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nuttx/arch/arm/src/stm32/stm32_i2c_alt.c

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/************************************************************************************
* arch/arm/src/stm32/stm32_i2c_alt.c
* STM32 I2C Hardware Layer - Device Driver
*
* Copyright (C) 2011 Uros Platise. All rights reserved.
* Author: Uros Platise <uros.platise@isotel.eu>
*
* With extensions, modifications by:
*
* Copyright (C) 2011-2014, 2016-2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Copyright( C) 2014 Patrizio Simona. All rights reserved.
* Author: Patrizio Simona <psimona@ethz.ch>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
************************************************************************************/
/* Supports:
* - Master operation, 100 kHz (standard) and 400 kHz (full speed)
* - Multiple instances (shared bus)
* - Interrupt based operation
*
* Structure naming:
* - Device: structure as defined by the nuttx/i2c/i2c.h
* - Instance: represents each individual access to the I2C driver, obtained by
* the i2c_init(); it extends the Device structure from the nuttx/i2c/i2c.h;
* Instance points to OPS, to common I2C Hardware private data and contains
* its own private data, as frequency, address, mode of operation (in the
* future)
* - Private: Private data of an I2C Hardware
*
* TODO
* - Trace events in polled operation fill trace table very quickly. Events 1111
* and 1004 get traced in an alternate fashion during polling causing multiple
* entries.
* - Check for all possible deadlocks (as BUSY='1' I2C needs to be reset in HW
* using the I2C_CR1_SWRST)
* - SMBus support (hardware layer timings are already supported) and add SMBA
* gpio pin
* - Slave support with multiple addresses (on multiple instances):
* - 2 x 7-bit address or
* - 1 x 10 bit addresses + 1 x 7 bit address (?)
* - plus the broadcast address (general call)
* - Multi-master support
* - DMA (to get rid of too many CPU wake-ups and interventions)
* - Be ready for IPMI
* - Write trace events to keep track of ISR flow
*/
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h>
#include <semaphore.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/irq.h>
#include <nuttx/clock.h>
#include <nuttx/semaphore.h>
#include <nuttx/i2c/i2c_master.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "stm32_rcc.h"
#include "stm32_i2c.h"
#include "stm32_waste.h"
/* At least one I2C peripheral must be enabled */
#if defined(CONFIG_STM32_I2C1) || defined(CONFIG_STM32_I2C2) || \
defined(CONFIG_STM32_I2C3)
/* This implementation is for the STM32 F1, F2, and F4 only */
/* Experimentally enabled for STM32L15XX */
#if defined(CONFIG_STM32_STM32L15XX) || defined(CONFIG_STM32_STM32F10XX) || \
defined(CONFIG_STM32_STM32F20XX) || defined(CONFIG_STM32_STM32F4XXX)
/************************************************************************************
* Pre-processor Definitions
************************************************************************************/
/* Configuration ********************************************************************/
/* CONFIG_I2C_POLLED may be set so that I2C interrupts will not be used. Instead,
* CPU-intensive polling will be used.
*/
/* Interrupt wait timeout in seconds and milliseconds */
#if !defined(CONFIG_STM32_I2CTIMEOSEC) && !defined(CONFIG_STM32_I2CTIMEOMS)
# define CONFIG_STM32_I2CTIMEOSEC 0
# define CONFIG_STM32_I2CTIMEOMS 500 /* Default is 500 milliseconds */
#elif !defined(CONFIG_STM32_I2CTIMEOSEC)
# define CONFIG_STM32_I2CTIMEOSEC 0 /* User provided milliseconds */
#elif !defined(CONFIG_STM32_I2CTIMEOMS)
# define CONFIG_STM32_I2CTIMEOMS 0 /* User provided seconds */
#endif
/* Interrupt wait time timeout in system timer ticks */
#ifndef CONFIG_STM32_I2CTIMEOTICKS
# define CONFIG_STM32_I2CTIMEOTICKS \
(SEC2TICK(CONFIG_STM32_I2CTIMEOSEC) + MSEC2TICK(CONFIG_STM32_I2CTIMEOMS))
#endif
#ifndef CONFIG_STM32_I2C_DYNTIMEO_STARTSTOP
# define CONFIG_STM32_I2C_DYNTIMEO_STARTSTOP TICK2USEC(CONFIG_STM32_I2CTIMEOTICKS)
#endif
/* On the STM32F103ZE, there is an internal conflict between I2C1 and FSMC. In that
* case, it is necessary to disable FSMC before each I2C1 access and re-enable FSMC
* when the I2C access completes.
*/
#undef I2C1_FSMC_CONFLICT
#if defined(CONFIG_STM32_STM32F10XX) && defined(CONFIG_STM32_FSMC) && defined(CONFIG_STM32_I2C1)
# define I2C1_FSMC_CONFLICT
#endif
/* Macros to convert a I2C pin to a GPIO output */
#if defined(CONFIG_STM32_STM32L15XX)
# define I2C_OUTPUT (GPIO_OUTPUT | GPIO_OUTPUT_SET | GPIO_OPENDRAIN | \
GPIO_SPEED_40MHz)
#elif defined(CONFIG_STM32_STM32F10XX)
# define I2C_OUTPUT (GPIO_OUTPUT | GPIO_OUTPUT_SET | GPIO_CNF_OUTOD | \
GPIO_MODE_50MHz)
#elif defined(CONFIG_STM32_STM32F20XX) || defined(CONFIG_STM32_STM32F4XXX)
# define I2C_OUTPUT (GPIO_OUTPUT | GPIO_FLOAT | GPIO_OPENDRAIN |\
GPIO_SPEED_50MHz | GPIO_OUTPUT_SET)
#endif
#define MKI2C_OUTPUT(p) (((p) & (GPIO_PORT_MASK | GPIO_PIN_MASK)) | I2C_OUTPUT)
/* Debug ****************************************************************************/
/* I2C event trace logic. NOTE: trace uses the internal, non-standard, low-level
* debug interface syslog() but does not require that any other debug
* is enabled.
*/
#ifndef CONFIG_I2C_TRACE
# define stm32_i2c_tracereset(p)
# define stm32_i2c_tracenew(p,s)
# define stm32_i2c_traceevent(p,e,a)
# define stm32_i2c_tracedump(p)
#endif
#ifndef CONFIG_I2C_NTRACE
# define CONFIG_I2C_NTRACE 32
#endif
/************************************************************************************
* Private Types
************************************************************************************/
/* Interrupt state */
enum stm32_intstate_e
{
INTSTATE_IDLE = 0, /* No I2C activity */
INTSTATE_WAITING, /* Waiting for completion of interrupt activity */
INTSTATE_DONE, /* Interrupt activity complete */
};
/* Trace events */
#ifdef CONFIG_I2C_TRACE
static const uint16_t I2CEVENT_NONE = 0; /* No events have occurred with this status */
static const uint16_t I2CEVENT_STATE_ERROR = 1000; /* No correct state detected, diver cannot handle state */
static const uint16_t I2CEVENT_ISR_SHUTDOWN = 1001; /* ISR gets shutdown */
static const uint16_t I2CEVENT_ISR_EMPTY_CALL = 1002; /* ISR gets called but no I2C logic comes into play */
static const uint16_t I2CEVENT_MSG_HANDLING = 1003; /* Message Handling 1/1: advances the msg processing param = msgc */
static const uint16_t I2CEVENT_POLL_DEV_NOT_RDY = 1004; /* During polled operation if device is not ready yet */
static const uint16_t I2CEVENT_ISR_SR1ERROR = 1005; /* ERROR set in SR1 at end of transfer */
static const uint16_t I2CEVENT_ISR_CALL = 1111; /* ISR called */
static const uint16_t I2CEVENT_SENDADDR = 5; /* Start/Master bit set and address sent, param = priv->msgv->addr(EV5 in reference manual) */
static const uint16_t I2CEVENT_ADDR_HDL_READ_1 = 51; /* Read of length 1 address handling, param = 0 */
static const uint16_t I2CEVENT_ADDR_HDL_READ_2 = 52; /* Read of length 2 address handling, param = 0 */
static const uint16_t I2CEVENT_EMPTY_MSG = 5000; /* Empty message detected, param=0 */
static const uint16_t I2CEVENT_ADDRESS_ACKED = 6; /* Address has been ACKed(i.e. it's a valid address) param = address */
static const uint16_t I2CEVENT_ADDRESS_ACKED_READ_1 = 63; /* Event when reading single byte just after address is beeing ACKed, param = 0 */
static const uint16_t I2CEVENT_ADDRESS_ACKED_READ_2 = 61; /* Event when reading two bytes just after address is beeing ACKed, param = 0 */
static const uint16_t I2CEVENT_ADDRESS_ACKED_WRITE = 681; /* Address has been ACKed(i.e. it's a valid address) in write mode and byte has been written */
static const uint16_t I2CEVENT_ADDRESS_NACKED = 6000; /* Address has been NACKed(i.e. it's an invalid address) param = address */
static const uint16_t I2CEVENT_READ = 7; /* RxNE = 1 therefore can be read, param = dcnt */
static const uint16_t I2CEVENT_READ_3 = 72; /* EV7_2 reference manual, reading byte N-2 and N-1 when N >=3 */
static const uint16_t I2CEVENT_READ_2 = 73; /* EV7_3 reference manual, reading byte 1 and 2 when N == 2 */
static const uint16_t I2CEVENT_READ_SR_EMPTY = 79; /* DR is full but SR is empty, does not read DR and waits for SR to fill in next ISR */
static const uint16_t I2CEVENT_READ_LAST_BYTE = 72; /* EV7_2 reference manual last two bytes are in SR and DR */
static const uint16_t I2CEVENT_READ_ERROR = 7000; /* read mode error */
static const uint16_t I2CEVENT_WRITE_TO_DR = 8; /* EV8 reference manual, writing into the data register param = byte to send */
static const uint16_t I2CEVENT_WRITE_STOP = 82; /* EV8_2 reference manual, set stop bit after write is finished */
static const uint16_t I2CEVENT_WRITE_RESTART = 83; /* Re-send start bit as next packet is a read */
