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 <[email protected]>
Signed-off-by: Luigi Semenzato <[email protected]>
Signed-off-by: Vincent Palatin <[email protected]>
Acked-by: Dmitry Torokhov <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

Author: sjg20

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>;
+};

drivers/input/keyboard/Kconfig

@@ -628,4 +628,16 @@ config KEYBOARD_W90P910
 	  To compile this driver as a module, choose M here: the
 	  module will be called w90p910_keypad.
 
+config KEYBOARD_CROS_EC
+	tristate "ChromeOS EC keyboard"
+	select INPUT_MATRIXKMAP
+	depends on MFD_CROS_EC
+	help
+	  Say Y here to enable the matrix keyboard used by ChromeOS devices
+	  and implemented on the ChromeOS EC. You must enable one bus option
+	  (MFD_CROS_EC_I2C or MFD_CROS_EC_SPI) to use this.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called cros_ec_keyb.
+
 endif

drivers/input/keyboard/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_KEYBOARD_AMIGA)		+= amikbd.o
 obj-$(CONFIG_KEYBOARD_ATARI)		+= atakbd.o
 obj-$(CONFIG_KEYBOARD_ATKBD)		+= atkbd.o
 obj-$(CONFIG_KEYBOARD_BFIN)		+= bf54x-keys.o
+obj-$(CONFIG_KEYBOARD_CROS_EC)		+= cros_ec_keyb.o
 obj-$(CONFIG_KEYBOARD_DAVINCI)		+= davinci_keyscan.o
 obj-$(CONFIG_KEYBOARD_EP93XX)		+= ep93xx_keypad.o
 obj-$(CONFIG_KEYBOARD_GOLDFISH_EVENTS)	+= goldfish_events.o