i2c_dev: deprecate .gpio_port.

This won't work on F2, which at times has SDA and SCL on different
ports (e.g. I2C3 SDA on PC9, SCL on PA8). Add .sda_port and .scl_port
replacements, which are used when the now-deprecated .gpio_port is
null. Use them correctly everywhere, with some new i2c_private.h
helper functionality.

Sigh. The F1 I2C code tries too hard to guess what you wanted; it's
not porting well at all.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

4 files changed, 77 insertions, 23 deletions

diff --git a/libmaple/i2c.c b/libmaple/i2c.c
index 0e6a64c..3c92bef 100644
--- a/libmaple/i2c.c
+++ b/libmaple/i2c.c
@@ -120,29 +120,29 @@ void i2c_bus_reset(const i2c_dev *dev) {
      * Make sure the bus is free by clocking it until any slaves release the
      * bus.
      */
-    while (!gpio_read_bit(dev->gpio_port, dev->sda_pin)) {
+    while (!gpio_read_bit(sda_port(dev), dev->sda_pin)) {
         /* Wait for any clock stretching to finish */
-        while (!gpio_read_bit(dev->gpio_port, dev->scl_pin))
+        while (!gpio_read_bit(scl_port(dev), dev->scl_pin))
             ;
         delay_us(10);
 
         /* Pull low */
-        gpio_write_bit(dev->gpio_port, dev->scl_pin, 0);
+        gpio_write_bit(scl_port(dev), dev->scl_pin, 0);
         delay_us(10);
 
         /* Release high again */
-        gpio_write_bit(dev->gpio_port, dev->scl_pin, 1);
+        gpio_write_bit(scl_port(dev), dev->scl_pin, 1);
         delay_us(10);
     }
 
     /* Generate start then stop condition */
-    gpio_write_bit(dev->gpio_port, dev->sda_pin, 0);
+    gpio_write_bit(sda_port(dev), dev->sda_pin, 0);
     delay_us(10);
-    gpio_write_bit(dev->gpio_port, dev->scl_pin, 0);
+    gpio_write_bit(scl_port(dev), dev->scl_pin, 0);
     delay_us(10);
-    gpio_write_bit(dev->gpio_port, dev->scl_pin, 1);
+    gpio_write_bit(scl_port(dev), dev->scl_pin, 1);
     delay_us(10);
-    gpio_write_bit(dev->gpio_port, dev->sda_pin, 1);
+    gpio_write_bit(sda_port(dev), dev->sda_pin, 1);
 }
 
 /**
diff --git a/libmaple/i2c_private.h b/libmaple/i2c_private.h
index 05a293c..5b79516 100644
--- a/libmaple/i2c_private.h
+++ b/libmaple/i2c_private.h
@@ -27,10 +27,15 @@
 #ifndef _LIBMAPLE_I2C_PRIVATE_H_
 #define _LIBMAPLE_I2C_PRIVATE_H_
 
-#define I2C_DEV(num, port, sda, scl)              \
+#include <libmaple/i2c_common.h>
+
+/* For old-style definitions (SDA/SCL on same GPIO device) */
+#define I2C_DEV_OLD(num, port, sda, scl)          \
     {                                             \
         .regs         = I2C##num##_BASE,          \
         .gpio_port    = port,                     \
+        .scl_port     = NULL,                     \
+        .sda_port     = NULL,                     \
         .sda_pin      = sda,                      \
         .scl_pin      = scl,                      \
         .clk_id       = RCC_I2C##num,             \
@@ -39,9 +44,33 @@
         .state        = I2C_STATE_DISABLED,       \
     }
 
-struct i2c_dev;
-void _i2c_irq_handler(struct i2c_dev *dev);
-void _i2c_irq_error_handler(struct i2c_dev *dev);
+/* For new-style definitions (SDA/SCL may be on different GPIO devices) */
+#define I2C_DEV_NEW(num, sdaport, sdabit, sclport, sclbit)          \
+    {                                                               \
+        .regs         = I2C##num##_BASE,                            \
+        .gpio_port    = NULL,                                       \
+        .scl_port     = sclport,                                    \
+        .scl_pin      = sclbit,                                     \
+        .sda_port     = sdaport,                                    \
+        .sda_pin      = sdabit,                                     \
+        .clk_id       = RCC_I2C##num,                               \
+        .ev_nvic_line = NVIC_I2C##num##_EV,                         \
+        .er_nvic_line = NVIC_I2C##num##_ER,                         \
+        .state        = I2C_STATE_DISABLED,                         \
+    }
+
+void _i2c_irq_handler(i2c_dev *dev);
+void _i2c_irq_error_handler(i2c_dev *dev);
+
+struct gpio_dev;
+
+static inline struct gpio_dev* scl_port(const i2c_dev *dev) {
+    return (dev->gpio_port == NULL) ? dev->scl_port : dev->gpio_port;
+}
+
+static inline struct gpio_dev* sda_port(const i2c_dev *dev) {
+    return (dev->gpio_port == NULL) ? dev->sda_port : dev->gpio_port;
+}
 
