Rgb matrix arm (#3648)

* Addition of I2C master driver for STM32, Generalization of ISSI3731 driver

- Addition of an i2c_master driver for STM32 to replicate expectations of AVR driver.
- Moved ISSI3731 driver one level up to make it accesible by both architectures.
- Renamed ISSI3731 functions to a more general name for preparation of other ISSI drivers.
- Added compiler directives where necessary to differenciate each architecture.

* converted tabs to spaces

5 files changed, 422 insertions, 271 deletions

diff --git a/drivers/arm/i2c_master.c b/drivers/arm/i2c_master.c
new file mode 100644
index 0000000000..2fdd9f65e1
--- /dev/null
+++ b/drivers/arm/i2c_master.c
@@ -0,0 +1,103 @@
+/* Copyright 2018 Jack Humbert
+ * Copyright 2018 Yiancar
+ *
+ * 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/>.
+ */
+
+/* This library follows the convention of the AVR i2c_master library.
+ * As a result addresses are expected to be already shifted (addr << 1).
+ * I2CD1 is the default driver which corresponds to pins B6 and B7. This
+ * can be changed.
+ * Please ensure that HAL_USE_I2C is TRUE in the halconf.h file and that
+ * STM32_I2C_USE_I2C1 is TRUE in the mcuconf.h file.
+ */
+
+#include "i2c_master.h"
+#include <string.h>
+#include <hal.h>
+
+static uint8_t i2c_address;
+
+// This configures the I2C clock to 400Mhz assuming a 72Mhz clock
+// For more info : https://www.st.com/en/embedded-software/stsw-stm32126.html
+static const I2CConfig i2cconfig = {
+  STM32_TIMINGR_PRESC(15U) |
+  STM32_TIMINGR_SCLDEL(4U) | STM32_TIMINGR_SDADEL(2U) |
+  STM32_TIMINGR_SCLH(15U)  | STM32_TIMINGR_SCLL(21U),
+  0,
+  0
+};
+
+void i2c_init(void)
+{
+  palSetGroupMode(GPIOB,6,7, PAL_MODE_INPUT);       // Try releasing special pins for a short time
+  chThdSleepMilliseconds(10);
+
+  palSetPadMode(GPIOB, 6, PAL_MODE_ALTERNATE(4) | PAL_STM32_OTYPE_OPENDRAIN | PAL_STM32_PUPDR_PULLUP);
+  palSetPadMode(GPIOB, 7, PAL_MODE_ALTERNATE(4) | PAL_STM32_OTYPE_OPENDRAIN | PAL_STM32_PUPDR_PULLUP);
+
+  //i2cInit(); //This is invoked by halInit() so no need to redo it.
+}
+
+// This is usually not needed
+uint8_t i2c_start(uint8_t address)
+{
+  i2c_address = address;
+  i2cStart(&I2C_DRIVER, &i2cconfig);
+  return 0;
+}
+
+uint8_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout)
+{
+  i2c_address = address;
+  i2cStart(&I2C_DRIVER, &i2cconfig);
+  return i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), data, length, 0, 0, MS2ST(timeout));
+}
+
+uint8_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout)
+{
+  i2c_address = address;
+  i2cStart(&I2C_DRIVER, &i2cconfig);
+  return i2cMasterReceiveTimeout(&I2C_DRIVER, (i2c_address >> 1), data, length, MS2ST(timeout));
+}
+
+uint8_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout)
+{
+  i2c_address = devaddr;
+  i2cStart(&I2C_DRIVER, &i2cconfig);
+
+  uint8_t complete_packet[length + 1];
+  for(uint8_t i = 0; i < length; i++)
+  {
+    complete_packet[i+1] = data[i];
+  }
+  complete_packet[0] = regaddr
+
+  return i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), complete_packet, length + 1, 0, 0, MS2ST(timeout));
+}
+
+uint8_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout)
+{
+  i2c_address = devaddr;
+  i2cStart(&I2C_DRIVER, &i2cconfig);
+  return i2cMasterTransmitTimeout(&I2C_DRIVER, (i2c_address >> 1), regaddr, 1, data, length, MS2ST(timeout));
+}
+
+// This is usually not needed. It releases the driver to allow pins to become GPIO again.
+uint8_t i2c_stop(uint16_t timeout)
+{
+  i2c_address = address;
