[PATCH] hwmon: ltc2990: support all measurement modes

2016-11-16 Thread Tom Levens 
Updated ltc2990 driver to support all possible measurement modes that
the chip provides. Mode can be set through a device tree attribute or by
writing to the "mode" sysfs attribute.

Signed-off-by: Tom Levens 
---
 .../devicetree/bindings/hwmon/ltc2990.txt  |   15 +
 Documentation/hwmon/ltc2990|   25 ++-
 drivers/hwmon/Kconfig  |7 +-
 drivers/hwmon/ltc2990.c|  268 +---
 4 files changed, 266 insertions(+), 49 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/hwmon/ltc2990.txt

diff --git a/Documentation/devicetree/bindings/hwmon/ltc2990.txt 
b/Documentation/devicetree/bindings/hwmon/ltc2990.txt
new file mode 100644
index 000..0a17e8d
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/ltc2990.txt
@@ -0,0 +1,15 @@
+ltc2990
+
+Required properties:
+- compatible: must be "lltc,ltc2990"
+- reg: I2C slave address
+
+Optional properties:
+- mode: measurement mode (0-7), see Documentation/hwmon/ltc2990 for details
+
+Example:
+ltc2990@4c {
+   compatible = "lltc,ltc2990";
+   mode = <7>;
+   reg = <0x4c>;
+};
diff --git a/Documentation/hwmon/ltc2990 b/Documentation/hwmon/ltc2990
index c25211e..a97df88 100644
--- a/Documentation/hwmon/ltc2990
+++ b/Documentation/hwmon/ltc2990
@@ -8,6 +8,7 @@ Supported chips:
 Datasheet: http://www.linear.com/product/ltc2990
 
 Author: Mike Looijmans 
+Tom Levens 
 
 
 Description
@@ -16,10 +17,8 @@ Description
 LTC2990 is a Quad I2C Voltage, Current and Temperature Monitor.
 The chip's inputs can measure 4 voltages, or two inputs together (1+2 and 3+4)
 can be combined to measure a differential voltage, which is typically used to
-measure current through a series resistor, or a temperature.
-
-This driver currently uses the 2x differential mode only. In order to support
-other modes, the driver will need to be expanded.
+measure current through a series resistor, or a temperature with an external
+diode.
 
 
 Usage Notes
@@ -32,12 +31,20 @@ devices explicitly.
 Sysfs attributes
 
 
+in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
+temp1_input   Internal chip temperature in millidegrees Celcius
+mode  Set the measurement mode (range 0 to 7)
+
+A subset of the following attributes are visible, depending on the programmed
+measurement mode.
+
+in[1-4]_input Voltage at V[1-4] pin in millivolt
+temp2_input   External temperature sensor TR1 in millidegrees Celcius
+temp3_input   External temperature sensor TR2 in millidegrees Celcius
+curr1_input   Current in mA across V1-V2 assuming a 1mOhm sense resistor
+curr2_input   Current in mA across V3-V4 assuming a 1mOhm sense resistor
+
 The "curr*_input" measurements actually report the voltage drop across the
 input pins in microvolts. This is equivalent to the current through a 1mOhm
 sense resistor. Divide the reported value by the actual sense resistor value
 in mOhm to get the actual value.
-
-in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
-temp1_input   Internal chip temperature in millidegrees Celcius
-curr1_input   Current in mA across v1-v2 assuming a 1mOhm sense resistor.
-curr2_input   Current in mA across v3-v4 assuming a 1mOhm sense resistor.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 45cef3d..f7096ca 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -699,15 +699,12 @@ config SENSORS_LTC2945
  be called ltc2945.
 
 config SENSORS_LTC2990
-   tristate "Linear Technology LTC2990 (current monitoring mode only)"
+   tristate "Linear Technology LTC2990"
depends on I2C
help
  If you say yes here you get support for Linear Technology LTC2990
  I2C System Monitor. The LTC2990 supports a combination of voltage,
- current and temperature monitoring, but in addition to the Vcc supply
- voltage and chip temperature, this driver currently only supports
- reading two currents by measuring two differential voltages across
- series resistors.
+ current and temperature monitoring.
 
  This driver can also be built as a module. If so, the module will
  be called ltc2990.
diff --git a/drivers/hwmon/ltc2990.c b/drivers/hwmon/ltc2990.c
index 8f8fe05..b6f910d 100644
--- a/drivers/hwmon/ltc2990.c
+++ b/drivers/hwmon/ltc2990.c
@@ -4,11 +4,10 @@
  * Copyright (C) 2014 Topic Embedded Products
  * Author: Mike Looijmans 
  *
- * License: GPLv2
+ * Copyright (C) 2016 European Organization for Nuclear Research (CERN)
+ * Author: Tom Levens 
  *
- * This driver assumes the chip is wired as a dual current monitor, and
- * reports the voltage drop across two series resistors. It also reports
- * the chip's internal temperature and Vcc power supply voltage.
+ * License: GPLv2
  */
 
 #include 
@@

Re: [PATCH] hwmon: ltc2990: support all measurement modes

2016-11-16 Thread Guenter Roeck 

On 11/16/2016 05:53 AM, Tom Levens wrote:

Updated ltc2990 driver to support all possible measurement modes that
the chip provides. Mode can be set through a device tree attribute or by
writing to the "mode" sysfs attribute.

