usbpd: support dynamic PDO selection

Support dynamic PDO selection CONFIG_USB_PD_DPS.
This config controls the charging voltage and power according to the
input power and battery configuration.

DPS would continuously evaluate the system load and current charging
voltage, and decide a new one by below:
1. If the PDO can fulfill system desired power.
2. If the PDO is efficient for the battery configuration.

To detect if the system load cannot be fulfilled by the current PDO,
it checks:
1. if the input current closes to the PDO current limit.
2. if the input power closes to the PDO maximum power.

To detect if the system load can be fulfilled by a more efficient PDO,
it checks:
- if the voltage of a new PDO is closer to the battery voltage than the
   current PDO, and the power is able fulfill the system load.

BUG=b:169532537
TEST=1. tested on asurada, the charging voltage is able to switch to
     different PDOs under different system loads
     2. tested that the DPS is able to switch charge port
     (e.g. C1 12V -> C0 9V) based on the provided PDOs.
BRANCH=asurada

Change-Id: I7c7706b331dc0d4f8ac68569dc7ed852fc9308e3
Signed-off-by: Eric Yilun Lin <yllin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2897064
Tested-by: Eric Yilun Lin <yllin@google.com>
Reviewed-by: Diana Z <dzigterman@chromium.org>
Commit-Queue: Eric Yilun Lin <yllin@google.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/config.h b/include/config.h
index 1366d86662..f157047273 100644
--- a/include/config.h
+++ b/include/config.h
@@ -4115,6 +4115,15 @@
 #undef CONFIG_USB_PD_TCPMV2
 
 /*
+ * Enable dynamic PDO selection.
+ *
+ * DPS picks a power efficient voltage regarding to the battery configuration
+ * and the system loading. It monitors PIn (Power In), so VBUS/IBUS ADC
+ * should be supported on the platform.
+ */
+#undef CONFIG_USB_PD_DPS
+
+/*
  * Device Types for TCPMv2.
  *
  * Exactly one must be defined when CONFIG_USB_PD_TCPMV2 is defined.