14 files changed, 3037 insertions, 0 deletions
diff --git a/drivers/led/issi/is31fl3218.c b/drivers/led/issi/is31fl3218.c
new file mode 100644
index 0000000000..d43863ac4b
--- /dev/null
+++ b/drivers/led/issi/is31fl3218.c
@@ -0,0 +1,96 @@
+/* Copyright 2018 Jason Williams (Wilba)
+ *
+ * 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 "is31fl3218.h"
+#include "i2c_master.h"
+
+// This is the full 8-bit address
+#define ISSI_ADDRESS 0b10101000
+
+// These are the register addresses
+#define ISSI_REG_SHUTDOWN 0x00
+#define ISSI_REG_PWM 0x01
+#define ISSI_REG_CONTROL 0x13
+#define ISSI_REG_UPDATE 0x16
+#define ISSI_REG_RESET 0x17
+
+// Default timeout if no I2C response
+#define ISSI_TIMEOUT 100
+
+// Reusable buffer for transfers
+uint8_t g_twi_transfer_buffer[20];
+
+// IS31FL3218 has 18 PWM outputs and a fixed I2C address, so no chaining.
+// If used as RGB LED driver, LEDs are assigned RGB,RGB,RGB,RGB,RGB,RGB
+uint8_t g_pwm_buffer[18];
+bool    g_pwm_buffer_update_required = false;
+
+void IS31FL3218_write_register(uint8_t reg, uint8_t data) {
+    g_twi_transfer_buffer[0] = reg;
+    g_twi_transfer_buffer[1] = data;
+    i2c_transmit(ISSI_ADDRESS, g_twi_transfer_buffer, 2, ISSI_TIMEOUT);
+}
+
+void IS31FL3218_write_pwm_buffer(uint8_t *pwm_buffer) {
+    g_twi_transfer_buffer[0] = ISSI_REG_PWM;
+    for (int i = 0; i < 18; i++) {
+        g_twi_transfer_buffer[1 + i] = pwm_buffer[i];
+    }
+
+    i2c_transmit(ISSI_ADDRESS, g_twi_transfer_buffer, 19, ISSI_TIMEOUT);
+}
+
+void IS31FL3218_init(void) {
+    // In case we ever want to reinitialize (?)
+    IS31FL3218_write_register(ISSI_REG_RESET, 0x00);
+
+    // Turn off software shutdown
+    IS31FL3218_write_register(ISSI_REG_SHUTDOWN, 0x01);
+
+    // Set all PWM values to zero
+    for (uint8_t i = 0; i < 18; i++) {
+        IS31FL3218_write_register(ISSI_REG_PWM + i, 0x00);
+    }
+
+    // Enable all channels
+    for (uint8_t i = 0; i < 3; i++) {
+        IS31FL3218_write_register(ISSI_REG_CONTROL + i, 0b00111111);
+    }
+
+    // Load PWM registers and LED Control register data
+    IS31FL3218_write_register(ISSI_REG_UPDATE, 0x01);
+}
+
+void IS31FL3218_set_color(int index, uint8_t red, uint8_t green, uint8_t blue) {
+    g_pwm_buffer[index * 3 + 0]  = red;
+    g_pwm_buffer[index * 3 + 1]  = green;
+    g_pwm_buffer[index * 3 + 2]  = blue;
+    g_pwm_buffer_update_required = true;
+}
+
+void IS31FL3218_set_color_all(uint8_t red, uint8_t green, uint8_t blue) {
+    for (int i = 0; i < 6; i++) {
+        IS31FL3218_set_color(i, red, green, blue);
+    }
+}
+
+void IS31FL3218_update_pwm_buffers(void) {
+    if (g_pwm_buffer_update_required) {
+        IS31FL3218_write_pwm_buffer(g_pwm_buffer);
+        // Load PWM registers and LED Control register data
+        IS31FL3218_write_register(ISSI_REG_UPDATE, 0x01);
+    }
+    g_pwm_buffer_update_required = false;
+}
diff --git a/drivers/led/issi/is31fl3218.h b/drivers/led/issi/is31fl3218.h
new file mode 100644
index 0000000000..fa760da191
--- /dev/null
+++ b/drivers/led/issi/is31fl3218.h
@@ -0,0 +1,25 @@
+/* Copyright 2018 Jason Williams (Wilba)
+ *
+ * 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 <stdint.h>
+#include <stdbool.h>
+
+void IS31FL3218_init(void);
+void IS31FL3218_set_color(int index, uint8_t red, uint8_t green, uint8_t blue);
+void IS31FL3218_set_color_all(uint8_t red, uint8_t green, uint8_t blue);
+void IS31FL3218_update_pwm_buffers(void);
diff --git a/drivers/led/issi/is31fl3731-simple.c b/drivers/led/issi/is31fl3731-simple.c
new file mode 100644
index 0000000000..d295772f5e
--- /dev/null
+++ b/drivers/led/issi/is31fl3731-simple.c
