• Tony Lindgren's avatar
    phy: cpcap-usb: Prevent USB line glitches from waking up modem · e0fcfcda
    Tony Lindgren authored
    [ Upstream commit 63078b6b ]
    
    The micro-USB connector on Motorola Mapphone devices can be muxed between
    the SoC and the mdm6600 modem. But even when used for the SoC, configuring
    the PHY with ID pin grounded will wake up the modem from idle state. Looks
    like the issue is probably caused by line glitches.
    
    We can prevent the glitches by using a previously unknown mode of the
    GPIO mux to prevent the USB lines from being connected to the moden while
    configuring the USB PHY, and enable the USB lines after configuring the
    PHY.
    
    Note that this only prevents waking up mdm6600 as regular USB A-host mode,
    and does not help when connected to a lapdock. The lapdock specific issue
    still needs to be debugged separately.
    
    Cc: Merlijn Wajer <merlijn@wizzup.org>
    Cc: Pavel Machek <pavel@ucw.cz>
    Cc: Sebastian Reichel <sre@kernel.org>
    Acked-by: default avatarPavel Machek <pavel@ucw.cz>
    Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
    Signed-off-by: default avatarKishon Vijay Abraham I <kishon@ti.com>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    e0fcfcda
phy-cpcap-usb.c 15.7 KB