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

[Hans de Goede <hdegoede@redhat.com>]

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@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
>>>>