stm32f1/i2c: do not block in case of error
Due to the errata of some of the stm32f1xx family, the i2c lines need to be toggled when setting up the peripheral. This however seems to hang some i2c slaves which do not ack the first message sent after initialization. This caused the code to be stucked waiting for the never coming ACK. The same situation could occur when a byte was not acked due to whatever reason. The previous implementation of the i2c driver didn't allow recovery on these situations. Now the driver does not block forever but rather returns a <0 code to indicate that the transaction was not succesful.
This commit is contained in:
Victor Arino
parent
da5b03df5d
commit
a477d6f81d
@ -19,6 +19,7 @@
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*
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* @author Hauke Petersen <hauke.petersen@fu-berlin.de>
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* @author Thomas Eichinger <thomas.eichinger@fu-berlin.de>
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* @author Víctor Ariño <victor.arino@triagnosys.com>
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*
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* @}
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*/
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@ -41,10 +42,10 @@
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/* static function definitions */
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static void _i2c_init(I2C_TypeDef *i2c, int ccr);
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static void _pin_config(gpio_t pin_scl, gpio_t pin_sda);
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static void _start(I2C_TypeDef *dev, uint8_t address, uint8_t rw_flag);
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static void _start(I2C_TypeDef *dev, uint8_t address, uint8_t rw_flag, char *err);
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static inline void _clear_addr(I2C_TypeDef *dev);
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static inline void _write(I2C_TypeDef *dev, char *data, int length);
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static inline void _stop(I2C_TypeDef *dev);
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static inline void _write(I2C_TypeDef *dev, char *data, int length, char *err);
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static inline void _stop(I2C_TypeDef *dev, char *err);
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/**
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* @brief Array holding one pre-initialized mutex for each I2C device
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@ -64,6 +65,21 @@ static mutex_t locks[] = {
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#endif
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};
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static char err_flag[] = {
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#if I2C_0_EN
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[I2C_0] = 0x00,
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#endif
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#if I2C_1_EN
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[I2C_1] = 0x00,
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#endif
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#if I2C_2_EN
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[I2C_2] = 0x00
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#endif
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#if I2C_3_EN
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[I2C_3] = 0x00
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#endif
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};
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int i2c_init_master(i2c_t dev, i2c_speed_t speed)
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{
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I2C_TypeDef *i2c;
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@ -194,7 +210,11 @@ int i2c_read_bytes(i2c_t dev, uint8_t address, char *data, int length)
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}
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DEBUG("Send Slave address and wait for ADDR == 1\n");
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_start(i2c, address, I2C_FLAG_READ);
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_start(i2c, address, I2C_FLAG_READ, &err_flag[dev]);
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if (err_flag[dev]) {
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return -2;
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}
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DEBUG("Clear ADDR\n");
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_clear_addr(i2c);
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@ -276,11 +296,16 @@ int i2c_read_regs(i2c_t dev, uint8_t address, uint8_t reg, char *data, int lengt
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/* send start condition and slave address */
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DEBUG("Send slave address and clear ADDR flag\n");
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_start(i2c, address, I2C_FLAG_WRITE);
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_start(i2c, address, I2C_FLAG_WRITE, &err_flag[dev]);
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_clear_addr(i2c);
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DEBUG("Write reg into DR\n");
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i2c->DR = reg;
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_stop(i2c);
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_stop(i2c, &err_flag[dev]);
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if (err_flag[dev]) {
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return -2;
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}
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DEBUG("Now start a read transaction\n");
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return i2c_read_bytes(dev, address, data, length);
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}
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@ -306,15 +331,21 @@ int i2c_write_bytes(i2c_t dev, uint8_t address, char *data, int length)
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/* start transmission and send slave address */
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DEBUG("sending start sequence\n");
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_start(i2c, address, I2C_FLAG_WRITE);
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_start(i2c, address, I2C_FLAG_WRITE, &err_flag[dev]);
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_clear_addr(i2c);
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/* send out data bytes */
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_write(i2c, data, length);
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_write(i2c, data, length, &err_flag[dev]);
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/* end transmission */
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DEBUG("Ending transmission\n");
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_stop(i2c);
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_stop(i2c, &err_flag[dev]);
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DEBUG("STOP condition was send out\n");
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return length;
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if (err_flag[dev]) {
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return -2;
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}
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else {
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return length;
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}
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}
