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authorBadhri Jagan Sridharan <badhri@google.com>2020-12-02 07:08:38 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-12-09 16:49:54 +0300
commit28b43d3d746b89fc112fe681e018b39b43495dad (patch)
treef1065b2ccfceb23a41cfe7905c1c84eb81c4908c /include/linux/usb
parent3bac42f02d41dd85da7afb9ffc3f4539fad20cc5 (diff)
downloadlinux-28b43d3d746b89fc112fe681e018b39b43495dad.tar.xz
usb: typec: tcpm: Introduce vsafe0v for vbus
TCPM at present lacks the notion of VSAFE0V. There are three vbus threshold levels that are critical to track: a. vSafe5V - VBUS “5 volts” as defined by the USB PD specification. b. vSinkDisconnect - Threshold used for transition from Attached.SNK to Unattached.SNK. c. vSafe0V - VBUS “0 volts” as defined by the USB PD specification. Tracking vSafe0V is crucial for entry into Try.SNK and Attached.SRC and turning vbus back on by the source in response to hard reset. >From "4.5.2.2.8.2 Exiting from AttachWait.SRC State" section in the Type-C spec: "The port shall transition to Attached.SRC when VBUS is at vSafe0V and the SRC.Rd state is detected on exactly one of the CC1 or CC2 pins for at least tCCDebounce." "A DRP that strongly prefers the Sink role may optionally transition to Try.SNK instead of Attached.SRC when VBUS is at vSafe0V and the SRC.Rd state is detected on exactly one of the CC1 or CC2 pins for at least tCCDebounce." >From "7.1.5 Response to Hard Resets" section in the PD spec: "After establishing the vSafe0V voltage condition on VBUS, the Source Shall wait tSrcRecover before re-applying VCONN and restoring VBUS to vSafe5V." vbus_present in the TCPM code tracks vSafe5V(vbus_present is true) and vSinkDisconnect(vbus_present is false). This change adds is_vbus_vsafe0v callback which when set makes TCPM query for vSafe0V voltage level when needed. Since not all TCPC controllers might have the capability to report vSafe0V, TCPM assumes that vSafe0V is same as vSinkDisconnect when is_vbus_vsafe0v callback is not set. This allows TCPM to continue to support controllers which don't have the support for reporting vSafe0V. Introducing vSafe0V helps fix the failure reported at "Step 15. CVS verifies PUT remains in AttachWait.SRC for 500ms" of "TD 4.7.2 Try. SNK DRP Connect DRP Test" of "Universal Serial Bus Type-C (USB Type-C) Functional Test Specification Chapters 4 and 5". Here the compliance tester intentionally maintains vbus at greater than vSafe0V and expects the Product under test to stay in AttachWait.SRC till vbus drops to vSafe0V. Reviewed-by: Guenter Roeck <linux@roeck-us.net> Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Signed-off-by: Badhri Jagan Sridharan <badhri@google.com> Link: https://lore.kernel.org/r/20201202040840.663578-1-badhri@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/linux/usb')
-rw-r--r--include/linux/usb/tcpm.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
index efaedd7e8a18..f4a18427f5c4 100644
--- a/include/linux/usb/tcpm.h
+++ b/include/linux/usb/tcpm.h
@@ -98,6 +98,12 @@ enum tcpm_transmit_type {
* 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.
+ * @is_vbus_vsafe0v:
+ * Optional; TCPCI spec based TCPC implementations are expected to
+ * detect VSAFE0V voltage level at vbus. When detection of VSAFE0V
+ * is supported by TCPC, set this callback for TCPM to query
+ * whether vbus is at VSAFE0V when needed.
+ * Returns true when vbus is at VSAFE0V, false otherwise.
*/
struct tcpc_dev {
struct fwnode_handle *fwnode;
@@ -128,6 +134,7 @@ struct tcpc_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);
+ bool (*is_vbus_vsafe0v)(struct tcpc_dev *dev);
};
struct tcpm_port;