*
* -->
*
+ * \addtogroup i2c_api
* \brief I2C generic driver functions.
*
+ * Some hardware requires you to declare the number of transferred
+ * bytes and the communication direction before actually reading or writing
+ * to the bus.
+ * Furthermore, sometimes you need to specify the first transferred byte
+ * before any data is sent over the bus.
+ *
+ * The usage pattern for writing is the following:
+ * \code
+ * i2c_init(args...);
+ * ...
+ * i2c_start_w(args...);
+ * i2c_write(i2c, buf, len);
+ * \endcode
+ * The flags in i2c_start_w determine if the stop command is sent after
+ * the data. Notice that you don't need to explicitly call a stop function
+ * after the write.
+ *
+ * Reading is a bit more complicated and it largely depends on the specific
+ * slave hardware.
+ * In general, the hardware may require you to first write something, then
+ * read the data without closing the communication. For example, EPROMs
+ * require first to write the reading address and then to read the actual
+ * data.
+ * Here is an example of how you can deal with such hardware:
+ *
+ * \code
+ * // init a session without closing it
+ * i2c_start_w(i2c, dev, bytes, I2C_NOSTOP);
+ * // write the address to read from
+ * i2c_write(i2c, addr, bytes);
+ * if (i2c_error(i2c))
+ * // check for errors during setup
+ * //...
+ * // now start the real data transfer
+ * i2c_start_r(i2c, dev, bytes, I2C_STOP);
+ * i2c_read(i2c, buf, bytes);
+ * // check for errors
+ * if (i2c_error(i2c))
+ * //...
+ * \endcode
+ *
+ * It's not guaranteed that after a single call to i2c_putc, i2c_getc etc.
+ * data will pass on the bus (this is hardware dependent).
+ * However, it IS guaranteed after you have sent all the data.
+ *
+ * You can check error conditions by calling the function i2c_error after
+ * each function call. (This is similar to libc errno handling).
+ *
* \author Francesco Sacchi <batt@develer.com>
*
* $WIZ$ module_name = "i2c"
#define I2C_READBIT BV(0)
+/** \defgroup i2c_driver I2C driver
+ */
+
+/*
+ * The following macros are needed to maintain compatibility with older i2c API.
+ * They can be safely removed once the old API is removed.
+ */
+
+ /**
+ * \addtogroup i2c_api
+ * \{
+ */
#if COMPILER_C99
#define i2c_init(...) PP_CAT(i2c_init ## _, COUNT_PARMS(__VA_ARGS__)) (__VA_ARGS__)
#define i2c_start_w(...) PP_CAT(i2c_start_w ## _, COUNT_PARMS(__VA_ARGS__)) (__VA_ARGS__)
#define i2c_start_r(...) PP_CAT(i2c_start_r ## _, COUNT_PARMS(__VA_ARGS__)) (__VA_ARGS__)
#else
+ /**
+ * Initialize I2C module.
+ *
+ * To initialize the module you can write this code:
+ * \code
+ * I2c ctx;
+ * i2c_init(&ctx, 0, CONFIG_I2C_FREQ);
+ * \endcode
+ * This macro expands in two versions, depending on the number of
+ * parameters, to maintain compatibility with old API:
+ * \li i2c_init_3(I2c *i2c, int dev, uint32_t clock)
+ * \li i2c_init_0(void)
+ *
+ * Do NOT use the above functions directly, use i2c_init().
+ * \note Use the version with 3 parameters, the other one is only for
+ * legacy code.
+ */
#define i2c_init(args...) PP_CAT(i2c_init ## _, COUNT_PARMS(args)) (args)
+
+ /**
+ * Start a write session.
+ *
+ * To start a write session, use the following code:
+ * \code
+ * i2c_start_w(i2c, dev, bytes, I2C_STOP);
+ * \endcode
+ *
+ * This macro expands in two versions, depending on the number of parameters:
+ * \li i2c_start_w_4(I2c *i2c, uint16_t slave_addr, size_t size, int flags)
+ * \li i2c_builtin_start_w(uint8_t id): Deprecated API, don't use in new projects
+ * \li i2c_bitbang_start_w(uint8_t id): Deprecated API, don't use in new projects
+ *
+ * Do NOT use the above functions directly, use i2c_start_w().
+ * \note Use the version with 4 parameters, the others are only for legacy code
+ */
#define i2c_start_w(args...) PP_CAT(i2c_start_w ## _, COUNT_PARMS(args)) (args)
+
+ /**
+ * Start a read session.