static const uint16_t I2CEVENT_WRITE_NO_RESTART = 84; /* don't restart as packet flag says so */
static const uint16_t I2CEVENT_WRITE_ERROR = 8000; /* Error in write mode, param = 0 */
static const uint16_t I2CEVENT_WRITE_FLAG_ERROR = 8001; /* Next message has unrecognized flag, param = priv->msgv->flags */
#endif /* CONFIG_I2C_TRACE */
/* Trace data */
struct stm32_trace_s
{
uint32_t status; /* I2C 32-bit SR2|SR1 status */
uint32_t count; /* Interrupt count when status change */
uint32_t event; /* Last event that occurred with this status */
uint32_t parm; /* Parameter associated with the event */
clock_t time; /* First of event or first status */
};
/* I2C Device hardware configuration */
struct stm32_i2c_config_s
{
uint32_t base; /* I2C base address */
uint32_t clk_bit; /* Clock enable bit */
uint32_t reset_bit; /* Reset bit */
uint32_t scl_pin; /* GPIO configuration for SCL as SCL */
uint32_t sda_pin; /* GPIO configuration for SDA as SDA */
#ifndef CONFIG_I2C_POLLED
uint32_t ev_irq; /* Event IRQ */
uint32_t er_irq; /* Error IRQ */
#endif
};
/* I2C Device Private Data */
struct stm32_i2c_priv_s
{
const struct i2c_ops_s *ops; /* Standard I2C operations */
const struct stm32_i2c_config_s *config; /* Port configuration */
int refs; /* Referernce count */
sem_t sem_excl; /* Mutual exclusion semaphore */
#ifndef CONFIG_I2C_POLLED
sem_t sem_isr; /* Interrupt wait semaphore */
#endif
volatile uint8_t intstate; /* Interrupt handshake (see enum stm32_intstate_e) */
uint8_t msgc; /* Message count */
struct i2c_msg_s *msgv; /* Message list */
uint8_t *ptr; /* Current message buffer */
uint32_t frequency; /* Current I2C frequency */
int dcnt; /* Current message length */
uint16_t flags; /* Current message flags */
bool check_addr_ACK; /* Flag to signal if on next interrupt address has ACKed */
uint8_t total_msg_len; /* Flag to signal a short read sequence */
/* I2C trace support */
#ifdef CONFIG_I2C_TRACE
int tndx; /* Trace array index */
clock_t start_time; /* Time when the trace was started */
/* The actual trace data */
struct stm32_trace_s trace[CONFIG_I2C_NTRACE];
#endif
uint32_t status; /* End of transfer SR2|SR1 status */
};
/************************************************************************************
* Private Function Prototypes
************************************************************************************/
static inline uint16_t stm32_i2c_getreg(FAR struct stm32_i2c_priv_s *priv,
uint8_t offset);
static inline void stm32_i2c_putreg(FAR struct stm32_i2c_priv_s *priv, uint8_t offset,
uint16_t value);
static inline void stm32_i2c_modifyreg(FAR struct stm32_i2c_priv_s *priv,
uint8_t offset, uint16_t clearbits,
uint16_t setbits);
static inline void stm32_i2c_sem_wait(FAR struct stm32_i2c_priv_s *priv);
#ifdef CONFIG_STM32_I2C_DYNTIMEO
static useconds_t stm32_i2c_tousecs(int msgc, FAR struct i2c_msg_s *msgs);
#endif /* CONFIG_STM32_I2C_DYNTIMEO */
static inline int stm32_i2c_sem_waitdone(FAR struct stm32_i2c_priv_s *priv);
static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv);
static inline void stm32_i2c_sem_post(FAR struct stm32_i2c_priv_s *priv);
static inline void stm32_i2c_sem_init(FAR struct stm32_i2c_priv_s *priv);
static inline void stm32_i2c_sem_destroy(FAR struct stm32_i2c_priv_s *priv);
#ifdef CONFIG_I2C_TRACE
static void stm32_i2c_tracereset(FAR struct stm32_i2c_priv_s *priv);
static void stm32_i2c_tracenew(FAR struct stm32_i2c_priv_s *priv, uint16_t status);
static void stm32_i2c_traceevent(FAR struct stm32_i2c_priv_s *priv,
uint16_t event, uint32_t parm);
static void stm32_i2c_tracedump(FAR struct stm32_i2c_priv_s *priv);
#endif /* CONFIG_I2C_TRACE */
static void stm32_i2c_setclock(FAR struct stm32_i2c_priv_s *priv,
uint32_t frequency);
static inline void stm32_i2c_sendstart(FAR struct stm32_i2c_priv_s *priv);
static inline void stm32_i2c_clrstart(FAR struct stm32_i2c_priv_s *priv);
static inline void stm32_i2c_sendstop(FAR struct stm32_i2c_priv_s *priv);
static inline uint32_t stm32_i2c_getstatus(FAR struct stm32_i2c_priv_s *priv);
#ifdef I2C1_FSMC_CONFLICT
static inline uint32_t stm32_i2c_disablefsmc(FAR struct stm32_i2c_priv_s *priv);
static inline void stm32_i2c_enablefsmc(uint32_t ahbenr);
#endif /* I2C1_FSMC_CONFLICT */
static int stm32_i2c_isr_process(struct stm32_i2c_priv_s * priv);
#ifndef CONFIG_I2C_POLLED
static int stm32_i2c_isr(int irq, void *context, FAR void *arg);
#endif /* !CONFIG_I2C_POLLED */
static int stm32_i2c_init(FAR struct stm32_i2c_priv_s *priv);
static int stm32_i2c_deinit(FAR struct stm32_i2c_priv_s *priv);
static int stm32_i2c_transfer(FAR struct i2c_master_s *dev, FAR struct i2c_msg_s *msgs,
int count);
#ifdef CONFIG_I2C_RESET
static int stm32_i2c_reset(FAR struct i2c_master_s *dev);
#endif
/************************************************************************************
* Private Data
************************************************************************************/
/* I2C interface */
static const struct i2c_ops_s stm32_i2c_ops =
{
.transfer = stm32_i2c_transfer
#ifdef CONFIG_I2C_RESET
, .reset = stm32_i2c_reset
#endif
};
#ifdef CONFIG_STM32_I2C1
static const struct stm32_i2c_config_s stm32_i2c1_config =
{
.base = STM32_I2C1_BASE,
.clk_bit = RCC_APB1ENR_I2C1EN,
.reset_bit = RCC_APB1RSTR_I2C1RST,
.scl_pin = GPIO_I2C1_SCL,
.sda_pin = GPIO_I2C1_SDA,
#ifndef CONFIG_I2C_POLLED
.ev_irq = STM32_IRQ_I2C1EV,
.er_irq = STM32_IRQ_I2C1ER
#endif
};
static struct stm32_i2c_priv_s stm32_i2c1_priv =
{
.ops = &stm32_i2c_ops,
.config = &stm32_i2c1_config,
.refs = 0,
.intstate = INTSTATE_IDLE,
.msgc = 0,
.msgv = NULL,
.ptr = NULL,
.dcnt = 0,
.flags = 0,
.status = 0
};
#endif
#ifdef CONFIG_STM32_I2C2
static const struct stm32_i2c_config_s stm32_i2c2_config =
{
.base = STM32_I2C2_BASE,
.clk_bit = RCC_APB1ENR_I2C2EN,
.reset_bit = RCC_APB1RSTR_I2C2RST,
.scl_pin = GPIO_I2C2_SCL,
.sda_pin = GPIO_I2C2_SDA,
#ifndef CONFIG_I2C_POLLED
.ev_irq = STM32_IRQ_I2C2EV,
.er_irq = STM32_IRQ_I2C2ER
#endif
};
static struct stm32_i2c_priv_s stm32_i2c2_priv =
{
.ops = &stm32_i2c_ops,
.config = &stm32_i2c2_config,
.refs = 0,
.intstate = INTSTATE_IDLE,
.msgc = 0,
.msgv = NULL,
.ptr = NULL,
.dcnt = 0,
.flags = 0,
.status = 0
};
#endif
#ifdef CONFIG_STM32_I2C3
static const struct stm32_i2c_config_s stm32_i2c3_config =
{
.base = STM32_I2C3_BASE,
.clk_bit = RCC_APB1ENR_I2C3EN,
.reset_bit = RCC_APB1RSTR_I2C3RST,
.scl_pin = GPIO_I2C3_SCL,
.sda_pin = GPIO_I2C3_SDA,
#ifndef CONFIG_I2C_POLLED
.ev_irq = STM32_IRQ_I2C3EV,
.er_irq = STM32_IRQ_I2C3ER
#endif
};
static struct stm32_i2c_priv_s stm32_i2c3_priv =
{
.ops = &stm32_i2c_ops,
.config = &stm32_i2c3_config,
.refs = 0,
.intstate = INTSTATE_IDLE,
.msgc = 0,
.msgv = NULL,
.ptr = NULL,
.dcnt = 0,
.flags = 0,
.status = 0
};
#endif
/************************************************************************************
* Private Functions
************************************************************************************/
/************************************************************************************
* Name: stm32_i2c_getreg
*
* Description:
* Get a 16-bit register value by offset
*
************************************************************************************/
static inline uint16_t stm32_i2c_getreg(FAR struct stm32_i2c_priv_s *priv,
uint8_t offset)
{
return getreg16(priv->config->base + offset);
}
/************************************************************************************
* Name: stm32_i2c_putreg
*
* Description:
* Put a 16-bit register value by offset
*
************************************************************************************/
static inline void stm32_i2c_putreg(FAR struct stm32_i2c_priv_s *priv, uint8_t offset,
uint16_t value)
{
putreg16(value, priv->config->base + offset);
}
/************************************************************************************
* Name: stm32_i2c_modifyreg
*
* Description:
* Modify a 16-bit register value by offset
*
************************************************************************************/
static inline void stm32_i2c_modifyreg(FAR struct stm32_i2c_priv_s *priv,
uint8_t offset, uint16_t clearbits,
uint16_t setbits)
{
modifyreg16(priv->config->base + offset, clearbits, setbits);
}
/************************************************************************************
* Name: stm32_i2c_sem_wait
*
* Description:
* Take the exclusive access, waiting as necessary
*
************************************************************************************/
static inline void stm32_i2c_sem_wait(FAR struct stm32_i2c_priv_s *priv)
{
int ret;
do
{
/* Take the semaphore (perhaps waiting) */
ret = nxsem_wait(&priv->sem_excl);
/* The only case that an error should occur here is if the wait was
* awakened by a signal.
