[PATCH 4/5] Documentation/hwmon: Add TSC1641 driver documentation

[Igor Reznichenko <igor@reznichenko.net>]

Add hwmon documentation for the TSC1641 driver. This includes
description and the sysfs attributes.

Signed-off-by: Igor Reznichenko <igor@reznichenko.net>
---
 Documentation/hwmon/index.rst   |  1 +
 Documentation/hwmon/tsc1641.rst | 73 +++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 Documentation/hwmon/tsc1641.rst

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 51a5bdf75b08..4fb9f91f83b3 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -253,6 +253,7 @@ Hardware Monitoring Kernel Drivers
    tps40422
    tps53679
    tps546d24
+   tsc1641
    twl4030-madc-hwmon
    ucd9000
    ucd9200
diff --git a/Documentation/hwmon/tsc1641.rst b/Documentation/hwmon/tsc1641.rst
new file mode 100644
index 000000000000..a93d1e72c70e
--- /dev/null
+++ b/Documentation/hwmon/tsc1641.rst
@@ -0,0 +1,73 @@
+Kernel driver tsc1641
+=====================
+
+Supported chips:
+
+  * ST TSC1641
+
+    Prefix: 'tsc1641'
+
+    Addresses scanned: -
+
+    Datasheet:
+	https://www.st.com/resource/en/datasheet/tsc1641.pdf
+
+Author:
+	- Igor Reznichenko <igor@reznichenko.net>
+
+
+Description
+-----------
+
+The TSC1641 is a high-precision current, voltage, power, and temperature
+monitoring analog front-end (AFE). It monitors current into a shunt resistor and load
+voltage up to 60 V in a synchronized way. Digital bus interface is I2C/SMbus.
+The TSC1641 allows the assertion of several alerts regarding the voltage, current,
+power and temperature.
+
+Sysfs entries
+-------------
+
+==================== =======================================================
+in0_input            bus voltage (mV)
+in0_crit             bus voltage crit alarm limit (mV)
+in0_crit_alarm       bus voltage crit alarm limit exceeded
+in0_lcrit            bus voltage low-crit alarm limit (mV)
+in0_lcrit_alarm      bus voltage low-crit alarm limit exceeded
+
+curr1_input          current measurement (mA)
+curr1_crit           current crit alarm limit (mA)
+curr1_crit_alarm     current crit alarm limit exceeded
+curr1_lcrit          current low-crit alarm limit (mA)
+curr1_lcrit_alarm    current low-crit alarm limit exceeded
+
+power1_input         power measurement (uW)
+power1_crit          power crit alarm limit (uW)
+power1_crit_alarm    power crit alarm limit exceeded
+
+shunt_resistor       shunt resistor value (uOhms)
+shunt_voltage_uvolts shunt voltage raw measurement (uV)
+
+temp1_input          temperature measurement (mdegC)
+temp1_crit           temperature crit alarm limit (mdegC)
+temp1_crit_alarm     temperature crit alarm limit exceeded
+
+update_interval      data conversion time (1 - 33ms), longer conversion time corresponds
+                     to higher effective resolution in bits
+==================== =======================================================
+
+General Remarks
+---------------
+
+The TSC1641 driver requires the value of the external shunt resistor to
+correctly compute current and power measurements. The resistor value, in
+micro-ohms, should be provided either through the device tree property
+"shunt-resistor" or via the writable sysfs attribute "shunt_resistor".
+Please refer to the Documentation/devicetree/bindings/hwmon/st,tsc1641.yaml
+for bindings if the device tree is used.
+
+If the shunt resistor value is not specified in the device tree, the driver
+initializes it to 0 uOhm by default. In this state, current and power
+measurements will read as zero and are considered invalid. To enable these
+measurements, users must configure the correct shunt resistor value at
+runtime by writing to the "shunt_resistor" sysfs attribute.
-- 
2.43.0