hwmon: (pmbus) Add ltc4286 driver

Add a driver to support ltc4286 chip

Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
Link: https://lore.kernel.org/r/20231123015440.199822-3-Delphine_CC_Chiu@Wiwynn.com
[groeck: Fixed formatting]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

2 files changed, 96 insertions, 0 deletions

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index 095c36f5e8a1f5..f85f2ac5af453c 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -128,6 +128,7 @@ Hardware Monitoring Kernel Drivers
    ltc4245
    ltc4260
    ltc4261
+   ltc4286
    max127
    max15301
    max16064
diff --git a/Documentation/hwmon/ltc4286.rst b/Documentation/hwmon/ltc4286.rst
new file mode 100644
index 00000000000000..2cd149676d8636
--- /dev/null
+++ b/Documentation/hwmon/ltc4286.rst
@@ -0,0 +1,95 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver ltc4286
+=====================
+
+Supported chips:
+
+  * Analog Devices LTC4286
+
+    Prefix: 'ltc4286'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4286.pdf
+
+  * Analog Devices LTC4287
+
+    Prefix: 'ltc4287'
+
+    Addresses scanned: -
+
+    Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4287.pdf
+
+Author: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Analog Devices LTC4286
+and LTC4287 Hot-Swap Controller and Digital Power Monitors.
+
+LTC4286 and LTC4287 are hot-swap controllers that allow a circuit board
+to be removed from or inserted into a live backplane. They also feature
+current and voltage readback via an integrated 12 bit analog-to-digital
+converter (ADC), accessed using a PMBus interface.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for
+details.
+
+The shunt value in micro-ohms can be set via device tree at compile-time. Please
+refer to the Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml for bindings
+if the device tree is used.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data. Please see
+Documentation/hwmon/pmbus.rst for details.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. Limits are read-write, history reset
+attributes are write-only, all other attributes are read-only.
+
+======================= =======================================================
+in1_label		"vin"
+in1_input		Measured voltage.
+in1_alarm		Input voltage alarm.
+in1_min 		Minimum input voltage.
+in1_max 		Maximum input voltage.
+
+in2_label		"vout1"
+in2_input		Measured voltage.
+in2_alarm		Output voltage alarm.
+in2_min 		Minimum output voltage.
+in2_max 		Maximum output voltage.
+
+curr1_label		"iout1"
+curr1_input		Measured current.
+curr1_alarm		Output current alarm.
+curr1_max		Maximum current.
+
+power1_label		"pin"
+power1_input		Input power.
+power1_alarm		Input power alarm.
+power1_max		Maximum poewr.
+
+temp1_input		Chip temperature.
+temp1_min		Minimum chip temperature.
+temp1_max		Maximum chip temperature.
+temp1_crit		Critical chip temperature.
+temp1_alarm		Chip temperature alarm.
+======================= =======================================================