riot-ci/RIOT
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

drivers/periph: introduced new I2C interface

Browse Source
This commit is contained in:
Hauke Petersen 2017-02-08 13:20:49 +01:00 committed by dylad
parent 5e1467e747
commit 45ab3ea89d
1 changed files with 301 additions and 137 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

438
drivers/include/periph/i2c.h
View File

@ -1,5 +1,5 @@
/* /*
* Copyright (C) 2014-2015 Freie Universität Berlin * Copyright (C) 2014-2017 Freie Universität Berlin
* *
* This file is subject to the terms and conditions of the GNU Lesser * This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level * General Public License v2.1. See the file LICENSE in the top level
@ -11,20 +11,53 @@
* @ingroup drivers_periph * @ingroup drivers_periph
* @brief Low-level I2C peripheral driver * @brief Low-level I2C peripheral driver
* *
* This is a simple I2C interface to allow platform independent access to a * This interface provides a simple abstraction to use the MCUs I2C peripherals.
* MCU's I2C bus and peripherals. This interface is intentionally designed as * It provides support for 7-bit and 10-bit addressing and can be used for
* simple as possible, to allow for easy implementation and maximal portability. * different kind of register addressing schemes.
* *
* @note The current version of this interface only supports the
* 7-bit addressing mode, right justified.
* *
* @note This interface is due for remodeling, hence API changes are to * @section sec_usage Usage
* be expected for upcoming releases.
* *
* ## A note on pull-up resistors for SDA/SCL * Example for reading a 8-bit register on a device, using a 10-bit device
* address and 8-bit register addresses and using a RESTART condition (CAUTION:
* this example does not check any return values...):
*
* @code{c}
* // initialize the bus (this is normally done during boot time)
* i2c_init(dev);
* ...
* // before accessing the bus, we need to acquire it
* i2c_acquire(dev);
* // next we write the register address, but create no STOP condition when done
* i2c_write_byte(dev, device_addr, reg_addr, (i2C_NOSTOP | I2C_ADDR10));
* // and now we read the register value
* i2c_read(dev, device_addr, &reg_value, 1, I2C_ADDR10);
* // finally we have to release the bus
* i2c_release(dev);
* @endcode
*
* Example for writing a 16-bit register with 16-bit register addressing and
* 7-bit device addressing:
*
* @code{c}
* // initialize the bus
* i2c_init(dev);
* ...
* // first, acquire the shared bus again
* i2c_acquire(dev);
* // write the 16-bit register address to the device and prevent STOP condition
* i2c_write(dev, device_addr, reg_addr, I2C_NOSTOP);
* // and write the data after a REPEATED START
* i2c_write(dev, device_addr, reg_data, 2, 0);
* // and finally free the bus again
* i2c_release(dev);
* @endcode
*
*
* @section sec_pull Pull Resistors
* *
* The I2C signal lines SDA/SCL need external pull-up resistors which connect * The I2C signal lines SDA/SCL need external pull-up resistors which connect
* the lines to the positive voltage supply VCC. The I2C driver implementation * the lines to the positive voltage supply Vcc. The I2C driver implementation
* should enable the pin's internal pull-up resistors. There are however some * should enable the pin's internal pull-up resistors. There are however some
* use cases for which the internal pull resistors are not strong enough and the * use cases for which the internal pull resistors are not strong enough and the
* I2C bus will show faulty behavior. This can for example happen when * I2C bus will show faulty behavior. This can for example happen when
@ -52,6 +85,24 @@
* For more details refer to section 7.1 in:<br> * For more details refer to section 7.1 in:<br>
* http://www.nxp.com/documents/user_manual/UM10204.pdf * http://www.nxp.com/documents/user_manual/UM10204.pdf
* *
*
* @section sec_pm (Low-) power implications
*
* The I2C interface realizes a transaction-based access scheme to the bus. From
* a power management perspective, we can leverage this by only powering on the
* I2C peripheral while it is actually used, that is inside an i2c_acquire() -
* i2c_release() block.
*
* After initialization, the I2C peripheral **should** be powered off (e.g.
* through peripheral clock gating). It should only be powered on once a
* transaction on the I2C bus starts, namely in the i2c_acquire() function. Once
* the transaction is finished, the corresponding I2C peripheral **should** be
* powered off again in the i2c_release() function.
*
* If the implementation puts the active thread to sleep while a transfer is in
* progress (e.g. when using DMA), the implementation might need to block
* certain power states.
