cros: adds cros_ec keyboard driver

This patch adds the driver for keyboard that's controlled by ChromeOS EC.
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Hung-ying Tyan <tyanh@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>

README

@@ -1443,6 +1443,11 @@ CBFS (Coreboot Filesystem) support
 		Export function i8042_kbd_init, i8042_tstc and i8042_getc
 		for cfb_console. Supports cursor blinking.
 
+		CONFIG_CROS_EC_KEYB
+		Enables a Chrome OS keyboard using the CROS_EC interface.
+		This uses CROS_EC to communicate with a second microcontroller
+		which provides key scans on request.
+
 - Video support:
 		CONFIG_VIDEO
 

doc/device-tree-bindings/input/cros-ec-keyb.txt

+CROS_EC Keyboard
+
+The CROS_EC (Matrix Keyboard Protocol) allows communcation with a secondary
+micro used for keyboard, and possible other features.
+
+The CROS_EC keyboard uses this protocol to receive key scans and produce input
+in U-Boot.
+
+Required properties :
+- compatible : "google,cros-ec-keyb"
+- google,key-rows : Number of key rows
+- google,key-columns : Number of key columns
+
+Optional properties, in addition to those specified by the shared
+matrix-keyboard bindings:
+
+- linux,fn-keymap: a second keymap, same specification as the
+  matrix-keyboard-controller spec but to be used when the KEY_FN modifier
+  key is pressed.
+- google,repeat-delay-ms : delay in milliseconds before repeat starts
+- google,repeat-rate-ms : delay between each subsequent key press
+- google,ghost-filter : enable ghost filtering for this device
+
+Example, taken from daisy:
+
+cros-ec-keyb {
+	compatible = "google,cros-ec-keyb";
+	google,key-rows = <8>;
+	google,key-columns = <13>;
+	google,ghost-filter;
+	google,repeat-delay-ms = <240>;
+	google,repeat-rate-ms = <30>;
+	/*
+		* 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 0x0002003c 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/Makefile

@@ -27,6 +27,7 @@ LIB	:= $(obj)libinput.o
 
 COBJS-$(CONFIG_I8042_KBD) += i8042.o
 COBJS-$(CONFIG_TEGRA_KEYBOARD) += tegra-kbc.o
+COBJS-$(CONFIG_CROS_EC_KEYB) += cros_ec_keyb.o
 ifdef CONFIG_PS2KBD
 COBJS-y += keyboard.o pc_keyb.o
 COBJS-$(CONFIG_PS2MULT) += ps2mult.o ps2ser.o

