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Date:   Tue, 30 Oct 2018 15:42:47 -0500
From:   Rob Herring <robh@kernel.org>
To:     Manish Narani <manish.narani@xilinx.com>
Cc:     jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de,
        pmeerw@pmeerw.net, mark.rutland@arm.com, michal.simek@xilinx.com,
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Subject: Re: [PATCH v3 1/3] dt-bindings: iio: adc: Add Xilinx AMS binding
 documentation
Message-ID: <20181030204247.GA22521@bogus>
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 <1540815026-1012-2-git-send-email-manish.narani@xilinx.com>
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On Mon, Oct 29, 2018 at 05:40:24PM +0530, Manish Narani wrote:
> Xilinx AMS have several ADC channels that can be used for measurement of
> different voltages and temperatures. Document the same in the bindings.
> 
> Signed-off-by: Manish Narani <manish.narani@xilinx.com>
> ---
>  .../devicetree/bindings/iio/adc/xilinx-ams.txt     | 183 +++++++++++++++++++++
>  1 file changed, 183 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/xilinx-ams.txt
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/xilinx-ams.txt b/Documentation/devicetree/bindings/iio/adc/xilinx-ams.txt
> new file mode 100644
> index 0000000..1635576
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/xilinx-ams.txt
> @@ -0,0 +1,183 @@
> +Xilinx AMS controller
> +`````````````````````
> +The AMS includes an ADC as well as on-chip sensors that can be used to

AMS stands for?

> +sample external voltages and monitor on-die operating conditions, such as
> +temperature and supply voltage levels.
> +The AMS has two SYSMON blocks which are PL (Programmable Logic) SYSMON and
> +PS (Processing System) SYSMON.
> +All designs should have AMS registers, but PS and PL are optional. The
> +AMS controller can work with only PS, only PL and both PS and PL
> +configurations. Please specify registers according to your design. Devicetree
> +should always have AMS module property. Providing PS & PL module is optional.
> +
> +Required properties:
> +	- compatible: Should be "xlnx,zynqmp-ams"
> +	- reg: Should specify AMS register space
> +	- interrupts: Interrupt number for the AMS control interface
> +	- interrupt-names: Interrupt name, must be "ams-irq"
> +	- clocks: Should contain a clock specifier for the device
> +	- ranges: keep the property empty to map child address space
> +	          (for PS and/or PL) nodes 1:1 onto the parent address
> +	          space
> +
> +	AMS sub-nodes:
> +		- ams_ps : Used as PS-SYSMON node
> +		- ams_pl : Used as PL-SYSMON node

Don't use '_' in node or property names.

> +
> +
> +
> +AMS PS-SYSMON
> +`````````````
> +PS (Processing System) SYSMON is memory mapped to PS. This block has built-in
> +alarm generation logic that is used to interrupt the processor based on
> +condition set.
> +
> +Required properties:
> +	- compatible: Should be "xlnx,zynqmp-ams-ps"
> +	- reg: Register space for PS-SYSMON
> +
> +
> +
> +AMS PL-SYSMON
> +`````````````
> +PL-SYSMON is capable of monitoring off chip voltage and temperature. PL-SYSMON
> +block has DRP, JTAG and I2C interface to enable monitoring from external master.
> +Out of this interface currently only DRP is supported. This block has alarm
> +generation logic that is used to interrupt the processor based on condition set.
> +
> +Required properties:
> +	- compatible: Should be "xlnx,zynqmp-ams-pl"
> +	- reg: Register space for PL-SYSMON
> +
> +PL-SYSMON optional sub-nodes:
> +	- xlnx,ext-channels: List of external channels that are connected to the
> +	                     AMS PL module.
> +
> +	  The child nodes of PL-SYSMON represent the external channels which are
> +	  connected to this Module. If the property is not present
> +	  no external channels will be assumed to be connected.
> +
> +	  Each child node represents one channel and has the following
> +	  properties:
> +
> +	Required properties:
> +		* reg: Pair of pins the channel is connected to.
> +
> +		    'reg' value		Channel Name		Channel Number
> +		    -----------		------------		--------------
> +			 0		VP/VN			      30
> +			 1		VUSER0			      31
> +			 2		VUSER1			      32
> +			 3		VUSER3			      33
> +			 4		VUSER4			      34
> +			 5		VAUXP[0]/VAUXN[0]	      35
> +			 6		VAUXP[1]/VAUXN[1]	      36
> +			...
> +			20		VAUXP[15]/VAUXN[15]	      50

Why this reg to channel mapping? Just use channel numbers for reg. I'm 
confused by this table and the one below.

> +
> +		Each channel number should only be used at most once. For
> +		more details on channels, refer to the table given at the end.
> +
> +	Optional properties:
> +		* xlnx,bipolar: If set the channel is used in bipolar
> +		  mode.
> +
> +
> +Example:
> +	xilinx_ams: ams@ffa50000 {
> +		compatible = "xlnx,zynqmp-ams";
> +		interrupt-parent = <&gic>;
> +		interrupts = <0 56 4>;
> +		interrupt-names = "ams-irq";
> +		reg = <0x0 0xffa50000 0x0 0x800>;
> +		reg-names = "ams-base";
> +		#address-cells = <1>;
> +		#size-cells = <1>;
> +		#io-channel-cells = <1>;
> +		ranges = <0 0 0xffa50800 0x400
> +			  1 0 0xffa50c00 0x400>;

This doesn't work. This is mapping child addresses 0 and 1, but both 
child nodes are at address 0. I believe you want the length to be 0x800 
and drop the 2nd entry.

