hwmon: (pmbus) Add tps40422 front-end driver

For TI power management chip TPS40422, READ_TEMPERATURE_2 command is supported on
page 1 of the chip, but the original driver(pmbus.c) only tried to detect this command
on page 0, this will lead to a result that the temperature sensor in page 1 couldn't
be detected. This change is to isolate the tps40422 driver from pmbus.c into a solo
front-end driver.

Signed-off-by: Zhu Laiwen <richard.zhu@nsn.com>
[Guenter Roeck: Dropped unnecessary license text (fixes checkpatch warning)]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

2 files changed, 66 insertions, 3 deletions

diff --git a/Documentation/hwmon/pmbus b/Documentation/hwmon/pmbus
index cf756ed48ff9..a3557da8f5b4 100644
--- a/Documentation/hwmon/pmbus
+++ b/Documentation/hwmon/pmbus
@@ -23,12 +23,11 @@ Supported chips:
 	http://www.lineagepower.com/oem/pdf/PDT012A0X.pdf
 	http://www.lineagepower.com/oem/pdf/UDT020A0X.pdf
 	http://www.lineagepower.com/oem/pdf/MDT040A0X.pdf
-  * Texas Instruments TPS40400, TPS40422
-    Prefixes: 'tps40400', 'tps40422'
+  * Texas Instruments TPS40400
+    Prefixes: 'tps40400'
     Addresses scanned: -
     Datasheets:
 	http://www.ti.com/lit/gpn/tps40400
-	http://www.ti.com/lit/gpn/tps40422
   * Generic PMBus devices
     Prefix: 'pmbus'
     Addresses scanned: -
diff --git a/Documentation/hwmon/tps40422 b/Documentation/hwmon/tps40422
new file mode 100644
index 000000000000..24bb0688d515
--- /dev/null
+++ b/Documentation/hwmon/tps40422
@@ -0,0 +1,64 @@
+Kernel driver tps40422
+======================
+
+Supported chips:
+  * TI TPS40422
+    Prefix: 'tps40422'
+    Addresses scanned: -
+    Datasheet: http://www.ti.com/lit/gpn/tps40422
+
+Author: Zhu Laiwen <richard.zhu@nsn.com>
+
+
+Description
+-----------
+
+This driver supports TI TPS40422 Dual-Output or Two-Phase Synchronous Buck
+Controller with PMBus
+
+The driver is a client driver to the core PMBus driver.
+Please see Documentation/hwmon/pmbus 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 for
+details.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported.
+
+in[1-2]_label		"vout[1-2]"
+in[1-2]_input		Measured voltage. From READ_VOUT register.
+in[1-2]_alarm		voltage alarm.
+
+curr[1-2]_input		Measured current. From READ_IOUT register.
+curr[1-2]_label		"iout[1-2]"
+curr1_max		Maximum current. From IOUT_OC_WARN_LIMIT register.
+curr1_crit		Critical maximum current. From IOUT_OC_FAULT_LIMIT register.
+curr1_max_alarm		Current high alarm. From IOUT_OC_WARN_LIMIT status.
+curr1_crit_alarm	Current critical high alarm. From IOUT_OC_FAULT status.
+curr2_alarm		Current high alarm. From IOUT_OC_WARNING status.
+
+temp1_input		Measured temperature. From READ_TEMPERATURE_2 register on page 0.
+temp1_max		Maximum temperature. From OT_WARN_LIMIT register.
+temp1_crit		Critical high temperature. From OT_FAULT_LIMIT register.
+temp1_max_alarm		Chip temperature high alarm. Set by comparing
+			READ_TEMPERATURE_2 on page 0 with OT_WARN_LIMIT if TEMP_OT_WARNING
+			status is set.
+temp1_crit_alarm	Chip temperature critical high alarm. Set by comparing
+			READ_TEMPERATURE_2 on page 0 with OT_FAULT_LIMIT if TEMP_OT_FAULT
+			status is set.
+temp2_input		Measured temperature. From READ_TEMPERATURE_2 register on page 1.
+temp2_alarm		Chip temperature alarm on page 1.