@@ -0,0 +1,233 @@
+/* Copyright 2017 Jason Williams
+ * Copyright 2018 Jack Humbert
+ * Copyright 2019 Clueboard
+ *
+ * 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 "is31fl3731-simple.h"
+#include "i2c_master.h"
+#include "wait.h"
+
+// This is a 7-bit address, that gets left-shifted and bit 0
+// set to 0 for write, 1 for read (as per I2C protocol)
+// The address will vary depending on your wiring:
+// 0b1110100 AD <-> GND
+// 0b1110111 AD <-> VCC
+// 0b1110101 AD <-> SCL
+// 0b1110110 AD <-> SDA
+#define ISSI_ADDR_DEFAULT 0x74
+
+#define ISSI_REG_CONFIG 0x00
+#define ISSI_REG_CONFIG_PICTUREMODE 0x00
+#define ISSI_REG_CONFIG_AUTOPLAYMODE 0x08
+#define ISSI_REG_CONFIG_AUDIOPLAYMODE 0x18
+
+#define ISSI_CONF_PICTUREMODE 0x00
+#define ISSI_CONF_AUTOFRAMEMODE 0x04
+#define ISSI_CONF_AUDIOMODE 0x08
+
+#define ISSI_REG_PICTUREFRAME 0x01
+
+#define ISSI_REG_SHUTDOWN 0x0A
+#define ISSI_REG_AUDIOSYNC 0x06
+
+#define ISSI_COMMANDREGISTER 0xFD
+#define ISSI_BANK_FUNCTIONREG 0x0B  // helpfully called 'page nine'
+
+#ifndef ISSI_TIMEOUT
+#    define ISSI_TIMEOUT 100
+#endif
+
+#ifndef ISSI_PERSISTENCE
+#    define ISSI_PERSISTENCE 0
+#endif
+
+// Transfer buffer for TWITransmitData()
+uint8_t g_twi_transfer_buffer[20];
+
+// These buffers match the IS31FL3731 PWM registers 0x24-0xB3.
+// Storing them like this is optimal for I2C transfers to the registers.
+// We could optimize this and take out the unused registers from these
+// buffers and the transfers in IS31FL3731_write_pwm_buffer() but it's
+// probably not worth the extra complexity.
+uint8_t g_pwm_buffer[LED_DRIVER_COUNT][144];
+bool    g_pwm_buffer_update_required[LED_DRIVER_COUNT] = {false};
+
+/* There's probably a better way to init this... */
+#if LED_DRIVER_COUNT == 1
+uint8_t g_led_control_registers[LED_DRIVER_COUNT][18] = {{0}};
+#elif LED_DRIVER_COUNT == 2
+uint8_t g_led_control_registers[LED_DRIVER_COUNT][18] = {{0}, {0}};
+#elif LED_DRIVER_COUNT == 3
+uint8_t g_led_control_registers[LED_DRIVER_COUNT][18] = {{0}, {0}, {0}};
+#elif LED_DRIVER_COUNT == 4
+uint8_t g_led_control_registers[LED_DRIVER_COUNT][18] = {{0}, {0}, {0}, {0}};
+#endif
+bool g_led_control_registers_update_required[LED_DRIVER_COUNT] = {false};
+
+// This is the bit pattern in the LED control registers
+// (for matrix A, add one to register for matrix B)
+//
+//  reg -  b7  b6  b5  b4  b3  b2  b1  b0
+// 0x00 - R08,R07,R06,R05,R04,R03,R02,R01
+// 0x02 - G08,G07,G06,G05,G04,G03,G02,R00
+// 0x04 - B08,B07,B06,B05,B04,B03,G01,G00
+// 0x06 -  - , - , - , - , - ,B02,B01,B00
+// 0x08 -  - , - , - , - , - , - , - , -
+// 0x0A - B17,B16,B15, - , - , - , - , -
+// 0x0C - G17,G16,B14,B13,B12,B11,B10,B09
+// 0x0E - R17,G15,G14,G13,G12,G11,G10,G09
+// 0x10 - R16,R15,R14,R13,R12,R11,R10,R09
+
+void IS31FL3731_write_register(uint8_t addr, uint8_t reg, uint8_t data) {
+    g_twi_transfer_buffer[0] = reg;
+    g_twi_transfer_buffer[1] = data;
+
+#if ISSI_PERSISTENCE > 0
+    for (uint8_t i = 0; i < ISSI_PERSISTENCE; i++) {
+        if (i2c_transmit(addr << 1, g_twi_transfer_buffer, 2, ISSI_TIMEOUT) == 0) {
+            break;
+        }
+    }
+#else
+    i2c_transmit(addr << 1, g_twi_transfer_buffer, 2, ISSI_TIMEOUT);
+#endif
+}
+
+void IS31FL3731_write_pwm_buffer(uint8_t addr, uint8_t *pwm_buffer) {
+    // assumes bank is already selected
+
+    // transmit PWM registers in 9 transfers of 16 bytes
+    // g_twi_transfer_buffer[] is 20 bytes
+
+    // iterate over the pwm_buffer contents at 16 byte intervals
+    for (int i = 0; i < 144; i += 16) {
+        // set the first register, e.g. 0x24, 0x34, 0x44, etc.
