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UPSTREAM: usb: typec: tcpci: don't touch CC line if it's Vconn source

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With the AMS and Collision Avoidance, tcpm often needs to change the CC's
termination. When one CC line is sourcing Vconn, if we still change its
termination, the voltage of the another CC line is likely to be fluctuant
and unstable.

Therefore, we should verify whether a CC line is sourcing Vconn before
changing its termination and only change the termination that is not
a Vconn line. This can be done by reading the Vconn Present bit of
POWER_ STATUS register. To determine the polarity, we can read the
Plug Orientation bit of TCPC_CONTROL register. Since Vconn can only be
sourced if Plug Orientation is set.

Bug: 254441685
Fixes: 0908c5aca3 ("usb: typec: tcpm: AMS and Collision Avoidance")
cc: <stable@vger.kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20220113092943.752372-1-xu.yang_2@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 5638b0dfb6)
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: I99269bf66fea9735b1227386f8beafce4187b9f4
This commit is contained in:
Xu Yang
2022-01-13 17:29:43 +08:00
committed by Treehugger Robot
parent 8f2ac1deb1
commit 2317bc5306
2 changed files with 27 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
drivers/usb/typec/tcpm/tcpci.c
View File

@@ -85,9 +85,25 @@ static int tcpci_write16(struct tcpci *tcpci, unsigned int reg, u16 val)
static int tcpci_set_cc(struct tcpc_dev *tcpc, enum typec_cc_status cc)
{
struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
bool vconn_pres;
enum typec_cc_polarity polarity = TYPEC_POLARITY_CC1;
unsigned int reg;
int ret;
ret = regmap_read(tcpci->regmap, TCPC_POWER_STATUS, &reg);
if (ret < 0)
return ret;
vconn_pres = !!(reg & TCPC_POWER_STATUS_VCONN_PRES);
if (vconn_pres) {
ret = regmap_read(tcpci->regmap, TCPC_TCPC_CTRL, &reg);
if (ret < 0)
return ret;
if (reg & TCPC_TCPC_CTRL_ORIENTATION)
polarity = TYPEC_POLARITY_CC2;
}
switch (cc) {
case TYPEC_CC_RA:
reg = (TCPC_ROLE_CTRL_CC_RA << TCPC_ROLE_CTRL_CC1_SHIFT) |
@@ -122,6 +138,16 @@ static int tcpci_set_cc(struct tcpc_dev *tcpc, enum typec_cc_status cc)
break;
}
if (vconn_pres) {
if (polarity == TYPEC_POLARITY_CC2) {
reg &= ~(TCPC_ROLE_CTRL_CC1_MASK << TCPC_ROLE_CTRL_CC1_SHIFT);
reg |= (TCPC_ROLE_CTRL_CC_OPEN << TCPC_ROLE_CTRL_CC1_SHIFT);
} else {
reg &= ~(TCPC_ROLE_CTRL_CC2_MASK << TCPC_ROLE_CTRL_CC2_SHIFT);
reg |= (TCPC_ROLE_CTRL_CC_OPEN << TCPC_ROLE_CTRL_CC2_SHIFT);
}
}
ret = regmap_write(tcpci->regmap, TCPC_ROLE_CTRL, reg);
if (ret < 0)
return ret;

1
drivers/usb/typec/tcpm/tcpci.h
View File

@@ -98,6 +98,7 @@
#define TCPC_POWER_STATUS_SOURCING_VBUS BIT(4)
#define TCPC_POWER_STATUS_VBUS_DET BIT(3)
#define TCPC_POWER_STATUS_VBUS_PRES BIT(2)
#define TCPC_POWER_STATUS_VCONN_PRES BIT(1)
#define TCPC_POWER_STATUS_SINKING_VBUS BIT(0)
#define TCPC_FAULT_STATUS 0x1f