From 0bf84d974e94d4f612a1287b0a8901af4f729503 Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Tue, 4 Nov 2014 09:58:31 -0800
Subject: [PATCH 1/9] Si5351C: Extract low-level driver code.

---
 firmware/common/hackrf_core.c          |  1 +
 firmware/common/si5351c.c              | 50 +----------------
 firmware/common/si5351c.h              |  5 --
 firmware/common/si5351c_drv.c          | 74 ++++++++++++++++++++++++++
 firmware/common/si5351c_drv.h          | 41 ++++++++++++++
 firmware/hackrf-common.cmake           |  1 +
 firmware/hackrf_usb/usb_api_register.c |  2 +-
 7 files changed, 120 insertions(+), 54 deletions(-)
 create mode 100644 firmware/common/si5351c_drv.c
 create mode 100644 firmware/common/si5351c_drv.h

diff --git a/firmware/common/hackrf_core.c b/firmware/common/hackrf_core.c
index b862ba4f..cd1c8005 100644
--- a/firmware/common/hackrf_core.c
+++ b/firmware/common/hackrf_core.c
@@ -23,6 +23,7 @@
 
 #include "hackrf_core.h"
 #include "si5351c.h"
+#include "si5351c_drv.h"
 #include "max2837.h"
 #include "rffc5071.h"
 #include "sgpio.h"
diff --git a/firmware/common/si5351c.c b/firmware/common/si5351c.c
index 58b614dc..3be5041a 100644
--- a/firmware/common/si5351c.c
+++ b/firmware/common/si5351c.c
@@ -21,57 +21,11 @@
  */
 
 #include "si5351c.h"
-#include <libopencm3/lpc43xx/i2c.h>
+
+#include "si5351c_drv.h"
 
 enum pll_sources active_clock_source;
 
-/* FIXME return i2c0 status from each function */
-
-/* write to single register */
-void si5351c_write_single(uint8_t reg, uint8_t val)
-{
-	i2c0_tx_start();
-	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
-	i2c0_tx_byte(reg);
-	i2c0_tx_byte(val);
-	i2c0_stop();
-}
-
-/* read single register */
-uint8_t si5351c_read_single(uint8_t reg)
-{
-	uint8_t val;
-
-	/* set register address with write */
-	i2c0_tx_start();
-	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
-	i2c0_tx_byte(reg);
-
-	/* read the value */
-	i2c0_tx_start();
-	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_READ);
-	val = i2c0_rx_byte();
-	i2c0_stop();
-
-	return val;
-}
-
-/*
- * Write to one or more contiguous registers. data[0] should be the first
- * register number, one or more values follow.
- */
-void si5351c_write(uint8_t* const data, const uint_fast8_t data_count)
-{
-	uint_fast8_t i;
-
-	i2c0_tx_start();
-	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
-	
-	for (i = 0; i < data_count; i++)
-		i2c0_tx_byte(data[i]);
-	i2c0_stop();
-}
-
 /* Disable all CLKx outputs. */
 void si5351c_disable_all_outputs()
 {
diff --git a/firmware/common/si5351c.h b/firmware/common/si5351c.h
index b62279d7..fcc2d2b8 100644
--- a/firmware/common/si5351c.h
+++ b/firmware/common/si5351c.h
@@ -31,7 +31,6 @@ extern "C"
 #include <stdint.h>
 
 #define SI_INTDIV(x)  (x*128-512)
-#define SI5351C_I2C_ADDR (0x60 << 1)
 
 #define SI5351C_CLK_POWERDOWN	(1<<7)
 #define SI5351C_CLK_INT_MODE	(1<<6)
@@ -76,10 +75,6 @@ void si5351c_configure_multisynth(const uint_fast8_t ms_number,
 void si5351c_configure_clock_control(const enum pll_sources source);
 void si5351c_enable_clock_outputs();
 void si5351c_set_int_mode(const uint_fast8_t ms_number, const uint_fast8_t on);
-
-void si5351c_write_single(uint8_t reg, uint8_t val);
-uint8_t si5351c_read_single(uint8_t reg);
-void si5351c_write(uint8_t* const data, const uint_fast8_t data_count);
 void si5351c_set_clock_source(const enum pll_sources source);
 void si5351c_activate_best_clock_source(void);
 
diff --git a/firmware/common/si5351c_drv.c b/firmware/common/si5351c_drv.c
new file mode 100644
index 00000000..e63912c1
--- /dev/null
+++ b/firmware/common/si5351c_drv.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2012 Michael Ossmann <mike@ossmann.com>
+ * Copyright 2012 Jared Boone <jared@sharebrained.com>
+ *
+ * This file is part of HackRF.
+ *
+ * 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, 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "si5351c_drv.h"
+
+#include <libopencm3/lpc43xx/i2c.h>
+
+#define SI5351C_I2C_ADDR (0x60 << 1)
+
+/* FIXME return i2c0 status from each function */
+
+/* write to single register */
+void si5351c_write_single(uint8_t reg, uint8_t val)
+{
+	i2c0_tx_start();
+	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
+	i2c0_tx_byte(reg);
+	i2c0_tx_byte(val);
+	i2c0_stop();
+}
+
+/* read single register */
+uint8_t si5351c_read_single(uint8_t reg)
+{
+	uint8_t val;
+
+	/* set register address with write */
+	i2c0_tx_start();
+	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
+	i2c0_tx_byte(reg);
+
+	/* read the value */
+	i2c0_tx_start();
+	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_READ);
+	val = i2c0_rx_byte();
+	i2c0_stop();
+
+	return val;
+}
+
+/*
+ * Write to one or more contiguous registers. data[0] should be the first
+ * register number, one or more values follow.
+ */
+void si5351c_write(uint8_t* const data, const uint_fast8_t data_count)
+{
+	uint_fast8_t i;
+
+	i2c0_tx_start();
+	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
+	
+	for (i = 0; i < data_count; i++)
+		i2c0_tx_byte(data[i]);
+	i2c0_stop();
+}
diff --git a/firmware/common/si5351c_drv.h b/firmware/common/si5351c_drv.h
new file mode 100644
index 00000000..501b221e
--- /dev/null
+++ b/firmware/common/si5351c_drv.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2012 Michael Ossmann <mike@ossmann.com>
+ * Copyright 2012 Jared Boone <jared@sharebrained.com>
+ *
+ * This file is part of HackRF.
+ *
+ * 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, 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __SI5351C_DRV_H
+#define __SI5351C_DRV_H
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+#include <stdint.h>
+
+void si5351c_write_single(uint8_t reg, uint8_t val);
+uint8_t si5351c_read_single(uint8_t reg);
+void si5351c_write(uint8_t* const data, const uint_fast8_t data_count);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __SI5351C_DRV_H */
diff --git a/firmware/hackrf-common.cmake b/firmware/hackrf-common.cmake
index df5d5c96..9b4fb9a9 100644
--- a/firmware/hackrf-common.cmake
+++ b/firmware/hackrf-common.cmake
@@ -134,6 +134,7 @@ macro(DeclareTargets)
 		${PATH_HACKRF_FIRMWARE_COMMON}/sgpio.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/rf_path.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/si5351c.c
+		${PATH_HACKRF_FIRMWARE_COMMON}/si5351c_drv.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/max2837.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/max5864.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/rffc5071.c
diff --git a/firmware/hackrf_usb/usb_api_register.c b/firmware/hackrf_usb/usb_api_register.c
index d822c924..9478e7c1 100644
--- a/firmware/hackrf_usb/usb_api_register.c
+++ b/firmware/hackrf_usb/usb_api_register.c
@@ -24,7 +24,7 @@
 
 #include <usb_queue.h>
 #include <max2837.h>
-#include <si5351c.h>
+#include <si5351c_drv.h>
 #include <rffc5071.h>
 
 #include <stddef.h>

From 3bc41f1480401ea09b49bd1c06bfb28865b8b148 Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Tue, 4 Nov 2014 10:45:24 -0800
Subject: [PATCH 2/9] Si5351C: Un-singleton the high- and low-level drivers.
 Proper.