+        g_twi_transfer_buffer[0] = 0x24 + i;
+        // copy the data from i to i+15
+        // device will auto-increment register for data after the first byte
+        // thus this sets registers 0x24-0x33, 0x34-0x43, etc. in one transfer
+        for (int j = 0; j < 16; j++) {
+            g_twi_transfer_buffer[1 + j] = pwm_buffer[i + j];
+        }
+
+#if ISSI_PERSISTENCE > 0
+        for (uint8_t i = 0; i < ISSI_PERSISTENCE; i++) {
+            if (i2c_transmit(addr << 1, g_twi_transfer_buffer, 17, ISSI_TIMEOUT) == 0) break;
+        }
+#else
+        i2c_transmit(addr << 1, g_twi_transfer_buffer, 17, ISSI_TIMEOUT);
+#endif
+    }
+}
+
+void IS31FL3731_init(uint8_t addr) {
+    // In order to avoid the LEDs being driven with garbage data
+    // in the LED driver's PWM registers, first enable software shutdown,
+    // then set up the mode and other settings, clear the PWM registers,
+    // then disable software shutdown.
+
+    // select "function register" bank
+    IS31FL3731_write_register(addr, ISSI_COMMANDREGISTER, ISSI_BANK_FUNCTIONREG);
+
+    // enable software shutdown
+    IS31FL3731_write_register(addr, ISSI_REG_SHUTDOWN, 0x00);
+
+    // this delay was copied from other drivers, might not be needed
+    wait_ms(10);
+
+    // picture mode
+    IS31FL3731_write_register(addr, ISSI_REG_CONFIG, ISSI_REG_CONFIG_PICTUREMODE);
+    // display frame 0
+    IS31FL3731_write_register(addr, ISSI_REG_PICTUREFRAME, 0x00);
+    // audio sync off
+    IS31FL3731_write_register(addr, ISSI_REG_AUDIOSYNC, 0x00);
+
+    // select bank 0
+    IS31FL3731_write_register(addr, ISSI_COMMANDREGISTER, 0);
+
+    // turn off all LEDs in the LED control register
+    for (int i = 0x00; i <= 0x11; i++) {
+        IS31FL3731_write_register(addr, i, 0x00);
+    }
+
+    // turn off all LEDs in the blink control register (not really needed)
+    for (int i = 0x12; i <= 0x23; i++) {
+        IS31FL3731_write_register(addr, i, 0x00);
+    }
+
+    // set PWM on all LEDs to 0
+    for (int i = 0x24; i <= 0xB3; i++) {
+        IS31FL3731_write_register(addr, i, 0x00);
+    }
+
+    // select "function register" bank
+    IS31FL3731_write_register(addr, ISSI_COMMANDREGISTER, ISSI_BANK_FUNCTIONREG);
+
+    // disable software shutdown
+    IS31FL3731_write_register(addr, ISSI_REG_SHUTDOWN, 0x01);
+
+    // select bank 0 and leave it selected.
