From: lottaviano Date: Mon, 25 Oct 2010 16:55:21 +0000 (+0000) Subject: doc: Add documentation for new I2C API and razionalize using modules X-Git-Tag: 2.6.0~5^2~60 X-Git-Url: https://codewiz.org/gitweb?a=commitdiff_plain;h=7fda050003b7efc92c54ab6b3d9b826007d42fb5;p=bertos.git doc: Add documentation for new I2C API and razionalize using modules git-svn-id: https://src.develer.com/svnoss/bertos/trunk@4460 38d2e660-2303-0410-9eaa-f027e97ec537 --- diff --git a/Doxyfile-common b/Doxyfile-common index 2c7958d8..2c45544f 100644 --- a/Doxyfile-common +++ b/Doxyfile-common @@ -1243,6 +1243,7 @@ PREDEFINED = __doxygen__ \ CONFIG_KFILE_GETS=1 \ CONFIG_XMODEM_RECV=1 \ CONFIG_XMODEM_SEND=1 \ + CONFIG_I2C_DISABLE_OLD_API=0 \ COMPILER_VARIADIC_MACROS=1 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then diff --git a/bertos/drv/i2c.h b/bertos/drv/i2c.h index f7812d4e..193e7b2e 100644 --- a/bertos/drv/i2c.h +++ b/bertos/drv/i2c.h @@ -30,8 +30,57 @@ * * --> * + * \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 * * $WIZ$ module_name = "i2c" @@ -54,15 +103,79 @@ #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 +/**\}*/ /** @@ -71,8 +184,8 @@ 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, @@ -82,50 +195,63 @@ enum 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 @@ -152,9 +278,17 @@ bool i2c_send(const void *_buf, size_t count); 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 @@ -162,14 +296,18 @@ bool i2c_recv(void *_buf, size_t count); #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) @@ -214,6 +352,13 @@ void i2c_hw_bitbangInit(I2c *i2c, int dev); 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); @@ -228,6 +373,19 @@ INLINE void i2c_start(I2c *i2c, uint16_t slave_addr, size_t size) 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); @@ -235,6 +393,13 @@ INLINE void i2c_start_r_4(I2c *i2c, uint16_t slave_addr, size_t size, int flags) 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); @@ -242,6 +407,11 @@ INLINE void i2c_start_w_4(I2c *i2c, uint16_t slave_addr, size_t size, int flags) 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); @@ -262,6 +432,11 @@ INLINE uint8_t i2c_getc(I2c *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); @@ -279,6 +454,12 @@ INLINE void i2c_putc(I2c *i2c, uint8_t data) } } +/** + * 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); @@ -295,7 +476,12 @@ INLINE void i2c_write(I2c *i2c, const void *_buf, size_t count) 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); @@ -312,6 +498,9 @@ INLINE void i2c_read(I2c *i2c, void *_buf, size_t count) i2c->vt->read(i2c, _buf, count); } +/** + * Return the error condition of the bus and clear errors. + */ INLINE int i2c_error(I2c *i2c) { ASSERT(i2c); @@ -321,13 +510,26 @@ INLINE int i2c_error(I2c *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