I2C: Restore on F1, refactoring prep for F2.

Bring back <libmaple/i2c.h> support on STM32F1 with a view towards how
it'll be implemented on STM32F2. There are still many F1-isms in
libmaple/i2c.c and <libmaple/i2c.h>, to be dealt with subsequently.

Move device declarations and base pointer definitions to a new F1
<series/i2c.h>. The register maps and bit definitions themselves are
identical on both series, so leave them in the libmaple header.

Add i2c_private.h, which contains:

- I2C_DEV(), a convenience macro for defining an i2c_dev, and
- declarations for the event and error IRQ handlers.

The IRQ handlers are large, and I2C is slow anyway, so I see no reason
to make them inline in the private header (as we do for some other
peripherals). We just expose the existing ones that were formerly
static in libmaple/i2c.c, but prefix the names with underscore.

Move the device declarations and IRQ handlers into new
stm32f1/i2c.c. These use the i2c_private.h API.

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

1 files changed, 4 insertions, 3 deletions

diff --git a/libmaple/rules.mk b/libmaple/rules.mk
index 41f5601..71979f0 100644
--- a/libmaple/rules.mk
+++ b/libmaple/rules.mk
@@ -27,10 +27,11 @@ cSRCS_$(d) += timer.c
 cSRCS_$(d) += usart.c
 cSRCS_$(d) += usart_private.c
 cSRCS_$(d) += util.c
-# These still need to be brought back for F1:
-# cSRCS_$(d) += i2c.c
-
 sSRCS_$(d) := exc.S
+# I2C support must be ported to F2:
+ifeq ($(MCU_SERIES),stm32f1)
+cSRCS_$(d) += i2c.c
+endif
 
 cFILES_$(d) := $(cSRCS_$(d):%=$(d)/%)
 sFILES_$(d) := $(sSRCS_$(d):%=$(d)/%)