+    // most usage after initialization is just writing PWM buffers in bank 0
+    // as there's not much point in double-buffering
+    IS31FL3731_write_register(addr, ISSI_COMMANDREGISTER, 0);
+}
+
+void IS31FL3731_set_value(int index, uint8_t value) {
+    if (index >= 0 && index < DRIVER_LED_TOTAL) {
+        is31_led led = g_is31_leds[index];
+
+        // Subtract 0x24 to get the second index of g_pwm_buffer
+        g_pwm_buffer[led.driver][led.v - 0x24]   = value;
+        g_pwm_buffer_update_required[led.driver] = true;
+    }
+}
+
+void IS31FL3731_set_value_all(uint8_t value) {
+    for (int i = 0; i < DRIVER_LED_TOTAL; i++) {
+        IS31FL3731_set_value(i, value);
+    }
+}
+
+void IS31FL3731_set_led_control_register(uint8_t index, bool value) {
+    is31_led led = g_is31_leds[index];
+
+    uint8_t control_register = (led.v - 0x24) / 8;
+    uint8_t bit_value        = (led.v - 0x24) % 8;
+
+    if (value) {
+        g_led_control_registers[led.driver][control_register] |= (1 << bit_value);
+    } else {
+        g_led_control_registers[led.driver][control_register] &= ~(1 << bit_value);
+    }
+
+    g_led_control_registers_update_required[led.driver] = true;
+}
+
+void IS31FL3731_update_pwm_buffers(uint8_t addr, uint8_t index) {
+    if (g_pwm_buffer_update_required[index]) {
+        IS31FL3731_write_pwm_buffer(addr, g_pwm_buffer[index]);
+        g_pwm_buffer_update_required[index] = false;
+    }
+}
+
+void IS31FL3731_update_led_control_registers(uint8_t addr, uint8_t index) {
+    if (g_led_control_registers_update_required[index]) {
+        for (int i = 0; i < 18; i++) {
+            IS31FL3731_write_register(addr, i, g_led_control_registers[index][i]);
+        }
+        g_led_control_registers_update_required[index] = false;
+    }
+}
diff --git a/drivers/led/issi/is31fl3731-simple.h b/drivers/led/issi/is31fl3731-simple.h
new file mode 100644
index 0000000000..ecde31eed5
--- /dev/null
+++ b/drivers/led/issi/is31fl3731-simple.h
@@ -0,0 +1,208 @@
+/* Copyright 2017 Jason Williams
+ * Copyright 2018 Jack Humbert
+ * Copyright 2019 Clueboard
+ *
+ * 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 <stdint.h>
+#include <stdbool.h>
+#include "progmem.h"
+
+typedef struct is31_led {
+    uint8_t driver : 2;
+    uint8_t v;
+} __attribute__((packed)) is31_led;
+
+extern const is31_led __flash g_is31_leds[DRIVER_LED_TOTAL];
+
+void IS31FL3731_init(uint8_t addr);
+void IS31FL3731_write_register(uint8_t addr, uint8_t reg, uint8_t data);
+void IS31FL3731_write_pwm_buffer(uint8_t addr, uint8_t *pwm_buffer);
+
+void IS31FL3731_set_value(int index, uint8_t value);
+void IS31FL3731_set_value_all(uint8_t value);
+
+void IS31FL3731_set_led_control_register(uint8_t index, bool value);
+
+// This should not be called from an interrupt
+// (eg. from a timer interrupt).
+// Call this while idle (in between matrix scans).
+// If the buffer is dirty, it will update the driver with the buffer.
+void IS31FL3731_update_pwm_buffers(uint8_t addr, uint8_t index);
+void IS31FL3731_update_led_control_registers(uint8_t addr, uint8_t index);
+
+#define C1_1 0x24
+#define C1_2 0x25
+#define C1_3 0x26
+#define C1_4 0x27
+#define C1_5 0x28
+#define C1_6 0x29
+#define C1_7 0x2A
+#define C1_8 0x2B
+
+#define C1_9 0x2C
+#define C1_10 0x2D
+#define C1_11 0x2E
+#define C1_12 0x2F
+#define C1_13 0x30
+#define C1_14 0x31
+#define C1_15 0x32
+#define C1_16 0x33
+
+#define C2_1 0x34
+#define C2_2 0x35
+#define C2_3 0x36
+#define C2_4 0x37
+#define C2_5 0x38
+#define C2_6 0x39
+#define C2_7 0x3A
+#define C2_8 0x3B
+
+#define C2_9 0x3C
+#define C2_10 0x3D
+#define C2_11 0x3E
+#define C2_12 0x3F
+#define C2_13 0x40
+#define C2_14 0x41
+#define C2_15 0x42
+#define C2_16 0x43
+
+#define C3_1 0x44
+#define C3_2 0x45
+#define C3_3 0x46
+#define C3_4 0x47
+#define C3_5 0x48