---
 firmware/common/hackrf_core.c          | 61 ++++++++++++-----------
 firmware/common/hackrf_core.h          |  4 ++
 firmware/common/si5351c.c              | 69 +++++++++++++-------------
 firmware/common/si5351c.h              | 31 ++++++------
 firmware/common/si5351c_drv.c          | 14 +++---
 firmware/common/si5351c_drv.h          | 10 ++--
 firmware/hackrf_usb/hackrf_usb.c       |  2 +-
 firmware/hackrf_usb/usb_api_register.c |  6 +--
 8 files changed, 106 insertions(+), 91 deletions(-)

diff --git a/firmware/common/hackrf_core.c b/firmware/common/hackrf_core.c
index cd1c8005..792beec3 100644
--- a/firmware/common/hackrf_core.c
+++ b/firmware/common/hackrf_core.c
@@ -23,7 +23,6 @@
 
 #include "hackrf_core.h"
 #include "si5351c.h"
-#include "si5351c_drv.h"
 #include "max2837.h"
 #include "rffc5071.h"
 #include "sgpio.h"
@@ -36,6 +35,10 @@
 
 #define WAIT_CPU_CLOCK_INIT_DELAY   (10000)
 
+si5351c_driver_t clock_gen = {
+	.i2c_address = 0x60,
+};
+
 void delay(uint32_t duration)
 {
 	uint32_t i;
@@ -119,9 +122,9 @@ bool sample_rate_frac_set(uint32_t rate_num, uint32_t rate_denom)
 
 	/* Can we enable integer mode ? */
 	if (a & 0x1 || b)
-		si5351c_set_int_mode(0, 0);
+		si5351c_set_int_mode(&clock_gen, 0, 0);
 	else
-		si5351c_set_int_mode(0, 1);
+		si5351c_set_int_mode(&clock_gen, 0, 1);
 
 	/* Final MS values */
 	MSx_P1 = 128*a + (128 * b/c) - 512;
@@ -129,13 +132,13 @@ bool sample_rate_frac_set(uint32_t rate_num, uint32_t rate_denom)
 	MSx_P3 = c;
 
 	/* MS0/CLK0 is the source for the MAX5864/CPLD (CODEC_CLK). */
-	si5351c_configure_multisynth(0, MSx_P1, MSx_P2, MSx_P3, 1);
+	si5351c_configure_multisynth(&clock_gen, 0, MSx_P1, MSx_P2, MSx_P3, 1);
 
 	/* MS0/CLK1 is the source for the CPLD (CODEC_X2_CLK). */
-	si5351c_configure_multisynth(1, 0, 0, 0, 0);//p1 doesn't matter
+	si5351c_configure_multisynth(&clock_gen, 1, 0, 0, 0, 0);//p1 doesn't matter
 
 	/* MS0/CLK2 is the source for SGPIO (CODEC_X2_CLK) */
-	si5351c_configure_multisynth(2, 0, 0, 0, 0);//p1 doesn't matter
+	si5351c_configure_multisynth(&clock_gen, 2, 0, 0, 0, 0);//p1 doesn't matter
 
 	return true;
 }
@@ -175,13 +178,13 @@ bool sample_rate_set(const uint32_t sample_rate_hz) {
 	 * values are irrelevant. */
 	
 	/* MS0/CLK1 is the source for the MAX5864 codec. */
-	si5351c_configure_multisynth(1, 4608, 0, 1, r_div_sample);
+	si5351c_configure_multisynth(&clock_gen, 1, 4608, 0, 1, r_div_sample);
 
 	/* MS0/CLK2 is the source for the CPLD codec clock (same as CLK1). */
-	si5351c_configure_multisynth(2, 4608, 0, 1, r_div_sample);
+	si5351c_configure_multisynth(&clock_gen, 2, 4608, 0, 1, r_div_sample);
 
 	/* MS0/CLK3 is the source for the SGPIO clock. */
-	si5351c_configure_multisynth(3, 4608, 0, 1, r_div_sgpio);
+	si5351c_configure_multisynth(&clock_gen, 3, 4608, 0, 1, r_div_sgpio);
 	
 	return true;
 #endif
@@ -238,13 +241,13 @@ bool sample_rate_set(const uint32_t sample_rate_hz) {
 	}
 	
 	/* MS0/CLK0 is the source for the MAX5864/CPLD (CODEC_CLK). */
-	si5351c_configure_multisynth(0, p1, p2, p3, 1);
+	si5351c_configure_multisynth(&clock_gen, 0, p1, p2, p3, 1);
 
 	/* MS0/CLK1 is the source for the CPLD (CODEC_X2_CLK). */
-	si5351c_configure_multisynth(1, p1, 0, 1, 0);//p1 doesn't matter
+	si5351c_configure_multisynth(&clock_gen, 1, p1, 0, 1, 0);//p1 doesn't matter
 
 	/* MS0/CLK2 is the source for SGPIO (CODEC_X2_CLK) */
-	si5351c_configure_multisynth(2, p1, 0, 1, 0);//p1 doesn't matter
+	si5351c_configure_multisynth(&clock_gen, 2, p1, 0, 1, 0);//p1 doesn't matter
 
 	return true;
 #endif
@@ -267,13 +270,13 @@ void cpu_clock_init(void)
 
 	i2c0_init(15);
 
-	si5351c_disable_all_outputs();
-	si5351c_disable_oeb_pin_control();
-	si5351c_power_down_all_clocks();
-	si5351c_set_crystal_configuration();
-	si5351c_enable_xo_and_ms_fanout();
-	si5351c_configure_pll_sources();
-	si5351c_configure_pll_multisynth();
+	si5351c_disable_all_outputs(&clock_gen);
+	si5351c_disable_oeb_pin_control(&clock_gen);
+	si5351c_power_down_all_clocks(&clock_gen);
+	si5351c_set_crystal_configuration(&clock_gen);
+	si5351c_enable_xo_and_ms_fanout(&clock_gen);
+	si5351c_configure_pll_sources(&clock_gen);
+	si5351c_configure_pll_multisynth(&clock_gen);
 
 #ifdef JELLYBEAN
 	/*
@@ -289,13 +292,13 @@ void cpu_clock_init(void)
 	 */
 
 	/* MS0/CLK0 is the source for the MAX2837 clock input. */
-	si5351c_configure_multisynth(0, 2048, 0, 1, 0); /* 40MHz */
+	si5351c_configure_multisynth(&clock_gen, 0, 2048, 0, 1, 0); /* 40MHz */
 
 	/* MS4/CLK4 is the source for the LPC43xx microcontroller. */
-	si5351c_configure_multisynth(4, 8021, 0, 3, 0); /* 12MHz */
+	si5351c_configure_multisynth(&clock_gen, 4, 8021, 0, 3, 0); /* 12MHz */
 
 	/* MS5/CLK5 is the source for the RFFC5071 mixer. */
-	si5351c_configure_multisynth(5, 1536, 0, 1, 0); /* 50MHz */
+	si5351c_configure_multisynth(&clock_gen, 5, 1536, 0, 1, 0); /* 50MHz */
 #endif
 
 #if (defined JAWBREAKER || defined HACKRF_ONE)
@@ -312,28 +315,28 @@ void cpu_clock_init(void)
 	 */
 
 	/* MS3/CLK3 is the source for the external clock output. */
-	si5351c_configure_multisynth(3, 80*128-512, 0, 1, 0); /* 800/80 = 10MHz */
+	si5351c_configure_multisynth(&clock_gen, 3, 80*128-512, 0, 1, 0); /* 800/80 = 10MHz */
 
 	/* MS4/CLK4 is the source for the RFFC5071 mixer. */
-	si5351c_configure_multisynth(4, 16*128-512, 0, 1, 0); /* 800/16 = 50MHz */
+	si5351c_configure_multisynth(&clock_gen, 4, 16*128-512, 0, 1, 0); /* 800/16 = 50MHz */
  
  	/* MS5/CLK5 is the source for the MAX2837 clock input. */
-	si5351c_configure_multisynth(5, 20*128-512, 0, 1, 0); /* 800/20 = 40MHz */
+	si5351c_configure_multisynth(&clock_gen, 5, 20*128-512, 0, 1, 0); /* 800/20 = 40MHz */
 
 	/* MS6/CLK6 is unused. */
 	/* MS7/CLK7 is the source for the LPC43xx microcontroller. */
 	uint8_t ms7data[] = { 90, 255, 20, 0 };
-	si5351c_write(ms7data, sizeof(ms7data));
+	si5351c_write(&clock_gen, ms7data, sizeof(ms7data));
 #endif
 
 	/* Set to 10 MHz, the common rate between Jellybean and Jawbreaker. */
 	sample_rate_set(10000000);
 
