diff options
Diffstat (limited to 'nuttx/arch/arm/src')
-rw-r--r-- | nuttx/arch/arm/src/stm32/stm32_i2c.c | 80 |
1 files changed, 61 insertions, 19 deletions
diff --git a/nuttx/arch/arm/src/stm32/stm32_i2c.c b/nuttx/arch/arm/src/stm32/stm32_i2c.c index 15f22e602..dd551bf3b 100644 --- a/nuttx/arch/arm/src/stm32/stm32_i2c.c +++ b/nuttx/arch/arm/src/stm32/stm32_i2c.c @@ -429,12 +429,25 @@ 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) { - /* "This [START] bit is set and cleared by software and cleared by hardware + /* "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, 0); + stm32_i2c_modifyreg(priv, STM32_I2C_CR1_OFFSET, + I2C_CR1_START|I2C_CR1_STOP|I2C_CR1_PEC, 0); } static inline void stm32_i2c_sendstop(FAR struct stm32_i2c_priv_s *priv) @@ -871,6 +884,7 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int struct stm32_i2c_inst_s *inst = (struct stm32_i2c_inst_s *)dev; uint32_t status = 0; uint32_t ahbenr; + uint16_t regval; int status_errno = 0; ASSERT(count); @@ -879,15 +893,43 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int ahbenr = stm32_i2c_disablefsmc(inst->priv); - /* Wait as stop might still be in progress - * - * \todo GET RID OF THIS PERFORMANCE LOSS and for() loop + /* 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." */ - - for (; stm32_i2c_getreg(inst->priv, STM32_I2C_CR1_OFFSET) & I2C_CR1_STOP; ) + + for (;;) { - up_waste(); + /* Check for STOP condition */ + + regval = stm32_i2c_getreg(inst->priv, STM32_I2C_CR1_OFFSET); + if ((regval & I2C_CR1_STOP) == 0) + { + break; + } + + /* Check for timeout error */ + + regval = stm32_i2c_getreg(inst->priv, STM32_I2C_SR1_OFFSET); + if ((regval & I2C_SR1_TIMEOUT) != 0) + { + break; + } } + + /* Clear any pending error interrupts */ + + stm32_i2c_putreg(inst->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(inst->priv); /* Old transfers are done */ @@ -898,10 +940,6 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int stm32_i2c_setclock(inst->priv, inst->frequency); - /* Clear any pending error interrupts */ - - stm32_i2c_putreg(inst->priv, STM32_I2C_SR1_OFFSET, 0); - /* Trigger start condition, then the process moves into the ISR. I2C * interrupts will be enabled within stm32_i2c_waitisr(). */ @@ -917,10 +955,10 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int status = stm32_i2c_getstatus(inst->priv); status_errno = ETIMEDOUT; - /* " 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." + /* "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(inst->priv); @@ -936,6 +974,8 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int if ((status & I2C_SR1_ERRORMASK) != 0) { + /* I2C_SR1_ERRORMASK is the 'OR' of the following individual bits: */ + if (status & I2C_SR1_BERR) { /* Bus Error */ @@ -975,7 +1015,7 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int /* This is not an error and should never happen since SMBus is not enabled */ - else if (status & I2C_SR1_SMBALERT) + 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. @@ -987,9 +1027,11 @@ int stm32_i2c_process(FAR struct i2c_dev_s *dev, FAR struct i2c_msg_s *msgs, int /* 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 buy indication if stm32_i2c_sem_waitisr() + * fails above; Otherwise it is cleared. */ - else if (status & (I2C_SR2_BUSY << 16)) + else if ((status & (I2C_SR2_BUSY << 16)) != 0) { /* I2C Bus is for some reason busy */ @@ -1016,7 +1058,7 @@ int stm32_i2c_write(FAR struct i2c_dev_s *dev, const uint8_t *buffer, int buflen .buffer = (uint8_t *)buffer, .length = buflen }; - + return stm32_i2c_process(dev, &msgv, 1); } |