Subject: Re: [PATCH v2 1/3] dt-bindings: arm: amlogic: Add SoC information
 bindings
To: Rob Herring <robh@kernel.org>
References: <1496742340-10307-1-git-send-email-narmstrong@baylibre.com>
 <1496742340-10307-2-git-send-email-narmstrong@baylibre.com>
 <20170609133717.gkqnyatqezkrcaeg@rob-hp-laptop>
Cc: khilman@baylibre.com, carlo@caione.org,
        linux-amlogic@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
From: Neil Armstrong <narmstrong@baylibre.com>
Organization: Baylibre
Message-ID: <955d2903-9057-919b-004d-b1f5985dca5c@baylibre.com>
Date: Fri, 9 Jun 2017 15:58:30 +0200
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On 06/09/2017 03:37 PM, Rob Herring wrote:
> On Tue, Jun 06, 2017 at 11:45:38AM +0200, Neil Armstrong wrote:
>> Add bindings for the SoC information register of the Amlogic SoCs.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
>> ---
>>  Documentation/devicetree/bindings/arm/amlogic.txt | 32 +++++++++++++++++++++++
>>  1 file changed, 32 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/arm/amlogic.txt b/Documentation/devicetree/bindings/arm/amlogic.txt
>> index 5c01e65..ae3e8ed 100644
>> --- a/Documentation/devicetree/bindings/arm/amlogic.txt
>> +++ b/Documentation/devicetree/bindings/arm/amlogic.txt
>> @@ -60,3 +60,35 @@ Board compatible values (alphabetically, grouped by SoC):
>>    - "amlogic,q201" (Meson gxm s912)
>>    - "kingnovel,r-box-pro" (Meson gxm S912)
>>    - "nexbox,a1" (Meson gxm s912)
>> +
>> +Amlogic Meson Firmware registers Interface
>> +------------------------------------------
>> +
>> +The Meson SoCs have a register bank with status and data shared with the
>> +secure firmware.
>> +
>> +Required properties:
>> + - compatible: For Meson GX SoCs, must be "amlogic,meson-gx-ao-secure", "syscon", "simple-mfd"
>> +
>> +Sub-nodes should indentify components of this register interface :
>> +
>> +Meson GX SoC Information
>> +------------------------
>> +A firmware register encodes the SoC type, package and revision information on
>> +the Meson GX SoCs.
>> +If present, a device node for this register should be added.
>> +
>> +Required properties:
>> +  - compatible: For Meson GX SoCs, must be "amlogic,meson-gx-chipid".
>> +
>> +Example
>> +-------
>> +
>> +ao-secure@140 {
>> +	compatible = "amlogic,meson-gx-ao-secure", "syscon", "simple-mfd";
>> +	reg = <0x0 0x140 0x0 0x140>;
>> +
>> +	chipid {
>> +		compatible = "amlogic,meson-gx-chipid";
> 
> No registers for this block? If not, this node is pointless. 
> "amlogic,meson-gx-ao-secure" should be specific enough to determine if 
> you have this block or not and the driver for it can create a device if 
> the OS needs it.
> 
> Rob
> 

Well OK, but since it's a firmware interface, it can be handy to list the
possible capabilities, not especially tied to a driver.

Neil