-	si5351c_set_clock_source(PLL_SOURCE_XTAL);
+	si5351c_set_clock_source(&clock_gen, PLL_SOURCE_XTAL);
 	// soft reset
 	uint8_t resetdata[] = { 177, 0xac };
-	si5351c_write(resetdata, sizeof(resetdata));
-	si5351c_enable_clock_outputs();
+	si5351c_write(&clock_gen, resetdata, sizeof(resetdata));
+	si5351c_enable_clock_outputs(&clock_gen);
 
 	//FIXME disable I2C
 	/* Kick I2C0 down to 400kHz when we switch over to APB1 clock = 204MHz */
diff --git a/firmware/common/hackrf_core.h b/firmware/common/hackrf_core.h
index 8ce6c943..7ad1ad50 100644
--- a/firmware/common/hackrf_core.h
+++ b/firmware/common/hackrf_core.h
@@ -32,6 +32,8 @@ extern "C"
 #include <stdint.h>
 #include <stdbool.h>
 
+#include "si5351c_drv.h"
+
 /* hardware identification number */
 #define BOARD_ID_JELLYBEAN  0
 #define BOARD_ID_JAWBREAKER 1
@@ -350,6 +352,8 @@ typedef enum {
 
 void delay(uint32_t duration);
 
+extern si5351c_driver_t clock_gen;
+
 void cpu_clock_init(void);
 void cpu_clock_pll1_low_speed(void);
 void cpu_clock_pll1_max_speed(void);
diff --git a/firmware/common/si5351c.c b/firmware/common/si5351c.c
index 3be5041a..f6b4483a 100644
--- a/firmware/common/si5351c.c
+++ b/firmware/common/si5351c.c
@@ -27,21 +27,21 @@
 enum pll_sources active_clock_source;
 
 /* Disable all CLKx outputs. */
-void si5351c_disable_all_outputs()
+void si5351c_disable_all_outputs(si5351c_driver_t* const drv)
 {
 	uint8_t data[] = { 3, 0xFF };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
 /* Turn off OEB pin control for all CLKx */
-void si5351c_disable_oeb_pin_control()
+void si5351c_disable_oeb_pin_control(si5351c_driver_t* const drv)
 {
 	uint8_t data[] = { 9, 0xFF };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
 /* Power down all CLKx */
-void si5351c_power_down_all_clocks()
+void si5351c_power_down_all_clocks(si5351c_driver_t* const drv)
 {
 	uint8_t data[] = { 16
 	, SI5351C_CLK_POWERDOWN
@@ -53,7 +53,7 @@ void si5351c_power_down_all_clocks()
 	, SI5351C_CLK_POWERDOWN | SI5351C_CLK_INT_MODE 
 	, SI5351C_CLK_POWERDOWN | SI5351C_CLK_INT_MODE
 	};
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
 /*
@@ -61,20 +61,20 @@ void si5351c_power_down_all_clocks()
  * Reads as 0xE4 on power-up
  * Set to 8pF based on crystal specs and HackRF One testing
  */
-void si5351c_set_crystal_configuration()
+void si5351c_set_crystal_configuration(si5351c_driver_t* const drv)
 {
 	uint8_t data[] = { 183, 0x80 };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
 /*
  * Register 187: Fanout Enable
  * Turn on XO and MultiSynth fanout only.
  */
-void si5351c_enable_xo_and_ms_fanout()
+void si5351c_enable_xo_and_ms_fanout(si5351c_driver_t* const drv)
 {
 	uint8_t data[] = { 187, 0xD0 };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
 /*
@@ -83,34 +83,35 @@ void si5351c_enable_xo_and_ms_fanout()
  * PLLA_SRC=0 (XTAL)
  * PLLB_SRC=1 (CLKIN)
  */
-void si5351c_configure_pll_sources(void)
+void si5351c_configure_pll_sources(si5351c_driver_t* const drv)
 {
 	uint8_t data[] = { 15, 0x08 };
 
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
 /* MultiSynth NA (PLLA) and NB (PLLB) */
-void si5351c_configure_pll_multisynth(void)
+void si5351c_configure_pll_multisynth(si5351c_driver_t* const drv)
 {
 	//init plla to (0x0e00+512)/128*25mhz xtal = 800mhz -> int mode
 	uint8_t data[] = { 26, 0x00, 0x01, 0x00, 0x0E, 0x00, 0x00, 0x00, 0x00 };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 
 	/* 10 MHz input on CLKIN for PLLB */
 	data[0] = 34;
 	data[4] = 0x26;
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
-void si5351c_reset_pll(void)
+void si5351c_reset_pll(si5351c_driver_t* const drv)
 {
 	/* reset PLLA and PLLB */
 	uint8_t data[] = { 177, 0xA0 };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
-void si5351c_configure_multisynth(const uint_fast8_t ms_number,
+void si5351c_configure_multisynth(si5351c_driver_t* const drv,
+		const uint_fast8_t ms_number,
 		const uint32_t p1, const uint32_t p2, const uint32_t p3,
     	const uint_fast8_t r_div)
 {
@@ -137,7 +138,7 @@ void si5351c_configure_multisynth(const uint_fast8_t ms_number,
 			(((p3 >> 16) & 0xF) << 4) | (((p2 >> 16) & 0xF) << 0),
 			(p2 >> 8) & 0xFF,
 			(p2 >> 0) & 0xFF };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 
 #ifdef JELLYBEAN
@@ -186,15 +187,15 @@ void si5351c_configure_multisynth(const uint_fast8_t ms_number,
  *   CLK5_SRC=3 (MS5 as input source)
  *   CLK5_IDRV=3 (8mA)
  */
-void si5351c_configure_clock_control()
+void si5351c_configure_clock_control(si5351c_driver_t* const drv)
 {
 	uint8_t data[] = { 16, 0x4F, 0x4B, 0x4B, 0x4B, 0x0F, 0x4F, 0xC0, 0xC0 };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 #endif
 
 #if (defined JAWBREAKER || defined HACKRF_ONE)
-void si5351c_configure_clock_control(const enum pll_sources source)
+void si5351c_configure_clock_control(si5351c_driver_t* const drv, const enum pll_sources source)
 {
 	uint8_t pll;
 
@@ -215,54 +216,54 @@ void si5351c_configure_clock_control(const enum pll_sources source)
 	,SI5351C_CLK_POWERDOWN | SI5351C_CLK_INT_MODE /*not connected, but: plla int mode*/
 	,SI5351C_CLK_INT_MODE | SI5351C_CLK_PLL_SRC(pll) | SI5351C_CLK_SRC(SI5351C_CLK_SRC_MULTISYNTH_SELF) | SI5351C_CLK_IDRV(SI5351C_CLK_IDRV_8MA)
 	 };
-	si5351c_write(data, sizeof(data));
+	si5351c_write(drv, data, sizeof(data));
 }
 #endif
 
 /* Enable CLK outputs 0, 1, 2, 3, 4, 5, 7 only. */
- void si5351c_enable_clock_outputs()
+ void si5351c_enable_clock_outputs(si5351c_driver_t* const drv)
  {
 	uint8_t data[] = { 3, 0x40 };
- 	si5351c_write(data, sizeof(data));
+ 	si5351c_write(drv, data, sizeof(data));
  }
 
 
- void si5351c_set_int_mode(const uint_fast8_t ms_number, const uint_fast8_t on){
+ void si5351c_set_int_mode(si5351c_driver_t* const drv, const uint_fast8_t ms_number, const uint_fast8_t on){
   uint8_t data[] = {16, 0};
 
   if(ms_number < 8){
       data[0] = 16 + ms_number;
-      data[1] = si5351c_read_single(data[0]);
+      data[1] = si5351c_read_single(drv, data[0]);
 
       if(on)
           data[1] |= SI5351C_CLK_INT_MODE;
       else
           data[1] &= ~(SI5351C_CLK_INT_MODE);
 
-      si5351c_write(data, 2);
+      si5351c_write(drv, data, 2);
   }
 
  }
 
-void si5351c_set_clock_source(const enum pll_sources source)
+void si5351c_set_clock_source(si5351c_driver_t* const drv, const enum pll_sources source)
 {
-	si5351c_configure_clock_control(source);
+	si5351c_configure_clock_control(drv, source);
 	active_clock_source = source;
 }
 
