hwmon: Add support for Lattice's POWR1220 power manager IC

This patch adds support for Lattice's POWR1220 power manager IC. Read
access to all the ADCs on the chip are supported through the hwmon
sysfs files.

Signed-off-by: Scott Kanowitz <skanowitz@echo360.com>
[Guenter Roeck: Removed some extra ( )]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 45 insertions, 0 deletions

diff --git a/Documentation/hwmon/powr1220 b/Documentation/hwmon/powr1220
new file mode 100644
index 000000000000..21e44f71ae6e
--- /dev/null
+++ b/Documentation/hwmon/powr1220
@@ -0,0 +1,45 @@
+Kernel driver powr1220
+==================
+
+Supported chips:
+  * Lattice POWR1220AT8
+    Prefix: 'powr1220'
+    Addresses scanned: none
+    Datasheet: Publicly available at the Lattice website
+               http://www.latticesemi.com/
+
+Author: Scott Kanowitz <scott.kanowitz@gmail.com>
+
+Description
+-----------
+
+This driver supports the Lattice POWR1220AT8 chip. The POWR1220
+includes voltage monitoring for 14 inputs as well as trim settings
+for output voltages and GPIOs. This driver implements the voltage
+monitoring portion of the chip.
+
+Voltages are sampled by a 12-bit ADC with a step size of 2 mV.
+An in-line attenuator allows measurements from 0 to 6 V. The
+attenuator is enabled or disabled depending on the setting of the
+input's max value. The driver will enable the attenuator for any
+value over the low measurement range maximum of 2 V.
+
+The input naming convention is as follows:
+
+driver name    pin name
+in0            VMON1
+in1            VMON2
+in2            VMON3
+in2            VMON4
+in4            VMON5
+in5            VMON6
+in6            VMON7
+in7            VMON8
+in8            VMON9
+in9            VMON10
+in10           VMON11
+in11           VMON12
+in12           VCCA
+in13           VCCINP
+
+The ADC readings are updated on request with a minimum period of 1s.