*
* @{ * @{
* @file * @file
* @brief Low-level I2C peripheral driver interface definition * @brief Low-level I2C peripheral driver interface definition
@ -64,52 +115,51 @@
#define PERIPH_I2C_H #define PERIPH_I2C_H
#include <stdint.h> #include <stdint.h>
#include <stddef.h>
#include <limits.h> #include <limits.h>
#include "periph_conf.h"
#include "periph_cpu.h" #include "periph_cpu.h"
/**
* @todo Remove dev_enums.h include once all platforms are ported to the
* updated periph interface
*/
#include "periph/dev_enums.h"
#ifdef __cplusplus #ifdef __cplusplus
extern "C" { extern "C" {
#endif #endif
/**
* @brief Flag signaling a write operation on the bus
*/
#define I2C_FLAG_WRITE 0
/**
* @brief Flag signaling a read operation on the bus
*/
#define I2C_FLAG_READ 1
/** /**
* @brief Default I2C device access macro * @brief Default I2C device access macro
* @{
*/ */
#ifndef I2C_DEV #ifndef I2C_DEV
#define I2C_DEV(x) (x) #define I2C_DEV(x) (x)
#endif #endif
/** @} */
/** /**
* @brief Default I2C undefined value * @brief Default I2C undefined value
* @{
*/ */
#ifndef I2C_UNDEF #ifndef I2C_UNDEF
#define I2C_UNDEF (UINT_MAX) #define I2C_UNDEF (UINT_MAX)
#endif #endif
/** @} */
/** /**
* @brief Default i2c_t type definition * @brief Default i2c_t type definition
* @{
*/ */
#ifndef HAVE_I2C_T #ifndef HAVE_I2C_T
typedef unsigned int i2c_t; typedef unsigned int i2c_t;
#endif #endif
/** @} */
/**
* @brief Read bit needs to be set when reading
*/
#define I2C_READ (0x0001)
/** /**
* @brief Default mapping of I2C bus speed values * @brief Default mapping of I2C bus speed values
* @{
*/ */
#ifndef HAVE_I2C_SPEED_T #ifndef HAVE_I2C_SPEED_T
typedef enum { typedef enum {
@ -120,18 +170,69 @@ typedef enum {
I2C_SPEED_HIGH, /**< high speed mode: ~3.4Mbit/s */ I2C_SPEED_HIGH, /**< high speed mode: ~3.4Mbit/s */
} i2c_speed_t; } i2c_speed_t;
#endif #endif
/** @} */
/** /**
* @brief Initialize an I2C device to run as bus master * @brief I2C transfer flags
* @{
*/
#ifndef HAVE_I2C_FLAGS_T
typedef enum {
I2C_ADDR10 = 0x01, /**< use 10-bit device addressing */
I2C_REG16 = 0x02, /**< use 16-bit register addressing */
I2C_NOSTOP = 0x04, /**< do not issue a STOP condition after transfer */
I2C_NOSTART = 0x08 /**< skip START sequence, ignores address field */
} i2c_flags_t;
#endif
/** @} */
/**
* @brief I2C transfer results
*/
enum {
/**
* @brief All bytes were transferred successfully
*/
I2C_ACK = 0,
/**
* @brief NACK when transferring the address byte
*
* After the address + the read/write bit were send, we got an NACK as
* response. This means most probably, that there is no slave with the used
* address on the bus, or the slave did just not respond for some reason.
*/
I2C_ADDR_NACK = -1,
/**
* @brief NACK while writing data bytes
*
* The slave responded to a data byte written to it with a NACK.
*/
I2C_DATA_NACK = -2,
/**
* @brief Internal error
*
* This status code is returned, on any other internal error that might
* have occurred. Possible reasons are not supported modes (e.g. 10-bit
* addressing).
*/
I2C_ERR = -3
};
/**
* @brief Initialize the given I2C bus
* *
* @param[in] dev the device to initialize * The given I2C device will be initialized with the parameters as specified in
* @param[in] speed the selected bus speed * the boards periph_conf.h, using the pins and the speed value given there.
*
* The bus MUST not be acquired before initializing it, as this is handled
* internally by the i2c_init function!
*
* @param[in] dev the device to initialize
* *
* @return 0 on successful initialization * @return 0 on successful initialization
* @return -1 on undefined device given * @return -1 on undefined device given
* @return -2 on unsupported speed value
*/ */
int i2c_init_master(i2c_t dev, i2c_speed_t speed); int i2c_init(i2c_t dev);
/** /**
* @brief Get mutually exclusive access to the given I2C bus * @brief Get mutually exclusive access to the given I2C bus
@ -139,150 +240,213 @@ int i2c_init_master(i2c_t dev, i2c_speed_t speed);
* In case the I2C device is busy, this function will block until the bus is * In case the I2C device is busy, this function will block until the bus is
* free again. * free again.