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int i2c_write_reg(i2c_t dev, uint8_t address, uint8_t reg, char data)
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@ -337,16 +368,22 @@ int i2c_write_regs(i2c_t dev, uint8_t address, uint8_t reg, char *data, int leng
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}
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/* start transmission and send slave address */
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_start(i2c, address, I2C_FLAG_WRITE);
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_start(i2c, address, I2C_FLAG_WRITE, &err_flag[dev]);
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_clear_addr(i2c);
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/* send register address and wait for complete transfer to be finished*/
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_write(i2c, (char *)(®), 1);
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_write(i2c, (char *)(®), 1, &err_flag[dev]);
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/* write data to register */
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_write(i2c, data, length);
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_write(i2c, data, length, &err_flag[dev]);
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/* finish transfer */
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_stop(i2c);
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/* return number of bytes send */
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return length;
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_stop(i2c, &err_flag[dev]);
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if (err_flag[dev]) {
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return -2;
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}
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else {
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/* return number of bytes send */
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return length;
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}
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}
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void i2c_poweron(i2c_t dev)
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@ -372,22 +409,24 @@ void i2c_poweroff(i2c_t dev)
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}
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}
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static void _start(I2C_TypeDef *dev, uint8_t address, uint8_t rw_flag)
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static void _start(I2C_TypeDef *dev, uint8_t address, uint8_t rw_flag, char *err)
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{
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/* flag that there's no error (yet) */
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*err = 0x00;
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/* wait for device to be ready */
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DEBUG("Wait for device to be ready\n");
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while (dev->SR2 & I2C_SR2_BUSY);
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while (dev->SR2 & I2C_SR2_BUSY) ;
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/* generate start condition */
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DEBUG("Generate start condition\n");
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dev->CR1 |= I2C_CR1_START;
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DEBUG("Wait for SB flag to be set\n");
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while (!(dev->SR1 & I2C_SR1_SB));
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while (!(dev->SR1 & I2C_SR1_SB)) ;
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/* send address and read/write flag */
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DEBUG("Send address\n");
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dev->DR = (address << 1) | rw_flag;
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/* clear ADDR flag by reading first SR1 and then SR2 */
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DEBUG("Wait for ADDR flag to be set\n");
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while (!(dev->SR1 & I2C_SR1_ADDR));
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while (!(dev->SR1 & I2C_SR1_ADDR) && !(*err)) ;
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}
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static inline void _clear_addr(I2C_TypeDef *dev)
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@ -396,28 +435,28 @@ static inline void _clear_addr(I2C_TypeDef *dev)
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dev->SR2;
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}
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static inline void _write(I2C_TypeDef *dev, char *data, int length)
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static inline void _write(I2C_TypeDef *dev, char *data, int length, char *err)
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{
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DEBUG("Looping through bytes\n");
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for (int i = 0; i < length; i++) {
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for (int i = 0; i < length && !(*err); i++) {
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/* write data to data register */
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dev->DR = (uint8_t)data[i];
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DEBUG("Written %i byte to data reg, now waiting for DR to be empty again\n", i);
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/* wait for transfer to finish */
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while (!(dev->SR1 & I2C_SR1_TXE));
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while (!(dev->SR1 & I2C_SR1_TXE) && !(*err)) ;
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DEBUG("DR is now empty again\n");
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}
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}
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static inline void _stop(I2C_TypeDef *dev)
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static inline void _stop(I2C_TypeDef *dev, char *err)
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{
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/* make sure last byte was send */
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while (!(dev->SR1 & I2C_SR1_BTF));
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while (!(dev->SR1 & I2C_SR1_BTF) && !(*err)) ;
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/* send STOP condition */
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dev->CR1 |= I2C_CR1_STOP;
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/* wait until transmission is complete */
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while (dev->SR2 & I2C_SR2_BUSY);
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while (dev->SR2 & I2C_SR2_BUSY) ;
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}
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#if I2C_0_EN
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@ -447,7 +486,10 @@ void I2C_0_ERR_ISR(void)
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if (state & I2C_SR1_SMBALERT) {
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DEBUG("SMBALERT\n");
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}
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while (1);
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/* record and clear errors */
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err_flag[I2C_0] = (state >> 8);
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I2C_0_DEV->SR1 &= 0x00ff;
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}
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#endif
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