-void si5351c_activate_best_clock_source(void)
+void si5351c_activate_best_clock_source(si5351c_driver_t* const drv)
 {
-	uint8_t device_status = si5351c_read_single(0);
+	uint8_t device_status = si5351c_read_single(drv, 0);
 
 	if (device_status & SI5351C_LOS) {
 		/* CLKIN not detected */
 		if (active_clock_source == PLL_SOURCE_CLKIN) {
-			si5351c_set_clock_source(PLL_SOURCE_XTAL);
+			si5351c_set_clock_source(drv, PLL_SOURCE_XTAL);
 		}
 	} else {
 		/* CLKIN detected */
 		if (active_clock_source == PLL_SOURCE_XTAL) {
-			si5351c_set_clock_source(PLL_SOURCE_CLKIN);
+			si5351c_set_clock_source(drv, PLL_SOURCE_CLKIN);
 		}
 	}
 }
diff --git a/firmware/common/si5351c.h b/firmware/common/si5351c.h
index fcc2d2b8..7151f990 100644
--- a/firmware/common/si5351c.h
+++ b/firmware/common/si5351c.h
@@ -30,6 +30,8 @@ extern "C"
 
 #include <stdint.h>
 
+#include "si5351c_drv.h"
+
 #define SI_INTDIV(x)  (x*128-512)
 
 #define SI5351C_CLK_POWERDOWN	(1<<7)
@@ -61,22 +63,23 @@ enum pll_sources {
 	PLL_SOURCE_CLKIN = 1,
 };
 
-void si5351c_disable_all_outputs();
-void si5351c_disable_oeb_pin_control();
-void si5351c_power_down_all_clocks();
-void si5351c_set_crystal_configuration();
-void si5351c_enable_xo_and_ms_fanout();
-void si5351c_configure_pll_sources(void);
-void si5351c_configure_pll_multisynth(void);
-void si5351c_reset_pll(void);
-void si5351c_configure_multisynth(const uint_fast8_t ms_number,
+void si5351c_disable_all_outputs(si5351c_driver_t* const drv);
+void si5351c_disable_oeb_pin_control(si5351c_driver_t* const drv);
+void si5351c_power_down_all_clocks(si5351c_driver_t* const drv);
+void si5351c_set_crystal_configuration(si5351c_driver_t* const drv);
+void si5351c_enable_xo_and_ms_fanout(si5351c_driver_t* const drv);
+void si5351c_configure_pll_sources(si5351c_driver_t* const drv);
+void si5351c_configure_pll_multisynth(si5351c_driver_t* const drv);
+void si5351c_reset_pll(si5351c_driver_t* const drv);
+void si5351c_configure_multisynth(si5351c_driver_t* const drv,
+		const uint_fast8_t ms_number,
     	const uint32_t p1, const uint32_t p2, const uint32_t p3,
     	const uint_fast8_t r_div);
-void si5351c_configure_clock_control(const enum pll_sources source);
-void si5351c_enable_clock_outputs();
-void si5351c_set_int_mode(const uint_fast8_t ms_number, const uint_fast8_t on);
-void si5351c_set_clock_source(const enum pll_sources source);
-void si5351c_activate_best_clock_source(void);
+void si5351c_configure_clock_control(si5351c_driver_t* const drv, const enum pll_sources source);
+void si5351c_enable_clock_outputs(si5351c_driver_t* const drv);
+void si5351c_set_int_mode(si5351c_driver_t* const drv, const uint_fast8_t ms_number, const uint_fast8_t on);
+void si5351c_set_clock_source(si5351c_driver_t* const drv, const enum pll_sources source);
+void si5351c_activate_best_clock_source(si5351c_driver_t* const drv);
 
 #ifdef __cplusplus
 }
diff --git a/firmware/common/si5351c_drv.c b/firmware/common/si5351c_drv.c
index e63912c1..4cb58cd6 100644
--- a/firmware/common/si5351c_drv.c
+++ b/firmware/common/si5351c_drv.c
@@ -29,28 +29,28 @@
 /* FIXME return i2c0 status from each function */
 
 /* write to single register */
-void si5351c_write_single(uint8_t reg, uint8_t val)
+void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val)
 {
 	i2c0_tx_start();
-	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
+	i2c0_tx_byte((drv->i2c_address << 1) | I2C_WRITE);
 	i2c0_tx_byte(reg);
 	i2c0_tx_byte(val);
 	i2c0_stop();
 }
 
 /* read single register */
-uint8_t si5351c_read_single(uint8_t reg)
+uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
 {
 	uint8_t val;
 
 	/* set register address with write */
 	i2c0_tx_start();
-	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
+	i2c0_tx_byte((drv->i2c_address << 1) | I2C_WRITE);
 	i2c0_tx_byte(reg);
 
 	/* read the value */
 	i2c0_tx_start();
-	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_READ);
+	i2c0_tx_byte((drv->i2c_address << 1) | I2C_READ);
 	val = i2c0_rx_byte();
 	i2c0_stop();
 
@@ -61,12 +61,12 @@ uint8_t si5351c_read_single(uint8_t reg)
  * Write to one or more contiguous registers. data[0] should be the first
  * register number, one or more values follow.
  */
-void si5351c_write(uint8_t* const data, const uint_fast8_t data_count)
+void si5351c_write(si5351c_driver_t* const drv, uint8_t* const data, const uint_fast8_t data_count)
 {
 	uint_fast8_t i;
 
 	i2c0_tx_start();
-	i2c0_tx_byte(SI5351C_I2C_ADDR | I2C_WRITE);
+	i2c0_tx_byte((drv->i2c_address << 1) | I2C_WRITE);
 	
 	for (i = 0; i < data_count; i++)
 		i2c0_tx_byte(data[i]);
diff --git a/firmware/common/si5351c_drv.h b/firmware/common/si5351c_drv.h
index 501b221e..61c6f374 100644
--- a/firmware/common/si5351c_drv.h
+++ b/firmware/common/si5351c_drv.h
@@ -30,9 +30,13 @@ extern "C"
 
 #include <stdint.h>
 
-void si5351c_write_single(uint8_t reg, uint8_t val);
-uint8_t si5351c_read_single(uint8_t reg);
-void si5351c_write(uint8_t* const data, const uint_fast8_t data_count);
+typedef struct {
+	uint8_t i2c_address;
+} si5351c_driver_t;
+
+void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val);
+uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg);
+void si5351c_write(si5351c_driver_t* const drv, uint8_t* const data, const uint_fast8_t data_count);
 
 #ifdef __cplusplus
 }
diff --git a/firmware/hackrf_usb/hackrf_usb.c b/firmware/hackrf_usb/hackrf_usb.c
index 42fc4482..0ed260c5 100644
--- a/firmware/hackrf_usb/hackrf_usb.c
+++ b/firmware/hackrf_usb/hackrf_usb.c
@@ -75,7 +75,7 @@ void set_transceiver_mode(const transceiver_mode_t new_transceiver_mode) {
 	}
 
 	if( _transceiver_mode != TRANSCEIVER_MODE_OFF ) {
-		si5351c_activate_best_clock_source();
+		si5351c_activate_best_clock_source(&clock_gen);
 		baseband_streaming_enable();
 	}
 }
diff --git a/firmware/hackrf_usb/usb_api_register.c b/firmware/hackrf_usb/usb_api_register.c
index 9478e7c1..35b9e012 100644
--- a/firmware/hackrf_usb/usb_api_register.c
+++ b/firmware/hackrf_usb/usb_api_register.c
@@ -22,9 +22,9 @@
 
 #include "usb_api_register.h"
 
+#include <hackrf_core.h>
 #include <usb_queue.h>
 #include <max2837.h>
-#include <si5351c_drv.h>
 #include <rffc5071.h>
 
 #include <stddef.h>
@@ -75,7 +75,7 @@ usb_request_status_t usb_vendor_request_write_si5351c(
 	if( stage == USB_TRANSFER_STAGE_SETUP ) {
 		if( endpoint->setup.index < 256 ) {
 			if( endpoint->setup.value < 256 ) {
-				si5351c_write_single(endpoint->setup.index, endpoint->setup.value);
+				si5351c_write_single(&clock_gen, endpoint->setup.index, endpoint->setup.value);
 				usb_transfer_schedule_ack(endpoint->in);
 				return USB_REQUEST_STATUS_OK;
 			}
@@ -92,7 +92,7 @@ usb_request_status_t usb_vendor_request_read_si5351c(
 ) {
 	if( stage == USB_TRANSFER_STAGE_SETUP ) {
 		if( endpoint->setup.index < 256 ) {
-			const uint8_t value = si5351c_read_single(endpoint->setup.index);
+			const uint8_t value = si5351c_read_single(&clock_gen, endpoint->setup.index);
 			endpoint->buffer[0] = value;
 			usb_transfer_schedule_block(endpoint->in, &endpoint->buffer, 1,
 						    NULL, NULL);

From 721f74867779291e11dcf69ffe313b45213f84cf Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Wed, 12 Nov 2014 10:21:34 -0800
Subject: [PATCH 3/9] Si5351C: Change write data arg to be const.

