From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: RFC v2: Zynq Clock Controller
Date: Mon, 25 Mar 2013 17:29:33 -0600 [thread overview]
Message-ID: <5150DDDD.9010904@wwwdotorg.org> (raw)
In-Reply-To: <128fc723-ace7-4f4c-95d9-971b42a52080@CH1EHSMHS028.ehs.local>
On 03/22/2013 04:41 PM, S?ren Brinkmann wrote:
> Hi Lars,
>
> On Thu, Mar 21, 2013 at 07:32:52PM +0100, Lars-Peter Clausen wrote:
>> On 03/21/2013 12:56 AM, S?ren Brinkmann wrote:
>>> Hi,
>>>
>>> I spent some time working on this and incorporating feedback. Here's an updated proposal for a clock controller for Zynq:
>>>
>>> Required properties:
>>> - #clock-cells : Must be 1
>>> - compatible : "xlnx,ps7-clkc" (this may become 'xlnx,zynq-clkc' terminology differs a bit between Xilinx internal and mainline)
>>> - ps-clk-frequency : Frequency of the oscillator providing ps_clk in HZ
>>> (usually 33 MHz oscillators are used for Zynq platforms)
>>> - clock-output-names : List of strings used to name the clock outputs. Shall be a list of the outputs given below.
>>>
>>> Optional properties:
>>> - clocks : as described in the clock bindings
>>> - clock-names : as described in the clock bindings
>>>
>>> Clock inputs:
>>> The following strings are optional parameters to the 'clock-names' property in
>>> order to provide optional (E)MIO clock sources.
>>> - swdt_ext_clk
>>> - gem0_emio_clk
>>> - gem1_emio_clk
>>> - mio_clk_XX # with XX = 00..53
>>>
>>> Example:
>>> clkc: clkc {
>>> #clock-cells = <1>;
>>> compatible = "xlnx,ps7-clkc";
>>> ps-clk-frequency = <33333333>;
>>
>> The input frequency should be a clock as well.
>
> Again, monolithic vs split. I don't see a reason not to just internally
> call clk_register_fixed_rate(). That way its children do not have to
> cope with a variable name for the xtal.
> Also, with my proposal 'clocks' and 'clock-names' would be purely
> optional properties, only required if optional external inputs are
> present. Having the xtal defined externally would add mandatory entries for
> those props.
But isn't the clock source board-specific? It's a completely separate
object from Zynq's own clock controller HW, and as such should be
represented by a separate DT node, right?
The issue with parent clock names is simply a red herring. A solution is
needed to registered clock with a parent clock object, rather than a
parent clock name. Then, the parent names are completely irrelevant.
next prev parent reply other threads:[~2013-03-25 23:29 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-20 23:56 RFC v2: Zynq Clock Controller Sören Brinkmann
2013-03-21 18:32 ` Lars-Peter Clausen
2013-03-22 22:41 ` Sören Brinkmann
2013-03-25 14:46 ` Lars-Peter Clausen
2013-03-25 17:08 ` Sören Brinkmann
2013-03-25 17:19 ` Lars-Peter Clausen
2013-03-25 17:59 ` Sören Brinkmann
2013-03-25 18:10 ` Lars-Peter Clausen
2013-03-25 18:12 ` Sören Brinkmann
2013-03-26 0:49 ` Sören Brinkmann
2013-03-25 23:29 ` Stephen Warren [this message]
2013-03-25 23:59 ` Sören Brinkmann
2013-03-25 18:13 ` Stephen Warren
2013-03-25 18:27 ` Sören Brinkmann
2013-03-25 23:33 ` Stephen Warren
2013-03-26 0:03 ` Sören Brinkmann
2013-03-27 2:18 ` Mike Turquette
2013-03-29 22:36 ` Sören Brinkmann
2013-04-03 0:34 ` Mike Turquette
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