* *
* @param[in] dev I2C device to access * @param[in] dev I2C device to access
* *
* @return 0 on success * @return 0 on success
* @return -1 on error
*/ */
int i2c_acquire(i2c_t dev); int i2c_acquire(i2c_t dev);
/** /**
* @brief Release the given I2C device to be used by others * @brief Release the given I2C device to be used by others
* *
* @param[in] dev I2C device to release * @param[in] dev I2C device to release
*
* @return 0 on success
* @return -1 on error
*/ */
int i2c_release(i2c_t dev); void i2c_release(i2c_t dev);
/** /**
* @brief Read one byte from an I2C device with the given address * @brief Read data from the given I2C device
* *
* @param[in] dev I2C peripheral device * @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device * @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[out] data the result that was read * @param[out] data memory location to store received data
* @param[in] len the number of bytes to read into @p data
* @param[in] flags optional flags (see @ref i2c_flags_t)
* *
* @return the number of bytes that were read * @return I2C_ACK on successful transfer of @p len byte
* @return -1 on undefined device given * @return I2C_ADDR_NACK if response to address byte was NACK
* @return -2 on invalid address * @return I2C_ERR for any other error
*/ */
int i2c_read_byte(i2c_t dev, uint8_t address, void *data); int i2c_read(i2c_t dev, uint16_t addr, void *data, size_t len, uint8_t flags);
/** /**
* @brief Read multiple bytes from an I2C device with the given address * @brief Convenience function for reading one byte from a given register
* address
*
* @note This function is using a repeated start sequence for reading from
* the specified register address.
* *
* @param[in] dev I2C peripheral device * @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device * @param[in] reg register address to read from (8- or 16-bit,
* right-aligned)
* @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[out] data memory location to store received data
* @param[in] flags optional flags (see @ref i2c_flags_t)
*
* @return I2C_ACK on successful transfer of @p len byte
* @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_ERR for any other error
*/
int i2c_read_reg(i2c_t dev, uint16_t addr, uint16_t reg,
void *data, uint8_t flags);
/**
* @brief Convenience function for reading several bytes from a given
* register address
*
* @note This function is using a repeated start sequence for reading from
* the specified register address.
*
* @param[in] dev I2C peripheral device
* @param[in] reg register address to read from (8- or 16-bit,
* right-aligned)
* @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[out] data memory location to store received data
* @param[in] len the number of bytes to read into @p data
* @param[in] flags optional flags (see @ref i2c_flags_t)
*
* @return I2C_ACK on successful transfer of @p len byte
* @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_ERR for any other error
*/
int i2c_read_regs(i2c_t dev, uint16_t addr, uint16_t reg,
void *data, size_t len, uint8_t flags);
/**
* @brief Convenience function for reading one byte from a device
*
* @note This function is using a repeated start sequence for reading from
* the specified register address.
*
* @param[in] dev I2C peripheral device
* @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[out] data memory location to store received data
* @param[in] flags optional flags (see @ref i2c_flags_t)
*
* @return I2C_ACK on successful transfer of @p len byte
* @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_ERR for any other error
*/
int i2c_read_byte(i2c_t dev, uint16_t addr, void *data, uint8_t flags);
/**
* @brief Convenience function for reading one byte from a given register
* address
*
* @note This function is using a repeated start sequence for reading from
* the specified register address.
*
* @param[in] dev I2C peripheral device
* @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[out] data memory location to store received data
* @param[in] len the number of bytes to read into @p data
* @param[in] flags optional flags (see @ref i2c_flags_t)
*
* @return I2C_ACK on successful transfer of @p len byte
* @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_ERR for any other error
*/
int i2c_read_bytes(i2c_t dev, uint16_t addr,
void *data, size_t len, uint8_t flags);
/**
* @brief Write data from/to the given I2C device
*
* @param[in] dev I2C peripheral device
* @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[out] data array holding the received bytes * @param[out] data array holding the received bytes
* @param[in] length the number of bytes to read into `data` * @param[in] len the number of bytes to write
* @param[in] flags optional flags (see @ref i2c_flags_t)
* *
* @return the number of bytes that were read * @return I2C_ACK on successful transfer of @p len byte
* @return -1 on undefined device given * @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_ERR for any other error
*/ */
int i2c_read_bytes(i2c_t dev, uint8_t address, void *data, int length); int i2c_write(i2c_t dev, uint16_t addr,
const void *data, size_t len, uint8_t flags);
/** /**
* @brief Read one byte from a register at the I2C slave with the given * @brief Convenience function for writing a single byte onto the bus
* address *
* @param[in] dev I2C peripheral device
* @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[in] data byte to write to the device
* @param[in] flags optional flags (see @ref i2c_flags_t)
*
* @return I2C_ACK on successful transfer of @p data
* @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_DATA_NACK if response to the data byte was NACK
* @return I2C_ERR for any other error
*/
int i2c_write_byte(i2c_t dev, uint16_t addr, uint8_t data, uint8_t flags);
/**
* @brief Convenience function for writing several bytes onto the bus
*
* @param[in] dev I2C peripheral device
* @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[in] data array holding the bytes to write to the device
* @param[in] len the number of bytes to write
* @param[in] flags optional flags (see @ref i2c_flags_t)
*
* @return I2C_ACK on successful transfer of @p data
* @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_DATA_NACK if response to the data byte was NACK
* @return I2C_ERR for any other error
*/
int i2c_write_bytes(i2c_t dev, uint16_t addr, const void *data,
size_t len, uint8_t flags);
/**
* @brief Convenience function for writing one byte to a given
* register address
*
* @note This function is using a repeated start sequence for writing to the
* specified register address.
