From f6c61cff8bcb58b8dfb645d4243a049908c02024 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Thu, 28 Oct 2010 20:31:50 +0200 Subject: hwmon: (lm85) Add support for ADT7468 high-frequency PWM mode The ADT7468 supports a high-frequency PWM output mode where all PWM outputs are driven by a 22.5 kHz clock. Add support for this mode, and document it, as it may surprise the user that setting one PWM output frequency also affects the other PWM outputs. Signed-off-by: Jean Delvare Cc: Darrick J. Wong Acked-by: Guenter Roeck --- Documentation/hwmon/lm85 | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'Documentation') diff --git a/Documentation/hwmon/lm85 b/Documentation/hwmon/lm85 index 83cd5bb1ac79..239258a63c81 100644 --- a/Documentation/hwmon/lm85 +++ b/Documentation/hwmon/lm85 @@ -101,6 +101,13 @@ Devices has confirmed this "bug". The ADT7463 is reported to work as described in the documentation. The current lm85 driver does not show the offset register. +The ADT7468 has a high-frequency PWM mode, where all PWM outputs are +driven by a 22.5 kHz clock. This is a global mode, not per-PWM output, +which means that setting any PWM frequency above 11.3 kHz will switch +all 3 PWM outputs to a 22.5 kHz frequency. Conversely, setting any PWM +frequency below 11.3 kHz will switch all 3 PWM outputs to a frequency +between 10 and 100 Hz, which can then be tuned separately. + See the vendor datasheets for more information. There is application note from National (AN-1260) with some additional information about the LM85. The Analog Devices datasheet is very detailed and describes a procedure for -- cgit v1.2.3