*/
DEBUGASSERT(ret == OK || ret == -EINTR);
}
while (ret == -EINTR);
}
/************************************************************************************
* Name: stm32_i2c_tousecs
*
* Description:
* Return a micro-second delay based on the number of bytes left to be processed.
*
************************************************************************************/
#ifdef CONFIG_STM32_I2C_DYNTIMEO
static useconds_t stm32_i2c_tousecs(int msgc, FAR struct i2c_msg_s *msgs)
{
size_t bytecount = 0;
int i;
/* Count the number of bytes left to process */
for (i = 0; i < msgc; i++)
{
bytecount += msgs[i].length;
}
/* Then return a number of microseconds based on a user provided scaling
* factor.
*/
return (useconds_t)(CONFIG_STM32_I2C_DYNTIMEO_USECPERBYTE * bytecount);
}
#endif
/************************************************************************************
* Name: stm32_i2c_sem_waitdone
*
* Description:
* Wait for a transfer to complete
*
************************************************************************************/
#ifndef CONFIG_I2C_POLLED
static int stm32_i2c_sem_waitdone(FAR struct stm32_i2c_priv_s *priv)
{
struct timespec abstime;
irqstate_t flags;
uint32_t regval;
int ret;
flags = enter_critical_section();
/* Enable I2C interrupts */
regval = stm32_i2c_getreg(priv, STM32_I2C_CR2_OFFSET);
regval |= (I2C_CR2_ITERREN | I2C_CR2_ITEVFEN);
stm32_i2c_putreg(priv, STM32_I2C_CR2_OFFSET, regval);
/* Signal the interrupt handler that we are waiting. NOTE: Interrupts
* are currently disabled but will be temporarily re-enabled below when
* nxsem_timedwait() sleeps.
*/
priv->intstate = INTSTATE_WAITING;
do
{
/* Get the current time */
(void)clock_gettime(CLOCK_REALTIME, &abstime);
/* Calculate a time in the future */
#if CONFIG_STM32_I2CTIMEOSEC > 0
abstime.tv_sec += CONFIG_STM32_I2CTIMEOSEC;
#endif
/* Add a value proportional to the number of bytes in the transfer */
#ifdef CONFIG_STM32_I2C_DYNTIMEO
abstime.tv_nsec += 1000 * stm32_i2c_tousecs(priv->msgc, priv->msgv);
if (abstime.tv_nsec >= 1000 * 1000 * 1000)
{
abstime.tv_sec++;
abstime.tv_nsec -= 1000 * 1000 * 1000;
}
#elif CONFIG_STM32_I2CTIMEOMS > 0
abstime.tv_nsec += CONFIG_STM32_I2CTIMEOMS * 1000 * 1000;
if (abstime.tv_nsec >= 1000 * 1000 * 1000)
{
abstime.tv_sec++;
abstime.tv_nsec -= 1000 * 1000 * 1000;
}
#endif
/* Wait until either the transfer is complete or the timeout expires */
ret = nxsem_timedwait(&priv->sem_isr, &abstime);
if (ret < 0 && ret != -EINTR)
{
/* Break out of the loop on irrecoverable errors. This would
* include timeouts and mystery errors reported by nxsem_timedwait.
* NOTE that we try again if we are awakened by a signal (EINTR).
*/
break;
}
}
/* Loop until the interrupt level transfer is complete. */
while (priv->intstate != INTSTATE_DONE);
/* Set the interrupt state back to IDLE */
priv->intstate = INTSTATE_IDLE;
/* Disable I2C interrupts */
regval = stm32_i2c_getreg(priv, STM32_I2C_CR2_OFFSET);
regval &= ~I2C_CR2_ALLINTS;
stm32_i2c_putreg(priv, STM32_I2C_CR2_OFFSET, regval);
leave_critical_section(flags);
return ret;
}
#else
static int stm32_i2c_sem_waitdone(FAR struct stm32_i2c_priv_s *priv)
{
clock_t timeout;
clock_t start;
clock_t elapsed;
int ret;
/* Get the timeout value */
#ifdef CONFIG_STM32_I2C_DYNTIMEO
timeout = USEC2TICK(stm32_i2c_tousecs(priv->msgc, priv->msgv));
#else
timeout = CONFIG_STM32_I2CTIMEOTICKS;
#endif
/* Signal the interrupt handler that we are waiting. NOTE: Interrupts
* are currently disabled but will be temporarily re-enabled below when
* nxsem_timedwait() sleeps.
*/
priv->intstate = INTSTATE_WAITING;
start = clock_systimer();
do
{
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
/* Poll by simply calling the timer interrupt handler until it
* reports that it is done.
*/
stm32_i2c_isr_process(priv);
}
/* Loop until the transfer is complete. */
while (priv->intstate != INTSTATE_DONE && elapsed < timeout);
i2cinfo("intstate: %d elapsed: %ld threshold: %ld status: %08x\n",
priv->intstate, (long)elapsed, (long)timeout, priv->status);
/* Set the interrupt state back to IDLE */
ret = priv->intstate == INTSTATE_DONE ? OK : -ETIMEDOUT;
priv->intstate = INTSTATE_IDLE;
return ret;
}
#endif
/************************************************************************************
* Name: stm32_i2c_sem_waitstop
*
* Description:
* Wait for a STOP to complete
*
************************************************************************************/
static inline void stm32_i2c_sem_waitstop(FAR struct stm32_i2c_priv_s *priv)
{
clock_t start;
clock_t elapsed;
clock_t timeout;
uint32_t cr1;
uint32_t sr1;
/* Select a timeout */
#ifdef CONFIG_STM32_I2C_DYNTIMEO
timeout = USEC2TICK(CONFIG_STM32_I2C_DYNTIMEO_STARTSTOP);
#else
timeout = CONFIG_STM32_I2CTIMEOTICKS;
#endif
/* Wait as stop might still be in progress; but stop might also
* be set because of a timeout error: "The [STOP] bit is set and
* cleared by software, cleared by hardware when a Stop condition is
* detected, set by hardware when a timeout error is detected."
*/
start = clock_systimer();
do
{
/* Calculate the elapsed time */
elapsed = clock_systimer() - start;
/* Check for STOP condition */
cr1 = stm32_i2c_getreg(priv, STM32_I2C_CR1_OFFSET);
if ((cr1 & I2C_CR1_STOP) == 0)
{
return;
}
/* Check for timeout error */
sr1 = stm32_i2c_getreg(priv, STM32_I2C_SR1_OFFSET);
if ((sr1 & I2C_SR1_TIMEOUT) != 0)
{
return;
}
}
/* Loop until the stop is complete or a timeout occurs. */
while (elapsed < timeout);
/* If we get here then a timeout occurred with the STOP condition
* still pending.
*/
i2cinfo("Timeout with CR1: %04x SR1: %04x\n", cr1, sr1);
}
/************************************************************************************
* Name: stm32_i2c_sem_post
*
* Description:
* Release the mutual exclusion semaphore
*
************************************************************************************/
static inline void stm32_i2c_sem_post(FAR struct stm32_i2c_priv_s *priv)
{
nxsem_post(&priv->sem_excl);
}
/************************************************************************************
* Name: stm32_i2c_sem_init
*
* Description:
* Initialize semaphores
*
************************************************************************************/
static inline void stm32_i2c_sem_init(FAR struct stm32_i2c_priv_s *priv)
{
nxsem_init(&priv->sem_excl, 0, 1);
#ifndef CONFIG_I2C_POLLED
/* This semaphore is used for signaling and, hence, should not have
* priority inheritance enabled.
*/
nxsem_init(&priv->sem_isr, 0, 0);
nxsem_setprotocol(&priv->sem_isr, SEM_PRIO_NONE);
#endif
}
/************************************************************************************
* Name: stm32_i2c_sem_destroy
*
* Description:
* Destroy semaphores.
