summaryrefslogtreecommitdiff
path: root/Documentation/hwmon/g760a.rst
diff options
context:
space:
mode:
authorMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-04-17 06:46:29 -0300
committerGuenter Roeck <linux@roeck-us.net>2019-04-17 10:37:23 -0700
commit7ebd8b66dd9e5a0b65e5ee5e2b8e7ca382ec97b7 (patch)
tree9db30159bd32bec125c7d49e80a79bb7c4da0c8e /Documentation/hwmon/g760a.rst
parentb04f2f7d387b3160883c2a1f5e2285483a791e82 (diff)
docs: hwmon: Add an index file and rename docs to *.rst
Now that all files were converted to ReST format, rename them and add an index. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'Documentation/hwmon/g760a.rst')
-rw-r--r--Documentation/hwmon/g760a.rst40
1 files changed, 40 insertions, 0 deletions
diff --git a/Documentation/hwmon/g760a.rst b/Documentation/hwmon/g760a.rst
new file mode 100644
index 000000000000..d82952cc8319
--- /dev/null
+++ b/Documentation/hwmon/g760a.rst
@@ -0,0 +1,40 @@
+Kernel driver g760a
+===================
+
+Supported chips:
+
+ * Global Mixed-mode Technology Inc. G760A
+
+ Prefix: 'g760a'
+
+ Datasheet: Publicly available at the GMT website
+
+ http://www.gmt.com.tw/product/datasheet/EDS-760A.pdf
+
+Author: Herbert Valerio Riedel <hvr@gnu.org>
+
+Description
+-----------
+
+The GMT G760A Fan Speed PWM Controller is connected directly to a fan
+and performs closed-loop control of the fan speed.
+
+The fan speed is programmed by setting the period via 'pwm1' of two
+consecutive speed pulses. The period is defined in terms of clock
+cycle counts of an assumed 32kHz clock source.
+
+Setting a period of 0 stops the fan; setting the period to 255 sets
+fan to maximum speed.
+
+The measured fan rotation speed returned via 'fan1_input' is derived
+from the measured speed pulse period by assuming again a 32kHz clock
+source and a 2 pulse-per-revolution fan.
+
+The 'alarms' file provides access to the two alarm bits provided by
+the G760A chip's status register: Bit 0 is set when the actual fan
+speed differs more than 20% with respect to the programmed fan speed;
+bit 1 is set when fan speed is below 1920 RPM.
+
+The g760a driver will not update its values more frequently than every
+other second; reading them more often will do no harm, but will return
+'old' values.