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    usb: typec: tcpm: Do not disconnect link for self powered devices · 4a91c26e
    Badhri Jagan Sridharan 提交于
    [ Upstream commit 23b5f73266e59a598c1e5dd435d87651b5a7626b ]
    
    During HARD_RESET the data link is disconnected.
    For self powered device, the spec is advising against doing that.
    
    >From USB_PD_R3_0
    7.1.5 Response to Hard Resets
    Device operation during and after a Hard Reset is defined as follows:
    Self-powered devices Should Not disconnect from USB during a Hard Reset
    (see Section 9.1.2).
    Bus powered devices will disconnect from USB during a Hard Reset due to the
    loss of their power source.
    
    Tackle this by letting TCPM know whether the device is self or bus powered.
    
    This overcomes unnecessary port disconnections from hard reset.
    Also, speeds up the enumeration time when connected to Type-A ports.
    Signed-off-by: NBadhri Jagan Sridharan <badhri@google.com>
    Reviewed-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
    ---------
    Version history:
    V3:
    Rebase on top of usb-next
    
    V2:
    Based on feedback from heikki.krogerus@linux.intel.com
    - self_powered added to the struct tcpm_port which is populated from
      a. "connector" node of the device tree in tcpm_fw_get_caps()
      b. "self_powered" node of the tcpc_config in tcpm_copy_caps
    
    Based on feedbase from linux@roeck-us.net
    - Code was refactored
    - SRC_HARD_RESET_VBUS_OFF sets the link state to false based
      on self_powered flag
    
    V1 located here:
    https://lkml.org/lkml/2018/9/13/94Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    Signed-off-by: NSasha Levin <sashal@kernel.org>
    Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
    4a91c26e
tcpm.h 5.7 KB