*
************************************************************************************/
static inline void stm32_i2c_sem_destroy(FAR struct stm32_i2c_priv_s *priv)
{
nxsem_destroy(&priv->sem_excl);
#ifndef CONFIG_I2C_POLLED
nxsem_destroy(&priv->sem_isr);
#endif
}
/************************************************************************************
* Name: stm32_i2c_trace*
*
* Description:
* I2C trace instrumentation
*
************************************************************************************/
#ifdef CONFIG_I2C_TRACE
static void stm32_i2c_traceclear(FAR struct stm32_i2c_priv_s *priv)
{
struct stm32_trace_s *trace = &priv->trace[priv->tndx];
trace->status = 0; /* I2C 32-bit SR2|SR1 status */
trace->count = 0; /* Interrupt count when status change */
trace->event = I2CEVENT_NONE; /* Last event that occurred with this status */
trace->parm = 0; /* Parameter associated with the event */
trace->time = 0; /* Time of first status or event */
}
static void stm32_i2c_tracereset(FAR struct stm32_i2c_priv_s *priv)
{
/* Reset the trace info for a new data collection */
priv->tndx = 0;
priv->start_time = clock_systimer();
stm32_i2c_traceclear(priv);
}
static void stm32_i2c_tracenew(FAR struct stm32_i2c_priv_s *priv, uint16_t status)
{
struct stm32_trace_s *trace = &priv->trace[priv->tndx];
/* Is the current entry uninitialized? Has the status changed? */
if (trace->count == 0 || status != trace->status)
{
/* Yes.. Was it the status changed? */
if (trace->count != 0)
{
/* Yes.. bump up the trace index (unless we are out of trace entries) */
if (priv->tndx >= (CONFIG_I2C_NTRACE-1))
{
i2cerr("ERROR: Trace table overflow\n");
return;
}
priv->tndx++;
trace = &priv->trace[priv->tndx];
}
/* Initialize the new trace entry */
stm32_i2c_traceclear(priv);
trace->status = status;
trace->count = 1;
trace->time = clock_systimer();
}
else
{
/* Just increment the count of times that we have seen this status */
trace->count++;
}
}
static void stm32_i2c_traceevent(FAR struct stm32_i2c_priv_s *priv,
uint16_t event, uint32_t parm)
{
struct stm32_trace_s *trace;
if (event != I2CEVENT_NONE || event != I2CEVENT_POLL_DEV_NOT_RDY)
{
trace = &priv->trace[priv->tndx];
/* Initialize the new trace entry */
trace->event = event;
trace->parm = parm;
/* Bump up the trace index (unless we are out of trace entries) */
if (priv->tndx >= (CONFIG_I2C_NTRACE-1))
{
i2cerr("ERROR: Trace table overflow\n");
return;
}
priv->tndx++;
stm32_i2c_traceclear(priv);
}
}
static void stm32_i2c_tracedump(FAR struct stm32_i2c_priv_s *priv)
{
struct stm32_trace_s *trace;
int i;
syslog(LOG_DEBUG, "Elapsed time: %ld\n",
(long)(clock_systimer() - priv->start_time));
for (i = 0; i <= priv->tndx; i++)
{
trace = &priv->trace[i];
syslog(LOG_DEBUG,
"%2d. STATUS: %08x COUNT: %4d EVENT: %4d PARM: %08x TIME: %d\n",
i+1, trace->status, trace->count, trace->event, trace->parm,
trace->time - priv->start_time);
}
}
#endif /* CONFIG_I2C_TRACE */
/************************************************************************************
* Name: stm32_i2c_setclock
*
* Description:
* Set the I2C clock
*
************************************************************************************/
static void stm32_i2c_setclock(FAR struct stm32_i2c_priv_s *priv, uint32_t frequency)
{
uint16_t cr1;
uint16_t ccr;
uint16_t trise;
uint16_t freqmhz;
uint16_t speed;
/* Has the I2C bus frequency changed? */
if (frequency != priv->frequency)
{
/* Disable the selected I2C peripheral to configure TRISE */
cr1 = stm32_i2c_getreg(priv, STM32_I2C_CR1_OFFSET);
stm32_i2c_putreg(priv, STM32_I2C_CR1_OFFSET, cr1 & ~I2C_CR1_PE);
/* Update timing and control registers */
freqmhz = (uint16_t)(STM32_PCLK1_FREQUENCY / 1000000);
ccr = 0;
/* Configure speed in standard mode */
if (frequency <= 100000)
{
/* Standard mode speed calculation */
speed = (uint16_t)(STM32_PCLK1_FREQUENCY / (frequency << 1));
/* The CCR fault must be >= 4 */
if (speed < 4)
{
/* Set the minimum allowed value */
speed = 4;
}
ccr |= speed;
/* Set Maximum Rise Time for standard mode */
trise = freqmhz + 1;
}
/* Configure speed in fast mode */
else /* (frequency <= 400000) */
{
/* Fast mode speed calculation with Tlow/Thigh = 16/9 */
#ifdef CONFIG_STM32_I2C_DUTY16_9
speed = (uint16_t)(STM32_PCLK1_FREQUENCY / (frequency * 25));
/* Set DUTY and fast speed bits */
ccr |= (I2C_CCR_DUTY | I2C_CCR_FS);
#else
/* Fast mode speed calculation with Tlow/Thigh = 2 */
speed = (uint16_t)(STM32_PCLK1_FREQUENCY / (frequency * 3));
/* Set fast speed bit */
ccr |= I2C_CCR_FS;
#endif
/* Verify that the CCR speed value is nonzero */
if (speed < 1)
{
/* Set the minimum allowed value */
speed = 1;
}
ccr |= speed;
/* Set Maximum Rise Time for fast mode */
trise = (uint16_t)(((freqmhz * 300) / 1000) + 1);
}
/* Write the new values of the CCR and TRISE registers */
stm32_i2c_putreg(priv, STM32_I2C_CCR_OFFSET, ccr);
stm32_i2c_putreg(priv, STM32_I2C_TRISE_OFFSET, trise);
/* Bit 14 of OAR1 must be configured and kept at 1 */
stm32_i2c_putreg(priv, STM32_I2C_OAR1_OFFSET, I2C_OAR1_ONE);
/* Re-enable the peripheral (or not) */
stm32_i2c_putreg(priv, STM32_I2C_CR1_OFFSET, cr1);
/* Save the new I2C frequency */
priv->frequency = frequency;
}
}
/************************************************************************************
* Name: stm32_i2c_sendstart
*
* Description:
* Send the START conditions/force Master mode
*
************************************************************************************/
static inline void stm32_i2c_sendstart(FAR struct stm32_i2c_priv_s *priv)
{
/* Disable ACK on receive by default and generate START */
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_ACK, I2C_CR1_START);
}
/************************************************************************************
* Name: stm32_i2c_clrstart
*
* Description:
* Clear the STOP, START or PEC condition on certain error recovery steps.
*
************************************************************************************/
static inline void stm32_i2c_clrstart(FAR struct stm32_i2c_priv_s *priv)
{
/* "Note: When the STOP, START or PEC bit is set, the software must
* not perform any write access to I2C_CR1 before this bit is
* cleared by hardware. Otherwise there is a risk of setting a
* second STOP, START or PEC request."
*
* "The [STOP] bit is set and cleared by software, cleared by hardware
* when a Stop condition is detected, set by hardware when a timeout
* error is detected.
*
* "This [START] bit is set and cleared by software and cleared by hardware
* when start is sent or PE=0." The bit must be cleared by software if the
* START is never sent.
*
* "This [PEC] bit is set and cleared by software, and cleared by hardware
* when PEC is transferred or by a START or Stop condition or when PE=0."
*/
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET,
I2C_CR1_START | I2C_CR1_STOP | I2C_CR1_PEC, 0);
}
/************************************************************************************
* Name: stm32_i2c_sendstop
*
* Description:
* Send the STOP conditions
*
************************************************************************************/
static inline void stm32_i2c_sendstop(FAR struct stm32_i2c_priv_s *priv)
{
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_ACK, I2C_CR1_STOP);
}
/************************************************************************************
* Name: stm32_i2c_getstatus
*
* Description:
* Get 32-bit status (SR1 and SR2 combined)
*
************************************************************************************/
static inline uint32_t stm32_i2c_getstatus(FAR struct stm32_i2c_priv_s *priv)
{
uint32_t status = stm32_i2c_getreg(priv, STM32_I2C_SR1_OFFSET);
status |= (stm32_i2c_getreg(priv, STM32_I2C_SR2_OFFSET) << 16);
return status;
}
/************************************************************************************
* Name: stm32_i2c_disablefsmc
*
* Description:
* FSMC must be disable while accessing I2C1 because it uses a common resource
* (LBAR)
*
* NOTE: This is an issue with the STM32F103ZE, but may not be an issue with other
* STM32s. You may need to experiment
*
************************************************************************************/
#ifdef I2C1_FSMC_CONFLICT
static inline uint32_t stm32_i2c_disablefsmc(FAR struct stm32_i2c_priv_s *priv)
{
uint32_t ret = 0;
uint32_t regval;
/* Is this I2C1 */
#if defined(CONFIG_STM32_I2C2) || defined(CONFIG_STM32_I2C3)
if (priv->config->base == STM32_I2C1_BASE)
#endif
{
/* Disable FSMC unconditionally */
ret = getreg32(STM32_RCC_AHBENR);
regval = ret & ~RCC_AHBENR_FSMCEN;
putreg32(regval, STM32_RCC_AHBENR);
}
return ret;
}
/************************************************************************************
* Name: stm32_i2c_enablefsmc
*
* Description:
* Re-enable the FSMC
*
************************************************************************************/
static inline void stm32_i2c_enablefsmc(uint32_t ahbenr)
{
uint32_t regval;
/* Enable AHB clocking to the FSMC only if it was previously enabled. */
if ((ahbenr & RCC_AHBENR_FSMCEN) != 0)
{
regval = getreg32(STM32_RCC_AHBENR);
regval |= RCC_AHBENR_FSMCEN;
putreg32(regval, STM32_RCC_AHBENR);
}
}
#else
# define stm32_i2c_disablefsmc(priv) (0)
# define stm32_i2c_enablefsmc(ahbenr)
#endif /* I2C1_FSMC_CONFLICT */
/************************************************************************************
* Name: stm32_i2c_isr_process
*
* Description:
* Common interrupt service routine (ISR) that handles I2C protocol logic.
