Re: [PATCH v6 03/14] usb: typec: tcpci: update ROLE_CONTROL for DRP

Heikki Krogerus
2020-09-15T12:14:34Z

On Mon, Aug 31, 2020 at 07:59:16PM -0700, Badhri Jagan Sridharan wrote:
> ROLE_CONTROL register would not have the actual CC terminations
> unless the port does not set ROLE_CONTROL.DRP. For DRP ports,
> CC_STATUS.cc1/cc2 indicates the final terminations applied
> when TCPC enters potential_connect_as_source/_sink.
> For DRP ports, infer port role from CC_STATUS and set corresponding
> CC terminations before setting the orientation.
>
> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
> Changes since v1:
> - Changing patch version to v6 to fix version number confusion.
> ---
> drivers/usb/typec/tcpm/tcpci.c | 37 +++++++++++++++++++++++++++++++++-
> 1 file changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> index 7d36d5e2d3f7..7d9491ba62fb 100644
> --- a/drivers/usb/typec/tcpm/tcpci.c
> +++ b/drivers/usb/typec/tcpm/tcpci.c
> @@ -191,12 +191,47 @@ static int tcpci_set_polarity(struct tcpc_dev *tcpc,
> struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> unsigned int reg;
> int ret;
> + enum typec_cc_status cc1, cc2;
>
> - /* Keep the disconnect cc line open */
> + /* Obtain Rp setting from role control */
> ret = regmap_read(tcpci->regmap, TCPC_ROLE_CTRL, &reg);
> if (ret < 0)
> return ret;
>
> + ret = tcpci_get_cc(tcpc, &cc1, &cc2);
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * When port has drp toggling enabled, ROLE_CONTROL would only have the initial
> + * terminations for the toggling and does not indicate the final cc
> + * terminations when ConnectionResult is 0 i.e. drp toggling stops and
> + * the connection is resolbed. Infer port role from TCPC_CC_STATUS based on the
> + * terminations seen. The port role is then used to set the cc terminations.
> + */
> + if (reg & TCPC_ROLE_CTRL_DRP) {
> + /* Disable DRP for the OPEN setting to take effect */
> + reg = reg & ~TCPC_ROLE_CTRL_DRP;
> +
> + if (polarity == TYPEC_POLARITY_CC2) {
> + reg &= ~(TCPC_ROLE_CTRL_CC2_MASK << TCPC_ROLE_CTRL_CC2_SHIFT);
> + /* Local port is source */
> + if (cc2 == TYPEC_CC_RD)
> + /* Role control would have the Rp setting when DRP was enabled */
> + reg |= TCPC_ROLE_CTRL_CC_RP << TCPC_ROLE_CTRL_CC2_SHIFT;
> + else
> + reg |= TCPC_ROLE_CTRL_CC_RD << TCPC_ROLE_CTRL_CC2_SHIFT;
> + } else {
> + reg &= ~(TCPC_ROLE_CTRL_CC1_MASK << TCPC_ROLE_CTRL_CC1_SHIFT);
> + /* Local port is source */
> + if (cc1 == TYPEC_CC_RD)
> + /* Role control would have the Rp setting when DRP was enabled */
> + reg |= TCPC_ROLE_CTRL_CC_RP << TCPC_ROLE_CTRL_CC1_SHIFT;
> + else
> + reg |= TCPC_ROLE_CTRL_CC_RD << TCPC_ROLE_CTRL_CC1_SHIFT;
> + }
> + }
> +
> if (polarity == TYPEC_POLARITY_CC2)
> reg |= TCPC_ROLE_CTRL_CC_OPEN << TCPC_ROLE_CTRL_CC1_SHIFT;
> else
> --
> 2.28.0.402.g5ffc5be6b7-goog

--
heikki