diff --git a/drivers/include/periph/i2c.h b/drivers/include/periph/i2c.h
index 1d6f414b39..1965e1fc01 100644
--- a/drivers/include/periph/i2c.h
+++ b/drivers/include/periph/i2c.h
@@ -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
* General Public License v2.1. See the file LICENSE in the top level
@@ -11,20 +11,53 @@
* @ingroup drivers_periph
* @brief Low-level I2C peripheral driver
*
- * This is a simple I2C interface to allow platform independent access to a
- * MCU's I2C bus and peripherals. This interface is intentionally designed as
- * simple as possible, to allow for easy implementation and maximal portability.
+ * This interface provides a simple abstraction to use the MCUs I2C peripherals.
+ * It provides support for 7-bit and 10-bit addressing and can be used for
+ * 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
- * be expected for upcoming releases.
+ * @section sec_usage Usage
*
- * ## 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, ®_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 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
* 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
@@ -52,6 +85,24 @@
* For more details refer to section 7.1 in:
* 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
* @brief Low-level I2C peripheral driver interface definition
@@ -64,52 +115,51 @@
#define PERIPH_I2C_H
#include
+#include
#include
+#include "periph_conf.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
extern "C" {
#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
+ * @{
*/
#ifndef I2C_DEV
#define I2C_DEV(x) (x)
#endif
+/** @} */
/**
* @brief Default I2C undefined value
+ * @{
*/
#ifndef I2C_UNDEF
#define I2C_UNDEF (UINT_MAX)
#endif
+/** @} */
/**
* @brief Default i2c_t type definition
+ * @{
*/
#ifndef HAVE_I2C_T
typedef unsigned int i2c_t;
#endif
+/** @} */
+
+/**
+ * @brief Read bit needs to be set when reading
+ */
+#define I2C_READ (0x0001)
/**
* @brief Default mapping of I2C bus speed values
+ * @{
*/
#ifndef HAVE_I2C_SPEED_T
typedef enum {
@@ -120,18 +170,69 @@ typedef enum {
I2C_SPEED_HIGH, /**< high speed mode: ~3.4Mbit/s */
} i2c_speed_t;
#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
- * @param[in] speed the selected bus speed
+ * The given I2C device will be initialized with the parameters as specified in
+ * 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 -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
@@ -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
* free again.
*
- * @param[in] dev I2C device to access
+ * @param[in] dev I2C device to access
*
- * @return 0 on success
- * @return -1 on error
+ * @return 0 on success
*/
int i2c_acquire(i2c_t dev);
/**
* @brief Release the given I2C device to be used by others
*
- * @param[in] dev I2C device to release
- *
- * @return 0 on success
- * @return -1 on error
+ * @param[in] dev I2C device to release
*/
-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] address bus address of the target device
- * @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] 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 -1 on undefined device given
- * @return -2 on invalid address
+ * @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, 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] 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[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 -1 on undefined device given
+ * @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, 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
- * address
+ * @brief Convenience function for writing a single byte onto the bus
+ *
+ * @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] address bus address of the target device
- * @param[in] reg the register address on the targeted I2C device
- * @param[out] data the result that was read
+ * @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 the number of bytes that were read
- * @return -1 on undefined device given
+ * @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_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
- * address
+ * @brief Convenience function for writing data 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] address bus address of the target device
- * @param[in] reg the register address on the targeted I2C device
- * @param[out] data array holding the received bytes
- * @param[in] length the number of bytes to read into `data`
+ * @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 write
+ * @param[in] flags optional flags (see @ref i2c_flags_t)
*
- * @return the number of bytes that were read
- * @return -1 on undefined device given
+ * @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_read_regs(i2c_t dev, uint8_t address, uint8_t reg,
- void *data, int length);
+int i2c_write_regs(i2c_t dev, uint16_t addr, uint16_t reg,
+ 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
}
#endif
#endif /* PERIPH_I2C_H */
-/** @} */
+/** @} */
\ No newline at end of file