X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fdrv%2Fi2c.h;h=7e43c63bd8ca00b0f8a727c7b5f18184cf648016;hb=31347827ab36869b5a1242009b3f6f74527c92ea;hp=f09ec44f8b7a8f53e8a7b3e9d5f70aa0812feff9;hpb=de804c94d5c897a2d93584a852a91df531dac07e;p=bertos.git diff --git a/bertos/drv/i2c.h b/bertos/drv/i2c.h index f09ec44f..7e43c63b 100644 --- a/bertos/drv/i2c.h +++ b/bertos/drv/i2c.h @@ -30,25 +30,514 @@ * * --> * - * \brief I2C generic driver functions (interface). + * \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). * - * \version $Id$ * \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) -void i2c_init(void); -bool i2c_start_w(uint8_t id); -bool i2c_start_r(uint8_t id); -void i2c_stop(void); -bool i2c_put(uint8_t _data); -int i2c_get(bool ack); +/** \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 +/**\}*/ + + +/** + * \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 + * 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 +/**@}*/ + +/** + * \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 */ + + + #endif