+ *
+ * To start a read session, use the following code:
+ * \code
+ * i2c_start_r(i2c, dev, bytes, I2C_STOP);
+ * \endcode
+ *
+ * This macro expands in two versions, depending on the number of parameters:
+ * \li i2c_start_r_4(I2c *i2c, uint16_t slave_addr, size_t size, int flags)
+ * \li i2c_builtin_start_r(uint8_t id): Deprecated API, don't use in new projects
+ * \li i2c_bitbang_start_r(uint8_t id): Deprecated API, don't use in new projects
+ *
+ * Do NOT use the above functions directly, use i2c_start_r().
+ * \note Use the version with 4 parameters, the others are only for legacy code
+ */
#define i2c_start_r(args...) PP_CAT(i2c_start_r ## _, COUNT_PARMS(args)) (args)
#endif
+/**\}*/
/**
enum
{
I2C_BITBANG_OLD = -1,
- I2C_BITBANG0 = 1000,
- I2C_BITBANG1,
+ I2C_BITBANG0 = 1000, ///< Use bitbang on port 0
+ I2C_BITBANG1, ///< Use bitbang on port 1
I2C_BITBANG2,
I2C_BITBANG3,
I2C_BITBANG4,
I2C_BITBANG8,
I2C_BITBANG9,
- I2C_BITBANG_CNT /**< Number of serial ports */
+ I2C_BITBANG_CNT /**< Number of i2c ports */
};
+/**
+ * \defgroup old_i2c_api Old I2C API
+ * \ingroup i2c_driver
+ *
+ * This is the old and deprecated I2C API. It is maintained for backward
+ * compatibility only, don't use it in new projects.
+ * @{
+ */
#if !CONFIG_I2C_DISABLE_OLD_API
/**
+ * \ingroup old_i2c_api
* I2C Backends.
* Sometimes your cpu does not have a builtin
* i2c driver or you don't want, for some reason, to
* use that.
* With this you can choose, at compile time, which backend to use.
+ * @{
*/
#define I2C_BACKEND_BUILTIN 0 ///< Uses cpu builtin i2c driver
#define I2C_BACKEND_BITBANG 1 ///< Uses emulated bitbang driver
+/**@}*/
/**
- * I2c builtin prototypes.
+ * \name I2c builtin prototypes.
+ * \ingroup old_i2c_api
* Do NOT use these function directly, instead,
* you can call the ones named without "_builtin_"
- * and specify in cfg_i2c.h ( \see CONFIG_I2C_BACKEND)
+ * and specify in cfg_i2c.h (CONFIG_I2C_BACKEND)
* that you want the builtin backend.
- * \{
+ * @{
*/
bool i2c_builtin_start_w(uint8_t id);
bool i2c_builtin_start_r(uint8_t id);
void i2c_builtin_stop(void);
bool i2c_builtin_put(uint8_t _data);
int i2c_builtin_get(bool ack);
-/*\}*/
+/**@}*/
/**
- * I2c bitbang prototypes.
- * Same thing here: do NOT use these function directly, instead,
+ * \name I2c bitbang prototypes.
+ * \ingroup old_i2c_api
+ * Do NOT use these function directly, instead,
* you can call the ones named without "_bitbang_"
- * and specify in cfg_i2c.h ( \see CONFIG_I2C_BACKEND)
+ * and specify in cfg_i2c.h (CONFIG_I2C_BACKEND)
* that you want the bitbang backend.
- * \{
+ * @{
*/
bool i2c_bitbang_start_w(uint8_t id);
bool i2c_bitbang_start_r(uint8_t id);
void i2c_bitbang_stop(void);
bool i2c_bitbang_put(uint8_t _data);
int i2c_bitbang_get(bool ack);
-/*\}*/
+/**@}*/
#ifndef CONFIG_I2C_BACKEND
#define CONFIG_I2C_BACKEND I2C_BACKEND_BUILTIN
bool i2c_recv(void *_buf, size_t count);
#endif /* !CONFIG_I2C_DISABLE_OLD_API */
+/**@}*/
-/*
- * I2C error flags
+/** \defgroup i2c_api I2C driver API
+ * \ingroup i2c_driver
+ * \{
+ */
+
+/**
+ * \name I2C error flags
+ * \ingroup i2c_api
+ * @{
*/
#define I2C_OK 0 ///< I2C no errors flag
#define I2C_DATA_NACK BV(4) ///< I2C generic error
#define I2C_ARB_LOST BV(2) ///< I2C arbitration lost error
#define I2C_START_TIMEOUT BV(0) ///< I2C timeout error on start
#define I2C_NO_ACK BV(1) ///< I2C no ack for sla start
+/**@}*/
-/*
- * I2C command flags
+/**
+ * \name I2C command flags
+ * \ingroup i2c_api
+ * @{
*/
#define I2C_NOSTOP 0 ///< Do not program the stop for current transition
#define I2C_STOP BV(0) ///< Program the stop for current transition
-#define I2C_START_R BV(1) ///< Start read command
-#define I2C_START_W 0 ///< Start write command
+/** @} */
+#define I2C_START_R BV(1) // Start read command
+#define I2C_START_W 0 // Start write command
#define I2C_TEST_START(flag) ((flag) & I2C_START_R)
void i2c_genericWrite(I2c *i2c, const void *_buf, size_t count);
void i2c_genericRead(I2c *i2c, void *_buf, size_t count);
+/*
+ * Start a i2c transfer.