*
* This ISR is activated and deactivated by stm32_i2c_waitdone(). Interrupt fires
* on(both ITEVFEN and ITBUFEN are set):
*
* - Start bit
* - Address sent
* - 10-bit header sent
* - Data byte transfer finished
* - Receive buffer not empty
* - Transmit buffer empty
*
* Input Parameters:
* priv - The private struct of the I2C driver.
*
* Returned Value:
*
************************************************************************************/
static int stm32_i2c_isr_process(struct stm32_i2c_priv_s *priv)
{
#ifndef CONFIG_I2C_POLLED
uint32_t regval;
#endif
uint32_t status;
i2cinfo("I2C ISR called\n");
/* Get state of the I2C controller (register SR1 only)
*
* Get control register SR1 only as reading both SR1 and SR2 clears the ADDR
* flag(possibly others) causing the hardware to advance to the next state
* without the proper action being taken.
*/
status = stm32_i2c_getreg(priv, STM32_I2C_SR1_OFFSET);
/* Update private version of the state */
priv->status = status;
/* Check if this is a new transmission so to set up the
* trace table accordingly.
*/
stm32_i2c_tracenew(priv, status);
stm32_i2c_traceevent(priv, I2CEVENT_ISR_CALL, 0);
/* Messages handling (1/2)
*
* Message handling should only operate when a message has been completely
* sent and after the ISR had the chance to run to set bits after the last
* written/read byte, i.e. priv->dcnt == -1. This is also the case in when
* the ISR is called for the first time. This can seen in stm32_i2c_transfer()
* before entering the stm32_i2c_sem_waitdone() waiting process.
*
* Message handling should only operate when:
* - A message has been completely sent and there are still messages
* to send(i.e. msgc > 0).
* - After the ISR had the chance to run to set start bit or termination
* flags after the last written/read byte(after last byte dcnt=0, msg
* handling dcnt = -1).
*
* When the ISR is called for the first time the same conditions hold.
* This can seen in stm32_i2c_transfer() before entering the
* stm32_i2c_sem_waitdone() waiting process.
*/
if (priv->dcnt == -1 && priv->msgc > 0)
{
i2cinfo("Switch to new message\n");
/* Get current message to process data and copy to private structure */
priv->ptr = priv->msgv->buffer; /* Copy buffer to private struct */
priv->dcnt = priv->msgv->length; /* Set counter of current msg length */
priv->total_msg_len = priv->msgv->length; /* Set total msg length */
priv->flags = priv->msgv->flags; /* Copy flags to private struct */
i2cinfo("Current flags %i\n", priv->flags);
/* Decrease counter to indicate the number of messages left to process */
priv->msgc--;
/* Decrease message pointer. If last message set next message vector to null */
if (priv->msgc == 0)
{
/* No more messages, don't need to increment msgv. This pointer will be set
* to zero when reaching the termination of the ISR calls, i.e. Messages
* handling(2/2).
*/
}
else
{
/* If not last message increment to next message to process */
priv->msgv++;
}
/* Trace event */
stm32_i2c_traceevent(priv, I2CEVENT_MSG_HANDLING, priv->msgc);
}
/* Note the event where we are on the last message and after the last
* byte is handled at the bottom of this function, as it terminates
* the repeated calls to the ISR.
*/
/* I2C protocol logic
*
* I2C protocol logic follows. It's organized in an if else chain such that
* only one mode of operation is executed every time the ISR is called.
*/
/* Address Handling
*
* Check if a start bit was set and transmit address with proper format.
*
* Note:
* On first call the start bit has been set by stm32_i2c_waitdone()
* Otherwise it will be set from this ISR.
*
* Remember that after a start bit an address has always to be sent.
*/
if ((status & I2C_SR1_SB) != 0)
{
/* Start bit is set */
i2cinfo("Entering address handling, status = %i\n", status);
/* Check for empty message (for robustness) */
if (priv->dcnt > 0)
{
/* When reading messages of length 1 or 2 actions have to be taken
* during this event. The following block handles that.
*/
if (priv->total_msg_len == 1 && (priv->flags & I2C_M_READ))
{
i2cinfo("short read N=1: setting NACK\n");
/* Set POS bit to zero (can be up from a previous 2 byte receive) */
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_POS, 0);
/* Immediately set NACK */
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_ACK, 0);
stm32_i2c_traceevent(priv, I2CEVENT_ADDR_HDL_READ_1, 0);
}
else if (priv->total_msg_len == 2 && (priv->flags & I2C_M_READ))
{
i2cinfo("short read N=2: setting POS and ACK bits\n");
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, 0, I2C_CR1_POS);
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, 0, I2C_CR1_ACK);
stm32_i2c_traceevent(priv, I2CEVENT_ADDR_HDL_READ_2, 0);
}
else
{
/* Enable ACK after address byte */
i2cinfo("setting ACK\n");
/* Set POS bit to zero (can be up from a previous 2 byte receive) */
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_POS, 0);
/* ACK is the expected answer for N>=3 reads and writes */
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, 0, I2C_CR1_ACK);
}
/* Send address byte with correct 8th bit set(for writing or reading)
* Transmission happens after having written to the data register
* STM32_I2C_DR
*/
stm32_i2c_putreg(priv, STM32_I2C_DR_OFFSET,
(priv->flags & I2C_M_TEN) ?
0 :((priv->msgv->addr << 1) | (priv->flags & I2C_M_READ)));
i2cinfo("Address sent. Addr=%#02x Write/Read bit=%i\n",
priv->msgv->addr, (priv->flags & I2C_M_READ));
/* Flag that address has just been sent */
priv->check_addr_ACK = true;
stm32_i2c_traceevent(priv, I2CEVENT_SENDADDR, priv->msgv->addr);
}
else
{
/* TODO: untested!! */
i2cwarn("WARNING: An empty message has been detected, ignoring and passing to next message.\n");
/* Trace event */
stm32_i2c_traceevent(priv, I2CEVENT_EMPTY_MSG, 0);
/* Set condition to activate msg handling */
priv->dcnt = -1;
/* Restart ISR by setting an interrupt buffer bit */
stm32_i2c_modifyreg(priv, STM32_I2C_CR2_OFFSET, 0, I2C_CR2_ITBUFEN);
}
}
/* Address cleared event
*
* Check if the address cleared, i.e. the driver found a valid address.
* If a NACK was received the address is invalid, if an ACK was
* received the address is valid and transmission can continue.
*/
/* Check for NACK after an address */
#ifndef CONFIG_I2C_POLLED
/* When polling the i2c ISR it's not possible to determine when
* an address has been ACKed(i.e. the address is valid).
*
* The mechanism to deal a NACKed address is to wait for the I2C
* call to timeout (value defined in defconfig by one of the
* following: CONFIG_STM32_I2C_DYNTIMEO, CONFIG_STM32_I2CTIMEOSEC,
* CONFIG_STM32_I2CTIMEOMS, CONFIG_STM32_I2CTIMEOTICKS).
*
* To be safe in the case of a timeout/NACKed address a stop bit
* is set on the bus to clear it. In POLLED operation it's done
* stm32_i2c_transfer() after the call to stm32_i2c_sem_waitdone().
*
* In ISR driven operation the stop bit in case of a NACKed address
* is set in the ISR itself.
*
* Note: this commentary is found in both places.
*/
else if ((status & I2C_SR1_ADDR) == 0 && priv->check_addr_ACK)
{
i2cinfo("Invalid Address. Setting stop bit and clearing message\n");
i2cinfo("status %i\n", status);
/* Set condition to terminate msg chain transmission as address is invalid. */
priv->dcnt = -1;
priv->msgc = 0;
i2cinfo("dcnt %i , msgc %i\n", priv->dcnt, priv->msgc);
/* Reset flag to check for valid address */
priv->check_addr_ACK = false;
/* Send stop bit to clear bus */
stm32_i2c_sendstop(priv);
/* Trace event */
stm32_i2c_traceevent(priv, I2CEVENT_ADDRESS_NACKED, priv->msgv->addr);
}
#endif
/* ACK in read mode, ACK in write mode is handled separately */
else if ((priv->flags & I2C_M_READ) != 0 && (status & I2C_SR1_ADDR) != 0 &&
priv->check_addr_ACK)
{
/* Reset check addr flag as we are handling this event */
priv->check_addr_ACK = false;
/* Clear ADDR flag by reading SR2 and adding it to status */
status |= (stm32_i2c_getreg(priv, STM32_I2C_SR2_OFFSET) << 16);
/* Note:
*
* When reading a single byte the stop condition has to be set
* immediately after clearing the state flags, which happens
* when reading SR2(as SR1 has already been read).
*
* Similarly when reading 2 bytes the NACK bit has to be set as just
* after the clearing of the address.
