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drivers: i2c_ll_stm32_v1: clear stop bit befor setting start bit

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Sometimes the stop bit is still set when starting the next transaction.
When that happens the hardware will generate a start directly followed
by a stop. This will not be detected by the driver and it will endlessly
wait for the next interrupt that will never come.

Signed-off-by: Erwin Rol <erwin@erwinrol.com>
This commit is contained in:
Erwin Rol 2020-07-30 18:14:56 +02:00 committed by Maureen Helm
parent 379b93f0d3
commit d49b3e1b68
1 changed files with 15 additions and 3 deletions
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18
drivers/i2c/i2c_ll_stm32_v1.c
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@ -28,6 +28,18 @@ LOG_MODULE_REGISTER(i2c_ll_stm32_v1);
#define I2C_REQUEST_READ 0x01
#define HEADER 0xF0
static void stm32_i2c_generate_start_condition(I2C_TypeDef *i2c)
{
uint16_t cr1 = LL_I2C_ReadReg(i2c, CR1);
if (cr1 & I2C_CR1_STOP) {
LOG_DBG("%s: START while STOP active!", __func__);
LL_I2C_WriteReg(i2c, CR1, cr1 & ~I2C_CR1_STOP);
}
LL_I2C_GenerateStartCondition(i2c);
}
#ifdef CONFIG_I2C_STM32_INTERRUPT
static void stm32_i2c_disable_transfer_interrupts(struct device *dev)
@ -110,7 +122,7 @@ static inline void msg_init(struct device *dev, struct i2c_msg *msg,
LL_I2C_DisableBitPOS(i2c);
LL_I2C_AcknowledgeNextData(i2c, LL_I2C_ACK);
if (msg->flags & I2C_MSG_RESTART) {
LL_I2C_GenerateStartCondition(i2c);
stm32_i2c_generate_start_condition(i2c);
}
}
@ -204,7 +216,7 @@ static inline void handle_addr(struct device *dev)
if (!data->current.is_write && data->current.is_restart) {
data->current.is_restart = 0U;
LL_I2C_ClearFlag_ADDR(i2c);
LL_I2C_GenerateStartCondition(i2c);
stm32_i2c_generate_start_condition(i2c);
return;
}
@ -778,7 +790,7 @@ int32_t stm32_i2c_msg_read(struct device *dev, struct i2c_msg *msg,
}
LL_I2C_ClearFlag_ADDR(i2c);
LL_I2C_GenerateStartCondition(i2c);
stm32_i2c_generate_start_condition(i2c);
timeout = STM32_I2C_TIMEOUT_USEC;
while (!LL_I2C_IsActiveFlag_SB(i2c)) {
if (stm32_i2c_wait_timeout(&timeout)) {