+#define C3_6 0x49
+#define C3_7 0x4A
+#define C3_8 0x4B
+
+#define C3_9 0x4C
+#define C3_10 0x4D
+#define C3_11 0x4E
+#define C3_12 0x4F
+#define C3_13 0x50
+#define C3_14 0x51
+#define C3_15 0x52
+#define C3_16 0x53
+
+#define C4_1 0x54
+#define C4_2 0x55
+#define C4_3 0x56
+#define C4_4 0x57
+#define C4_5 0x58
+#define C4_6 0x59
+#define C4_7 0x5A
+#define C4_8 0x5B
+
+#define C4_9 0x5C
+#define C4_10 0x5D
+#define C4_11 0x5E
+#define C4_12 0x5F
+#define C4_13 0x60
+#define C4_14 0x61
+#define C4_15 0x62
+#define C4_16 0x63
+
+#define C5_1 0x64
+#define C5_2 0x65
+#define C5_3 0x66
+#define C5_4 0x67
+#define C5_5 0x68
+#define C5_6 0x69
+#define C5_7 0x6A
+#define C5_8 0x6B
+
+#define C5_9 0x6C
+#define C5_10 0x6D
+#define C5_11 0x6E
+#define C5_12 0x6F
+#define C5_13 0x70
+#define C5_14 0x71
+#define C5_15 0x72
+#define C5_16 0x73
+
+#define C6_1 0x74
+#define C6_2 0x75
+#define C6_3 0x76
+#define C6_4 0x77
+#define C6_5 0x78
+#define C6_6 0x79
+#define C6_7 0x7A
+#define C6_8 0x7B
+
+#define C6_9 0x7C
+#define C6_10 0x7D
+#define C6_11 0x7E
+#define C6_12 0x7F
+#define C6_13 0x80
+#define C6_14 0x81
+#define C6_15 0x82
+#define C6_16 0x83
+
+#define C7_1 0x84
+#define C7_2 0x85
+#define C7_3 0x86
+#define C7_4 0x87
+#define C7_5 0x88
+#define C7_6 0x89
+#define C7_7 0x8A
+#define C7_8 0x8B
+
+#define C7_9 0x8C
+#define C7_10 0x8D
+#define C7_11 0x8E
+#define C7_12 0x8F
+#define C7_13 0x90
+#define C7_14 0x91
+#define C7_15 0x92
+#define C7_16 0x93
+
+#define C8_1 0x94
+#define C8_2 0x95
+#define C8_3 0x96
+#define C8_4 0x97
+#define C8_5 0x98
+#define C8_6 0x99
+#define C8_7 0x9A
+#define C8_8 0x9B
+
+#define C8_9 0x9C
+#define C8_10 0x9D
+#define C8_11 0x9E
+#define C8_12 0x9F
+#define C8_13 0xA0
+#define C8_14 0xA1
+#define C8_15 0xA2
+#define C8_16 0xA3
+
+#define C9_1 0xA4
+#define C9_2 0xA5
+#define C9_3 0xA6
+#define C9_4 0xA7
+#define C9_5 0xA8
+#define C9_6 0xA9
+#define C9_7 0xAA
+#define C9_8 0xAB
+
+#define C9_9 0xAC
+#define C9_10 0xAD
+#define C9_11 0xAE
+#define C9_12 0xAF
+#define C9_13 0xB0
+#define C9_14 0xB1
+#define C9_15 0xB2
+#define C9_16 0xB3
diff --git a/drivers/led/issi/is31fl3731.c b/drivers/led/issi/is31fl3731.c
new file mode 100644
index 0000000000..110bdc1be4
--- /dev/null
+++ b/drivers/led/issi/is31fl3731.c
@@ -0,0 +1,237 @@
+/* Copyright 2017 Jason Williams
+ * Copyright 2018 Jack Humbert
+ *
+ * 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 "is31fl3731.h"
+#include "i2c_master.h"
+#include "wait.h"
+
+// This is a 7-bit address, that gets left-shifted and bit 0
+// set to 0 for write, 1 for read (as per I2C protocol)
+// The address will vary depending on your wiring:
+// 0b1110100 AD <-> GND
+// 0b1110111 AD <-> VCC
+// 0b1110101 AD <-> SCL
+// 0b1110110 AD <-> SDA
+#define ISSI_ADDR_DEFAULT 0x74
+
+#define ISSI_REG_CONFIG 0x00
+#define ISSI_REG_CONFIG_PICTUREMODE 0x00
+#define ISSI_REG_CONFIG_AUTOPLAYMODE 0x08
+#define ISSI_REG_CONFIG_AUDIOPLAYMODE 0x18
+
+#define ISSI_CONF_PICTUREMODE 0x00
+#define ISSI_CONF_AUTOFRAMEMODE 0x04
+#define ISSI_CONF_AUDIOMODE 0x08
+
+#define ISSI_REG_PICTUREFRAME 0x01
+
+#define ISSI_REG_SHUTDOWN 0x0A
+#define ISSI_REG_AUDIOSYNC 0x06
+
+#define ISSI_COMMANDREGISTER 0xFD
+#define ISSI_BANK_FUNCTIONREG 0x0B  // helpfully called 'page nine'
+
+#ifndef ISSI_TIMEOUT
+#    define ISSI_TIMEOUT 100
+#endif
+
+#ifndef ISSI_PERSISTENCE
+#    define ISSI_PERSISTENCE 0
+#endif
+
+// Transfer buffer for TWITransmitData()
+uint8_t g_twi_transfer_buffer[20];
+
+// These buffers match the IS31FL3731 PWM registers 0x24-0xB3.
+// Storing them like this is optimal for I2C transfers to the registers.
+// We could optimize this and take out the unused registers from these
+// buffers and the transfers in IS31FL3731_write_pwm_buffer() but it's
+// probably not worth the extra complexity.
