I2C: Add support for manual / always-on gpio pullups

4 files changed, 61 insertions, 7 deletions

diff --git a/Makefile b/Makefile
index cbe93c8..3148fdc 100644
--- a/Makefile
+++ b/Makefile
@@ -71,8 +71,20 @@ ifneq (${timer_freq}, )
 	COMMON_FLAGS += -DF_TIMER=${timer_freq}
 endif
 
-ifeq (${softi2c_pullup}, 1)
-	COMMON_FLAGS += -DSOFTI2C_PULLUP
+ifeq (${softi2c_pullup}, internal)
+	COMMON_FLAGS += -DSOFTI2C_PULLUP_INTERNAL
+endif
+
+ifeq (${softi2c_pullup}, external)
+	COMMON_FLAGS += -DSOFTI2C_PULLUP_EXTERNAL
+endif
+
+ifeq (${softi2c_pullup}, gpio)
+	COMMON_FLAGS += -DSOFTI2C_PULLUP_FIXED_GPIO
+endif
+
+ifeq (${i2c_pullup}, gpio)
+	COMMON_FLAGS += -DI2C_PULLUP_FIXED_GPIO
 endif
 
 ifeq (${softi2c_timer}, 1)
diff --git a/include/driver/soft_i2c.h b/include/driver/soft_i2c.h
index aff63e3..f3ba14f 100644
--- a/include/driver/soft_i2c.h
+++ b/include/driver/soft_i2c.h
@@ -6,6 +6,9 @@ class SoftI2C {
 		SoftI2C(const SoftI2C &copy);
 
 		unsigned char sda, scl;
+#if SOFTI2C_PULLUP_EXTERNAL || SOFTI2C_PULLUP_FIXED_GPIO
+		unsigned char sda_pull, scl_pull;
+#endif
 
 		void start();
 		void stop();
@@ -13,7 +16,13 @@ class SoftI2C {
 		unsigned char rx(bool send_ack);
 
 	public:
+#if SOFTI2C_PULLUP_EXTERNAL || SOFTI2C_PULLUP_FIXED_GPIO
+		SoftI2C(unsigned char sda, unsigned char scl,
+				unsigned char sda_pull, unsigned char scl_pull) :
+			sda(sda), scl(scl), sda_pull(sda_pull), scl_pull(scl_pull) {}
+#else
 		SoftI2C(unsigned char sda, unsigned char scl) : sda(sda), scl(scl) {}
+#endif
 		signed char setup();
 		void scan(unsigned int *results);
 		signed char xmit(unsigned char address,
diff --git a/src/arch/msp430fr5969lp/driver/i2c.cc b/src/arch/msp430fr5969lp/driver/i2c.cc
index 5a47770..cb6fa79 100644
--- a/src/arch/msp430fr5969lp/driver/i2c.cc
+++ b/src/arch/msp430fr5969lp/driver/i2c.cc
@@ -10,6 +10,10 @@ volatile unsigned short old_ifg = 0;
 
 signed char I2C::setup()
 {
+#ifdef I2C_PULLUP_FIXED_GPIO
+	P1DIR |= BIT4 | BIT5;
+	P1OUT |= BIT4 | BIT5;
+#endif
 	UCB0CTL1 = UCSWRST;
 	UCB0CTLW0 = UCMODE_3 | UCMST | UCSYNC | UCSSEL_2 | UCSWRST | UCCLTO_1;
 	UCB0BRW = (F_CPU / F_I2C) - 1;
diff --git a/src/driver/soft_i2c.cc b/src/driver/soft_i2c.cc
index 39754a3..6523286 100644
--- a/src/driver/soft_i2c.cc
+++ b/src/driver/soft_i2c.cc
@@ -13,17 +13,22 @@
 #include "driver/timer.h"
 #endif
 
-#ifdef SOFTI2C_PULLUP
+#ifdef SOFTI2C_PULLUP_INTERNAL
 #define SDA_HIGH gpio.input(sda, 1)
 #define SDA_LOW gpio.output(sda, 0)
 #define SCL_HIGH gpio.input(scl, 1)
 #define SCL_LOW gpio.output(scl, 0)
-#else
+#elif SOFTI2C_PULLUP_EXTERNAL
+#define SDA_HIGH do { gpio.input(sda); gpio.write(sda_pull, 1); } while (0)
+#define SDA_LOW do { gpio.write(sda_pull, 0); gpio.output(sda); } while (0)
+#define SCL_HIGH do { gpio.input(scl); gpio.write(scl_pull, 1); } while (0)
+#define SCL_LOW do { gpio.write(scl_pull, 0); gpio.output(scl); } while (0)
+#else /* !SOFTI2C_PULLUP_{INTERNAL,EXTERNAL} */
 #define SDA_HIGH gpio.input(sda)
 #define SDA_LOW gpio.output(sda)
 #define SCL_HIGH gpio.input(scl)
 #define SCL_LOW gpio.output(scl)
-#endif
+#endif /* SOFTI2C_PULLUP */
 
 #ifndef SOFTI2C_TIMER
 
@@ -31,10 +36,24 @@
 #define I2C_WAIT arch.delay_us((500000UL / F_I2C) - 10)
 #else
 #define I2C_WAIT
-#endif
+#endif /* !SOFTI2C_TIMER */
 
 signed char SoftI2C::setup()
 {
+#ifdef SOFTI2C_PULLUP_EXTERNAL
+	gpio.output(sda_pull);
+	gpio.output(scl_pull);
+#endif
+#ifdef SOFTI2C_PULLUP_FIXED_GPIO
+#if MULTIPASS_ARCH_msp430fr5969lp
+	gpio.output(GPIO::p1_4);
+	gpio.output(GPIO::p1_5);
+	gpio.write(GPIO::p1_4, 1);
+	gpio.write(GPIO::p1_5, 1);
+#else
+#error "softi2c_pullup=gpio not supported on this architecture"
+#endif /* MULTIPASS_ARCH_* */
+#endif /* SOFTI2C_PULLUP_FIXED_GPIO */
 	SDA_HIGH;
 	SCL_HIGH;
 	return 0;
@@ -303,6 +322,13 @@ ON_TIMER_INTERRUPT_tail
 
 #endif
 
+#if SOFTI2C_PULLUP_EXTERNAL
+#ifdef MULTIPASS_ARCH_msp430fr5969lp
+SoftI2C i2c(GPIO::p1_6, GPIO::p1_7, GPIO::p1_4, GPIO::p1_5);
+#else
+#error "softi2c_pullup = external not supported on this architecture"
+#endif /* MULTIPASS_ARCH_* */
+#else
 #ifdef MULTIPASS_ARCH_esp8266
 SoftI2C i2c(GPIO::d6, GPIO::d7);
 #elif MULTIPASS_ARCH_arduino_nano
@@ -311,4 +337,7 @@ SoftI2C i2c(GPIO::pc4, GPIO::pc5);
 SoftI2C i2c(GPIO::pc4, GPIO::pc5);
 #elif MULTIPASS_ARCH_msp430fr5969lp
 SoftI2C i2c(GPIO::p1_6, GPIO::p1_7);
-#endif
+#elif MULTIPASS_ARCH_posix
+SoftI2C i2c(GPIO::px00, GPIO::px01);
+#endif /* MULTIPASS_ARCH_* */
+#endif /* !SOFTI2C_PULLUP_EXTERNAL */