[1/3] usb: typec: tcpm: Add start_srp_connection_detect callback

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Apr 15, 2019 at 07:53:58PM +0200, Hans de Goede wrote:
> Hi Guenter,
> 
> On 15-04-19 17:51, Guenter Roeck wrote:
> >On Sat, Apr 13, 2019 at 10:39:53PM +0200, Hans de Goede wrote:
> >>Some tcpc device-drivers need to explicitly be told to watch for connection
> >>events, otherwise the tcpc will not generate any TCPM_CC_EVENTs and devices
> >>being plugged into the Type-C port will not be noticed.
> >>
> >>For dual-role ports tcpm_start_drp_toggling() is used to tell the tcpc to
> >>watch for connection events. But for single-role ports we've so far been
> >>falling back to just calling tcpm_set_cc(). For some tcpc-s such as the
> >>fusb302 this is not enough and no TCPM_CC_EVENT will be generated.
> >>
> >>This commit adds a new start_srp_connection_detect callback to tcpc_dev
> >>and when this is implemented calls this in place of start_drp_toggling
> >>for SRP devices.
> >>
> >
> >Do we indeed need an additional callback for this purpose, or would a single
> >"start_connection_detect" call to replace start_drp_toggling be sufficient ?
> >If necessary, we could add the port type as argument (if the low level driver
> >doesn't already know that).
> 
> A single "start_connection_detect" call to replace start_drp_toggling will be
> sufficient AFAICT.
> 
> If you prefer that option, I can rework the patch-set accordingly.
> 

Yes, I do. I find it quite pointless to have two callbacks if exactly one
is ever called.

Thanks,
Guenter

> Regards,
> 
> Hans
> 
> 
> 
> >>Fixes: ea3b4d5523bc("usb: typec: fusb302: Resolve fixed power role ...")
> >>Cc: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
> >>Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> >>---
> >>  drivers/usb/typec/tcpm/tcpm.c | 8 ++++++++
> >>  include/linux/usb/tcpm.h      | 6 ++++++
> >>  2 files changed, 14 insertions(+)
> >>
> >>diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> >>index a2233d72ae7c..1af54af90b50 100644
> >>--- a/drivers/usb/typec/tcpm/tcpm.c
> >>+++ b/drivers/usb/typec/tcpm/tcpm.c
> >>@@ -2553,6 +2553,14 @@ static bool tcpm_start_drp_toggling(struct tcpm_port *port,
> >>  			return true;
> >>  	}
> >>+	if (port->tcpc->start_srp_connection_detect &&
> >>+	    port->port_type != TYPEC_PORT_DRP) {
> >>+		tcpm_log_force(port, "Start SRP connection detection");
> >>+		ret = port->tcpc->start_srp_connection_detect(port->tcpc, cc);
> >>+		if (!ret)
> >>+			return true;
> >>+	}
> >>+
> >>  	return false;
> >>  }
> >>diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
> >>index 0c532ca3f079..bf2bbbf2e2b2 100644
> >>--- a/include/linux/usb/tcpm.h
> >>+++ b/include/linux/usb/tcpm.h
> >>@@ -125,6 +125,10 @@ struct tcpc_config {
> >>   *		Optional; if supported by hardware, called to start DRP
> >>   *		toggling. DRP toggling is stopped automatically if
> >>   *		a connection is established.
> >>+ * @start_srp_connection_detect:
> >>+ *		Optional; if supported by hardware, called to start connection
> >>+ *		detection for single role ports. Connection detection is stopped
> >>+ *		automatically if a connection is established.
> >>   * @try_role:	Optional; called to set a preferred role
> >>   * @pd_transmit:Called to transmit PD message
> >>   * @mux:	Pointer to multiplexer data
> >>@@ -149,6 +153,8 @@ struct tcpc_dev {
> >>  			 enum typec_role role, enum typec_data_role data);
> >>  	int (*start_drp_toggling)(struct tcpc_dev *dev,
> >>  				  enum typec_cc_status cc);
> >>+	int (*start_srp_connection_detect)(struct tcpc_dev *dev,
> >>+					   enum typec_cc_status cc);
> >>  	int (*try_role)(struct tcpc_dev *dev, int role);
> >>  	int (*pd_transmit)(struct tcpc_dev *dev, enum tcpm_transmit_type type,
> >>  			   const struct pd_message *msg);
> >>-- 
> >>2.21.0
> >>