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MicroAPRS/bertos/drv/i2c.h

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/**
* \file
* <!--
* This file is part of BeRTOS.
*
* Bertos is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* As a special exception, you may use this file as part of a free software
* library without restriction. Specifically, if other files instantiate
* templates or use macros or inline functions from this file, or you compile
* this file and link it with other files to produce an executable, this
* file does not by itself cause the resulting executable to be covered by
* the GNU General Public License. This exception does not however
* invalidate any other reasons why the executable file might be covered by
* the GNU General Public License.
*
* Copyright 2005 Develer S.r.l. (http://www.develer.com/)
*
* -->
*
* \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 <batt@develer.com>
*
* $WIZ$ 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 <cfg/compiler.h>
#include <cfg/macros.h>
#include <cfg/debug.h>
#include <cpu/attr.h>
#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
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