+uint8_t g_pwm_buffer[DRIVER_COUNT][144];
+bool    g_pwm_buffer_update_required[DRIVER_COUNT] = {false};
+
+uint8_t g_led_control_registers[DRIVER_COUNT][18]             = {{0}};
+bool    g_led_control_registers_update_required[DRIVER_COUNT] = {false};
+
+// This is the bit pattern in the LED control registers
+// (for matrix A, add one to register for matrix B)
+//
+//  reg -  b7  b6  b5  b4  b3  b2  b1  b0
+// 0x00 - R08,R07,R06,R05,R04,R03,R02,R01
+// 0x02 - G08,G07,G06,G05,G04,G03,G02,R00
+// 0x04 - B08,B07,B06,B05,B04,B03,G01,G00
+// 0x06 -  - , - , - , - , - ,B02,B01,B00
+// 0x08 -  - , - , - , - , - , - , - , -
+// 0x0A - B17,B16,B15, - , - , - , - , -
+// 0x0C - G17,G16,B14,B13,B12,B11,B10,B09
+// 0x0E - R17,G15,G14,G13,G12,G11,G10,G09
+// 0x10 - R16,R15,R14,R13,R12,R11,R10,R09
+
+void IS31FL3731_write_register(uint8_t addr, uint8_t reg, uint8_t data) {
+    g_twi_transfer_buffer[0] = reg;
+    g_twi_transfer_buffer[1] = data;
+
+#if ISSI_PERSISTENCE > 0
+    for (uint8_t i = 0; i < ISSI_PERSISTENCE; i++) {
+        if (i2c_transmit(addr << 1, g_twi_transfer_buffer, 2, ISSI_TIMEOUT) == 0) break;
+    }
+#else
+    i2c_transmit(addr << 1, g_twi_transfer_buffer, 2, ISSI_TIMEOUT);
+#endif
+}
+
+void IS31FL3731_write_pwm_buffer(uint8_t addr, uint8_t *pwm_buffer) {
+    // assumes bank is already selected
+
+    // transmit PWM registers in 9 transfers of 16 bytes
+    // g_twi_transfer_buffer[] is 20 bytes
+
+    // iterate over the pwm_buffer contents at 16 byte intervals
+    for (int i = 0; i < 144; i += 16) {
+        // set the first register, e.g. 0x24, 0x34, 0x44, etc.
+        g_twi_transfer_buffer[0] = 0x24 + i;
+        // copy the data from i to i+15
+        // device will auto-increment register for data after the first byte
+        // thus this sets registers 0x24-0x33, 0x34-0x43, etc. in one transfer
+        for (int j = 0; j < 16; j++) {
+            g_twi_transfer_buffer[1 + j] = pwm_buffer[i + j];
+        }
+
+#if ISSI_PERSISTENCE > 0
+        for (uint8_t i = 0; i < ISSI_PERSISTENCE; i++) {
+            if (i2c_transmit(addr << 1, g_twi_transfer_buffer, 17, ISSI_TIMEOUT) == 0) break;
+        }
+#else
+        i2c_transmit(addr << 1, g_twi_transfer_buffer, 17, ISSI_TIMEOUT);
+#endif
+    }
+}
+
+void IS31FL3731_init(uint8_t addr) {
+    // In order to avoid the LEDs being driven with garbage data
+    // in the LED driver's PWM registers, first enable software shutdown,
+    // then set up the mode and other settings, clear the PWM registers,
+    // then disable software shutdown.
+
+    // select "function register" bank
+    IS31FL3731_write_register(addr, ISSI_COMMANDREGISTER, ISSI_BANK_FUNCTIONREG);
+
+    // enable software shutdown
+    IS31FL3731_write_register(addr, ISSI_REG_SHUTDOWN, 0x00);
+
+    // this delay was copied from other drivers, might not be needed
+    wait_ms(10);
+
+    // picture mode
+    IS31FL3731_write_register(addr, ISSI_REG_CONFIG, ISSI_REG_CONFIG_PICTUREMODE);
+    // display frame 0
+    IS31FL3731_write_register(addr, ISSI_REG_PICTUREFRAME, 0x00);
+    // audio sync off
+    IS31FL3731_write_register(addr, ISSI_REG_AUDIOSYNC, 0x00);
+
+    // select bank 0
+    IS31FL3731_write_register(addr, ISSI_COMMANDREGISTER, 0);
+
+    // turn off all LEDs in the LED control register
+    for (int i = 0x00; i <= 0x11; i++) {
+        IS31FL3731_write_register(addr, i, 0x00);
+    }
+
+    // turn off all LEDs in the blink control register (not really needed)
+    for (int i = 0x12; i <= 0x23; i++) {
+        IS31FL3731_write_register(addr, i, 0x00);
+    }
+
+    // set PWM on all LEDs to 0
+    for (int i = 0x24; i <= 0xB3; i++) {
+        IS31FL3731_write_register(addr, i, 0x00);
+    }
+
+    // select "function register" bank
+    IS31FL3731_write_register(addr, ISSI_COMMANDREGISTER, ISSI_BANK_FUNCTIONREG);
+
+    // disable software shutdown
+    IS31FL3731_write_register(addr, ISSI_REG_SHUTDOWN, 0x01);
+
+    // select bank 0 and leave it selected.