+  i2cStop(&I2C_DRIVER);
+  return 0;
+}
diff --git a/drivers/arm/i2c_master.h b/drivers/arm/i2c_master.h
new file mode 100644
index 0000000000..9d51245be1
--- /dev/null
+++ b/drivers/arm/i2c_master.h
@@ -0,0 +1,39 @@
+/* Copyright 2018 Jack Humbert
+ * Copyright 2018 Yiancar
+ *
+ * This program is free sofare: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Sofare 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/>.
+ */
+
+/* This library follows the convention of the AVR i2c_master library.
+ * As a result addresses are expected to be already shifted (addr << 1).
+ * I2CD1 is the default driver which corresponds to pins B6 and B7. This
+ * can be changed.
+ * Please ensure that HAL_USE_I2C is TRUE in the halconf.h file and that
+ * STM32_I2C_USE_I2C1 is TRUE in the mcuconf.h file.
+ */
+
+#include "ch.h"
+#include <hal.h>
+
+#ifndef I2C_DRIVER
+  #define I2C_DRIVER I2CD1
+#endif
+
+void i2c_init(void);
+uint8_t i2c_start(uint8_t address);
+uint8_t i2c_transmit(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout);
+uint8_t i2c_receive(uint8_t address, uint8_t* data, uint16_t length, uint16_t timeout);
+uint8_t i2c_writeReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);
+uint8_t i2c_readReg(uint8_t devaddr, uint8_t regaddr, uint8_t* data, uint16_t length, uint16_t timeout);
+void i2c_stop(void);
diff --git a/drivers/avr/is31fl3731.c b/drivers/avr/is31fl3731.c
deleted file mode 100644
index 70813464b2..0000000000
--- a/drivers/avr/is31fl3731.c
+++ /dev/null
@@ -1,262 +0,0 @@
-/* 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 <avr/interrupt.h>
-#include <avr/io.h>
-#include <util/delay.h>
-#include <string.h>
-#include "i2c_master.h"
-#include "progmem.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 = false;
-
-uint8_t g_led_control_registers[DRIVER_COUNT][18] = { { 0 }, { 0 } };
-bool g_led_control_registers_update_required = 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
-	_delay_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 = 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 = true;
-
-}
-
-void IS31FL3731_update_pwm_buffers( uint8_t addr1, uint8_t addr2 )
-{
-	if ( g_pwm_buffer_update_required )
-	{
-		IS31FL3731_write_pwm_buffer( addr1, g_pwm_buffer[0] );
-		IS31FL3731_write_pwm_buffer( addr2, g_pwm_buffer[1] );
-	}
-	g_pwm_buffer_update_required = false;
-}
-
-void IS31FL3731_update_led_control_registers( uint8_t addr1, uint8_t addr2 )
-{
-	if ( g_led_control_registers_update_required )
-	{
-		for ( int i=0; i<18; i++ )
-		{
-			IS31FL3731_write_register(addr1, i, g_led_control_registers[0][i] );
-			IS31FL3731_write_register(addr2, i, g_led_control_registers[1][i] );
-		}
-	}
-}
-
diff --git a/drivers/is31fl3731.c b/drivers/is31fl3731.c
new file mode 100644
index 0000000000..0524feb49f
--- /dev/null
+++ b/drivers/is31fl3731.c
@@ -0,0 +1,271 @@
+/* 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/>.
+ */
+
+#ifdef __AVR__
+#include <avr/interrupt.h>
+#include <avr/io.h>
+#include <util/delay.h>
+#else
+#include "wait.h"
+#endif
+
+#include "is31fl3731.h"
+#include <string.h>
+#include "i2c_master.h"
+#include "progmem.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 = false;
+
+uint8_t g_led_control_registers[DRIVER_COUNT][18] = { { 0 }, { 0 } };
+bool g_led_control_registers_update_required = 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 IS31_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 IS31_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 IS31_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
