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    Subject[PATCH 0/3] input/touchscreen: Synaptics RMI4 Touchscreen Driver
    This patch implements a driver supporting Synaptics ClearPad and other
    touchscreens that use the RMI4 protocol, as defined here:

    This patch is against the v2.6.38 tag of Linus' kernel tree, commit
    521cb40b0c44418a4fd36dc633f575813d59a43d. Note that previous patches
    were against the synaptics-rmi4 branch of Dmitry Torokhov's input
    tree. At Dmitry's request, we have switched the base for our work
    to v2.6.38 - this should make it easier for people to pick up and
    test this and future patches.

    I2C functionality was previously ACK'ed by Jean Delvare on 2010/05/29.

    SPI code is included, but not ready for prime time yet.

    This patch completely supersedes the previous patch of 2011/03/01. In addition
    to benefitting from more thorough review and testing, this version of the
    driver includes the following:

    - preliminary implementation of rmi_f11 relative motion support

    - support for RMI4 Function 19 (capacitive buttons)

    - fixes for a kernel panic in rmi_f34.c configuration

    - additional sysfs parameters, particularly for rmi_f11 (2D pointing)

    - major restructuring of platformdata to (hopefully) simplify its
    use while also allowing more operating parameters to be specified
    via the platformdata.

    - deletion of more legacy code and behavior

    This patch supports a system having one or more RMI sensors attached to it.
    Most devices have just a single touch sensor, but some have more than one.
    An example is the Fuse concept phone, which has 4 RMI sensors in it).
    Each sensor implements a number of RMI4 functions, which are best represented
    as devices on the bus.

    The patch is divide into three parts:

    1/3 - the core of the driver, implementing the logical rmi_bus and
    access to the physical bus (rmi_i2c and rmi_spi).

    2/3 - the sensor and function implementation.

    3/3 - Makefile and Kconfig

    The driver core manages the sensors on a device via the rmi bus (/sys/bus/rmi),
    handles interfunction communications (mostly IRQ notifications from F01 to
    other functions), and proxies register read/write requests to the appropriate
    physical layer for a given sensor.

    Individual sensors are presented on the bus as /sys/bus/rmi/devices/sensor00,
    /sys/bus/rmi/devices/sensor01/, and so on.

    Functions for each sensor are presented as devices next to that sensor, for
    example /sys/bus/rmi/devices/sensor00f01, /sys/bus/rmi/devices/sensor00f11,
    and so on.

    Sensor driver instances are attached to the bus using the kernel device discovery
    mechanism. A future release will do the same for function driver instances,
    but for now we use an ad hoc mechanism to match functions to sensors.

    We chose this approach because almost all RMI4 functions are independent
    of one another. The sole exception is F01, and its primary interaction
    with other functions is to notify them of the need to read or write data
    from or to the sensor. In the long term, this will allow 3rd parties to
    implement additional RMI functions in a modular fashion, without having
    to modify the core driver implementation or the implementation of unrelated

    Comments and other feedback on this driver are welcomed.

    Bill Manson
    Allie Xiong
    Christopher Heiny

    Cc: Jean Delvare <>
    Cc: Linus Walleij <>
    Cc: Naveen Kumar Gaddipati <>
    Cc: Joeri de Gram <>


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