+    // most usage after initialization is just writing PWM buffers in bank 0
+    // as there's not much point in double-buffering
+    IS31FL3731_write_register(addr, ISSI_COMMANDREGISTER, 0);
+}
+
+void IS31FL3731_set_color(int index, uint8_t red, uint8_t green, uint8_t blue) {
+    if (index >= 0 && index < DRIVER_LED_TOTAL) {
+        is31_led led = g_is31_leds[index];
+
+        // Subtract 0x24 to get the second index of g_pwm_buffer
+        g_pwm_buffer[led.driver][led.r - 0x24]   = red;
+        g_pwm_buffer[led.driver][led.g - 0x24]   = green;
+        g_pwm_buffer[led.driver][led.b - 0x24]   = blue;
+        g_pwm_buffer_update_required[led.driver] = true;
+    }
+}
+
+void IS31FL3731_set_color_all(uint8_t red, uint8_t green, uint8_t blue) {
+    for (int i = 0; i < DRIVER_LED_TOTAL; i++) {
+        IS31FL3731_set_color(i, red, green, blue);
+    }
+}
+
+void IS31FL3731_set_led_control_register(uint8_t index, bool red, bool green, bool blue) {
+    is31_led led = g_is31_leds[index];
+
+    uint8_t control_register_r = (led.r - 0x24) / 8;
+    uint8_t control_register_g = (led.g - 0x24) / 8;
+    uint8_t control_register_b = (led.b - 0x24) / 8;
+    uint8_t bit_r              = (led.r - 0x24) % 8;
+    uint8_t bit_g              = (led.g - 0x24) % 8;
+    uint8_t bit_b              = (led.b - 0x24) % 8;
+
+    if (red) {
+        g_led_control_registers[led.driver][control_register_r] |= (1 << bit_r);
+    } else {
+        g_led_control_registers[led.driver][control_register_r] &= ~(1 << bit_r);
+    }
+    if (green) {
+        g_led_control_registers[led.driver][control_register_g] |= (1 << bit_g);
+    } else {
+        g_led_control_registers[led.driver][control_register_g] &= ~(1 << bit_g);
+    }
+    if (blue) {
+        g_led_control_registers[led.driver][control_register_b] |= (1 << bit_b);
+    } else {
+        g_led_control_registers[led.driver][control_register_b] &= ~(1 << bit_b);
+    }
+
+    g_led_control_registers_update_required[led.driver] = true;
+}
+
+void IS31FL3731_update_pwm_buffers(uint8_t addr, uint8_t index) {
+    if (g_pwm_buffer_update_required[index]) {
+        IS31FL3731_write_pwm_buffer(addr, g_pwm_buffer[index]);
+    }
+    g_pwm_buffer_update_required[index] = false;
+}
+
+void IS31FL3731_update_led_control_registers(uint8_t addr, uint8_t index) {
+    if (g_led_control_registers_update_required[index]) {
+        for (int i = 0; i < 18; i++) {
+            IS31FL3731_write_register(addr, i, g_led_control_registers[index][i]);
+        }
+    }
+    g_led_control_registers_update_required[index] = false;
+}
diff --git a/drivers/led/issi/is31fl3731.h b/drivers/led/issi/is31fl3731.h
new file mode 100644
index 0000000000..803ea3ea12
--- /dev/null
+++ b/drivers/led/issi/is31fl3731.h
@@ -0,0 +1,209 @@
+/* Copyright 2017 Jason Williams
+ * Copyright 2018 Jack Humbert
+ *
+ * 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 <stdint.h>
+#include <stdbool.h>
+#include "progmem.h"
+
+typedef struct is31_led {
+    uint8_t driver : 2;
+    uint8_t r;
+    uint8_t g;
+    uint8_t b;
+} __attribute__((packed)) is31_led;
+
+extern const is31_led __flash g_is31_leds[DRIVER_LED_TOTAL];
+
+void IS31FL3731_init(uint8_t addr);
+void IS31FL3731_write_register(uint8_t addr, uint8_t reg, uint8_t data);
+void IS31FL3731_write_pwm_buffer(uint8_t addr, uint8_t *pwm_buffer);
+
+void IS31FL3731_set_color(int index, uint8_t red, uint8_t green, uint8_t blue);
+void IS31FL3731_set_color_all(uint8_t red, uint8_t green, uint8_t blue);
+
+void IS31FL3731_set_led_control_register(uint8_t index, bool red, bool green, bool blue);
+
+// This should not be called from an interrupt
+// (eg. from a timer interrupt).
