Add Word Per Minute calculation feature (#8054)

* Add Word Per Minute calculation feature

* Fix copyright info

* Remove header from quantum.c, setup overloadable keycode inclusion for WPM, update docs

* Simplify logic for keycode filtering

* Adding link from summary to wpm_feature info

* Update docs/feature_wpm.md

Typo in function prototype example in docs

Co-Authored-By: James Young <18669334+noroadsleft@users.noreply.github.com>

* Add WPM transport via i2c

Co-authored-by: James Young <18669334+noroadsleft@users.noreply.github.com>

8 files changed, 169 insertions, 0 deletions

diff --git a/common_features.mk b/common_features.mk
index 269ca2b137..50b1127dc6 100644
--- a/common_features.mk
+++ b/common_features.mk
@@ -322,6 +322,11 @@ ifeq ($(strip $(USB_HID_ENABLE)), yes)
     include $(TMK_DIR)/protocol/usb_hid.mk
 endif
 
+ifeq ($(strip $(WPM_ENABLE)), yes)
+    SRC += $(QUANTUM_DIR)/wpm.c
+    OPT_DEFS += -DWPM_ENABLE
+endif
+
 ifeq ($(strip $(ENCODER_ENABLE)), yes)
     SRC += $(QUANTUM_DIR)/encoder.c
     OPT_DEFS += -DENCODER_ENABLE
diff --git a/docs/_summary.md b/docs/_summary.md
index d6186bbf99..4a6e6996eb 100644
--- a/docs/_summary.md
+++ b/docs/_summary.md
@@ -80,6 +80,7 @@
     * [Terminal](feature_terminal.md)
     * [Unicode](feature_unicode.md)
     * [Userspace](feature_userspace.md)
+    * [WPM Calculation](feature_wpm.md)
 
   * Hardware Features
     * Displays
diff --git a/docs/feature_wpm.md b/docs/feature_wpm.md
new file mode 100644
index 0000000000..12dd080579
--- /dev/null
+++ b/docs/feature_wpm.md
@@ -0,0 +1,25 @@
+# Word Per Minute (WPM) Calculcation
+
+The WPM feature uses time between keystrokes to compute a rolling average words
+per minute rate and makes this available for various uses.
+
+Enable the WPM system by adding this to your `rules.mk`:
+
+    WPM_ENABLE = yes
+
+For split keyboards using soft serial, the computed WPM
+score will be available on the master AND slave half.
+
+## Public Functions
+
+`uint8_t get_current_wpm(void);`
+This function returns the current WPM as an unsigned integer.
+
+
+## Customized keys for WPM calc
+
+By default, the WPM score only includes letters, numbers, space and some
+punctuation.  If you want to change the set of characters considered as part of
+the WPM calculation, you can implement `wpm_keycode_user(uint16_t keycode)`
+and return true for any characters you would like included in the calculation,
+or false to not count that particular keycode.
diff --git a/quantum/quantum.c b/quantum/quantum.c
index 749a08eea9..49767819df 100644
--- a/quantum/quantum.c
+++ b/quantum/quantum.c
@@ -192,6 +192,12 @@ bool process_record_quantum(keyrecord_t *record) {
     }
 #endif
 
+#ifdef WPM_ENABLE
+    if (record->event.pressed) {
+	update_wpm(keycode);
+    }
+#endif
+
 #ifdef TAP_DANCE_ENABLE
     preprocess_tap_dance(keycode, record);
 #endif
@@ -645,6 +651,10 @@ void matrix_scan_quantum() {
     encoder_read();
 #endif
 
+#ifdef WPM_ENABLE
+  decay_wpm();
+#endif
+
 #ifdef HAPTIC_ENABLE
     haptic_task();
 #endif
diff --git a/quantum/quantum.h b/quantum/quantum.h
index d03ba5942a..191407fabb 100644
--- a/quantum/quantum.h
+++ b/quantum/quantum.h
@@ -178,6 +178,10 @@ extern layer_state_t layer_state;
 #    include "via.h"
 #endif
 
+#ifdef WPM_ENABLE
+#    include "wpm.h"
+#endif
+
 // Function substitutions to ease GPIO manipulation
 #if defined(__AVR__)
 typedef uint8_t pin_t;
diff --git a/quantum/split_common/transport.c b/quantum/split_common/transport.c
index ab421adc4a..3234a3ef55 100644
--- a/quantum/split_common/transport.c
+++ b/quantum/split_common/transport.c
@@ -35,6 +35,9 @@ typedef struct _I2C_slave_buffer_t {
 #    ifdef ENCODER_ENABLE
     uint8_t encoder_state[NUMBER_OF_ENCODERS];
 #    endif
+#    ifdef WPM_ENABLE
+    uint8_t current_wpm;
+#    endif
 } I2C_slave_buffer_t;
 
 static I2C_slave_buffer_t *const i2c_buffer = (I2C_slave_buffer_t *)i2c_slave_reg;
@@ -43,6 +46,7 @@ static I2C_slave_buffer_t *const i2c_buffer = (I2C_slave_buffer_t *)i2c_slave_re
 #    define I2C_RGB_START offsetof(I2C_slave_buffer_t, rgblight_sync)
 #    define I2C_KEYMAP_START offsetof(I2C_slave_buffer_t, smatrix)
 #    define I2C_ENCODER_START offsetof(I2C_slave_buffer_t, encoder_state)
+#    define I2C_WPM_START offsetof(I2C_slave_buffer_t, current_wpm)
 
