On Thu, Sep 29, 2016 at 7:35 AM, Jun Li <jun.li@xxxxxxx> wrote: > Hi Guenter, > >> -----Original Message----- >> From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb- >> owner@xxxxxxxxxxxxxxx] On Behalf Of Guenter Roeck >> Sent: Wednesday, August 24, 2016 5:11 AM >> To: Felipe Balbi <felipe.balbi@xxxxxxxxxxxxxxx> >> Cc: Chandra Sekhar Anagani <chandra.sekhar.anagani@xxxxxxxxx>; Bruce >> Ashfield <bruce.ashfield@xxxxxxxxxxxxx>; Bin Gao <bin.gao@xxxxxxxxx>; >> Pranav Tipnis <pranav.tipnis@xxxxxxxxx>; Heikki Krogerus >> <heikki.krogerus@xxxxxxxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; linux- >> usb@xxxxxxxxxxxxxxx; Guenter Roeck <groeck@xxxxxxxxxxxx> >> Subject: [RFC PATCH v3 1/2] usb: typec: USB Type-C Port Manager (tcpm) >> >> This driver implements the USB Type-C Power Delivery state machine >> for both source and sink ports. Alternate mode support is not >> fully implemented. >> >> The driver attaches to the USB Type-C class code implemented in >> the following patches. >> >> usb: typec: add driver for Intel Whiskey Cove PMIC USB Type-C PHY >> usb: USB Type-C connector class >> >> This driver only implements the state machine. Lower level drivers are >> responsible for >> - Reporting VBUS status and activating VBUS >> - Setting CC lines and providing CC line status >> - Setting line polarity >> - Activating and deactivating VCONN >> - Setting the current limit >> - Activating and deactivating PD message transfers >> - Sending and receiving PD messages >> >> The driver provides both a functional API as well as callbacks for >> lower level drivers. >> >> Signed-off-by: Guenter Roeck <groeck@xxxxxxxxxxxx> >> --- >> v3: >> - Improve TCPM state machine resiliency if there are spurious CC line >> changes >> while the state machine is in a transient change (waiting for a timeout) >> - Update current limit after CC voltage level changes on a port which is >> not >> PD capable. >> >> v2: >> - Only update polarity if setting it was successful >> If setting the CC line polarity in the driver was not successful, >> don't update the internal polarity state. >> - All PD messages are little endian; convert to and from CPU endianness. >> - Avoid comparisons against NULL. >> - Use u8/u16/u32 instead of uint8_t/uint16_t/uint32_t consistently. >> - Callbacks into tcpm need to be lockless to avoid timing problems >> in low level drivers. >> - Simplify callbacks; tcpm can request the current state of cc/vbus >> when it is ready to use it. >> >> drivers/usb/typec/Kconfig | 7 + >> drivers/usb/typec/Makefile | 1 + >> drivers/usb/typec/tcpm.c | 3163 >> ++++++++++++++++++++++++++++++++++++++++++++ >> drivers/usb/typec/tcpm.h | 137 ++ >> include/linux/usb/pd.h | 282 ++++ >> include/linux/usb/pd_bdo.h | 31 + >> include/linux/usb/pd_vdo.h | 412 ++++++ >> 7 files changed, 4033 insertions(+) >> create mode 100644 drivers/usb/typec/tcpm.c >> create mode 100644 drivers/usb/typec/tcpm.h >> create mode 100644 include/linux/usb/pd.h >> create mode 100644 include/linux/usb/pd_bdo.h >> create mode 100644 include/linux/usb/pd_vdo.h >> > > ... > >> + >> +static void run_state_machine(struct tcpm_port *port) >> +{ >> + int ret; >> + >> + port->enter_state = port->state; >> + switch (port->state) { >> + /* SRC states */ >> + case SRC_UNATTACHED: >> + tcpm_swap_complete(port, -ENOTCONN); >> + tcpm_src_detach(port); >> + tcpm_set_cc(port, TYPEC_CC_RP_DEF); >> + if (port->typec_caps.type == TYPEC_PORT_DRP) >> + tcpm_set_state(port, SNK_UNATTACHED, PD_T_DRP_SNK); > > With this and below, after disconnect, the DRP port state machine will be > in infinite loop of state transition between SRC_UNATTACHED <--> SNK_UNATTACHED, > correct? > Only while disconnected. It tries to alternatively connect as source and as sink (being configured as DRP). Once a CC line state change is reported it will transition out. I have a newer version of the patch (not yet published) which supports DRP toggling by the TCPC. With that enabled, TCPM does not change states until a CC state change is reported. Guenter > Li Jun > ... > >> + /* SNK states */ >> + case SNK_UNATTACHED: >> + tcpm_swap_complete(port, -ENOTCONN); >> + tcpm_snk_detach(port); >> + tcpm_set_cc(port, TYPEC_CC_RD); >> + if (port->typec_caps.type == TYPEC_PORT_DRP) >> + tcpm_set_state(port, SRC_UNATTACHED, PD_T_DRP_SRC); >> + break; >> -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