+    IS31_write_register( addr, ISSI_COMMANDREGISTER, ISSI_BANK_FUNCTIONREG );
+
+    // enable software shutdown
+    IS31_write_register( addr, ISSI_REG_SHUTDOWN, 0x00 );
+    // this delay was copied from other drivers, might not be needed
+    #ifdef __AVR__
+    _delay_ms( 10 );
+    #else
+    wait_ms(10);
+    #endif
+
+    // picture mode
+    IS31_write_register( addr, ISSI_REG_CONFIG, ISSI_REG_CONFIG_PICTUREMODE );
+    // display frame 0
+    IS31_write_register( addr, ISSI_REG_PICTUREFRAME, 0x00 );
+    // audio sync off
+    IS31_write_register( addr, ISSI_REG_AUDIOSYNC, 0x00 );
+
+    // select bank 0
+    IS31_write_register( addr, ISSI_COMMANDREGISTER, 0 );
+
+    // turn off all LEDs in the LED control register
+    for ( int i = 0x00; i <= 0x11; i++ )
+    {
+        IS31_write_register( addr, i, 0x00 );
+    }
+
+    // turn off all LEDs in the blink control register (not really needed)
+    for ( int i = 0x12; i <= 0x23; i++ )
+    {
+        IS31_write_register( addr, i, 0x00 );
+    }
+
+    // set PWM on all LEDs to 0
+    for ( int i = 0x24; i <= 0xB3; i++ )
+    {
+        IS31_write_register( addr, i, 0x00 );
+    }
+
+    // select "function register" bank
+    IS31_write_register( addr, ISSI_COMMANDREGISTER, ISSI_BANK_FUNCTIONREG );
+
+    // disable software shutdown
+    IS31_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
+    IS31_write_register( addr, ISSI_COMMANDREGISTER, 0 );
+
+}
+
+void IS31_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 = true;
+    }
+}
+
+void IS31_set_color_all( uint8_t red, uint8_t green, uint8_t blue )
+{
+    for ( int i = 0; i < DRIVER_LED_TOTAL; i++ )
+    {
+        IS31_set_color( i, red, green, blue );
+    }
+}
+
+void IS31_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 = true;
+
+}
+
+void IS31_update_pwm_buffers( uint8_t addr1, uint8_t addr2 )
+{
+    if ( g_pwm_buffer_update_required )
+    {
+        IS31_write_pwm_buffer( addr1, g_pwm_buffer[0] );
+        IS31_write_pwm_buffer( addr2, g_pwm_buffer[1] );
+    }
+    g_pwm_buffer_update_required = false;
+}
+
+void IS31_update_led_control_registers( uint8_t addr1, uint8_t addr2 )
+{
+    if ( g_led_control_registers_update_required )
+    {
+        for ( int i=0; i<18; i++ )
+        {
+            IS31_write_register(addr1, i, g_led_control_registers[0][i] );
+            IS31_write_register(addr2, i, g_led_control_registers[1][i] );
+        }
+    }
+}
+
diff --git a/drivers/avr/is31fl3731.h b/drivers/is31fl3731.h
index 3d30fc67b7..9e195c240e 100644
--- a/drivers/avr/is31fl3731.h
+++ b/drivers/is31fl3731.h
@@ -23,7 +23,7 @@
 #include <stdbool.h>
 
 typedef struct is31_led {
-	uint8_t driver:2;
+  uint8_t driver:2;
   uint8_t r;
   uint8_t g;
   uint8_t b;
@@ -31,21 +31,21 @@ typedef struct is31_led {
 
 extern const is31_led 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 IS31_init( uint8_t addr );
+void IS31_write_register( uint8_t addr, uint8_t reg, uint8_t data );
+void IS31_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 IS31_set_color( int index, uint8_t red, uint8_t green, uint8_t blue );
+void IS31_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 );
+void IS31_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 addr1, uint8_t addr2 );
-void IS31FL3731_update_led_control_registers( uint8_t addr1, uint8_t addr2 );
+void IS31_update_pwm_buffers( uint8_t addr1, uint8_t addr2 );
+void IS31_update_led_control_registers( uint8_t addr1, uint8_t addr2 );
 
 #define C1_1  0x24
 #define C1_2  0x25