merge libmaple docs ("leaflabs-docs") into ./docs

In the past, libample documentation was forked out of this repository
because the documentation had increased in scope. For the librambutan,
and the rambutan project in general, we will try to keep documentation
closer to the source code, so the librambutan-specific documentation
should live here. Other sections of leaflabs-docs will be culled in a
following commit.

This merge attempts to maintain history by using a subtree strategy.
Followed directions at:

    http://nuclearsquid.com/writings/subtree-merging-and-you/

Full history for files should be accessible using the "--follow" flag to
git log, eg:

    git log --follow docs/source/adc.rst

It should be possible to pull patches from leaflabs-docs with:

    git pull -s subtree leaflabs-docs master

... at least until the docs in this repository diverge significantly.

1 files changed, 124 insertions, 0 deletions

diff --git a/docs/source/libmaple/api/i2c.rst b/docs/source/libmaple/api/i2c.rst
new file mode 100644
index 0000000..ff380cc
--- /dev/null
+++ b/docs/source/libmaple/api/i2c.rst
@@ -0,0 +1,124 @@
+.. highlight:: c
+.. _libmaple-i2c:
+
+``i2c.h``
+=========
+
+Inter-Integrated Circuit (|i2c|) peripheral support.
+
+.. contents:: Contents
+   :local:
+
+Important Note
+--------------
+
+There are some important known problems with the built-in I2C
+peripherals.  For more information, see STM32F10xx8 and STM32F10xxB
+Errata sheet (ST Doc ID 14574 Rev 8), Section 2.11.1, 2.11.2.  An
+important consequence of these problems is that the |i2c| interrupt
+must not be preempted.  Consequently, (by default) Wirish uses an
+|i2c| interrupt priority which is the highest in the system (priority
+level 0).  Other interrupt priorities are set lower.
+
+Types
+-----
+
+.. doxygenstruct:: i2c_reg_map
+.. doxygenenum:: i2c_state
+.. doxygenstruct:: i2c_msg
+.. doxygenstruct:: i2c_dev
+
+Devices
+-------
+
+.. doxygenvariable:: I2C1
+.. doxygenvariable:: I2C2
+
+Functions
+---------
+
+.. doxygenfunction:: i2c_init
+.. doxygenfunction:: i2c_master_enable
+.. doxygenfunction:: i2c_master_xfer
+.. doxygenfunction:: i2c_bus_reset
+.. doxygenfunction:: i2c_disable
+.. doxygenfunction:: i2c_peripheral_enable
+.. doxygenfunction:: i2c_peripheral_disable
+.. doxygenfunction:: i2c_write
+.. doxygenfunction:: i2c_set_input_clk
+.. doxygenfunction:: i2c_set_clk_control
+.. doxygenfunction:: i2c_set_trise
+.. doxygenfunction:: i2c_start_condition
+.. doxygenfunction:: i2c_stop_condition
+.. doxygenfunction:: i2c_enable_irq
+.. doxygenfunction:: i2c_disable_irq
+.. doxygenfunction:: i2c_enable_ack
+.. doxygenfunction:: i2c_disable_ack
+
+Register Map Base Pointers
+--------------------------
+
+.. doxygendefine:: I2C1_BASE
+.. doxygendefine:: I2C2_BASE
+
+Register Bit Definitions
+------------------------
+
+Control register 1
+~~~~~~~~~~~~~~~~~~
+
+.. doxygendefine:: I2C_CR1_SWRST
+.. doxygendefine:: I2C_CR1_ALERT
+.. doxygendefine:: I2C_CR1_PEC
+.. doxygendefine:: I2C_CR1_POS
+.. doxygendefine:: I2C_CR1_ACK
+.. doxygendefine:: I2C_CR1_START
+.. doxygendefine:: I2C_CR1_STOP
+.. doxygendefine:: I2C_CR1_PE
+
+Control register 2
+~~~~~~~~~~~~~~~~~~
+
+.. doxygendefine:: I2C_CR2_LAST
+.. doxygendefine:: I2C_CR2_DMAEN
+.. doxygendefine:: I2C_CR2_ITBUFEN
+.. doxygendefine:: I2C_CR2_ITEVTEN
+.. doxygendefine:: I2C_CR2_ITERREN
+.. doxygendefine:: I2C_CR2_FREQ
+
+Clock control register
+~~~~~~~~~~~~~~~~~~~~~~
+
+.. doxygendefine:: I2C_CCR_FS
+.. doxygendefine:: I2C_CCR_DUTY
+.. doxygendefine:: I2C_CCR_CCR
+
+Status register 1
+~~~~~~~~~~~~~~~~~
+
+.. doxygendefine:: I2C_SR1_SB
+.. doxygendefine:: I2C_SR1_ADDR
+.. doxygendefine:: I2C_SR1_BTF
+.. doxygendefine:: I2C_SR1_ADD10
+.. doxygendefine:: I2C_SR1_STOPF
+.. doxygendefine:: I2C_SR1_RXNE
+.. doxygendefine:: I2C_SR1_TXE
+.. doxygendefine:: I2C_SR1_BERR
+.. doxygendefine:: I2C_SR1_ARLO
+.. doxygendefine:: I2C_SR1_AF
+.. doxygendefine:: I2C_SR1_OVR
+.. doxygendefine:: I2C_SR1_PECERR
+.. doxygendefine:: I2C_SR1_TIMEOUT
+.. doxygendefine:: I2C_SR1_SMBALERT
+
+Status register 2
+~~~~~~~~~~~~~~~~~
+
+.. doxygendefine:: I2C_SR2_MSL
+.. doxygendefine:: I2C_SR2_BUSY
+.. doxygendefine:: I2C_SR2_TRA
+.. doxygendefine:: I2C_SR2_GENCALL
+.. doxygendefine:: I2C_SR2_SMBDEFAULT
+.. doxygendefine:: I2C_SR2_SMBHOST
+.. doxygendefine:: I2C_SR2_DUALF
+.. doxygendefine:: I2C_SR2_PEC