Samus: Handle fan startup in the EC, not the fan controller

The fans on samus have a recommended minimum duty cycle of 20%
while running, but 30% in order to start. We've been using the
EC's built-in fan controller for the start requirement, but it
has a minimum fast-start duty cycle of 50%. It turns out that
that speed is noticeably noisy.

This change handles the startup with logic in the EC instead, so
that the fan only tries to spin at 30% initially (or if it drops
too much below the minimum turning speed).

BUG=chrome-os-partner:33429
BRANCH=ToT,samus
TEST=make buildall -j

Boot the system, let it idle with the browser windows closed, the
browse a bit, then idle. Listen for changes to the fans.

Before, I could hear the fans kick in and out as the AP load
changed. Now it's much quieter.

Change-Id: Id35215520c064eb6843686ec8bb5f3618dac6cf6
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/227658
Reviewed-by: Randall Spangler <rspangler@chromium.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/test/fan.tasklist b/test/fan.tasklist
new file mode 100644
index 0000000000..c72de237cd
--- /dev/null
+++ b/test/fan.tasklist
@@ -0,0 +1,17 @@
+/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/**
+ * List of enabled tasks in the priority order
+ *
+ * The first one has the lowest priority.
+ *
+ * For each task, use the macro TASK_TEST(n, r, d, s) where :
+ * 'n' in the name of the task
+ * 'r' in the main routine of the task
+ * 'd' in an opaque parameter passed to the routine at startup
+ * 's' is the stack size in bytes; must be a multiple of 8
+ */
+#define CONFIG_TEST_TASK_LIST   /* No test task */