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authorDirk Eibach <eibach@gdsys.de>2011-03-21 17:59:37 +0100
committerJean Delvare <khali@endymion.delvare>2011-03-21 17:59:37 +0100
commitc0046867f34bb81ec3f237ebbc5241ae678b8379 (patch)
treea5d9e95c3fcd09a53dac9ce88abb00f4bef4a4fc /Documentation
parentfdf241a8ed93236915c70717a4b6dfb856274496 (diff)
downloadlwn-c0046867f34bb81ec3f237ebbc5241ae678b8379.tar.gz
lwn-c0046867f34bb81ec3f237ebbc5241ae678b8379.zip
hwmon: (ads1015) Make gain and datarate configurable
Configuration for ads1015 gain and datarate is possible via devicetree or platform data. This is a followup patch to previous ads1015 patches on Jean Delvares tree. Signed-off-by: Dirk Eibach <eibach@gdsys.de> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/hwmon/ads1015.txt88
-rw-r--r--Documentation/hwmon/ads101549
2 files changed, 93 insertions, 44 deletions
diff --git a/Documentation/devicetree/bindings/hwmon/ads1015.txt b/Documentation/devicetree/bindings/hwmon/ads1015.txt
index 0f30616384c5..918a507d1159 100644
--- a/Documentation/devicetree/bindings/hwmon/ads1015.txt
+++ b/Documentation/devicetree/bindings/hwmon/ads1015.txt
@@ -5,25 +5,69 @@ This device is a 12-bit A-D converter with 4 inputs.
The inputs can be used single ended or in certain differential combinations.
For configuration all possible combinations are mapped to 8 channels:
-0: Voltage over AIN0 and AIN1.
-1: Voltage over AIN0 and AIN3.
-2: Voltage over AIN1 and AIN3.
-3: Voltage over AIN2 and AIN3.
-4: Voltage over AIN0 and GND.
-5: Voltage over AIN1 and GND.
-6: Voltage over AIN2 and GND.
-7: Voltage over AIN3 and GND.
-
-Optional properties:
-
- - exported-channels : exported_channels is a bitmask that specifies which
- channels should be accessable by the user.
-
-Example:
-ads1015@49 {
- compatible = "ti,ads1015";
- reg = <0x49>;
- exported-channels = <0x14>;
-};
-
-In this example only channel 2 and 4 would be accessable by the user.
+ 0: Voltage over AIN0 and AIN1.
+ 1: Voltage over AIN0 and AIN3.
+ 2: Voltage over AIN1 and AIN3.
+ 3: Voltage over AIN2 and AIN3.
+ 4: Voltage over AIN0 and GND.
+ 5: Voltage over AIN1 and GND.
+ 6: Voltage over AIN2 and GND.
+ 7: Voltage over AIN3 and GND.
+
+Each channel can be configured individually:
+ - pga is the programmable gain amplifier (values are full scale)
+ 0: +/- 6.144 V
+ 1: +/- 4.096 V
+ 2: +/- 2.048 V (default)
+ 3: +/- 1.024 V
+ 4: +/- 0.512 V
+ 5: +/- 0.256 V
+ - data_rate in samples per second
+ 0: 128
+ 1: 250
+ 2: 490
+ 3: 920
+ 4: 1600 (default)
+ 5: 2400
+ 6: 3300
+
+1) The /ads1015 node
+
+ Required properties:
+
+ - compatible : must be "ti,ads1015"
+ - reg : I2C bus address of the device
+ - #address-cells : must be <1>
+ - #size-cells : must be <0>
+
+ The node contains child nodes for each channel that the platform uses.
+
+ Example ADS1015 node:
+
+ ads1015@49 {
+ compatible = "ti,ads1015";
+ reg = <0x49>;
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ [ child node definitions... ]
+ }
+
+2) channel nodes
+
+ Required properties:
+
+ - reg : the channel number
+
+ Optional properties:
+
+ - ti,gain : the programmable gain amplifier setting
+ - ti,datarate : the converter data rate
+
+ Example ADS1015 channel node:
+
+ channel@4 {
+ reg = <4>;
+ ti,gain = <3>;
+ ti,datarate = <5>;
+ };
diff --git a/Documentation/hwmon/ads1015 b/Documentation/hwmon/ads1015
index 56ee7977b1a8..f6fe9c203733 100644
--- a/Documentation/hwmon/ads1015
+++ b/Documentation/hwmon/ads1015
@@ -19,7 +19,7 @@ This device is a 12-bit A-D converter with 4 inputs.
The inputs can be used single ended or in certain differential combinations.
-The inputs can be exported to 8 sysfs input files in0_input - in7_input:
+The inputs can be made available by 8 sysfs input files in0_input - in7_input:
in0: Voltage over AIN0 and AIN1.
in1: Voltage over AIN0 and AIN3.
in2: Voltage over AIN1 and AIN3.
@@ -29,39 +29,44 @@ in5: Voltage over AIN1 and GND.
in6: Voltage over AIN2 and GND.
in7: Voltage over AIN3 and GND.
-Which inputs are exported can be configured using platform data or devicetree.
+Which inputs are available can be configured using platform data or devicetree.
By default all inputs are exported.
Platform Data
-------------
-In linux/i2c/ads1015.h platform data is defined as:
-
-struct ads1015_platform_data {
- unsigned int exported_channels;
-};
-
-exported_channels is a bitmask that specifies which inputs should be exported.
+In linux/i2c/ads1015.h platform data is defined, channel_data contains
+configuration data for the used input combinations:
+- pga is the programmable gain amplifier (values are full scale)
+ 0: +/- 6.144 V
+ 1: +/- 4.096 V
+ 2: +/- 2.048 V
+ 3: +/- 1.024 V
+ 4: +/- 0.512 V
+ 5: +/- 0.256 V
+- data_rate in samples per second
+ 0: 128
+ 1: 250
+ 2: 490
+ 3: 920
+ 4: 1600
+ 5: 2400
+ 6: 3300
Example:
struct ads1015_platform_data data = {
- .exported_channels = (1 << 2) | (1 << 4)
+ .channel_data = {
+ [2] = { .enabled = true, .pga = 1, .data_rate = 0 },
+ [4] = { .enabled = true, .pga = 4, .data_rate = 5 },
+ }
};
-In this case only in2_input and in4_input would be created.
+In this case only in2_input (FS +/- 4.096 V, 128 SPS) and in4_input
+(FS +/- 0.512 V, 2400 SPS) would be created.
Devicetree
----------
-The ads1015 node may have an "exported-channels" property.
-exported_channels is a bitmask that specifies which inputs should be exported.
-
-Example:
-ads1015@49 {
- compatible = "ti,ads1015";
- reg = <0x49>;
- exported-channels = < 0x14 >;
-};
-
-In this case only in2_input and in4_input would be created.
+Configuration is also possible via devicetree:
+Documentation/devicetree/bindings/hwmon/ads1015.txt