*/
if (priv->dcnt == 1 && priv->total_msg_len == 1)
{
/* this should only happen when receiving a message of length 1 */
stm32_i2c_modifyreg(priv, STM32_I2C_CR2_OFFSET, 0, I2C_CR2_ITBUFEN);
stm32_i2c_sendstop(priv);
i2cinfo("Address ACKed beginning data reception\n");
i2cinfo("short read N=1: programming stop bit\n");
priv->dcnt--;
/* Trace */
stm32_i2c_traceevent(priv, I2CEVENT_ADDRESS_ACKED_READ_1, 0);
}
else if (priv->dcnt == 2 && priv->total_msg_len == 2)
{
/* This should only happen when receiving a message of length 2
* Set NACK
*/
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_ACK, 0);
i2cinfo("Address ACKed beginning data reception\n");
i2cinfo("short read N=2: programming NACK\n");
/* Trace */
stm32_i2c_traceevent(priv, I2CEVENT_ADDRESS_ACKED_READ_2, 0);
}
else
{
i2cinfo("Address ACKed beginning data reception\n");
/* Trace */
stm32_i2c_traceevent(priv, I2CEVENT_ADDRESS_ACKED, 0);
}
}
/* Write mode
*
* Handles all write related I2C protocol logic. Also handles the
* ACK event after clearing the ADDR flag as the write has to
* begin immediately after.
*/
else if ((priv->flags & (I2C_M_READ)) == 0 &&
(status & (I2C_SR1_ADDR | I2C_SR1_TXE)) != 0)
{
/* The has cleared(ADDR is set, ACK was received after the address)
* or the transmit buffer is empty flag has been set(TxE) then we can
* transmit the next byte.
*/
i2cinfo("Entering write mode dcnt = %i msgc = %i\n",
priv->dcnt, priv->msgc);
/* Clear ADDR flag by reading SR2 and adding it to status */
status |= (stm32_i2c_getreg(priv, STM32_I2C_SR2_OFFSET) << 16);
/* Address has cleared so don't check on next call */
priv->check_addr_ACK = false;
/* Check if we have transmitted the whole message or we are after
* the last byte where the stop condition or else(according to the
* msg flags) has to be set.
*/
if (priv->dcnt >= 1)
{
/* Transmitting message. Send byte == write data into write register */
stm32_i2c_putreg(priv, STM32_I2C_DR_OFFSET, *priv->ptr++);
/* Decrease current message length */
stm32_i2c_traceevent(priv, I2CEVENT_WRITE_TO_DR, priv->dcnt);
priv->dcnt--;
}
else if (priv->dcnt == 0)
{
/* After last byte, check what to do based on next message flags */
if (priv->msgc == 0)
{
/* If last message send stop bit */
stm32_i2c_sendstop(priv);
i2cinfo("Stop sent dcnt = %i msgc = %i\n", priv->dcnt, priv->msgc);
/* Decrease counter to get to next message */
priv->dcnt--;
i2cinfo("dcnt %i\n", priv->dcnt);
stm32_i2c_traceevent(priv, I2CEVENT_WRITE_STOP, priv->dcnt);
}
/* If there is a next message with no flags or the read flag
* a restart sequence has to be sent.
* Note msgv already points to the next message.
*/
else if (priv->msgc > 0 &&
(priv->msgv->flags == 0 || (priv->msgv[0].flags & I2C_M_READ) != 0))
{
stm32_i2c_sendstart(priv);
i2cinfo("Restart detected!\n");
i2cinfo("Nextflag %i\n", priv->msgv[0].flags);
/* Decrease counter to get to next message */
priv->dcnt--;
i2cinfo("dcnt %i\n", priv->dcnt);
stm32_i2c_traceevent(priv, I2CEVENT_WRITE_RESTART, priv->dcnt);
}
/* If there is a next message with the NO_RESTART flag
* do nothing.
*/
else if (priv->msgc > 0 && ((priv->msgv->flags & I2C_M_NOSTART) != 0))
{
/* Set condition to get to next message */
priv->dcnt = -1;
stm32_i2c_traceevent(priv, I2CEVENT_WRITE_NO_RESTART, priv->dcnt);
}
else
{
i2cerr("ERROR: Write mode: next message has an unrecognized flag.\n");
stm32_i2c_traceevent(priv, I2CEVENT_WRITE_FLAG_ERROR, priv->msgv->flags);
}
}
else
{
i2cerr("ERROR: Write mode error.\n");
stm32_i2c_traceevent(priv, I2CEVENT_WRITE_ERROR, 0);
}
}
/* Read mode
*
* Handles all read related I2C protocol logic.
*
* * * * * * * WARNING STM32F1xx HARDWARE ERRATA * * * * * * *
* source: https://github.com/hikob/openlab/blob/master/drivers/stm32/i2c.c
*
* RXNE-only events should not be handled since it sometimes
* fails. Only BTF & RXNE events should be handled (with the
* consequence of slowing down the transfer).
*
* It seems that when a RXNE interrupt is handled 'around'
* the end of the next byte reception, the DR register read
* is ignored by the i2c controller: it does not flush the
* DR with next byte
*
* Thus we read twice the same byte and we read effectively
* read one byte less than expected from the i2c slave point
* of view.
*
* Example:
* + we want to receive 6 bytes (B1 to B6)
* + the problem appear when reading B3
* -> we read B1 B2 B3 B3 B4 B5(B3 twice)
* -> the i2c transfer was B1 B2 B3 B4 B5(B6 is not sent)
*/
else if ((priv->flags & (I2C_M_READ)) != 0 && (status & I2C_SR1_RXNE) != 0)
{
/* When read flag is set and the receive buffer is not empty
* (RXNE is set) then the driver can read from the data register.
*/
i2cinfo("Entering read mode dcnt = %i msgc = %i, status %i\n",
priv->dcnt, priv->msgc, status);
/* Implementation of method 2 for receiving data following
* the stm32f1xx reference manual.
*/
/* Case total message length = 1 */
if (priv->dcnt == 0 && priv->total_msg_len == 1)
{
i2cinfo("short read N=1: Read data from data register(DR)\n");
*priv->ptr++ = stm32_i2c_getreg(priv, STM32_I2C_DR_OFFSET);
priv->dcnt--;
stm32_i2c_traceevent(priv, I2CEVENT_READ, 0);
}
/* Case total message length = 2 */
else if (priv->dcnt == 2 && priv->total_msg_len == 2 && !(status & I2C_SR1_BTF))
{
i2cinfo("short read N=2: DR full, SR empty. Waiting for more bytes.\n");
stm32_i2c_traceevent(priv, I2CEVENT_READ_SR_EMPTY, 0);
}
else if (priv->dcnt == 2 && priv->total_msg_len == 2 && (status & I2C_SR1_BTF))
{
i2cinfo("short read N=2: DR and SR full setting stop bit and reading twice\n");
stm32_i2c_sendstop(priv);
*priv->ptr++ = stm32_i2c_getreg(priv, STM32_I2C_DR_OFFSET);
priv->dcnt--;
*priv->ptr++ = stm32_i2c_getreg(priv, STM32_I2C_DR_OFFSET);
priv->dcnt--;
/* Stop request already programmed so set dcnt for next message */
priv->dcnt--;
/* Set trace */
stm32_i2c_traceevent(priv, I2CEVENT_READ_2, 0);
}
/* Case total message length >= 3 */
else if (priv->total_msg_len >= 3 && !(status & I2C_SR1_BTF))
{
/* If the shift register is still empty (i.e. BTF is low)
* then do nothing and wait for it to fill in the next ISR.
* (should not happen in ISR mode, but if using polled mode
* this should be able to handle it).
*/
i2cinfo("DR full, SR empty. Waiting for more bytes.\n");
stm32_i2c_traceevent(priv, I2CEVENT_READ_SR_EMPTY, 0);
}
else if (priv->dcnt >= 4 && priv->total_msg_len >= 3 && (status & I2C_SR1_BTF))
{
/* Read data from data register(DR). Note this clears the
* RXNE(receive buffer not empty) flag.
*/
i2cinfo("Read data from data register(DR)\n");
*priv->ptr++ = stm32_i2c_getreg(priv, STM32_I2C_DR_OFFSET);
/* Decrease current message length */
priv->dcnt--;
stm32_i2c_traceevent(priv, I2CEVENT_READ, 0);
}
else if (priv->dcnt == 3 && (status & I2C_SR1_BTF) && priv->total_msg_len >= 3)
{
/* This means that we are reading dcnt 3 and there is already dcnt 2 in
* the shift register.
* This coincides with EV7_2 in the reference manual.
*/
i2cinfo("Program NACK\n");
i2cinfo("Read data from data register(DR) dcnt=3\n");
stm32_i2c_traceevent(priv, I2CEVENT_READ_3, priv->dcnt);
/* Program NACK */
stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_ACK, 0);
/* Read dcnt = 3, to ensure a BTF event after having recieved
* in the shift register.
