02b332a063
Maxim TCPC has additional ADCs and low current(1ua) current source to measure the impedance of CC and SBU pins. When tcpm invokes the check_contaminant callback, Maxim TCPC measures the impedance of the CC & SBU pins and when the impedance measured is less than 1MOhm, it is assumed that USB-C port is contaminated. CC comparators are also checked to differentiate between presence of sink and contaminant. Once USB-C is deemed to be contaminated, MAXIM TCPC has additional hardware to disable normal DRP toggling cycle and enable 1ua on CC pins once every 2.4secs/4.8secs. Maxim TCPC interrupts AP once the impedance on the CC pin is above the 1MOhm threshold. The Maxim tcpc driver then signals TCPM_PORT_CLEAN to restart toggling. Renaming tcpci_maxim.c to tcpci_maxim_core.c and moving reg read/write helper functions to the tcpci_maxim.h header file. Signed-off-by: Badhri Jagan Sridharan <badhri@google.com> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Link: https://lore.kernel.org/r/20230114093246.1933321-3-badhri@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.