From b170291c3668807ed923748de2ebc7e707856f92 Mon Sep 17 00:00:00 2001 From: Vincent Palatin Date: Wed, 4 Jun 2014 11:45:13 -0700 Subject: [PATCH] zinger: do not cut output on up voltage transitions Update according to the current PD standard, a monotonic transition seems mandatory in all cases, so keep the voltage output enabled when increasing the output voltage. Signed-off-by: Vincent Palatin BRANCH=none BUG=chrome-os-partner:28331 TEST=connect Zinger to Fruitpie and probe the VBUS voltage during a transition. Change-Id: I3c728cc0049ca41536efd4f075139626b7d371da Reviewed-on: https://chromium-review.googlesource.com/202657 Reviewed-by: Alec Berg Commit-Queue: Vincent Palatin Tested-by: Vincent Palatin --- board/zinger/usb_pd_policy.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/board/zinger/usb_pd_policy.c b/board/zinger/usb_pd_policy.c index 04b04fca6b..e705bdf494 100644 --- a/board/zinger/usb_pd_policy.c +++ b/board/zinger/usb_pd_policy.c @@ -148,7 +148,8 @@ int pd_request_voltage(uint32_t rdo) ((pdo >> 10) & 0x3ff) * 50, (pdo & 0x3ff) * 10, ((rdo >> 10) & 0x3ff) * 10, (rdo & 0x3ff) * 10); - output_disable(); + if (idx - 1 < volt_idx) /* down voltage transition */ + output_disable(); /* TODO discharge ? */ volt_idx = idx - 1; set_output_voltage(voltages[volt_idx].select);