drivers/input/cros_ec_keyb.c

+/*
+ * Chromium OS Matrix Keyboard
+ *
+ * Copyright (c) 2012 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <cros_ec.h>
+#include <fdtdec.h>
+#include <input.h>
+#include <key_matrix.h>
+#include <stdio_dev.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+enum {
+	KBC_MAX_KEYS		= 8,	/* Maximum keys held down at once */
+};
+
+static struct keyb {
+	struct cros_ec_dev *dev;		/* The CROS_EC device */
+	struct input_config input;	/* The input layer */
+	struct key_matrix matrix;	/* The key matrix layer */
+	int key_rows;			/* Number of keyboard rows */
+	int key_cols;			/* Number of keyboard columns */
+	unsigned int repeat_delay_ms;	/* Time before autorepeat starts */
+	unsigned int repeat_rate_ms;	/* Autorepeat rate in ms */
+	int ghost_filter;		/* 1 to enable ghost filter, else 0 */
+	int inited;			/* 1 if keyboard is ready */
+} config;
+
+
+/**
+ * Check the keyboard controller and return a list of key matrix positions
+ * for which a key is pressed
+ *
+ * @param config	Keyboard config
+ * @param keys		List of keys that we have detected
+ * @param max_count	Maximum number of keys to return
+ * @return number of pressed keys, 0 for none
+ */
+static int check_for_keys(struct keyb *config,
+			   struct key_matrix_key *keys, int max_count)
+{
+	struct key_matrix_key *key;
+	struct mbkp_keyscan scan;
+	unsigned int row, col, bit, data;
+	int num_keys;
+
+	if (cros_ec_scan_keyboard(config->dev, &scan)) {
+		debug("%s: keyboard scan failed\n", __func__);
+		return -1;
+	}
+
+	for (col = num_keys = bit = 0; col < config->matrix.num_cols;
+			col++) {
+		for (row = 0; row < config->matrix.num_rows; row++) {
+			unsigned int mask = 1 << (bit & 7);
+
+			data = scan.data[bit / 8];
+			if ((data & mask) && num_keys < max_count) {
+				key = keys + num_keys++;
+				key->row = row;
+				key->col = col;
+				key->valid = 1;
+			}
+			bit++;
+		}
+	}
+
+	return num_keys;
+}
+
+/**
+ * Test if keys are available to be read
+ *
+ * @return 0 if no keys available, 1 if keys are available
+ */
+static int kbd_tstc(void)
+{
+	/* Just get input to do this for us */
+	return config.inited ? input_tstc(&config.input) : 0;
+}
+
+/**
+ * Read a key
+ *
+ * @return ASCII key code, or 0 if no key, or -1 if error
+ */
+static int kbd_getc(void)
+{
+	/* Just get input to do this for us */
+	return config.inited ? input_getc(&config.input) : 0;
+}
+
+/**
+ * Check the keyboard, and send any keys that are pressed.
+ *
+ * This is called by input_tstc() and input_getc() when they need more
+ * characters
+ *
+ * @param input		Input configuration
+ * @return 1, to indicate that we have something to look at
+ */
+int cros_ec_kbc_check(struct input_config *input)
+{
+	static struct key_matrix_key last_keys[KBC_MAX_KEYS];
+	static int last_num_keys;
+	struct key_matrix_key keys[KBC_MAX_KEYS];
+	int keycodes[KBC_MAX_KEYS];
+	int num_keys, num_keycodes;
+	int irq_pending, sent;
+
+	/*
+	 * Loop until the EC has no more keyscan records, or we have
+	 * received at least one character. This means we know that tstc()
+	 * will always return non-zero if keys have been pressed.
+	 *
+	 * Without this loop, a key release (which generates no new ascii
+	 * characters) will cause us to exit this function, and just tstc()
+	 * may return 0 before all keys have been read from the EC.
+	 */
+	do {
+		irq_pending = cros_ec_interrupt_pending(config.dev);
+		if (irq_pending) {
+			num_keys = check_for_keys(&config, keys, KBC_MAX_KEYS);
+			last_num_keys = num_keys;
+			memcpy(last_keys, keys, sizeof(keys));
+		} else {
+			/*
+			 * EC doesn't want to be asked, so use keys from last
+			 * time.
+			 */
+			num_keys = last_num_keys;
+			memcpy(keys, last_keys, sizeof(keys));
+		}
+
+		if (num_keys < 0)
+			return -1;
+		num_keycodes = key_matrix_decode(&config.matrix, keys,
+				num_keys, keycodes, KBC_MAX_KEYS);
+		sent = input_send_keycodes(input, keycodes, num_keycodes);
+	} while (irq_pending && !sent);
+
+	return 1;
+}
+
+/**
+ * Decode MBKP keyboard details from the device tree
+ *
+ * @param blob		Device tree blob
+ * @param node		Node to decode from
+ * @param config	Configuration data read from fdt
+ * @return 0 if ok, -1 on error
+ */
+static int cros_ec_keyb_decode_fdt(const void *blob, int node,
+				struct keyb *config)
+{
+	/*
+	 * Get keyboard rows and columns - at present we are limited to
+	 * 8 columns by the protocol (one byte per row scan)
+	 */
+	config->key_rows = fdtdec_get_int(blob, node, "google,key-rows", 0);
+	config->key_cols = fdtdec_get_int(blob, node, "google,key-columns", 0);
+	if (!config->key_rows || !config->key_cols ||
+			config->key_rows * config->key_cols / 8
+				> CROS_EC_KEYSCAN_COLS) {
+		debug("%s: Invalid key matrix size %d x %d\n", __func__,
+		      config->key_rows, config->key_cols);
+		return -1;
+	}
+	config->repeat_delay_ms = fdtdec_get_int(blob, node,
+						 "google,repeat-delay-ms", 0);
+	config->repeat_rate_ms = fdtdec_get_int(blob, node,
+						"google,repeat-rate-ms", 0);
+	config->ghost_filter = fdtdec_get_bool(blob, node,
+					       "google,ghost-filter");
+	return 0;
+}
+
+/**
+ * Set up the keyboard. This is called by the stdio device handler.
+ *
+ * We want to do this init when the keyboard is actually used rather than
+ * at start-up, since keyboard input may not currently be selected.
+ *
+ * @return 0 if ok, -1 on error
+ */
+static int cros_ec_init_keyboard(void)
+{
+	const void *blob = gd->fdt_blob;
+	int node;
+
+	config.dev = board_get_cros_ec_dev();
+	if (!config.dev) {
+		debug("%s: no cros_ec device: cannot init keyboard\n",
+		      __func__);
+		return -1;
+	}
+	node = fdtdec_next_compatible(blob, 0, COMPAT_GOOGLE_CROS_EC_KEYB);
+	if (node < 0) {
+		debug("%s: Node not found\n", __func__);
+		return -1;
+	}
+	if (cros_ec_keyb_decode_fdt(blob, node, &config))
+		return -1;
+	input_set_delays(&config.input, config.repeat_delay_ms,
+			 config.repeat_rate_ms);
+	if (key_matrix_init(&config.matrix, config.key_rows,
+			config.key_cols, config.ghost_filter)) {
+		debug("%s: cannot init key matrix\n", __func__);
+		return -1;
+	}
+	if (key_matrix_decode_fdt(&config.matrix, gd->fdt_blob, node)) {
+		debug("%s: Could not decode key matrix from fdt\n", __func__);
+		return -1;
+	}
+	config.inited = 1;
+	debug("%s: Matrix keyboard %dx%d ready\n", __func__, config.key_rows,
+	      config.key_cols);
+
+	return 0;
+}
+
+int drv_keyboard_init(void)
+{
+	struct stdio_dev dev;
+
+	if (input_init(&config.input, 0)) {
+		debug("%s: Cannot set up input\n", __func__);
+		return -1;
+	}
+	config.input.read_keys = cros_ec_kbc_check;
+
+	memset(&dev, '\0', sizeof(dev));
+	strcpy(dev.name, "cros-ec-keyb");
+	dev.flags = DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
+	dev.getc = kbd_getc;
+	dev.tstc = kbd_tstc;
+	dev.start = cros_ec_init_keyboard;
+
+	/* Register the device. cros_ec_init_keyboard() will be called soon */
+	return input_stdio_register(&dev);
+}

