From e186c770f736070635921917caad565faaaafd12 Mon Sep 17 00:00:00 2001 From: Shawn Nematbakhsh Date: Fri, 1 Jul 2016 16:21:46 -0700 Subject: [PATCH] tcpm: anx74xx: Improve CC eye diagram BUG=None TEST=Observe improvement on CC eye diagram BRANCH=None Change-Id: Ic7ab68427eb235c889c547a7d2a485047edce77d Signed-off-by: Shawn Nematbakhsh Reviewed-on: https://chromium-review.googlesource.com/358104 Commit-Ready: Shawn N Tested-by: Shawn N Reviewed-by: David Hendricks --- driver/tcpm/anx74xx.c | 8 ++++++++ driver/tcpm/anx74xx.h | 2 ++ 2 files changed, 10 insertions(+) diff --git a/driver/tcpm/anx74xx.c b/driver/tcpm/anx74xx.c index 652259ef1a..ed38fccb23 100644 --- a/driver/tcpm/anx74xx.c +++ b/driver/tcpm/anx74xx.c @@ -778,6 +778,14 @@ int anx74xx_tcpm_init(int port) /* HPD pin output enable*/ rv |= tcpc_write(port, ANX74XX_REG_HPD_CTRL_0, ANX74XX_REG_HPD_DEFAULT); + if (rv) + return EC_ERROR_UNKNOWN; + + /* Decrease BMC TX lowest swing voltage */ + rv |= tcpc_read(port, ANX74XX_REG_ANALOG_CTRL_11, ®); + if (rv) + return EC_ERROR_UNKNOWN; + rv = tcpc_write(port, ANX74XX_REG_ANALOG_CTRL_11, (reg & 0x3f) | 0x40); if (rv) return EC_ERROR_UNKNOWN; diff --git a/driver/tcpm/anx74xx.h b/driver/tcpm/anx74xx.h index b25de49bf4..972be9648a 100644 --- a/driver/tcpm/anx74xx.h +++ b/driver/tcpm/anx74xx.h @@ -69,6 +69,8 @@ #define ANX74XX_REG_AUX_SWAP_SET_CC1 0x30 #define ANX74XX_REG_AUX_SWAP_SET_CC2 0xc0 +#define ANX74XX_REG_ANALOG_CTRL_11 0x4c + #define ANX74XX_REG_MUX_DP_MODE_ACE_CC1 0x49 #define ANX74XX_REG_MUX_DP_MODE_ACE_CC2 0x86 #define ANX74XX_REG_MUX_DP_MODE_BDF_CC1 0x61