---
 firmware/common/si5351c_drv.c | 2 +-
 firmware/common/si5351c_drv.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/firmware/common/si5351c_drv.c b/firmware/common/si5351c_drv.c
index 4cb58cd6..4c17ae45 100644
--- a/firmware/common/si5351c_drv.c
+++ b/firmware/common/si5351c_drv.c
@@ -61,7 +61,7 @@ uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
  * Write to one or more contiguous registers. data[0] should be the first
  * register number, one or more values follow.
  */
-void si5351c_write(si5351c_driver_t* const drv, uint8_t* const data, const uint_fast8_t data_count)
+void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const uint_fast8_t data_count)
 {
 	uint_fast8_t i;
 
diff --git a/firmware/common/si5351c_drv.h b/firmware/common/si5351c_drv.h
index 61c6f374..2e94e0bd 100644
--- a/firmware/common/si5351c_drv.h
+++ b/firmware/common/si5351c_drv.h
@@ -36,7 +36,7 @@ typedef struct {
 
 void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val);
 uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg);
-void si5351c_write(si5351c_driver_t* const drv, uint8_t* const data, const uint_fast8_t data_count);
+void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const uint_fast8_t data_count);
 
 #ifdef __cplusplus
 }

From 4ea0f28d14a086c64c7e9f04707910b8776b4f02 Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Wed, 12 Nov 2014 10:23:00 -0800
Subject: [PATCH 4/9] SI5351C: Rewrite si5351c_write_single() to use
 si5351c_write().

---
 firmware/common/si5351c_drv.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/firmware/common/si5351c_drv.c b/firmware/common/si5351c_drv.c
index 4c17ae45..207269d6 100644
--- a/firmware/common/si5351c_drv.c
+++ b/firmware/common/si5351c_drv.c
@@ -31,11 +31,8 @@
 /* write to single register */
 void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val)
 {
-	i2c0_tx_start();
-	i2c0_tx_byte((drv->i2c_address << 1) | I2C_WRITE);
-	i2c0_tx_byte(reg);
-	i2c0_tx_byte(val);
-	i2c0_stop();
+	const uint8_t data_tx[] = { reg, val };
+	si5351c_write(drv, data_tx, 2);
 }
 
 /* read single register */

From 35b549816a387d2c579a5d106720636f8ee78cbf Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Wed, 12 Nov 2014 10:37:58 -0800
Subject: [PATCH 5/9] Si5351C: Widen write() data_count argument type to
 size_t.

---
 firmware/common/si5351c_drv.c | 2 +-
 firmware/common/si5351c_drv.h | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/firmware/common/si5351c_drv.c b/firmware/common/si5351c_drv.c
index 207269d6..85596839 100644
--- a/firmware/common/si5351c_drv.c
+++ b/firmware/common/si5351c_drv.c
@@ -58,7 +58,7 @@ uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
  * Write to one or more contiguous registers. data[0] should be the first
  * register number, one or more values follow.
  */
-void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const uint_fast8_t data_count)
+void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const size_t data_count)
 {
 	uint_fast8_t i;
 
diff --git a/firmware/common/si5351c_drv.h b/firmware/common/si5351c_drv.h
index 2e94e0bd..147e91fa 100644
--- a/firmware/common/si5351c_drv.h
+++ b/firmware/common/si5351c_drv.h
@@ -29,6 +29,7 @@ extern "C"
 #endif
 
 #include <stdint.h>
+#include <stddef.h>
 
 typedef struct {
 	uint8_t i2c_address;
@@ -36,7 +37,7 @@ typedef struct {
 
 void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val);
 uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg);
-void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const uint_fast8_t data_count);
+void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const size_t data_count);
 
 #ifdef __cplusplus
 }

From 080a1ba9ac97ef5817d0302f0a408d95403c058a Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Wed, 12 Nov 2014 10:45:26 -0800
Subject: [PATCH 6/9] Si5351C: Extract I2C code into single transfer function.

---
 firmware/common/si5351c_drv.c | 51 ++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 22 deletions(-)

diff --git a/firmware/common/si5351c_drv.c b/firmware/common/si5351c_drv.c
index 85596839..e2c87eff 100644
--- a/firmware/common/si5351c_drv.c
+++ b/firmware/common/si5351c_drv.c
@@ -28,6 +28,30 @@
 
 /* FIXME return i2c0 status from each function */
 
+static void i2c0_transfer(si5351c_driver_t* const drv,
+	const uint_fast8_t address,
+	const uint8_t* const data_tx, const size_t count_tx,
+	uint8_t* const data_rx, const size_t count_rx
+) {
+	(void)drv;
+	
+	i2c0_tx_start();
+	i2c0_tx_byte((address << 1) | I2C_WRITE);
+	for(size_t i=0; i<count_tx; i++) {
+		i2c0_tx_byte(data_tx[i]);
+	}
+
+	if( data_rx ) {
+		i2c0_tx_start();
+		i2c0_tx_byte((address << 1) | I2C_READ);
+		for(size_t i=0; i<count_rx; i++) {
+			data_rx[i] = i2c0_rx_byte();
+		}
+	}
+
+	i2c0_stop();
+}
+
 /* write to single register */
 void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val)
 {
@@ -38,20 +62,10 @@ void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val)
 /* read single register */
 uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
 {
-	uint8_t val;
-
-	/* set register address with write */
-	i2c0_tx_start();
-	i2c0_tx_byte((drv->i2c_address << 1) | I2C_WRITE);
-	i2c0_tx_byte(reg);
-
-	/* read the value */
-	i2c0_tx_start();
-	i2c0_tx_byte((drv->i2c_address << 1) | I2C_READ);
-	val = i2c0_rx_byte();
-	i2c0_stop();
-
-	return val;
+	const uint8_t data_tx[] = { reg };
+	uint8_t data_rx[] = { 0x00 };
+	i2c0_transfer(drv, drv->i2c_address, data_tx, 1, data_rx, 1);
+	return data_rx[0];
 }
 
 /*
@@ -60,12 +74,5 @@ uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
  */
 void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const size_t data_count)
 {
-	uint_fast8_t i;
-
-	i2c0_tx_start();
-	i2c0_tx_byte((drv->i2c_address << 1) | I2C_WRITE);
-	
-	for (i = 0; i < data_count; i++)
-		i2c0_tx_byte(data[i]);
-	i2c0_stop();
+	i2c0_transfer(drv, drv->i2c_address, data, data_count, NULL, 0);
 }

From eb0dea483fa120fc8c4252ba0c7331879fe3d189 Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Wed, 12 Nov 2014 13:56:58 -0800
Subject: [PATCH 7/9] I2C: Finish extracting from Si5351C code.

