lm4: Use low speed clock in deep sleep.

Changed the low power idle task to use the low speed clock in deep
sleep. The low power idle task is currently only enabled for Peppy,
Slippy, and Falco. This change decreases power consumption when
the AP is not running.

Note that the low speed clock is slow enough that the JTAG cannot be
used and the EC console UART cannot be used. To work around that,
this commit detects when the JTAG is in use and when the EC console
is in use, and will not use the low speed clock if either is in use.
The JTAG in use never clears after being set and the console in use
clears after a fixed timeout period.

BUG=None
BRANCH=None
TEST=Passes all unit tests.
Tested that the EC console works when in deep sleep.
Tested that it is possible to run flash_ec when in deep sleep and
using the low speed clock.

Change-Id: Ia65997eb8e607a5df9b2c7d68e4826bfb1e0194c
Signed-off-by: Alec Berg <alecaberg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/173326
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/common/console.c b/common/console.c
index 78fd96a7c7..f310ef41a7 100644
--- a/common/console.c
+++ b/common/console.c
@@ -4,7 +4,7 @@
  */
 
 /* Console module for Chrome EC */
-
+#include "clock.h"
 #include "console.h"
 #include "link_defs.h"
 #include "system.h"
@@ -519,6 +519,11 @@ static void console_handle_char(int c)
 
 void console_has_input(void)
 {
+#ifdef CONFIG_LOW_POWER_IDLE
+	/* Notify the clock module that the console is in use. */
+	clock_refresh_console_in_use();
+#endif
+
 	/* Wake up the console task */
 	task_wake(TASK_ID_CONSOLE);
 }