Signed-off-by: Tom Levens 
---
 .../devicetree/bindings/hwmon/ltc2990.txt  |   15 +
 Documentation/hwmon/ltc2990|   25 ++-
 drivers/hwmon/Kconfig  |7 +-
 drivers/hwmon/ltc2990.c|  268 +---
 4 files changed, 266 insertions(+), 49 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/hwmon/ltc2990.txt

diff --git a/Documentation/devicetree/bindings/hwmon/ltc2990.txt 
b/Documentation/devicetree/bindings/hwmon/ltc2990.txt
new file mode 100644
index 000..0a17e8d
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/ltc2990.txt
@@ -0,0 +1,15 @@
+ltc2990
+
+Required properties:
+- compatible: must be "lltc,ltc2990"
+- reg: I2C slave address
+
+Optional properties:
+- mode: measurement mode (0-7), see Documentation/hwmon/ltc2990 for details
+

This needs to be documented here.


+Example:
+ltc2990@4c {
+   compatible = "lltc,ltc2990";
+   mode = <7>;
+   reg = <0x4c>;
+};


Please submit as separate patch and copy devicetree maintainers for Ack.
You'll probably want to specify valid modes and their impact.


diff --git a/Documentation/hwmon/ltc2990 b/Documentation/hwmon/ltc2990
index c25211e..a97df88 100644
--- a/Documentation/hwmon/ltc2990
+++ b/Documentation/hwmon/ltc2990
@@ -8,6 +8,7 @@ Supported chips:
 Datasheet: http://www.linear.com/product/ltc2990

 Author: Mike Looijmans 
+Tom Levens 


 Description
@@ -16,10 +17,8 @@ Description
 LTC2990 is a Quad I2C Voltage, Current and Temperature Monitor.
 The chip's inputs can measure 4 voltages, or two inputs together (1+2 and 3+4)
 can be combined to measure a differential voltage, which is typically used to
-measure current through a series resistor, or a temperature.
-
-This driver currently uses the 2x differential mode only. In order to support
-other modes, the driver will need to be expanded.
+measure current through a series resistor, or a temperature with an external
+diode.


 Usage Notes
@@ -32,12 +31,20 @@ devices explicitly.
 Sysfs attributes
 

+in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
+temp1_input   Internal chip temperature in millidegrees Celcius
+mode  Set the measurement mode (range 0 to 7)
+

The mode is determined by the hardware configuration. It does not make sense
to have it user configurable.


+A subset of the following attributes are visible, depending on the programmed
+measurement mode.
+
+in[1-4]_input Voltage at V[1-4] pin in millivolt
+temp2_input   External temperature sensor TR1 in millidegrees Celcius
+temp3_input   External temperature sensor TR2 in millidegrees Celcius
+curr1_input   Current in mA across V1-V2 assuming a 1mOhm sense resistor
+curr2_input   Current in mA across V3-V4 assuming a 1mOhm sense resistor
+
 The "curr*_input" measurements actually report the voltage drop across the
 input pins in microvolts. This is equivalent to the current through a 1mOhm
 sense resistor. Divide the reported value by the actual sense resistor value
 in mOhm to get the actual value.
-
-in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
-temp1_input   Internal chip temperature in millidegrees Celcius
-curr1_input   Current in mA across v1-v2 assuming a 1mOhm sense resistor.
-curr2_input   Current in mA across v3-v4 assuming a 1mOhm sense resistor.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 45cef3d..f7096ca 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -699,15 +699,12 @@ config SENSORS_LTC2945
  be called ltc2945.

 config SENSORS_LTC2990
-   tristate "Linear Technology LTC2990 (current monitoring mode only)"
+   tristate "Linear Technology LTC2990"
depends on I2C
help
  If you say yes here you get support for Linear Technology LTC2990
  I2C System Monitor. The LTC2990 supports a combination of voltage,
- current and temperature monitoring, but in addition to the Vcc supply
- voltage and chip temperature, this driver currently only supports
- reading two currents by measuring two differential voltages across
- series resistors.
+ current and temperature monitoring.

  This driver can also be built as a module. If so, the module will
  be called ltc2990.
diff --git a/drivers/hwmon/ltc2990.c b/drivers/hwmon/ltc2990.c
index 8f8fe05..b6f910d 100644
--- a/drivers/hwmon/ltc2990.c
+++ b/drivers/hwmon/ltc2990.c
@@ -4,11 +4,10 @@
  * Copyright (C) 2014 Topic Embedded Products
  * Author: Mike Looijmans 
  *
- * License: GPLv2
+ * Copyright (C) 2016 European Organization for