---
 firmware/common/hackrf_core.c | 31 +++++++++++++++++--
 firmware/common/i2c_bus.c     | 35 +++++++++++++++++++++
 firmware/common/i2c_bus.h     | 50 ++++++++++++++++++++++++++++++
 firmware/common/i2c_lpc.c     | 57 +++++++++++++++++++++++++++++++++++
 firmware/common/i2c_lpc.h     | 41 +++++++++++++++++++++++++
 firmware/common/si5351c_drv.c | 34 ++-------------------
 firmware/common/si5351c_drv.h |  3 ++
 firmware/hackrf-common.cmake  |  2 ++
 firmware/libopencm3           |  2 +-
 9 files changed, 219 insertions(+), 36 deletions(-)
 create mode 100644 firmware/common/i2c_bus.c
 create mode 100644 firmware/common/i2c_bus.h
 create mode 100644 firmware/common/i2c_lpc.c
 create mode 100644 firmware/common/i2c_lpc.h

diff --git a/firmware/common/hackrf_core.c b/firmware/common/hackrf_core.c
index 792beec3..a562f7c6 100644
--- a/firmware/common/hackrf_core.c
+++ b/firmware/common/hackrf_core.c
@@ -27,7 +27,8 @@
 #include "rffc5071.h"
 #include "sgpio.h"
 #include "rf_path.h"
-#include <libopencm3/lpc43xx/i2c.h>
+#include "i2c_bus.h"
+#include "i2c_lpc.h"
 #include <libopencm3/lpc43xx/cgu.h>
 #include <libopencm3/lpc43xx/gpio.h>
 #include <libopencm3/lpc43xx/scu.h>
@@ -35,7 +36,28 @@
 
 #define WAIT_CPU_CLOCK_INIT_DELAY   (10000)
 
+i2c_bus_t i2c0 = {
+	.obj = (void*)I2C0_BASE,
+	.init = i2c_lpc_init,
+	.transfer = i2c_lpc_transfer,
+};
+
+i2c_bus_t i2c1 = {
+	.obj = (void*)I2C1_BASE,
+	.init = i2c_lpc_init,
+	.transfer = i2c_lpc_transfer,
+};
+
+const i2c_lpc_config_t i2c_config_si5351c_slow_clock = {
+	.duty_cycle_count = 15,
+};
+
+const i2c_lpc_config_t i2c_config_si5351c_fast_clock = {
+	.duty_cycle_count = 255,
+};
+
 si5351c_driver_t clock_gen = {
+	.bus = &i2c0,
 	.i2c_address = 0x60,
 };
 
@@ -268,7 +290,7 @@ void cpu_clock_init(void)
 	/* use IRC as clock source for APB3 */
 	CGU_BASE_APB3_CLK = CGU_BASE_APB3_CLK_CLK_SEL(CGU_SRC_IRC);
 
-	i2c0_init(15);
+	i2c_bus_init(clock_gen.bus, &i2c_config_si5351c_slow_clock);
 
 	si5351c_disable_all_outputs(&clock_gen);
 	si5351c_disable_oeb_pin_control(&clock_gen);
@@ -340,7 +362,7 @@ void cpu_clock_init(void)
 
 	//FIXME disable I2C
 	/* Kick I2C0 down to 400kHz when we switch over to APB1 clock = 204MHz */
-	i2c0_init(255);
+	i2c_bus_init(clock_gen.bus, &i2c_config_si5351c_fast_clock);
 
 	/*
 	 * 12MHz clock is entering LPC XTAL1/OSC input now.  On
@@ -615,6 +637,9 @@ void pin_setup(void) {
 	/* GPIO3[6] on P6_10  as output. */
 	GPIO3_DIR |= PIN_EN1V8;
 
+	/* enable input on SCL and SDA pins */
+	SCU_SFSI2C0 = SCU_I2C0_NOMINAL;
+
 	rf_path_pin_setup();
 	
 	/* Configure SSP1 Peripheral (to be moved later in SSP driver) */
diff --git a/firmware/common/i2c_bus.c b/firmware/common/i2c_bus.c
new file mode 100644
index 00000000..6b60455a
--- /dev/null
+++ b/firmware/common/i2c_bus.c
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of HackRF.
+ *
+ * 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, 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "i2c_bus.h"
+
+void i2c_bus_init(i2c_bus_t* const bus, const void* const config) {
+	bus->init(bus, config);
+}
+
+void i2c_bus_transfer(
+	i2c_bus_t* const bus,
+	const uint_fast8_t slave_address,
+	const uint8_t* const tx, const size_t tx_count,
+	uint8_t* const rx, const size_t rx_count
+) {
+	bus->transfer(bus, slave_address, tx, tx_count, rx, rx_count);
+}
diff --git a/firmware/common/i2c_bus.h b/firmware/common/i2c_bus.h
new file mode 100644
index 00000000..784fb602
--- /dev/null
+++ b/firmware/common/i2c_bus.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of HackRF.
+ *
+ * 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, 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __I2C_BUS_H__
+#define __I2C_BUS_H__
+
+#include <stdint.h>
+#include <stddef.h>
+
+struct i2c_bus_t;
+typedef struct i2c_bus_t i2c_bus_t;
+
+struct i2c_bus_t {
+	void* const obj;
+	void (*init)(i2c_bus_t* const bus, const void* const config);
+	void (*transfer)(
+		i2c_bus_t* const bus,
+		const uint_fast8_t slave_address,
+		const uint8_t* const tx, const size_t tx_count,
+		uint8_t* const rx, const size_t rx_count
+	);
+};
+
+void i2c_bus_init(i2c_bus_t* const bus, const void* const config);
+void i2c_bus_transfer(
+	i2c_bus_t* const bus,
+	const uint_fast8_t slave_address,
+	const uint8_t* const tx, const size_t tx_count,
+	uint8_t* const rx, const size_t rx_count
+);
+
+#endif/*__I2C_BUS_H__*/
diff --git a/firmware/common/i2c_lpc.c b/firmware/common/i2c_lpc.c
new file mode 100644
index 00000000..73c3e92c
--- /dev/null
+++ b/firmware/common/i2c_lpc.c
@@ -0,0 +1,57 @@
+/*
+ * Copyright 2012 Michael Ossmann <mike@ossmann.com>
+ * Copyright 2012 Jared Boone <jared@sharebrained.com>
+ *
+ * This file is part of HackRF.
+ *
+ * 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, 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include "i2c_lpc.h"
+
+#include <libopencm3/lpc43xx/i2c.h>
+
+/* FIXME return i2c0 status from each function */
+
+void i2c_lpc_init(i2c_bus_t* const bus, const void* const _config) {
+	const i2c_lpc_config_t* const config = _config;
+
+	const uint32_t port = (uint32_t)bus->obj;
+	i2c_init(port, config->duty_cycle_count);
+}
+
+void i2c_lpc_transfer(i2c_bus_t* const bus,
+	const uint_fast8_t slave_address,
+	const uint8_t* const data_tx, const size_t count_tx,
+	uint8_t* const data_rx, const size_t count_rx
+) {
+	const uint32_t port = (uint32_t)bus->obj;
+	i2c_tx_start(port);
+	i2c_tx_byte(port, (slave_address << 1) | I2C_WRITE);
+	for(size_t i=0; i<count_tx; i++) {
+		i2c_tx_byte(port, data_tx[i]);
+	}
+
+	if( data_rx ) {
+		i2c_tx_start(port);
+		i2c_tx_byte(port, (slave_address << 1) | I2C_READ);
+		for(size_t i=0; i<count_rx; i++) {
+			data_rx[i] = i2c_rx_byte(port);
+		}
+	}
+
+	i2c_stop(port);
+}
diff --git a/firmware/common/i2c_lpc.h b/firmware/common/i2c_lpc.h
new file mode 100644
index 00000000..16c04a22
--- /dev/null
+++ b/firmware/common/i2c_lpc.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
+ *
+ * This file is part of HackRF.
+ *
+ * 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, 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; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifndef __I2C_LPC_H__
+#define __I2C_LPC_H__
+
+#include <stdint.h>
+#include <stddef.h>
+
+#include "i2c_bus.h"
+
+typedef struct i2c_lpc_config_t {
+	const uint16_t duty_cycle_count;
+} i2c_lpc_config_t;
+
+void i2c_lpc_init(i2c_bus_t* const bus, const void* const config);
+void i2c_lpc_transfer(i2c_bus_t* const bus,
+	const uint_fast8_t slave_address,
+	const uint8_t* const data_tx, const size_t count_tx,
+	uint8_t* const data_rx, const size_t count_rx
+);
+
+#endif/*__I2C_LPC_H__*/
diff --git a/firmware/common/si5351c_drv.c b/firmware/common/si5351c_drv.c
index e2c87eff..2b788842 100644
--- a/firmware/common/si5351c_drv.c
+++ b/firmware/common/si5351c_drv.c
@@ -22,36 +22,6 @@
 
 #include "si5351c_drv.h"
 
