linux-kernel - Re: [PATCH 1/3] Documentation: dt: reset: Add TI SCI reset binding

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Message-ID: <b5acc586-c1ef-bc84-e238-4be0dbe9884f@ti.com>
Date:   Thu, 27 Oct 2016 14:24:41 -0500
From:   "Andrew F. Davis" <afd@...com>
To:     Suman Anna <s-anna@...com>, Nishanth Menon <nm@...com>,
        Tero Kristo <t-kristo@...com>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>
CC:     <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] Documentation: dt: reset: Add TI SCI reset binding

On 10/27/2016 12:07 PM, Suman Anna wrote:
> Hi Andrew,
> 
> On 10/26/2016 02:39 PM, Andrew F. Davis wrote:
>> Add TI SCI reset controller binding. This describes the DT binding
>> details for a reset controller node providing reset management services
>> to hardware blocks (reset consumers) using the Texas Instrument's System
>> Control Interface (TI SCI) protocol to communicate to a system controller
>> block present on the SoC.
>>
>> Signed-off-by: Andrew F. Davis <afd@...com>
>> [s-anna@...com: revise the binding format]
>> Signed-off-by: Suman Anna <s-anna@...com>
>> Signed-off-by: Nishanth Menon <nm@...com>
>> ---
>>  .../devicetree/bindings/reset/ti,sci-reset.txt     | 68 ++++++++++++++++++++++
>>  MAINTAINERS                                        |  1 +
>>  2 files changed, 69 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/reset/ti,sci-reset.txt
>>
>> diff --git a/Documentation/devicetree/bindings/reset/ti,sci-reset.txt b/Documentation/devicetree/bindings/reset/ti,sci-reset.txt
>> new file mode 100644
>> index 0000000..189e284
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/reset/ti,sci-reset.txt
>> @@ -0,0 +1,68 @@
>> +Texas Instruments System Control Interface (TI-SCI) Reset Controller
>> +=====================================================================
>> +
>> +Some TI SoCs contain a system controller (like the Power Management Micro
>> +Controller (PMMC) on Keystone K2G SoC) that are responsible for controlling
>> +the state of the various hardware modules present on the SoC. Communication
>> +between the host processor running an OS and the system controller happens
>> +through a protocol called TI System Control Interface (TI-SCI protocol).
>> +For TI SCI details, please refer to the document,
>> +Documentation/devicetree/bindings/arm/keystone/ti,sci.txt
>> +
>> +TI-SCI Reset Controller Node
>> +============================
>> +This reset controller node uses the TI SCI protocol to perform the reset
>> +management of various hardware modules present on the SoC.
>> +
>> +Required properties:
>> +--------------------
>> + - compatible	: Should be "ti,sci-reset"
>> + - ti,sci	: phandle to the TI SCI device to use for managing resets
> 
> This does not look correct. Looks like you may have posted an older
> series. We should not be needing the ti,sci property anymore and this
> node should be a child node of the pmmc. Look at Tero's ti-sci clock series.
> 
>> + - #reset-cells	: Should be 2. Please see the reset consumer node below for
>> +		  usage details.
>> +
>> +TI-SCI Reset Consumer Nodes
>> +===========================
>> +Each of the reset consumer nodes should have the following properties,
>> +in addition to their own properties.
>> +
>> +Required properties:
>> +--------------------
>> + - resets	: A phandle and reset specifier pair, one pair for each reset
>> +		  signal that affects the device, or that the device manages.
>> +		  The phandle should point to the TI-SCI reset controller node,
>> +		  and the reset specifier should have 2 cell-values. The first
>> +		  cell should contain the device ID, the values of which are
>> +		  specified in the <dt-bindings/genpd/<soc>.h> include file.
>> +		  The second cell should contain the reset mask value used by
>> +		  system controller, the values of which are specified in the
>> +		  include file <dt-bindings/reset/<soc>.h>, where <soc> is the
>> +		  name of the SoC involved, for example 'k2g'.
>> +
>> +Please also refer to Documentation/devicetree/bindings/reset/reset.txt for
>> +common reset controller usage by consumers.
>> +
>> +
>> +Example:
>> +--------
>> +The following example demonstrates both a TI-SCI reset controller node and a
>> +consumer (a DSP device) on the K2G SoC.
>> +
>> +#include <dt-bindings/genpd/k2g.h>
>> +#include <dt-bindings/reset/k2g.h>
>> +
>> +/ {
>> +	soc {
>> +		k2g_reset: k2g_reset {
>> +			compatible = "ti,sci-reset";
>> +			ti,sci = <&pmmc>;
>> +			#reset-cells = <2>;
>> +		};
> 
> This example is also wrong. Please update it to represent this node as a
> child node of the pmmc.
> 

Ah, yes, you are right, this change was handled transparently in code by
ti_sci_get_handle() so the documentation change was overlooked, will fix
for v2.

Thanks,
Andrew

> regards
> Suman
> 
>> +
>> +		dsp0: dsp0 {
>> +			...
>> +			resets = <&k2g_reset K2G_DEV_CGEM0 K2G_DEV_CGEM0_DSP0_RESET>;
>> +			...
>> +		};
>> +	};
>> +};
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 6e93976..d8068df 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -11899,6 +11899,7 @@ F:	drivers/soc/ti/ti_sci_pm_domains.c
>>  F:	Documentation/devicetree/bindings/clock/ti,sci-clk.txt
>>  F:	include/dt-bindings/clock/k2g.h
>>  F:	drivers/clk/keystone/sci-clk.c
>> +F:	Documentation/devicetree/bindings/reset/ti,sci-reset.txt
>>  
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>