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usb: typec: tcpm: Implement enabling Auto Discharge disconnect support

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TCPCI spec allows TCPC hardware to autonomously discharge the vbus
capacitance upon disconnect. The expectation is that the TCPM enables
AutoDischargeDisconnect while entering SNK/SRC_ATTACHED states. Hardware
then automously discharges vbus when the vbus falls below a certain
threshold i.e. VBUS_SINK_DISCONNECT_THRESHOLD.

Apart from enabling the vbus discharge circuit, AutoDischargeDisconnect
is also used a flag to move TCPCI based TCPC implementations into
Attached.Snk/Attached.Src state as mentioned in
Figure 4-15. TCPC State Diagram before a Connection of the
USB Type-C Port Controller Interface Specification.
In such TCPC implementations, setting AutoDischargeDisconnect would
prevent TCPC into entering "Connection_Invalid" state as well.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20201029063138.1429760-8-badhri@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Badhri Jagan Sridharan
2020-10-28 23:31:35 -07:00
committed by Greg Kroah-Hartman
parent 2fc58b36e9
commit f321a02cae
2 changed files with 71 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
include/linux/usb/tcpm.h
View File

@@ -86,6 +86,18 @@ enum tcpm_transmit_type {
* @frs_sourcing_vbus:
* Optional; Called to notify that vbus is now being sourced.
* Low level drivers can perform chip specific operations, if any.
* @enable_auto_vbus_discharge:
* Optional; TCPCI spec based TCPC implementations can optionally
* support hardware to autonomously dischrge vbus upon disconnecting
* as sink or source. TCPM signals TCPC to enable the mechanism upon
* entering connected state and signals disabling upon disconnect.
* @set_auto_vbus_discharge_threshold:
* Mandatory when enable_auto_vbus_discharge is implemented. TCPM
* calls this function to allow lower levels drivers to program the
* vbus threshold voltage below which the vbus discharge circuit
* will be turned on. requested_vbus_voltage is set to 0 when vbus
* is going to disappear knowingly i.e. during PR_SWAP and
* HARD_RESET etc.
*/
struct tcpc_dev {
struct fwnode_handle *fwnode;
@@ -113,6 +125,9 @@ struct tcpc_dev {
int (*set_bist_data)(struct tcpc_dev *dev, bool on);
int (*enable_frs)(struct tcpc_dev *dev, bool enable);
void (*frs_sourcing_vbus)(struct tcpc_dev *dev);
int (*enable_auto_vbus_discharge)(struct tcpc_dev *dev, bool enable);
int (*set_auto_vbus_discharge_threshold)(struct tcpc_dev *dev, enum typec_pwr_opmode mode,
bool pps_active, u32 requested_vbus_voltage);
};
struct tcpm_port;