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Avoid I2C timing computation when input clock is unchanged #646

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Merged
merged 5 commits into from
Sep 12, 2019
Merged

Avoid I2C timing computation when input clock is unchanged #646

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8087d8d
Avoid I2C timing computation when input clock is unchanged
ABOSTM Sep 11, 2019
67b44c2
Update cores/arduino/stm32/twi.c
ABOSTM Sep 12, 2019
1e72e40
Update cores/arduino/stm32/twi.c
ABOSTM Sep 12, 2019
1df79ae
Update cores/arduino/stm32/twi.c
ABOSTM Sep 12, 2019
574ea0f
Update cores/arduino/stm32/twi.c
ABOSTM Sep 12, 2019
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32 changes: 28 additions & 4 deletions cores/arduino/stm32/twi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -62,9 +62,6 @@ extern "C" {
#ifndef I2C_VALID_TIMING_NBR
#define I2C_VALID_TIMING_NBR 8U
#endif
#define I2C_SPEED_FREQ_STANDARD 0U /* 100 kHz */
#define I2C_SPEED_FREQ_FAST 1U /* 400 kHz */
#define I2C_SPEED_FREQ_FAST_PLUS 2U /* 1 MHz */
#define I2C_ANALOG_FILTER_DELAY_MIN 50U /* ns */
#ifndef I2C_ANALOG_FILTER_DELAY_MAX
#define I2C_ANALOG_FILTER_DELAY_MAX 260U /* ns */
Expand All @@ -82,6 +79,22 @@ extern "C" {
#define I2C_SCLL_MAX 256U
#define SEC2NSEC 1000000000UL

typedef enum {
I2C_SPEED_FREQ_STANDARD, /* 100 kHz */
I2C_SPEED_FREQ_FAST, /* 400 kHz */
I2C_SPEED_FREQ_FAST_PLUS, /* 1 MHz */
I2C_SPEED_FREQ_NUMBER /* Must be the last entry */
} i2c_speed_freq_t;

#ifdef I2C_TIMING
typedef struct {
uint32_t input_clock; /* I2C Input clock */
uint32_t timing; /* I2C timing corresponding to Input clock */
} I2C_timing_t;

static I2C_timing_t I2C_ClockTiming[I2C_SPEED_FREQ_NUMBER] = {0};
#endif

typedef struct {
uint32_t freq; /* Frequency in Hz */
uint32_t freq_min; /* Minimum frequency in Hz */
Expand Down Expand Up @@ -354,6 +367,16 @@ static uint32_t i2c_computeTiming(uint32_t clkSrcFreq, uint32_t i2c_speed)
uint8_t presc, scldel, sdadel;
uint32_t tafdel_min, tafdel_max;

if (i2c_speed > I2C_SPEED_FREQ_NUMBER) {
return ret;
}
/* Don't compute timing if already available value for the requested speed with the same I2C input frequency */
if ((I2C_ClockTiming[i2c_speed].input_clock == clkSrcFreq) && (I2C_ClockTiming[i2c_speed].timing != 0U)) {
return I2C_ClockTiming[i2c_speed].timing;
}

I2C_ClockTiming[i2c_speed].input_clock = clkSrcFreq; // Save the I2C input clock for which we will save timing

ti2cclk = (SEC2NSEC + (clkSrcFreq / 2U)) / clkSrcFreq;
ti2cspeed = (SEC2NSEC + (I2C_Charac[i2c_speed].freq / 2U)) / I2C_Charac[i2c_speed].freq;

Expand Down Expand Up @@ -437,6 +460,8 @@ static uint32_t i2c_computeTiming(uint32_t clkSrcFreq, uint32_t i2c_speed)
((sclh & 0xFFU) << 8) | \
((scll & 0xFFU) << 0);
prev_presc = presc;
/* Save I2C Timing found for further reuse (and avoid to compute again) */
I2C_ClockTiming[i2c_speed].timing = ret;
}
}
}
Expand Down Expand Up @@ -736,7 +761,6 @@ i2c_status_e i2c_master_write(i2c_t *obj, uint8_t dev_address,
Master restarts communication */
} while (((HAL_I2C_GetError(&(obj->handle)) & HAL_I2C_ERROR_AF) == HAL_I2C_ERROR_AF)
&& (delta < I2C_TIMEOUT_TICK));

return ret;
}

Expand Down