*/
*priv->ptr++ = stm32_i2c_getreg(priv, STM32_I2C_DR_OFFSET);
/* Decrease current message length */
priv->dcnt--;
}
else if (priv->dcnt == 2 && (status & I2C_SR1_BTF) && priv->total_msg_len >= 3)
{
i2cinfo("Program stop\n");
i2cinfo("Read data from data register(DR) dcnt=2\n");
i2cinfo("Read data from data register(SR) dcnt=1\n");
i2cinfo("Setting condition to stop ISR dcnt = -1\n");
stm32_i2c_traceevent(priv, I2CEVENT_READ_3, priv->dcnt);
/* Program stop */
stm32_i2c_sendstop(priv);
/* read dcnt = 2 */
*priv->ptr++ = stm32_i2c_getreg(priv, STM32_I2C_DR_OFFSET);
/* read last byte dcnt=1 */
*priv->ptr++ = stm32_i2c_getreg(priv, STM32_I2C_DR_OFFSET);
/* Stop already sent will not get another interrupt set
* condition to stop ISR
*/
priv->dcnt = -1;
}
/* Error handling for read mode */
else
{
i2cerr("ERROR: I2C read mode no correct state detected\n");
i2cerr(" state %i, dcnt=%i\n", status, priv->dcnt);
/* set condition to terminate ISR and wake waiting thread */
priv->dcnt = -1;
priv->msgc = 0;
stm32_i2c_traceevent(priv, I2CEVENT_READ_ERROR, 0);
}
/* Read rest of the state */
status |= (stm32_i2c_getreg(priv, STM32_I2C_SR2_OFFSET) << 16);
}
/* Empty call handler
*
* Case to handle an empty call to the ISR where it only has to
* Shutdown
*/
else if (priv->dcnt == -1 && priv->msgc == 0)
{
/* Read rest of the state */
status |= (stm32_i2c_getreg(priv, STM32_I2C_SR2_OFFSET) << 16);
i2cwarn("WARNING: Empty call to ISR: Stopping ISR\n");
stm32_i2c_traceevent(priv, I2CEVENT_ISR_EMPTY_CALL, 0);
}
/* Error handler
*
* Gets triggered if the driver does not recognize a situation(state)
* it can deal with.
* This should not happen in interrupt based operation(i.e. when
* CONFIG_I2C_POLLED is not set in the defconfig file).
* During polled operation(i.e. CONFIG_I2C_POLLED=y in defconfig)
* this case should do nothing but tracing the event that the
* device wasn't ready yet.
*/
else
{
#ifdef CONFIG_I2C_POLLED
stm32_i2c_traceevent(priv, I2CEVENT_POLL_DEV_NOT_RDY, 0);
#else
/* Read rest of the state */
status |= (stm32_i2c_getreg(priv, STM32_I2C_SR2_OFFSET) << 16);
i2cerr("ERROR: No correct state detected(start bit, read or write) \n");
i2cerr(" state %i\n", status);
/* Set condition to terminate ISR and wake waiting thread */
priv->dcnt = -1;
priv->msgc = 0;
stm32_i2c_traceevent(priv, I2CEVENT_STATE_ERROR, 0);
#endif
}
/* Messages handling(2/2)
*
* Transmission of the whole message chain has been completed. We have to
* terminate the ISR and wake up stm32_i2c_transfer() that is waiting for
* the ISR cycle to handle the sending/receiving of the messages.
*/
/* First check for errors */
if ((status & I2C_SR1_ERRORMASK) != 0)
{
stm32_i2c_traceevent(priv, I2CEVENT_ISR_SR1ERROR, status & I2C_SR1_ERRORMASK);
/* Clear interrupt flags */
stm32_i2c_putreg(priv, STM32_I2C_SR1_OFFSET, 0);
priv->dcnt = -1;
priv->msgc = 0;
}
if (priv->dcnt == -1 && priv->msgc == 0)
{
i2cinfo("Shutting down I2C ISR\n");
stm32_i2c_traceevent(priv, I2CEVENT_ISR_SHUTDOWN, 0);
/* Clear internal pointer to the message content.
* Good practice + done by last implementation when messages are finished
* (compatibility concerns)
*/
priv->msgv = NULL;
#ifdef CONFIG_I2C_POLLED
priv->intstate = INTSTATE_DONE;
#else
/* Clear all interrupts */
regval = stm32_i2c_getreg(priv, STM32_I2C_CR2_OFFSET);
regval &= ~I2C_CR2_ALLINTS;
stm32_i2c_putreg(priv, STM32_I2C_CR2_OFFSET, regval);
/* Is there a thread waiting for this event(there should be) */
if (priv->intstate == INTSTATE_WAITING)
{
/* Yes.. inform the thread that the transfer is complete
* and wake it up.
*/
nxsem_post(&priv->sem_isr);
priv->intstate = INTSTATE_DONE;
}
#endif
}
return OK;
}
/************************************************************************************
* Name: stm32_i2c_isr
*
* Description:
* Common I2C interrupt service routine
*
************************************************************************************/
#ifndef CONFIG_I2C_POLLED
static int stm32_i2c_isr(int irq, void *context, FAR void *arg)
{
struct stm32_i2c_priv_s *priv = (struct stm32_i2c_priv_s *)arg;
DEBUGASSERT(priv != NULL);
return stm32_i2c_isr_process(priv);
}
#endif
/************************************************************************************
* Name: stm32_i2c_init
*
* Description:
* Setup the I2C hardware, ready for operation with defaults
*
************************************************************************************/
static int stm32_i2c_init(FAR struct stm32_i2c_priv_s *priv)
{
/* Power-up and configure GPIOs */
/* Enable power and reset the peripheral */
modifyreg32(STM32_RCC_APB1ENR, 0, priv->config->clk_bit);
modifyreg32(STM32_RCC_APB1RSTR, 0, priv->config->reset_bit);
modifyreg32(STM32_RCC_APB1RSTR, priv->config->reset_bit, 0);
/* Configure pins */
if (stm32_configgpio(priv->config->scl_pin) < 0)
{
return ERROR;
}
if (stm32_configgpio(priv->config->sda_pin) < 0)
{
stm32_unconfiggpio(priv->config->scl_pin);
return ERROR;
}
/* Attach ISRs */
#ifndef CONFIG_I2C_POLLED
irq_attach(priv->config->ev_irq, stm32_i2c_isr, priv);
irq_attach(priv->config->er_irq, stm32_i2c_isr, priv);
up_enable_irq(priv->config->ev_irq);
up_enable_irq(priv->config->er_irq);
#endif
/* Set peripheral frequency, where it must be at least 2 MHz for 100 kHz
* or 4 MHz for 400 kHz. This also disables all I2C interrupts.
*/
stm32_i2c_putreg(priv, STM32_I2C_CR2_OFFSET, (STM32_PCLK1_FREQUENCY / 1000000));
/* Force a frequency update */
priv->frequency = 0;
stm32_i2c_setclock(priv, 100000);
/* Enable I2C */
stm32_i2c_putreg(priv, STM32_I2C_CR1_OFFSET, I2C_CR1_PE);
return OK;
}
/************************************************************************************
* Name: stm32_i2c_deinit
*
* Description:
* Shutdown the I2C hardware
*
************************************************************************************/
static int stm32_i2c_deinit(FAR struct stm32_i2c_priv_s *priv)
{
/* Disable I2C */
stm32_i2c_putreg(priv, STM32_I2C_CR1_OFFSET, 0);
/* Unconfigure GPIO pins */
stm32_unconfiggpio(priv->config->scl_pin);
stm32_unconfiggpio(priv->config->sda_pin);
/* Disable and detach interrupts */
#ifndef CONFIG_I2C_POLLED
up_disable_irq(priv->config->ev_irq);
up_disable_irq(priv->config->er_irq);
irq_detach(priv->config->ev_irq);
irq_detach(priv->config->er_irq);
#endif
/* Disable clocking */
modifyreg32(STM32_RCC_APB1ENR, priv->config->clk_bit, 0);
return OK;
}
/************************************************************************************
* Device Driver Operations
************************************************************************************/
/************************************************************************************
* Name: stm32_i2c_transfer
*
* Description:
* Generic I2C transfer function
*
************************************************************************************/
static int stm32_i2c_transfer(FAR struct i2c_master_s *dev, FAR struct i2c_msg_s *msgs,
int count)
{
FAR struct stm32_i2c_priv_s *priv = (FAR struct stm32_i2c_priv_s *)dev;
uint32_t status = 0;
#ifdef I2C1_FSMC_CONFLICT
uint32_t ahbenr;
#endif
int ret = 0;
DEBUGASSERT(dev != NULL && msgs != NULL && count > 0);
/* Ensure that address or flags don't change meanwhile */
stm32_i2c_sem_wait(priv);
#ifdef I2C1_FSMC_CONFLICT
/* Disable FSMC that shares a pin with I2C1 (LBAR) */
ahbenr = stm32_i2c_disablefsmc(priv);
#else
/* Wait for any STOP in progress. NOTE: If we have to disable the FSMC
* then we cannot do this at the top of the loop, unfortunately. The STOP
* will not complete normally if the FSMC is enabled.
*/
stm32_i2c_sem_waitstop(priv);
#endif
/* Clear any pending error interrupts */
stm32_i2c_putreg(priv, STM32_I2C_SR1_OFFSET, 0);
/* "Note: When the STOP, START or PEC bit is set, the software must
* not perform any write access to I2C_CR1 before this bit is
* cleared by hardware. Otherwise there is a risk of setting a
* second STOP, START or PEC request." However, if the bits are
* not cleared by hardware, then we will have to do that from hardware.
*/
stm32_i2c_clrstart(priv);
/* Old transfers are done */
priv->msgv = msgs;
priv->msgc = count;
/* Reset I2C trace logic */
stm32_i2c_tracereset(priv);
/* Set I2C clock frequency (on change it toggles I2C_CR1_PE !)
* REVISIT: Note that the frequency is set only on the first message.
* This could be extended to support different transfer frequencies for
* each message segment.
*/
stm32_i2c_setclock(priv, msgs->frequency);
/* Trigger start condition, then the process moves into the ISR. I2C
* interrupts will be enabled within stm32_i2c_waitdone().
*
* Initialize current message length counter to zero. This is needed to
* process the first message(first priv->msgv entry) correctly.
*/
priv->dcnt = -1;
priv->status = 0;
stm32_i2c_sendstart(priv);
/* Wait for an ISR, if there was a timeout, fetch latest status to get
* the BUSY flag.
