summaryrefslogtreecommitdiff
path: root/board
diff options
context:
space:
mode:
authorVic Yang <victoryang@chromium.org>2013-03-04 10:42:01 +0800
committerChromeBot <chrome-bot@google.com>2013-03-04 16:24:56 -0800
commit6249a400696f270e7c9216db8e2998d7331f4613 (patch)
treebe6828005a687d5d479f90b6f94f1bd54a332319 /board
parentd86df6c38883435c9df5de3bd7ba1c2b35b67316 (diff)
downloadchrome-ec-6249a400696f270e7c9216db8e2998d7331f4613.tar.gz
spring: set maximum allowed duty cycle
We should allow a minimum amount of current input in case the battery is dead. BUG=chrome-os-partner:14319 TEST=Boot with a dead battery BRANCH=none Change-Id: I3c172d43c8190ed2dc5d421dcf2b5aaf0e88ecd9 Signed-off-by: Vic Yang <victoryang@chromium.org> Reviewed-on: https://gerrit.chromium.org/gerrit/44510 Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
Diffstat (limited to 'board')
-rw-r--r--board/spring/usb_charging.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/board/spring/usb_charging.c b/board/spring/usb_charging.c
index ce864e1d9f..cf17170129 100644
--- a/board/spring/usb_charging.c
+++ b/board/spring/usb_charging.c
@@ -39,6 +39,7 @@
#define I_LIMIT_3000MA 0
/* PWM control loop parameters */
+#define PWM_CTRL_MAX_DUTY 96 /* Minimum current for dead battery */
#define PWM_CTRL_BEGIN_OFFSET 30
#define PWM_CTRL_OC_MARGIN 15
#define PWM_CTRL_OC_DETECT_TIME (800 * MSEC)
@@ -249,6 +250,8 @@ void board_pwm_nominal_duty_cycle(int percent)
if (battery_current(&dummy))
board_pwm_duty_cycle(percent);
+ else if (percent + PWM_CTRL_BEGIN_OFFSET > PWM_CTRL_MAX_DUTY)
+ board_pwm_duty_cycle(PWM_CTRL_MAX_DUTY);
else
board_pwm_duty_cycle(percent + PWM_CTRL_BEGIN_OFFSET);
nominal_pwm_duty = percent;