-#include <libopencm3/lpc43xx/i2c.h>
-
-#define SI5351C_I2C_ADDR (0x60 << 1)
-
-/* FIXME return i2c0 status from each function */
-
-static void i2c0_transfer(si5351c_driver_t* const drv,
-	const uint_fast8_t address,
-	const uint8_t* const data_tx, const size_t count_tx,
-	uint8_t* const data_rx, const size_t count_rx
-) {
-	(void)drv;
-	
-	i2c0_tx_start();
-	i2c0_tx_byte((address << 1) | I2C_WRITE);
-	for(size_t i=0; i<count_tx; i++) {
-		i2c0_tx_byte(data_tx[i]);
-	}
-
-	if( data_rx ) {
-		i2c0_tx_start();
-		i2c0_tx_byte((address << 1) | I2C_READ);
-		for(size_t i=0; i<count_rx; i++) {
-			data_rx[i] = i2c0_rx_byte();
-		}
-	}
-
-	i2c0_stop();
-}
-
 /* write to single register */
 void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val)
 {
@@ -64,7 +34,7 @@ uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
 {
 	const uint8_t data_tx[] = { reg };
 	uint8_t data_rx[] = { 0x00 };
-	i2c0_transfer(drv, drv->i2c_address, data_tx, 1, data_rx, 1);
+	i2c_bus_transfer(drv->bus, drv->i2c_address, data_tx, 1, data_rx, 1);
 	return data_rx[0];
 }
 
@@ -74,5 +44,5 @@ uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
  */
 void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const size_t data_count)
 {
-	i2c0_transfer(drv, drv->i2c_address, data, data_count, NULL, 0);
+	i2c_bus_transfer(drv->bus, drv->i2c_address, data, data_count, NULL, 0);
 }
diff --git a/firmware/common/si5351c_drv.h b/firmware/common/si5351c_drv.h
index 147e91fa..acb71459 100644
--- a/firmware/common/si5351c_drv.h
+++ b/firmware/common/si5351c_drv.h
@@ -31,7 +31,10 @@ extern "C"
 #include <stdint.h>
 #include <stddef.h>
 
+#include "i2c_bus.h"
+
 typedef struct {
+	i2c_bus_t* const bus;
 	uint8_t i2c_address;
 } si5351c_driver_t;
 
diff --git a/firmware/hackrf-common.cmake b/firmware/hackrf-common.cmake
index 9b4fb9a9..decd2bed 100644
--- a/firmware/hackrf-common.cmake
+++ b/firmware/hackrf-common.cmake
@@ -138,6 +138,8 @@ macro(DeclareTargets)
 		${PATH_HACKRF_FIRMWARE_COMMON}/max2837.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/max5864.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/rffc5071.c
+		${PATH_HACKRF_FIRMWARE_COMMON}/i2c_bus.c
+		${PATH_HACKRF_FIRMWARE_COMMON}/i2c_lpc.c
 		m0_bin.s
 	)
 
diff --git a/firmware/libopencm3 b/firmware/libopencm3
index 854c112a..aec04e96 160000
--- a/firmware/libopencm3
+++ b/firmware/libopencm3
@@ -1 +1 @@
-Subproject commit 854c112a0ea7b27e85a15345507c8a2e13e76607
+Subproject commit aec04e962c2264877580be30fe1e1178ce3f568c

From 28d629e0993985430284e2c4625af4c45d55ac0e Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Wed, 12 Nov 2014 18:32:00 -0800
Subject: [PATCH 8/9] Si5351C: Bring I2C wrapper into main driver.

---
 firmware/common/hackrf_core.h |  2 +-
 firmware/common/si5351c.c     | 27 +++++++++++++++++--
 firmware/common/si5351c.h     | 11 +++++++-
 firmware/common/si5351c_drv.c | 48 ----------------------------------
 firmware/common/si5351c_drv.h | 49 -----------------------------------
 firmware/hackrf-common.cmake  |  1 -
 6 files changed, 36 insertions(+), 102 deletions(-)
 delete mode 100644 firmware/common/si5351c_drv.c
 delete mode 100644 firmware/common/si5351c_drv.h

diff --git a/firmware/common/hackrf_core.h b/firmware/common/hackrf_core.h
index 7ad1ad50..ae7c7a2d 100644
--- a/firmware/common/hackrf_core.h
+++ b/firmware/common/hackrf_core.h
@@ -32,7 +32,7 @@ extern "C"
 #include <stdint.h>
 #include <stdbool.h>
 
-#include "si5351c_drv.h"
+#include "si5351c.h"
 
 /* hardware identification number */
 #define BOARD_ID_JELLYBEAN  0
diff --git a/firmware/common/si5351c.c b/firmware/common/si5351c.c
index f6b4483a..36730930 100644
--- a/firmware/common/si5351c.c
+++ b/firmware/common/si5351c.c
@@ -22,10 +22,33 @@
 
 #include "si5351c.h"
 
-#include "si5351c_drv.h"
-
 enum pll_sources active_clock_source;
 
+/* write to single register */
+void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val)
+{
+	const uint8_t data_tx[] = { reg, val };
+	si5351c_write(drv, data_tx, 2);
+}
+
+/* read single register */
+uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
+{
+	const uint8_t data_tx[] = { reg };
+	uint8_t data_rx[] = { 0x00 };
+	i2c_bus_transfer(drv->bus, drv->i2c_address, data_tx, 1, data_rx, 1);
+	return data_rx[0];
+}
+
+/*
+ * Write to one or more contiguous registers. data[0] should be the first
+ * register number, one or more values follow.
+ */
+void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const size_t data_count)
+{
+	i2c_bus_transfer(drv->bus, drv->i2c_address, data, data_count, NULL, 0);
+}
+
 /* Disable all CLKx outputs. */
 void si5351c_disable_all_outputs(si5351c_driver_t* const drv)
 {
diff --git a/firmware/common/si5351c.h b/firmware/common/si5351c.h
index 7151f990..d10a0a93 100644
--- a/firmware/common/si5351c.h
+++ b/firmware/common/si5351c.h
@@ -30,7 +30,7 @@ extern "C"
 
 #include <stdint.h>
 
-#include "si5351c_drv.h"
+#include "i2c_bus.h"
 
 #define SI_INTDIV(x)  (x*128-512)
 
@@ -63,6 +63,11 @@ enum pll_sources {
 	PLL_SOURCE_CLKIN = 1,
 };
 
+typedef struct {
+	i2c_bus_t* const bus;
+	uint8_t i2c_address;
+} si5351c_driver_t;
+
 void si5351c_disable_all_outputs(si5351c_driver_t* const drv);
 void si5351c_disable_oeb_pin_control(si5351c_driver_t* const drv);
 void si5351c_power_down_all_clocks(si5351c_driver_t* const drv);
@@ -81,6 +86,10 @@ void si5351c_set_int_mode(si5351c_driver_t* const drv, const uint_fast8_t ms_num
 void si5351c_set_clock_source(si5351c_driver_t* const drv, const enum pll_sources source);
 void si5351c_activate_best_clock_source(si5351c_driver_t* const drv);
 