 /* Auxiliary procedure for enabling an I2C peripheral; `flags' as for
  * i2c_master_enable(). */
diff --git a/libmaple/include/libmaple/i2c_common.h b/libmaple/include/libmaple/i2c_common.h
index 2f36f80..5d99530 100644
--- a/libmaple/include/libmaple/i2c_common.h
+++ b/libmaple/include/libmaple/i2c_common.h
@@ -65,7 +65,24 @@ typedef struct i2c_dev {
     struct i2c_msg *msg;        /**< Messages */
     uint32 error_flags;         /**< Error flags, set on I2C error condition */
     volatile uint32 timestamp;  /**< For internal use */
-    struct gpio_dev *gpio_port; /**< SDA, SCL pins' GPIO port */
+
+    /**
+     * @brief Deprecated. Use .scl_port or .sda_port instead.
+     * If non-null, this will be used as SDA, SCL pins' GPIO port. If
+     * null, then .sda_port will be used for SDA, and .sda_port for
+     * SDA. */
+    struct gpio_dev *gpio_port;
+
+    /**
+     * @brief SDA GPIO device (but see .gpio_port).
+     */
+    struct gpio_dev *sda_port;
+
+    /**
+     * @brief SCL GPIO device (but see .gpio_port).
+     */
+    struct gpio_dev *scl_port;
+
     uint16 msgs_left;           /**< Messages left */
     uint8 sda_pin;              /**< SDA bit on gpio_port */
     uint8 scl_pin;              /**< SCL bit on gpio_port */
diff --git a/libmaple/stm32f1/i2c.c b/libmaple/stm32f1/i2c.c
index 5797940..d864464 100644
--- a/libmaple/stm32f1/i2c.c
+++ b/libmaple/stm32f1/i2c.c
@@ -31,8 +31,8 @@
  * Devices
  */
 
-static i2c_dev i2c1 = I2C_DEV(1, &gpiob, 7, 6);
-static i2c_dev i2c2 = I2C_DEV(2, &gpiob, 11, 10);
+static i2c_dev i2c1 = I2C_DEV_OLD(1, &gpiob, 7, 6);
+static i2c_dev i2c2 = I2C_DEV_OLD(2, &gpiob, 11, 10);
 
 /** STM32F1 I2C device 1 */
 i2c_dev* const I2C1 = &i2c1;
@@ -43,20 +43,28 @@ i2c_dev* const I2C2 = &i2c2;
  * Routines
  */
 
+static int i2c1_wants_remap(const i2c_dev *dev) {
+    /* Check if we've got I2C1 configured for SDA/SCL remap on PB9/PB8 */
+    return (dev->clk_id == RCC_I2C1) &&
+        (scl_port(dev)->clk_id == RCC_GPIOB) &&
+        (sda_port(dev)->clk_id == RCC_GPIOB) &&
+        (dev->sda_pin == 9) &&
+        (dev->scl_pin == 8);
+}
+
 void i2c_config_gpios(const i2c_dev *dev) {
-    if ((dev->clk_id == RCC_I2C1) &&
-        (dev->sda_pin == 9) && (dev->scl_pin == 8)) {
+    if (i2c1_wants_remap(dev)) {
         afio_remap(AFIO_REMAP_I2C1);
     }
-    gpio_set_mode(dev->gpio_port, dev->sda_pin, GPIO_AF_OUTPUT_OD);
-    gpio_set_mode(dev->gpio_port, dev->scl_pin, GPIO_AF_OUTPUT_OD);
+    gpio_set_mode(sda_port(dev), dev->sda_pin, GPIO_AF_OUTPUT_OD);
+    gpio_set_mode(scl_port(dev), dev->scl_pin, GPIO_AF_OUTPUT_OD);
 }
 
 void i2c_master_release_bus(const i2c_dev *dev) {
-    gpio_write_bit(dev->gpio_port, dev->scl_pin, 1);
-    gpio_write_bit(dev->gpio_port, dev->sda_pin, 1);
-    gpio_set_mode(dev->gpio_port, dev->scl_pin, GPIO_OUTPUT_OD);
-    gpio_set_mode(dev->gpio_port, dev->sda_pin, GPIO_OUTPUT_OD);
+    gpio_write_bit(scl_port(dev), dev->scl_pin, 1);
+    gpio_write_bit(sda_port(dev), dev->sda_pin, 1);
+    gpio_set_mode(scl_port(dev), dev->scl_pin, GPIO_OUTPUT_OD);
+    gpio_set_mode(sda_port(dev), dev->sda_pin, GPIO_OUTPUT_OD);
 }
 
 /*