+// Call this while idle (in between matrix scans).
+// If the buffer is dirty, it will update the driver with the buffer.
+void IS31FL3731_update_pwm_buffers(uint8_t addr, uint8_t index);
+void IS31FL3731_update_led_control_registers(uint8_t addr, uint8_t index);
+
+#define C1_1 0x24
+#define C1_2 0x25
+#define C1_3 0x26
+#define C1_4 0x27
+#define C1_5 0x28
+#define C1_6 0x29
+#define C1_7 0x2A
+#define C1_8 0x2B
+
+#define C1_9 0x2C
+#define C1_10 0x2D
+#define C1_11 0x2E
+#define C1_12 0x2F
+#define C1_13 0x30
+#define C1_14 0x31
+#define C1_15 0x32
+#define C1_16 0x33
+
+#define C2_1 0x34
+#define C2_2 0x35
+#define C2_3 0x36
+#define C2_4 0x37
+#define C2_5 0x38
+#define C2_6 0x39
+#define C2_7 0x3A
+#define C2_8 0x3B
+
+#define C2_9 0x3C
+#define C2_10 0x3D
+#define C2_11 0x3E
+#define C2_12 0x3F
+#define C2_13 0x40
+#define C2_14 0x41
+#define C2_15 0x42
+#define C2_16 0x43
+
+#define C3_1 0x44
+#define C3_2 0x45
+#define C3_3 0x46
+#define C3_4 0x47
+#define C3_5 0x48
+#define C3_6 0x49
+#define C3_7 0x4A
+#define C3_8 0x4B
+
+#define C3_9 0x4C
+#define C3_10 0x4D
+#define C3_11 0x4E
+#define C3_12 0x4F
+#define C3_13 0x50
+#define C3_14 0x51
+#define C3_15 0x52
+#define C3_16 0x53
+
+#define C4_1 0x54
+#define C4_2 0x55
+#define C4_3 0x56
+#define C4_4 0x57
+#define C4_5 0x58
+#define C4_6 0x59
+#define C4_7 0x5A
+#define C4_8 0x5B
+
+#define C4_9 0x5C
+#define C4_10 0x5D
+#define C4_11 0x5E
+#define C4_12 0x5F
+#define C4_13 0x60
+#define C4_14 0x61
+#define C4_15 0x62
+#define C4_16 0x63
+
+#define C5_1 0x64
+#define C5_2 0x65
+#define C5_3 0x66
+#define C5_4 0x67
+#define C5_5 0x68
+#define C5_6 0x69
+#define C5_7 0x6A
+#define C5_8 0x6B
+
+#define C5_9 0x6C
+#define C5_10 0x6D
+#define C5_11 0x6E
+#define C5_12 0x6F
+#define C5_13 0x70
+#define C5_14 0x71
+#define C5_15 0x72
+#define C5_16 0x73
+
+#define C6_1 0x74
+#define C6_2 0x75
+#define C6_3 0x76
+#define C6_4 0x77
+#define C6_5 0x78
+#define C6_6 0x79
+#define C6_7 0x7A
+#define C6_8 0x7B
+
+#define C6_9 0x7C
+#define C6_10 0x7D
+#define C6_11 0x7E
+#define C6_12 0x7F
+#define C6_13 0x80
+#define C6_14 0x81
+#define C6_15 0x82
+#define C6_16 0x83
+
+#define C7_1 0x84
+#define C7_2 0x85
+#define C7_3 0x86
+#define C7_4 0x87
+#define C7_5 0x88
+#define C7_6 0x89
+#define C7_7 0x8A
+#define C7_8 0x8B
+
+#define C7_9 0x8C
+#define C7_10 0x8D
+#define C7_11 0x8E
+#define C7_12 0x8F
+#define C7_13 0x90
+#define C7_14 0x91
+#define C7_15 0x92
+#define C7_16 0x93
+
+#define C8_1 0x94
+#define C8_2 0x95
+#define C8_3 0x96
+#define C8_4 0x97
+#define C8_5 0x98
+#define C8_6 0x99
+#define C8_7 0x9A
+#define C8_8 0x9B
+
+#define C8_9 0x9C
+#define C8_10 0x9D
+#define C8_11 0x9E
+#define C8_12 0x9F
+#define C8_13 0xA0
+#define C8_14 0xA1
+#define C8_15 0xA2
+#define C8_16 0xA3
+
+#define C9_1 0xA4
+#define C9_2 0xA5