diff options
author | Bill Richardson <wfrichar@chromium.org> | 2014-10-21 14:21:45 -0700 |
---|---|---|
committer | chrome-internal-fetch <chrome-internal-fetch@google.com> | 2014-10-22 02:23:39 +0000 |
commit | 8cd9856cf8ef193ea094cf91c67e9aff25b2b521 (patch) | |
tree | 966a17e7cb8edf8fd6ae8ad6b410fd4b124759e1 /include/fan.h | |
parent | 7eaa290c35a1ca5571854c7d31a5a125af665b65 (diff) | |
download | chrome-ec-8cd9856cf8ef193ea094cf91c67e9aff25b2b521.tar.gz |
samus: change fan RPM values, enable fast-start
Updating the fan speeds according to the manufacturer's specs.
The fan vendor recommends that the minimum fan speed be a 20%
duty cycle. Since the built-in fan controller has a tach-based
feedback loop, I'm using the RPM value instead of the duty cycle
(20% is 2286 RPM, according to the vendor).
The vendor also wants a 30% duty cycle to start turning, but the
built-in fan controller provides support for fast-start too. The
controller's minimum fast-start duty cycle is 50%, but it also
has a programmable number of revolutions that it will wait before
backing off.
Holding my ear down close to the fans while they start and stop,
it seems that the minimum 2 revolution start period is sufficient
and provides the least noise. Of course, since I've never had any
problems starting the fans directly at 1000 RPM this noise is a
little more noticeable than that. It's quite possible that the
built-in controller is smart enough to make 1000 RPM work by
bumping the duty cycle up until the fans turn even if the fans
don't like it.
BUG=chrome-os-partner:32892
BRANCH=ToT,samus
TEST=manual
Listen closely and run the EC console "faninfo" command to see
the fans start and stop as the system boots and idles.
Change-Id: I47c9e7cef3f9f4bd815a13032fe10234decd62ed
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/224830
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Diffstat (limited to 'include/fan.h')
-rw-r--r-- | include/fan.h | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/include/fan.h b/include/fan.h index 0813535592..a8352987d8 100644 --- a/include/fan.h +++ b/include/fan.h @@ -21,8 +21,11 @@ struct fan_t { int enable_gpio; }; -/* Values for the flags field */ -#define FAN_USE_RPM_MODE (1 << 0) +/* Values for .flags field */ +/* Enable automatic RPM control using tach input */ +#define FAN_USE_RPM_MODE (1 << 0) +/* Require a higher duty cycle to start up than to keep running */ +#define FAN_USE_FAST_START (1 << 1) /* The list of fans is instantiated in board.c. */ extern const struct fan_t fans[]; @@ -82,9 +85,6 @@ enum fan_status { }; enum fan_status fan_get_status(int ch); -/* Flag to enable automatic RPM control using tach input */ -#define FAN_USE_RPM_MODE (1 << 0) - /* Initialize the HW according to the desired flags */ void fan_channel_setup(int ch, unsigned int flags); |