int stm32_i2c_configure_timing(struct device *dev, u32_t clock)
{
const struct i2c_stm32_config *cfg = DEV_CFG(dev);
struct i2c_stm32_data *data = DEV_DATA(dev);
I2C_TypeDef *i2c = cfg->i2c;
u32_t i2c_hold_time_min, i2c_setup_time_min;
u32_t i2c_h_min_time, i2c_l_min_time;
u32_t presc = 1;
u32_t timing = 0;
switch (I2C_SPEED_GET(data->dev_config)) {
case I2C_SPEED_STANDARD:
i2c_h_min_time = 4000;
i2c_l_min_time = 4700;
i2c_hold_time_min = 500;
i2c_setup_time_min = 1250;
break;
case I2C_SPEED_FAST:
i2c_h_min_time = 600;
i2c_l_min_time = 1300;
i2c_hold_time_min = 375;
i2c_setup_time_min = 500;
break;
default:
return -EINVAL;
}
/* Calculate period until prescaler matches */
do {
u32_t t_presc = clock / presc;
u32_t ns_presc = NSEC_PER_SEC / t_presc;
u32_t sclh = i2c_h_min_time / ns_presc;
u32_t scll = i2c_l_min_time / ns_presc;
u32_t sdadel = i2c_hold_time_min / ns_presc;
u32_t scldel = i2c_setup_time_min / ns_presc;
if ((sclh - 1) > 255 || (scll - 1) > 255) {
++presc;
continue;
}
if (sdadel > 15 || (scldel - 1) > 15) {
++presc;
continue;
}
timing = __LL_I2C_CONVERT_TIMINGS(presc - 1,
scldel - 1, sdadel, sclh - 1, scll - 1);
break;
} while (presc < 16);
if (presc >= 16) {
SYS_LOG_DBG("I2C:failed to find prescaler value");
return -EINVAL;
}
LL_I2C_SetTiming(i2c, timing);
return 0;
}
/**
* @brief Initialize the I2C registers according to the specified parameters in I2C_InitStruct.
* @param I2Cx I2C Instance.
* @param I2C_InitStruct pointer to a @ref LL_I2C_InitTypeDef structure.
* @retval An ErrorStatus enumeration value:
* - SUCCESS: I2C registers are initialized
* - ERROR: Not applicable
*/
uint32_t LL_I2C_Init(I2C_TypeDef *I2Cx, LL_I2C_InitTypeDef *I2C_InitStruct)
{
/* Check the I2C Instance I2Cx */
assert_param(IS_I2C_ALL_INSTANCE(I2Cx));
/* Check the I2C parameters from I2C_InitStruct */
assert_param(IS_LL_I2C_PERIPHERAL_MODE(I2C_InitStruct->PeripheralMode));
assert_param(IS_LL_I2C_ANALOG_FILTER(I2C_InitStruct->AnalogFilter));
assert_param(IS_LL_I2C_DIGITAL_FILTER(I2C_InitStruct->DigitalFilter));
assert_param(IS_LL_I2C_OWN_ADDRESS1(I2C_InitStruct->OwnAddress1));
assert_param(IS_LL_I2C_TYPE_ACKNOWLEDGE(I2C_InitStruct->TypeAcknowledge));
assert_param(IS_LL_I2C_OWN_ADDRSIZE(I2C_InitStruct->OwnAddrSize));
/* Disable the selected I2Cx Peripheral */
LL_I2C_Disable(I2Cx);
/*---------------------------- I2Cx CR1 Configuration ------------------------
* Configure the analog and digital noise filters with parameters :
* - AnalogFilter: I2C_CR1_ANFOFF bit
* - DigitalFilter: I2C_CR1_DNF[3:0] bits
*/
LL_I2C_ConfigFilters(I2Cx, I2C_InitStruct->AnalogFilter, I2C_InitStruct->DigitalFilter);
/*---------------------------- I2Cx TIMINGR Configuration --------------------
* Configure the SDA setup, hold time and the SCL high, low period with parameter :
* - Timing: I2C_TIMINGR_PRESC[3:0], I2C_TIMINGR_SCLDEL[3:0], I2C_TIMINGR_SDADEL[3:0],
* I2C_TIMINGR_SCLH[7:0] and I2C_TIMINGR_SCLL[7:0] bits
*/
LL_I2C_SetTiming(I2Cx, I2C_InitStruct->Timing);
/* Enable the selected I2Cx Peripheral */
LL_I2C_Enable(I2Cx);
/*---------------------------- I2Cx OAR1 Configuration -----------------------
* Disable, Configure and Enable I2Cx device own address 1 with parameters :
* - OwnAddress1: I2C_OAR1_OA1[9:0] bits
* - OwnAddrSize: I2C_OAR1_OA1MODE bit
*/
LL_I2C_DisableOwnAddress1(I2Cx);
LL_I2C_SetOwnAddress1(I2Cx, I2C_InitStruct->OwnAddress1, I2C_InitStruct->OwnAddrSize);
LL_I2C_EnableOwnAddress1(I2Cx);
/*---------------------------- I2Cx MODE Configuration -----------------------
* Configure I2Cx peripheral mode with parameter :
* - PeripheralMode: I2C_CR1_SMBDEN and I2C_CR1_SMBHEN bits
*/
LL_I2C_SetMode(I2Cx, I2C_InitStruct->PeripheralMode);
/*---------------------------- I2Cx CR2 Configuration ------------------------
* Configure the ACKnowledge or Non ACKnowledge condition
* after the address receive match code or next received byte with parameter :
* - TypeAcknowledge: I2C_CR2_NACK bit
*/
LL_I2C_AcknowledgeNextData(I2Cx, I2C_InitStruct->TypeAcknowledge);
return SUCCESS;
}