+ *
+ * \param i2c Context structure.
+ * \param slave_addr Address of slave device
+ * \param size Size of the transfer
+ */
INLINE void i2c_start(I2c *i2c, uint16_t slave_addr, size_t size)
{
ASSERT(i2c->vt);
i2c->vt->start(i2c, slave_addr);
}
+/**
+ * \name I2C interface functions
+ * \ingroup i2c_api
+ * @{
+ */
+
+/**
+ * Start a read session.
+ * \param i2c I2C context
+ * \param slave_addr Address of the slave device
+ * \param size Number of bytes to be read from device
+ * \param flags Session flags (I2C command flags)
+ */
INLINE void i2c_start_r_4(I2c *i2c, uint16_t slave_addr, size_t size, int flags)
{
ASSERT(i2c);
i2c_start(i2c, slave_addr, size);
}
+/**
+ * Start a write session.
+ * \param i2c I2C context
+ * \param slave_addr Address of the slave device
+ * \param size Size to be transferred
+ * \param flags Session flags
+ */
INLINE void i2c_start_w_4(I2c *i2c, uint16_t slave_addr, size_t size, int flags)
{
ASSERT(i2c);
i2c_start(i2c, slave_addr, size);
}
+/**
+ * Read a byte from I2C bus.
+ * \param i2c I2C context
+ * \return Byte read
+ */
INLINE uint8_t i2c_getc(I2c *i2c)
{
ASSERT(i2c);
return 0xFF;
}
+/**
+ * Write the byte \a data into I2C port \a i2c.
+ * \param i2c I2C context
+ * \param data Byte to be written
+ */
INLINE void i2c_putc(I2c *i2c, uint8_t data)
{
ASSERT(i2c);
}
}
+/**
+ * Write \a count bytes to port \a i2c, reading from \a _buf.
+ * \param i2c I2C context
+ * \param _buf User buffer to read from
+ * \param count Number of bytes to write
+ */
INLINE void i2c_write(I2c *i2c, const void *_buf, size_t count)
{
ASSERT(i2c);
i2c->vt->write(i2c, _buf, count);
}
-
+/**
+ * Read \a count bytes into buffer \a _buf from device \a i2c.
+ * \param i2c Context structure
+ * \param _buf Buffer to fill
+ * \param count Number of bytes to read
+ */
INLINE void i2c_read(I2c *i2c, void *_buf, size_t count)
{
ASSERT(i2c);
i2c->vt->read(i2c, _buf, count);
}
+/**
+ * Return the error condition of the bus and clear errors.
+ */
INLINE int i2c_error(I2c *i2c)
{
ASSERT(i2c);
return err;
}
+/**
+ * Initialize I2C context structure.
+ * \param i2c I2C context structure
+ * \param dev Number of device to be initialized. You can use I2C_BITBANG0
+ * and similar if you want to activate the bitbang driver.
+ * \param clock Peripheral clock
+ */
#define i2c_init_3(i2c, dev, clock) ((((dev) >= I2C_BITBANG0) | ((dev) == I2C_BITBANG_OLD)) ? \
i2c_hw_bitbangInit((i2c), (dev)) : i2c_hw_init((i2c), (dev), (clock)))
+/**@}*/
+/**\}*/ // i2c_api
#if !CONFIG_I2C_DISABLE_OLD_API
extern I2c local_i2c_old_api;
+/**
+ * Initialize I2C module (old API).
+ * \attention This function is deprecated. Use i2c_init(args...) in new code
+ */
INLINE void i2c_init_0(void)
{
#if CONFIG_I2C_BACKEND == I2C_BACKEND_BITBANG
projects / bertos.git / commitdiff