> +
> +		ams_ps: ams_ps@0,0 {
> +			compatible = "xlnx,zynqmp-ams-ps";
> +			reg = <0 0x400>;
> +		};
> +
> +		ams_pl: ams_pl@1,0 {
> +			compatible = "xlnx,zynqmp-ams-pl";
> +			reg = <0 0x400>;

And then this should be address 0x400.

> +			xlnx,ext-channels {
> +				channel@0 {
> +					reg = <0>;
> +					xlnx,bipolar;
> +				};
> +				channel@1 {
> +					reg = <1>;
> +				};
> +				channel@8 {
> +					reg = <8>;
> +					xlnx,bipolar;
> +				};
> +			};
> +		};
> +	};
> +
> +
> +AMS Channel Details
> +```````````````````
> +Sysmon Block	|Channel|			Details					|Measurement
> +		|Number	|							 	|Type
> +---------------------------------------------------------------------------------------------------------
> +AMS CTRL	|0	|System PLLs voltage measurement, VCC_PSPLL.			|Voltage
> +		|1	|Battery voltage measurement, VCC_PSBATT.			|Voltage
> +		|2	|PL Internal voltage measurement, VCCINT.			|Voltage
> +		|3	|Block RAM voltage measurement, VCCBRAM.			|Voltage
> +		|4	|PL Aux voltage measurement, VCCAUX.				|Voltage
> +		|5	|Voltage measurement for six DDR I/O PLLs, VCC_PSDDR_PLL.	|Voltage
> +		|6	|VCC_PSINTFP_DDR voltage measurement.				|Voltage
> +---------------------------------------------------------------------------------------------------------
> +PS Sysmon	|7	|LPD temperature measurement.					|Temperature
> +		|8	|FPD temperature measurement (REMOTE).				|Temperature
> +		|9	|VCC PS LPD voltage measurement (supply1).			|Voltage
> +		|10	|VCC PS FPD voltage measurement (supply2).			|Voltage
> +		|11	|PS Aux voltage reference (supply3).				|Voltage
> +		|12	|DDR I/O VCC voltage measurement.				|Voltage
> +		|13	|PS IO Bank 503 voltage measurement (supply5).			|Voltage
> +		|14	|PS IO Bank 500 voltage measurement (supply6).			|Voltage
> +		|15	|VCCO_PSIO1 voltage measurement.				|Voltage
> +		|16	|VCCO_PSIO2 voltage measurement.				|Voltage
> +		|17	|VCC_PS_GTR voltage measurement (VPS_MGTRAVCC).			|Voltage
> +		|18	|VTT_PS_GTR voltage measurement (VPS_MGTRAVTT).			|Voltage
> +		|19	|VCC_PSADC voltage measurement.					|Voltage
> +---------------------------------------------------------------------------------------------------------
> +PL Sysmon	|20	|PL temperature measurement.					|Temperature
> +		|21	|PL Internal voltage measurement, VCCINT.			|Voltage
> +		|22	|PL Auxiliary voltage measurement, VCCAUX.			|Voltage
> +		|23	|ADC Reference P+ voltage measurement.				|Voltage
> +		|24	|ADC Reference N- voltage measurement.				|Voltage
> +		|25	|PL Block RAM voltage measurement, VCCBRAM.			|Voltage
> +		|26	|LPD Internal voltage measurement, VCC_PSINTLP (supply4).	|Voltage
> +		|27	|FPD Internal voltage measurement, VCC_PSINTFP (supply5).	|Voltage
> +		|28	|PS Auxiliary voltage measurement (supply6).			|Voltage
> +		|29	|PL VCCADC voltage measurement (vccams).			|Voltage
> +		|30	|Differential analog input signal voltage measurment.		|Voltage
> +		|31	|VUser0 voltage measurement (supply7).				|Voltage
> +		|32	|VUser1 voltage measurement (supply8).				|Voltage
> +		|33	|VUser2 voltage measurement (supply9).				|Voltage
> +		|34	|VUser3 voltage measurement (supply10).				|Voltage
> +		|35	|Auxiliary ch 0 voltage measurement (VAux0).			|Voltage
> +		|36	|Auxiliary ch 1 voltage measurement (VAux1).			|Voltage
> +		|37	|Auxiliary ch 2 voltage measurement (VAux2).			|Voltage
> +		|38	|Auxiliary ch 3 voltage measurement (VAux3).			|Voltage
> +		|39	|Auxiliary ch 4 voltage measurement (VAux4).			|Voltage
> +		|40	|Auxiliary ch 5 voltage measurement (VAux5).			|Voltage
> +		|41	|Auxiliary ch 6 voltage measurement (VAux6).			|Voltage
> +		|42	|Auxiliary ch 7 voltage measurement (VAux7).			|Voltage
> +		|43	|Auxiliary ch 8 voltage measurement (VAux8).			|Voltage
> +		|44	|Auxiliary ch 9 voltage measurement (VAux9).			|Voltage
> +		|45	|Auxiliary ch 10 voltage measurement (VAux10).			|Voltage
> +		|46	|Auxiliary ch 11 voltage measurement (VAux11).			|Voltage
> +		|47	|Auxiliary ch 12 voltage measurement (VAux12).			|Voltage
> +		|48	|Auxiliary ch 13 voltage measurement (VAux13).			|Voltage
> +		|49	|Auxiliary ch 14 voltage measurement (VAux14).			|Voltage
> +		|50	|Auxiliary ch 15 voltage measurement (VAux15).			|Voltage
> +---------------------------------------------------------------------------------------------------------
> -- 
> 2.1.1
>