/** * \file * * * \defgroup i2c_driver I2C driver * \ingroup drivers * \{ * \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" * $WIZ$ module_configuration = "bertos/cfg/cfg_i2c.h" * $WIZ$ module_hw = "bertos/hw/hw_i2c_bitbang.h" * $WIZ$ module_depends = "i2c_bitbang" * $WIZ$ module_supports = "not atmega103 and not atmega168 and not at91" */ #ifndef DRV_I2C_H #define DRV_I2C_H #include "cfg/cfg_i2c.h" #include #include #include #include #define I2C_READBIT BV(0) /* * 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 /**\}*/ /** * \name I2C bitbang devices enum */ enum { I2C_BITBANG_OLD = -1, I2C_BITBANG0 = 1000, ///< Use bitbang on port 0 I2C_BITBANG1, ///< Use bitbang on port 1 I2C_BITBANG2, I2C_BITBANG3, I2C_BITBANG4, I2C_BITBANG5, I2C_BITBANG6, I2C_BITBANG7, I2C_BITBANG8, I2C_BITBANG9, I2C_BITBANG_CNT /**< Number of i2c ports */ }; /** \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_ERR BV(3) ///< 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 /**@}*/ /** * \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_TEST_START(flag) ((flag) & I2C_START_R) #define I2C_TEST_STOP(flag) ((flag) & I2C_STOP) struct I2cHardware; struct I2c; typedef void (*i2c_start_t)(struct I2c *i2c, uint16_t slave_addr); typedef uint8_t (*i2c_getc_t)(struct I2c *i2c); typedef void (*i2c_putc_t)(struct I2c *i2c, uint8_t data); typedef void (*i2c_write_t)(struct I2c *i2c, const void *_buf, size_t count); typedef void (*i2c_read_t)(struct I2c *i2c, void *_buf, size_t count); typedef struct I2cVT { i2c_start_t start; i2c_getc_t getc; i2c_putc_t putc; i2c_write_t write; i2c_read_t read; } I2cVT; typedef struct I2c { int errors; int flags; size_t xfer_size; struct I2cHardware* hw; const struct I2cVT *vt; } I2c; #include CPU_HEADER(i2c) /* * Low level i2c init implementation prototype. */ void i2c_hw_init(I2c *i2c, int dev, uint32_t clock); 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); ASSERT(i2c->vt->start); if (!i2c->errors) ASSERT(i2c->xfer_size == 0); i2c->errors = 0; i2c->xfer_size = 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); i2c->flags = flags | I2C_START_R; 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->flags = flags & ~I2C_START_R; 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); ASSERT(i2c->vt); ASSERT(i2c->vt->getc); ASSERT(i2c->xfer_size); ASSERT(I2C_TEST_START(i2c->flags) == I2C_START_R); if (!i2c->errors) { uint8_t data = i2c->vt->getc(i2c); i2c->xfer_size--; return data; } else 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); ASSERT(i2c->vt); ASSERT(i2c->vt->putc); ASSERT(i2c->xfer_size); ASSERT(I2C_TEST_START(i2c->flags) == I2C_START_W); if (!i2c->errors) { i2c->vt->putc(i2c, data); i2c->xfer_size--; } } /** * 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); ASSERT(i2c->vt); ASSERT(i2c->vt->write); ASSERT(_buf); ASSERT(count); ASSERT(count <= i2c->xfer_size); ASSERT(I2C_TEST_START(i2c->flags) == I2C_START_W); if (!i2c->errors) 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); ASSERT(i2c->vt); ASSERT(i2c->vt->read); ASSERT(_buf); ASSERT(count); ASSERT(count <= i2c->xfer_size); ASSERT(I2C_TEST_START(i2c->flags) == I2C_START_R); if (!i2c->errors) i2c->vt->read(i2c, _buf, count); } /** * Return the error condition of the bus and clear errors. */ INLINE int i2c_error(I2c *i2c) { ASSERT(i2c); int err = i2c->errors; i2c->errors = 0; 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 /** * \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 * \name 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. * Set the CONFIG_I2C_BACKEND configuration variable in cfg_i2c.h * @{ */ #define I2C_BACKEND_BUILTIN 0 ///< Uses cpu builtin i2c driver #define I2C_BACKEND_BITBANG 1 ///< Uses emulated bitbang driver /**@}*/ /** * \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 (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); /**@}*/ /** * \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 (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 #endif #if CONFIG_I2C_BACKEND == I2C_BACKEND_BUILTIN #define i2c_start_w_1 i2c_builtin_start_w #define i2c_start_r_1 i2c_builtin_start_r #define i2c_stop i2c_builtin_stop #define i2c_put i2c_builtin_put #define i2c_get i2c_builtin_get #elif CONFIG_I2C_BACKEND == I2C_BACKEND_BITBANG #define i2c_start_w_1 i2c_bitbang_start_w #define i2c_start_r_1 i2c_bitbang_start_r #define i2c_stop i2c_bitbang_stop #define i2c_put i2c_bitbang_put #define i2c_get i2c_bitbang_get #else #error Unsupported i2c backend. #endif bool i2c_send(const void *_buf, size_t count); bool i2c_recv(void *_buf, size_t count); /**@}*/ 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 i2c_init_3(&local_i2c_old_api, I2C_BITBANG_OLD, CONFIG_I2C_FREQ); #else i2c_init_3(&local_i2c_old_api, 0, CONFIG_I2C_FREQ); #endif } #endif /* !CONFIG_I2C_DISABLE_OLD_API */ /** \} */ //defgroup i2c_driver #endif