*/
if (stm32_i2c_sem_waitdone(priv) < 0)
{
status = stm32_i2c_getstatus(priv);
ret = -ETIMEDOUT;
i2cerr("ERROR: Timed out: CR1: 0x%04x status: 0x%08x\n",
stm32_i2c_getreg(priv, STM32_I2C_CR1_OFFSET), status);
/* "Note: When the STOP, START or PEC bit is set, the software must
* not perform any write access to I2C_CR1 before this bit is
* cleared by hardware. Otherwise there is a risk of setting a
* second STOP, START or PEC request."
*/
stm32_i2c_clrstart(priv);
#ifdef CONFIG_I2C_POLLED
/* When polling the i2c ISR it's not possible to determine when
* an address has been ACKed(i.e. the address is valid).
*
* The mechanism to deal a NACKed address is to wait for the I2C
* call to timeout(value defined in defconfig by one of the
* following: CONFIG_STM32_I2C_DYNTIMEO, CONFIG_STM32_I2CTIMEOSEC,
* CONFIG_STM32_I2CTIMEOMS, CONFIG_STM32_I2CTIMEOTICKS).
*
* To be safe in the case of a timeout/NACKed address a stop bit
* is set on the bus to clear it. In POLLED operation it's done
* stm32_i2c_transfer() after the call to stm32_i2c_sem_waitdone().
*
* In ISR driven operation the stop bit in case of a NACKed address
* is set in the ISR itself.
*
* Note: this commentary is found in both places.
*
*/
i2cinfo("Check if the address was valid\n");
stm32_i2c_sendstop(priv);
#endif
/* Clear busy flag in case of timeout */
status = priv->status & 0xffff;
}
else
{
/* clear SR2 (BUSY flag) as we've done successfully */
status = priv->status & 0xffff;
}
/* Check for error status conditions */
if ((status & I2C_SR1_ERRORMASK) != 0)
{
/* I2C_SR1_ERRORMASK is the 'OR' of the following individual bits: */
if (status & I2C_SR1_BERR)
{
/* Bus Error */
ret = -EIO;
}
else if (status & I2C_SR1_ARLO)
{
/* Arbitration Lost (master mode) */
ret = -EAGAIN;
}
else if (status & I2C_SR1_AF)
{
/* Acknowledge Failure */
ret = -ENXIO;
}
else if (status & I2C_SR1_OVR)
{
/* Overrun/Underrun */
ret = -EIO;
}
else if (status & I2C_SR1_PECERR)
{
/* PEC Error in reception */
ret = -EPROTO;
}
else if (status & I2C_SR1_TIMEOUT)
{
/* Timeout or Tlow Error */
ret = -ETIME;
}
/* This is not an error and should never happen since SMBus is not enabled */
else /* if (status & I2C_SR1_SMBALERT) */
{
/* SMBus alert is an optional signal with an interrupt line for devices
* that want to trade their ability to master for a pin.
*/
ret = -EINTR;
}
}
/* This is not an error, but should not happen. The BUSY signal can hang,
* however, if there are unhealthy devices on the bus that need to be reset.
* NOTE: We will only see this busy indication if stm32_i2c_sem_waitdone()
* fails above; Otherwise it is cleared.
*/
else if ((status & (I2C_SR2_BUSY << 16)) != 0)
{
/* I2C Bus is for some reason busy */
ret = -EBUSY;
}
/* Dump the trace result */
stm32_i2c_tracedump(priv);
#ifdef I2C1_FSMC_CONFLICT
/* Wait for any STOP in progress. NOTE: If we have to disable the FSMC
* then we cannot do this at the top of the loop, unfortunately. The STOP
* will not complete normally if the FSMC is enabled.
*/
stm32_i2c_sem_waitstop(priv);
/* Re-enable the FSMC */
stm32_i2c_enablefsmc(ahbenr);
#endif
stm32_i2c_sem_post(priv);
return ret;
}
/************************************************************************************
* Name: stm32_i2c_reset
*
* Description:
* Perform an I2C bus reset in an attempt to break loose stuck I2C devices.
*
* Input Parameters:
* dev - Device-specific state data
*
* Returned Value:
* Zero (OK) on success; a negated errno value on failure.
*
************************************************************************************/
#ifdef CONFIG_I2C_RESET
static int stm32_i2c_reset(FAR struct i2c_master_s * dev)
{
FAR struct stm32_i2c_priv_s *priv = (FAR struct stm32_i2c_priv_s *)dev;
unsigned int clock_count;
unsigned int stretch_count;
uint32_t scl_gpio;
uint32_t sda_gpio;
uint32_t frequency;
int ret = ERROR;
DEBUGASSERT(dev);
/* Our caller must own a ref */
DEBUGASSERT(priv->refs > 0);
/* Lock out other clients */
stm32_i2c_sem_wait(priv);
/* Save the current frequency */
frequency = priv->frequency;
/* De-init the port */
stm32_i2c_deinit(priv);
/* Use GPIO configuration to un-wedge the bus */
scl_gpio = MKI2C_OUTPUT(priv->config->scl_pin);
sda_gpio = MKI2C_OUTPUT(priv->config->sda_pin);
/* Let SDA go high */
stm32_gpiowrite(sda_gpio, 1);
/* Clock the bus until any slaves currently driving it let it go. */
clock_count = 0;
while (!stm32_gpioread(sda_gpio))
{
/* Give up if we have tried too hard */
if (clock_count++ > 10)
{
goto out;
}
/* Sniff to make sure that clock stretching has finished.
*
* If the bus never relaxes, the reset has failed.
*/
stretch_count = 0;
while (!stm32_gpioread(scl_gpio))
{
/* Give up if we have tried too hard */
if (stretch_count++ > 10)
{
goto out;
}
up_udelay(10);
}
/* Drive SCL low */
stm32_gpiowrite(scl_gpio, 0);
up_udelay(10);
/* Drive SCL high again */
stm32_gpiowrite(scl_gpio, 1);
up_udelay(10);
}
/* Generate a start followed by a stop to reset slave
* state machines.
*/
stm32_gpiowrite(sda_gpio, 0);
up_udelay(10);
stm32_gpiowrite(scl_gpio, 0);
up_udelay(10);
stm32_gpiowrite(scl_gpio, 1);
up_udelay(10);
stm32_gpiowrite(sda_gpio, 1);
up_udelay(10);
/* Revert the GPIO configuration. */
stm32_unconfiggpio(sda_gpio);
stm32_unconfiggpio(scl_gpio);
/* Re-init the port */
stm32_i2c_init(priv);
/* Restore the frequency */
stm32_i2c_setclock(priv, frequency);
ret = OK;
out:
/* Release the port for re-use by other clients */
stm32_i2c_sem_post(priv);
return ret;
}
#endif /* CONFIG_I2C_RESET */
/************************************************************************************
* Public Functions
************************************************************************************/
/************************************************************************************
* Name: stm32_i2cbus_initialize
*
* Description:
* Initialize one I2C bus
*
************************************************************************************/
FAR struct i2c_master_s *stm32_i2cbus_initialize(int port)
{
struct stm32_i2c_priv_s *priv = NULL;
irqstate_t flags;
#if STM32_PCLK1_FREQUENCY < 4000000
# warning STM32_I2C_INIT: Peripheral clock must be at least 4 MHz to support 400 kHz operation.
#endif
#if STM32_PCLK1_FREQUENCY < 2000000
# warning STM32_I2C_INIT: Peripheral clock must be at least 2 MHz to support 100 kHz operation.
return NULL;
#endif
/* Get I2C private structure */
switch (port)
{
#ifdef CONFIG_STM32_I2C1
case 1:
priv = (struct stm32_i2c_priv_s *)&stm32_i2c1_priv;
break;
#endif
#ifdef CONFIG_STM32_I2C2
case 2:
priv = (struct stm32_i2c_priv_s *)&stm32_i2c2_priv;
break;
#endif
#ifdef CONFIG_STM32_I2C3
case 3:
priv = (struct stm32_i2c_priv_s *)&stm32_i2c3_priv;
break;
#endif
default:
return NULL;
}
/* Initialize private data for the first time, increment reference count,
* power-up hardware and configure GPIOs.
*/
flags = enter_critical_section();
if ((volatile int)priv->refs++ == 0)
{
stm32_i2c_sem_init(priv);
stm32_i2c_init(priv);
}
leave_critical_section(flags);
return (struct i2c_master_s *)priv;
}
/************************************************************************************
* Name: stm32_i2cbus_uninitialize
*
* Description:
* Uninitialize an I2C bus
*
************************************************************************************/
int stm32_i2cbus_uninitialize(FAR struct i2c_master_s *dev)
{
FAR struct stm32_i2c_priv_s *priv = (FAR struct stm32_i2c_priv_s *)dev;
irqstate_t flags;
DEBUGASSERT(dev);
/* Decrement reference count and check for underflow */
if (priv->refs == 0)
{
return ERROR;
}
flags = enter_critical_section();
if (--priv->refs)
{
leave_critical_section(flags);
return OK;
}
leave_critical_section(flags);
/* Disable power and other HW resource (GPIO's) */
stm32_i2c_deinit(priv);
/* Release unused resources */
stm32_i2c_sem_destroy(priv);
return OK;
}
#endif /* CONFIG_STM32_STM32F10XX || CONFIG_STM32_STM32F20XX || CONFIG_STM32_STM32F4XXX */
#endif /* CONFIG_STM32_I2C1 || CONFIG_STM32_I2C2 || CONFIG_STM32_I2C3 */
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