* *
* @param[in] dev I2C peripheral device * @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device * @param[in] reg register address to read from (8- or 16-bit,
* @param[in] reg the register address on the targeted I2C device * right-aligned)
* @param[out] data the result that was read * @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[out] data memory location to store received data
* @param[in] flags optional flags (see @ref i2c_flags_t)
* *
* @return the number of bytes that were read * @return I2C_ACK on successful transfer of @p data
* @return -1 on undefined device given * @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_DATA_NACK if response to the data byte was NACK
* @return I2C_ERR for any other error
*/ */
int i2c_read_reg(i2c_t dev, uint8_t address, uint8_t reg, void *data); int i2c_write_reg(i2c_t dev, uint16_t addr, uint16_t reg,
uint8_t data, uint8_t flags);
/** /**
* @brief Read multiple bytes from a register at the I2C slave with the given * @brief Convenience function for writing data to a given register address
* address *
* @note This function is using a repeated start sequence for writing to the
* specified register address.
* *
* @param[in] dev I2C peripheral device * @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device * @param[in] reg register address to read from (8- or 16-bit,
* @param[in] reg the register address on the targeted I2C device * right-aligned)
* @param[out] data array holding the received bytes * @param[in] addr 7-bit or 10-bit device address (right-aligned)
* @param[in] length the number of bytes to read into `data` * @param[out] data memory location to store received data
* @param[in] len the number of bytes to write
* @param[in] flags optional flags (see @ref i2c_flags_t)
* *
* @return the number of bytes that were read * @return I2C_ACK on successful transfer of @p data
* @return -1 on undefined device given * @return I2C_ADDR_NACK if response to address byte was NACK
* @return I2C_DATA_NACK if response to the data byte was NACK
* @return I2C_ERR for any other error
*/ */
int i2c_read_regs(i2c_t dev, uint8_t address, uint8_t reg, int i2c_write_regs(i2c_t dev, uint16_t addr, uint16_t reg,
void *data, int length); const void *data, size_t len, uint8_t flags);
/**
* @brief Write one byte to an I2C device with the given address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] data byte to write to the device
*
* @return the number of bytes that were written
* @return -1 on undefined device given
*/
int i2c_write_byte(i2c_t dev, uint8_t address, uint8_t data);
/**
* @brief Write multiple bytes to an I2C device with the given address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] data array with bytes to write to the target device
* @param[in] length number of bytes to write to the target device
*
* @return the number of bytes that were written
* @return -1 on undefined device given
*/
int i2c_write_bytes(i2c_t dev, uint8_t address, const void *data, int length);
/**
* @brief Write one byte to a register at the I2C slave with the given address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] reg the register address on the targeted I2C device
* @param[in] data byte to write to the device
*
* @return the number of bytes that were written
* @return -1 on undefined device given
*/
int i2c_write_reg(i2c_t dev, uint8_t address, uint8_t reg, uint8_t data);
/**
* @brief Write multiple bytes to a register at the I2C slave with the given
* address
*
* @param[in] dev I2C peripheral device
* @param[in] address bus address of the target device
* @param[in] reg the register address on the targeted I2C device
* @param[in] data array with bytes to write to the target device
* @param[in] length number of bytes to write to the target device
*
* @return the number of bytes that were written
* @return -1 on undefined device given
*/
int i2c_write_regs(i2c_t dev, uint8_t address, uint8_t reg,
const void *data, int length);
/**
* @brief Power on the given I2C peripheral
*
* @param[in] dev the I2C device to power on
*/
void i2c_poweron(i2c_t dev);
/**
* @brief Power off the given I2C peripheral
*
* @param[in] dev the I2C device to power off
*/
void i2c_poweroff(i2c_t dev);
#ifdef __cplusplus #ifdef __cplusplus
} }
#endif #endif
#endif /* PERIPH_I2C_H */ #endif /* PERIPH_I2C_H */
/** @} */ /** @} */