephen Warren
2013-03-20 10:12 ` Joseph Lo
2013-03-20 15:54 ` Stephen Warren [this message]
2013-03-18 8:09 ` [PATCH V2 2/3] ARM: tegra: get PMC clock source from DT Joseph Lo
2013-03-19 16:40 ` Stephen Warren
2013-03-20 10:00 ` Joseph Lo
2013-03-20 15:51 ` Stephen Warren
2013-03-18 8:09 ` [PATCH V2 3/3] ARM: tegra: moving the CPU power timer function to PMC driver Joseph Lo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5149DBA8.4030308@wwwdotorg.org \
--to=swarren@wwwdotorg$(echo .)org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox