[RCF 2/3] hwmon: Document bindings for ads1118 adc driver

From: Joshua Clayton <stillcompiling@gmail.com>
To: Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <kernel@pengutronix.de>,
	Fabio Estevam <fabio.estevam@nxp.com>,
	Russell King <linux@armlinux.org.uk>,
	Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-hwmon@vger.kernel.org
Cc: Joshua Clayton <stillcompiling@gmail.com>
Subject: [RCF 2/3] hwmon: Document bindings for ads1118 adc driver
Date: Fri, 15 Jul 2016 17:18:22 -0700	[thread overview]
Message-ID: <49eddbb75c677db62701e229330f0f5c35983130.1468626668.git.stillcompiling@gmail.com> (raw)
In-Reply-To: <cover.1468626668.git.stillcompiling@gmail.com>
In-Reply-To: <cover.1468626668.git.stillcompiling@gmail.com>

ads1118 is a 4 input 16 bit adc with a buit-in temperature gauge

Signed-off-by: Joshua Clayton <stillcompiling@gmail.com>
---
 .../devicetree/bindings/hwmon/ads1118.txt          | 81 ++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/ads1118.txt

diff --git a/Documentation/devicetree/bindings/hwmon/ads1118.txt b/Documentation/devicetree/bindings/hwmon/ads1118.txt
new file mode 100644
index 0000000..41c66dc
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/ads1118.txt
@@ -0,0 +1,81 @@
+ADS1118 (SPI)
+
+The ADS1118 is 16-bit analog to digital converter with 4 inputs and a
+temperature sensor.
+The ADS1018 is a 12-bit version of the chip.
+
+The inputs can be single ended or differential pair combinations.
+
+Each channel, 0 - 4 may be configured as a single ended adc input.
+Channel 0 may be configured differentially with channel 1.
+Channels 0, 1, or 2 may be configured differentially with channel 3.
+
+To set up a differential pair, the lower channel should be have
+the ti,differential-endpoint property set to the higher channel in the pair.
+
+Each channel can be configured individually:
+ - fullscale voltage range values are +/- microvolts
+    6144000, 4096000, 2048000, 1024000, 512000, or 256000
+
+ - data_rate in samples per second
+    - for the ads1018:
+      128, 250, 490, 920, 1600, 2400, or 3300
+    - for the ads1118:
+      8, 16, 32, 64, 128, 250, or 860
+
+The sensor contains an internal pullup register to keep the data output
+high when not in use. This may be disabled, but is enabled by default.
+
+1) The /ads1118 node
+
+  Required properties:
+
+   - compatible : must be "ti,ads1018" or "ti,ads1118"
+   - spi-cpha : spi phase set to 1 (spi polarity is 0)
+   - reg : the spi chipselect address
+   - #address-cells : must be <1>
+   - #size-cells : must be <0>
+
+  Optional properties:
+
+   - ti,tempsensor: enable the temperature sensor
+   - ti,pullup-disable: disable the internal pullup resistor
+
+  The node contains child nodes for each channel that the platform uses.
+
+2) channel nodes
+
+  Required properties:
+
+   - reg : the channel number (0, 1, 2, or 3)
+
+  Optional properties:
+
+   - ti,differential-endpoint: differential second endpoint.
+   - ti,fullscale: fullscale range in +/- microvolts
+   - ti,datarate : the converter data rate in samples / second
+
+  Example ADS1118 node:
+
+	ads1118@0 {
+		compatible = "ti,ads1118";
+		spi-max-frequency = <2450000>;
+		reg = <0>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		ti,tempsensor;
+		voltage0@0 {
+			reg = <0>;
+			ti,fullscale = <6144000>;
+			ti,datarate = <860>;
+			ti,differential-endpoint = <1>;
+		};
+		voltage1@3 {
+			reg = <3>;
+			ti,fullscale = <6144000>;
+			ti,datarate = <475>;
+		};
+	};
+
+For the above example, The temperature sensor is enabled as well as
+channels 0 and 1 in differential mode, and channel 3 single ended.
-- 
2.7.4