include/fdtdec.h

@@ -85,6 +85,7 @@ enum fdt_compat_id {
 	COMPAT_WOLFSON_WM8994_CODEC,	/* Wolfson WM8994 Sound Codec */
 	COMPAT_SAMSUNG_EXYNOS_SPI,	/* Exynos SPI */
 	COMPAT_GOOGLE_CROS_EC,		/* Google CROS_EC Protocol */
+	COMPAT_GOOGLE_CROS_EC_KEYB,	/* Google CROS_EC Keyboard */
 	COMPAT_SAMSUNG_EXYNOS_EHCI,	/* Exynos EHCI controller */
 	COMPAT_SAMSUNG_EXYNOS_USB_PHY,	/* Exynos phy controller for usb2.0 */
 	COMPAT_SAMSUNG_EXYNOS_TMU,	/* Exynos TMU */

lib/fdtdec.c

@@ -58,6 +58,7 @@ static const char * const compat_names[COMPAT_COUNT] = {
 	COMPAT(WOLFSON_WM8994_CODEC, "wolfson,wm8994-codec"),
 	COMPAT(SAMSUNG_EXYNOS_SPI, "samsung,exynos-spi"),
 	COMPAT(GOOGLE_CROS_EC, "google,cros-ec"),
+	COMPAT(GOOGLE_CROS_EC_KEYB, "google,cros-ec-keyb"),
 	COMPAT(SAMSUNG_EXYNOS_EHCI, "samsung,exynos-ehci"),
 	COMPAT(SAMSUNG_EXYNOS_USB_PHY, "samsung,exynos-usb-phy"),
 	COMPAT(SAMSUNG_EXYNOS_TMU, "samsung,exynos-tmu"),