+void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val);
+uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg);
+void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const size_t data_count);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/firmware/common/si5351c_drv.c b/firmware/common/si5351c_drv.c
deleted file mode 100644
index 2b788842..00000000
--- a/firmware/common/si5351c_drv.c
+++ /dev/null
@@ -1,48 +0,0 @@
-/*
- * Copyright 2012 Michael Ossmann <mike@ossmann.com>
- * Copyright 2012 Jared Boone <jared@sharebrained.com>
- *
- * This file is part of HackRF.
- *
- * 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, 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; see the file COPYING.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street,
- * Boston, MA 02110-1301, USA.
- */
-
-#include "si5351c_drv.h"
-
-/* write to single register */
-void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val)
-{
-	const uint8_t data_tx[] = { reg, val };
-	si5351c_write(drv, data_tx, 2);
-}
-
-/* read single register */
-uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg)
-{
-	const uint8_t data_tx[] = { reg };
-	uint8_t data_rx[] = { 0x00 };
-	i2c_bus_transfer(drv->bus, drv->i2c_address, data_tx, 1, data_rx, 1);
-	return data_rx[0];
-}
-
-/*
- * Write to one or more contiguous registers. data[0] should be the first
- * register number, one or more values follow.
- */
-void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const size_t data_count)
-{
-	i2c_bus_transfer(drv->bus, drv->i2c_address, data, data_count, NULL, 0);
-}
diff --git a/firmware/common/si5351c_drv.h b/firmware/common/si5351c_drv.h
deleted file mode 100644
index acb71459..00000000
--- a/firmware/common/si5351c_drv.h
+++ /dev/null
@@ -1,49 +0,0 @@
-/*
- * Copyright 2012 Michael Ossmann <mike@ossmann.com>
- * Copyright 2012 Jared Boone <jared@sharebrained.com>
- *
- * This file is part of HackRF.
- *
- * 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, 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; see the file COPYING.  If not, write to
- * the Free Software Foundation, Inc., 51 Franklin Street,
- * Boston, MA 02110-1301, USA.
- */
-
-#ifndef __SI5351C_DRV_H
-#define __SI5351C_DRV_H
-
-#ifdef __cplusplus
-extern "C"
-{
-#endif
-
-#include <stdint.h>
-#include <stddef.h>
-
-#include "i2c_bus.h"
-
-typedef struct {
-	i2c_bus_t* const bus;
-	uint8_t i2c_address;
-} si5351c_driver_t;
-
-void si5351c_write_single(si5351c_driver_t* const drv, uint8_t reg, uint8_t val);
-uint8_t si5351c_read_single(si5351c_driver_t* const drv, uint8_t reg);
-void si5351c_write(si5351c_driver_t* const drv, const uint8_t* const data, const size_t data_count);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* __SI5351C_DRV_H */
diff --git a/firmware/hackrf-common.cmake b/firmware/hackrf-common.cmake
index decd2bed..b7a0ec91 100644
--- a/firmware/hackrf-common.cmake
+++ b/firmware/hackrf-common.cmake
@@ -134,7 +134,6 @@ macro(DeclareTargets)
 		${PATH_HACKRF_FIRMWARE_COMMON}/sgpio.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/rf_path.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/si5351c.c
-		${PATH_HACKRF_FIRMWARE_COMMON}/si5351c_drv.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/max2837.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/max5864.c
 		${PATH_HACKRF_FIRMWARE_COMMON}/rffc5071.c

From 02cc5814b15dfc666d6a0bcdedaec4583a659550 Mon Sep 17 00:00:00 2001
From: Jared Boone <jboone@earfeast.com>
Date: Thu, 13 Nov 2014 10:32:38 -0800
Subject: [PATCH 9/9] I2C: Interface: Rename init()->start(), add stop().

---
 firmware/common/hackrf_core.c | 10 ++++++----
 firmware/common/i2c_bus.c     |  8 ++++++--
 firmware/common/i2c_bus.h     |  6 ++++--
 firmware/common/i2c_lpc.c     |  7 ++++++-
 firmware/common/i2c_lpc.h     |  3 ++-
 firmware/libopencm3           |  2 +-
 6 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/firmware/common/hackrf_core.c b/firmware/common/hackrf_core.c
index a562f7c6..1af5e823 100644
--- a/firmware/common/hackrf_core.c
+++ b/firmware/common/hackrf_core.c
@@ -38,13 +38,15 @@
 
 i2c_bus_t i2c0 = {
 	.obj = (void*)I2C0_BASE,
-	.init = i2c_lpc_init,
+	.start = i2c_lpc_start,
+	.stop = i2c_lpc_stop,
 	.transfer = i2c_lpc_transfer,
 };
 
 i2c_bus_t i2c1 = {
 	.obj = (void*)I2C1_BASE,
-	.init = i2c_lpc_init,
+	.start = i2c_lpc_start,
+	.stop = i2c_lpc_stop,
 	.transfer = i2c_lpc_transfer,
 };
 
@@ -290,7 +292,7 @@ void cpu_clock_init(void)
 	/* use IRC as clock source for APB3 */
 	CGU_BASE_APB3_CLK = CGU_BASE_APB3_CLK_CLK_SEL(CGU_SRC_IRC);
 
-	i2c_bus_init(clock_gen.bus, &i2c_config_si5351c_slow_clock);
+	i2c_bus_start(clock_gen.bus, &i2c_config_si5351c_slow_clock);
 
 	si5351c_disable_all_outputs(&clock_gen);
 	si5351c_disable_oeb_pin_control(&clock_gen);
@@ -362,7 +364,7 @@ void cpu_clock_init(void)
 
 	//FIXME disable I2C
 	/* Kick I2C0 down to 400kHz when we switch over to APB1 clock = 204MHz */
-	i2c_bus_init(clock_gen.bus, &i2c_config_si5351c_fast_clock);
+	i2c_bus_start(clock_gen.bus, &i2c_config_si5351c_fast_clock);
 
 	/*
 	 * 12MHz clock is entering LPC XTAL1/OSC input now.  On
diff --git a/firmware/common/i2c_bus.c b/firmware/common/i2c_bus.c
index 6b60455a..7b5497e0 100644
--- a/firmware/common/i2c_bus.c
+++ b/firmware/common/i2c_bus.c
@@ -21,8 +21,12 @@
 
 #include "i2c_bus.h"
 
-void i2c_bus_init(i2c_bus_t* const bus, const void* const config) {
-	bus->init(bus, config);
+void i2c_bus_start(i2c_bus_t* const bus, const void* const config) {
+	bus->start(bus, config);
+}
+
+void i2c_bus_stop(i2c_bus_t* const bus) {
+	bus->stop(bus);
 }
 
 void i2c_bus_transfer(
diff --git a/firmware/common/i2c_bus.h b/firmware/common/i2c_bus.h
index 784fb602..04b83499 100644
--- a/firmware/common/i2c_bus.h
+++ b/firmware/common/i2c_bus.h
@@ -30,7 +30,8 @@ typedef struct i2c_bus_t i2c_bus_t;
 
 struct i2c_bus_t {
 	void* const obj;
-	void (*init)(i2c_bus_t* const bus, const void* const config);
+	void (*start)(i2c_bus_t* const bus, const void* const config);
+	void (*stop)(i2c_bus_t* const bus);
 	void (*transfer)(
 		i2c_bus_t* const bus,
 		const uint_fast8_t slave_address,
@@ -39,7 +40,8 @@ struct i2c_bus_t {
 	);
 };
 
-void i2c_bus_init(i2c_bus_t* const bus, const void* const config);
+void i2c_bus_start(i2c_bus_t* const bus, const void* const config);
+void i2c_bus_stop(i2c_bus_t* const bus);
 void i2c_bus_transfer(
 	i2c_bus_t* const bus,
 	const uint_fast8_t slave_address,
diff --git a/firmware/common/i2c_lpc.c b/firmware/common/i2c_lpc.c
index 73c3e92c..f7bf4393 100644
--- a/firmware/common/i2c_lpc.c
+++ b/firmware/common/i2c_lpc.c
@@ -26,13 +26,18 @@
 
 /* FIXME return i2c0 status from each function */
 
-void i2c_lpc_init(i2c_bus_t* const bus, const void* const _config) {
+void i2c_lpc_start(i2c_bus_t* const bus, const void* const _config) {
 	const i2c_lpc_config_t* const config = _config;
 
 	const uint32_t port = (uint32_t)bus->obj;
 	i2c_init(port, config->duty_cycle_count);
 }
 
+void i2c_lpc_stop(i2c_bus_t* const bus) {
+	const uint32_t port = (uint32_t)bus->obj;
+	i2c_disable(port);
+}
+
 void i2c_lpc_transfer(i2c_bus_t* const bus,
 	const uint_fast8_t slave_address,
 	const uint8_t* const data_tx, const size_t count_tx,
diff --git a/firmware/common/i2c_lpc.h b/firmware/common/i2c_lpc.h
index 16c04a22..32c79fcd 100644
--- a/firmware/common/i2c_lpc.h
+++ b/firmware/common/i2c_lpc.h
@@ -31,7 +31,8 @@ typedef struct i2c_lpc_config_t {
 	const uint16_t duty_cycle_count;
 } i2c_lpc_config_t;
 
-void i2c_lpc_init(i2c_bus_t* const bus, const void* const config);
+void i2c_lpc_start(i2c_bus_t* const bus, const void* const config);
+void i2c_lpc_stop(i2c_bus_t* const bus);
 void i2c_lpc_transfer(i2c_bus_t* const bus,
 	const uint_fast8_t slave_address,
 	const uint8_t* const data_tx, const size_t count_tx,
diff --git a/firmware/libopencm3 b/firmware/libopencm3
index aec04e96..10503c7c 160000
--- a/firmware/libopencm3
+++ b/firmware/libopencm3
@@ -1 +1 @@
-Subproject commit aec04e962c2264877580be30fe1e1178ce3f568c
+Subproject commit 10503c7cc19647393d98cc66c3dbaf20bd634494