input: Add ChromeOS EC keyboard driver

Use the key-matrix layer to interpret key scan information from the EC
and inject input based on the FDT-supplied key map. This driver registers
itself with the ChromeOS EC driver to perform communications.

The matrix-keypad FDT binding is used with a small addition to control
ghosting.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Luigi Semenzato <semenzato@chromium.org>
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/input/cros-ec-keyb.txt b/Documentation/devicetree/bindings/input/cros-ec-keyb.txt
new file mode 100644
index 000000000000..0f6355ce39b5
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/cros-ec-keyb.txt
@@ -0,0 +1,72 @@
+ChromeOS EC Keyboard
+
+Google's ChromeOS EC Keyboard is a simple matrix keyboard implemented on
+a separate EC (Embedded Controller) device. It provides a message for reading
+key scans from the EC. These are then converted into keycodes for processing
+by the kernel.
+
+This binding is based on matrix-keymap.txt and extends/modifies it as follows:
+
+Required properties:
+- compatible: "google,cros-ec-keyb"
+
+Optional properties:
+- google,needs-ghost-filter: True to enable a ghost filter for the matrix
+keyboard. This is recommended if the EC does not have its own logic or
+hardware for this.
+
+
+Example:
+
+cros-ec-keyb {
+        compatible = "google,cros-ec-keyb";
+        keypad,num-rows = <8>;
+        keypad,num-columns = <13>;
+        google,needs-ghost-filter;
+        /*
+         * Keymap entries take the form of 0xRRCCKKKK where
+         * RR=Row CC=Column KKKK=Key Code
+         * The values below are for a US keyboard layout and
+         * are taken from the Linux driver. Note that the
+         * 102ND key is not used for US keyboards.
+         */
+        linux,keymap = <
+                /* CAPSLCK F1         B          F10     */
+                0x0001003a 0x0002003b 0x00030030 0x00040044
+                /* N       =          R_ALT      ESC     */
+                0x00060031 0x0008000d 0x000a0064 0x01010001
+                /* F4      G          F7         H       */
+                0x0102003e 0x01030022 0x01040041 0x01060023
+                /* '       F9         BKSPACE    L_CTRL  */
+                0x01080028 0x01090043 0x010b000e 0x0200001d
+                /* TAB     F3         T          F6      */
+                0x0201000f 0x0202003d 0x02030014 0x02040040
+                /* ]       Y          102ND      [       */
+                0x0205001b 0x02060015 0x02070056 0x0208001a
+                /* F8      GRAVE      F2         5       */
+                0x02090042 0x03010029 0x0302003c 0x03030006
+                /* F5      6          -          \       */
+                0x0304003f 0x03060007 0x0308000c 0x030b002b
+                /* R_CTRL  A          D          F       */
+                0x04000061 0x0401001e 0x04020020 0x04030021
+                /* S       K          J          ;       */
+                0x0404001f 0x04050025 0x04060024 0x04080027
+                /* L       ENTER      Z          C       */
+                0x04090026 0x040b001c 0x0501002c 0x0502002e
+                /* V       X          ,          M       */
+                0x0503002f 0x0504002d 0x05050033 0x05060032
+                /* L_SHIFT /          .          SPACE   */
+                0x0507002a 0x05080035 0x05090034 0x050B0039
+                /* 1       3          4          2       */
+                0x06010002 0x06020004 0x06030005 0x06040003
+                /* 8       7          0          9       */
+                0x06050009 0x06060008 0x0608000b 0x0609000a
+                /* L_ALT   DOWN       RIGHT      Q       */
+                0x060a0038 0x060b006c 0x060c006a 0x07010010
+                /* E       R          W          I       */
+                0x07020012 0x07030013 0x07040011 0x07050017
+                /* U       R_SHIFT    P          O       */
+                0x07060016 0x07070036 0x07080019 0x07090018
+                /* UP      LEFT    */
+                0x070b0067 0x070c0069>;
+};