 #    define TIMEOUT 100
 
@@ -79,6 +83,14 @@ bool transport_master(matrix_row_t matrix[]) {
     encoder_update_raw(i2c_buffer->encoder_state);
 #    endif
 
+#    ifdef WPM_ENABLE
+    uint8_t current_wpm = get_current_wpm();
+    if(current_wpm != i2c_buffer->current_wpm) {
+        if (i2c_writeReg(SLAVE_I2C_ADDRESS, I2C_WPM_START, (void *)&current_wpm, sizeof(current_wpm), TIMEOUT) >= 0) {
+            i2c_buffer->current_wpm = current_wpm;
+        }
+    }
+#    endif
     return true;
 }
 
@@ -102,6 +114,10 @@ void transport_slave(matrix_row_t matrix[]) {
 #    ifdef ENCODER_ENABLE
     encoder_state_raw(i2c_buffer->encoder_state);
 #    endif
+
+#    ifdef WPM_ENABLE
+    set_current_wpm(i2c_buffer->current_wpm);
+#    endif
 }
 
 void transport_master_init(void) { i2c_init(); }
@@ -126,6 +142,9 @@ typedef struct _Serial_m2s_buffer_t {
 #    ifdef BACKLIGHT_ENABLE
     uint8_t backlight_level;
 #    endif
+#    ifdef WPM_ENABLE
+    uint8_t current_wpm;
+#    endif
 } Serial_m2s_buffer_t;
 
 #    if defined(RGBLIGHT_ENABLE) && defined(RGBLIGHT_SPLIT)
@@ -228,6 +247,10 @@ bool transport_master(matrix_row_t matrix[]) {
     encoder_update_raw((uint8_t *)serial_s2m_buffer.encoder_state);
 #    endif
 
+#    ifdef WPM_ENABLE
+    // Write wpm to slave
+    serial_m2s_buffer.current_wpm = get_current_wpm();
+#    endif
     return true;
 }
 
@@ -244,6 +267,10 @@ void transport_slave(matrix_row_t matrix[]) {
 #    ifdef ENCODER_ENABLE
     encoder_state_raw((uint8_t *)serial_s2m_buffer.encoder_state);
 #    endif
+
+#    ifdef WPM_ENABLE
+     set_current_wpm(serial_m2s_buffer.current_wpm);
+#    endif
 }
 
 #endif
diff --git a/quantum/wpm.c b/quantum/wpm.c
new file mode 100644
index 0000000000..d4c971f313
--- /dev/null
+++ b/quantum/wpm.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright 2020 Richard Sutherland (rich@brickbots.com)
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "wpm.h"
+
+//WPM Stuff
+static uint8_t current_wpm = 0;
+static uint8_t latest_wpm = 0;
+static uint16_t wpm_timer = 0;
+
+//This smoothing is 40 keystrokes
+static const float wpm_smoothing = 0.0487;
+
+void set_current_wpm(uint8_t new_wpm) { current_wpm = new_wpm; }
+
+uint8_t get_current_wpm(void) { return current_wpm; }
+
+bool wpm_keycode(uint16_t keycode) { return wpm_keycode_kb(keycode); }
+
+__attribute__((weak)) bool wpm_keycode_kb(uint16_t keycode) { return wpm_keycode_user(keycode); }
+
+__attribute__((weak)) bool wpm_keycode_user(uint16_t keycode) {
+
+    if ((keycode >= QK_MOD_TAP && keycode <= QK_MOD_TAP_MAX) || (keycode >= QK_LAYER_TAP && keycode <= QK_LAYER_TAP_MAX) || (keycode >= QK_MODS && keycode <= QK_MODS_MAX)) {
+        keycode = keycode & 0xFF;
+    } else if (keycode > 0xFF) {
+	keycode = 0;
+    }
+    if((keycode >= KC_A && keycode <= KC_0) || (keycode >= KC_TAB && keycode <= KC_SLASH)) {
+	return true;
+    }
+
+    return false;
+}
+
+
+void update_wpm(uint16_t keycode) {
+    if(wpm_keycode(keycode)) {
+	if(wpm_timer > 0) {
+	    latest_wpm = 60000 / timer_elapsed(wpm_timer) / 5;
+	    current_wpm = (latest_wpm - current_wpm) * wpm_smoothing + current_wpm;
+	}
+	wpm_timer = timer_read();
+    }
+}
+
+void decay_wpm(void) {
+  if (timer_elapsed(wpm_timer) > 1000) {
+	current_wpm = (0 - current_wpm) * wpm_smoothing +
+		current_wpm;
+	wpm_timer = timer_read();
+  }
+}
diff --git a/quantum/wpm.h b/quantum/wpm.h
new file mode 100644
index 0000000000..fa0b6d1288
--- /dev/null
+++ b/quantum/wpm.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2020 Richard Sutherland (rich@brickbots.com)
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "quantum.h"
+
+bool wpm_keycode(uint16_t keycode);
+bool wpm_keycode_kb(uint16_t keycode);
+bool wpm_keycode_user(uint16_t keycode);
+
+void set_current_wpm(uint8_t);
+uint8_t get_current_wpm(void);
+void update_wpm(uint16_t);
+
+void decay_wpm(void);