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

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Hi,

On 15-04-19 20:38, Guenter Roeck wrote:
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.

Ok, I've refactored this as requested for v2.

Regards,

Hans


Fixes: ea3b4d5523bc("usb: typec: fusb302: Resolve fixed power role ...")
Cc: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
  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




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