Skip to content

Update i2c to support CPU frequency changes #2287

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jan 8, 2019
Merged

Update i2c to support CPU frequency changes #2287

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
83 changes: 67 additions & 16 deletions cores/esp32/esp32-hal-i2c.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@
#include "soc/i2c_struct.h"
#include "soc/dport_reg.h"
#include "esp_attr.h"

#include "esp32-hal-cpu.h" // cpu clock change support 31DEC2018
//#define I2C_DEV(i) (volatile i2c_dev_t *)((i)?DR_REG_I2C1_EXT_BASE:DR_REG_I2C_EXT_BASE)
//#define I2C_DEV(i) ((i2c_dev_t *)(REG_I2C_BASE(i)))
#define I2C_SCL_IDX(p) ((p==0)?I2CEXT0_SCL_OUT_IDX:((p==1)?I2CEXT1_SCL_OUT_IDX:0))
Expand Down Expand Up @@ -206,8 +206,8 @@ static i2c_t _i2c_bus_array[2] = {
{(volatile i2c_dev_t *)(DR_REG_I2C1_EXT_BASE_FIXED), 1, -1, -1,I2C_NONE,I2C_NONE,I2C_ERROR_OK,NULL,NULL,NULL,0,0,0,0,0}
};
#else
#define I2C_MUTEX_LOCK() do {} while (xSemaphoreTake(i2c->lock, portMAX_DELAY) != pdPASS)
#define I2C_MUTEX_UNLOCK() xSemaphoreGive(i2c->lock)
#define I2C_MUTEX_LOCK() do {} while (xSemaphoreTakeRecursive(i2c->lock, portMAX_DELAY) != pdPASS)
#define I2C_MUTEX_UNLOCK() xSemaphoreGiveRecursive(i2c->lock)

static i2c_t _i2c_bus_array[2] = {
{(volatile i2c_dev_t *)(DR_REG_I2C_EXT_BASE_FIXED), NULL, 0, -1, -1, I2C_NONE,I2C_NONE,I2C_ERROR_OK,NULL,NULL,NULL,0,0,0,0,0,0},
Expand Down Expand Up @@ -445,6 +445,39 @@ static void IRAM_ATTR i2cTriggerDumps(i2c_t * i2c, uint8_t trigger, const char l
}
// end of debug support routines

/* Start of CPU Clock change Support
*/

static void i2cApbChangeCallback(void * arg, apb_change_ev_t ev_type, uint32_t old_apb, uint32_t new_apb){
i2c_t* i2c = (i2c_t*) arg; // recover data
if(i2c == NULL) { // point to peripheral control block does not exits
return false;
}
uint32_t oldFreq=0;
switch(ev_type){
case APB_BEFORE_CHANGE :
if(new_apb < 3000000) {// too slow
log_e("apb speed %d too slow",new_apb);
break;
}
I2C_MUTEX_LOCK(); // lock will spin until current transaction is completed
break;
case APB_AFTER_CHANGE :
oldFreq = (i2c->dev->scl_low_period.period+i2c->dev->scl_high_period.period); //read old apbCycles
if(oldFreq>0) { // was configured with value
oldFreq = old_apb / oldFreq;
i2cSetFrequency(i2c,oldFreq);
}
I2C_MUTEX_UNLOCK();
break;
default :
log_e("unk ev %u",ev_type);
I2C_MUTEX_UNLOCK();
}
return;
}
/* End of CPU Clock change Support
*/
static void IRAM_ATTR i2cSetCmd(i2c_t * i2c, uint8_t index, uint8_t op_code, uint8_t byte_num, bool ack_val, bool ack_exp, bool ack_check)
{
I2C_COMMAND_t cmd;
Expand Down Expand Up @@ -1221,6 +1254,12 @@ i2c_err_t i2cProcQueue(i2c_t * i2c, uint32_t *readCount, uint16_t timeOutMillis)
I2C_MUTEX_UNLOCK();
return I2C_ERROR_MEMORY;
}
if( !addApbChangeCallback( i2c, i2cApbChangeCallback)) {
log_e("install apb Callback failed");
I2C_MUTEX_UNLOCK();
return I2C_ERROR_DEV;
}

}
//hang until it completes.

Expand Down Expand Up @@ -1352,6 +1391,9 @@ static void i2cReleaseISR(i2c_t * i2c)
if(i2c->intr_handle) {
esp_intr_free(i2c->intr_handle);
i2c->intr_handle=NULL;
if (!removeApbChangeCallback( i2c, i2cApbChangeCallback)) {
log_e("unable to release apbCallback");
}
}
}

Expand Down Expand Up @@ -1437,15 +1479,15 @@ i2c_err_t i2cDetachSDA(i2c_t * i2c, int8_t sda)
* PUBLIC API
* */
// 24Nov17 only supports Master Mode
i2c_t * i2cInit(uint8_t i2c_num, int8_t sda, int8_t scl, uint32_t frequency) //before this is called, pins should be detached, else glitch
{
i2c_t * i2cInit(uint8_t i2c_num, int8_t sda, int8_t scl, uint32_t frequency) {
log_v("num=%d sda=%d scl=%d freq=%d",i2c_num, sda, scl, frequency);
if(i2c_num > 1) {
return NULL;
}

i2c_t * i2c = &_i2c_bus_array[i2c_num];

// pins should be detached, else glitch
if(i2c->sda >= 0){
i2cDetachSDA(i2c, i2c->sda);
}
Expand All @@ -1457,7 +1499,7 @@ i2c_t * i2cInit(uint8_t i2c_num, int8_t sda, int8_t scl, uint32_t frequency) //b

#if !CONFIG_DISABLE_HAL_LOCKS
if(i2c->lock == NULL) {
i2c->lock = xSemaphoreCreateMutex();
i2c->lock = xSemaphoreCreateRecursiveMutex();
if(i2c->lock == NULL) {
return NULL;
}
Expand Down Expand Up @@ -1604,7 +1646,8 @@ i2c_err_t i2cRead(i2c_t * i2c, uint16_t address, uint8_t* buff, uint16_t size, b
return last_error;
}

#define MIN_I2C_CLKS 100
#define MIN_I2C_CLKS 100 // minimum ratio between cpu and i2c Bus clocks
#define INTERRUPT_CYCLE_OVERHEAD 16000 // number of cpu clocks necessary to respond to interrupt
i2c_err_t i2cSetFrequency(i2c_t * i2c, uint32_t clk_speed)
{
if(i2c == NULL) {
Expand All @@ -1614,17 +1657,18 @@ i2c_err_t i2cSetFrequency(i2c_t * i2c, uint32_t clk_speed)
uint32_t period = (apb/clk_speed) / 2;

if((apb/8192 > clk_speed)||(apb/MIN_I2C_CLKS < clk_speed)){ //out of bounds
log_w("i2c freq(%d) out of bounds.vs APB Clock(%d), min=%d, max=%d",clk_speed,apb,(apb/8192),(apb/MIN_I2C_CLKS));
log_d("i2c freq(%d) out of bounds.vs APB Clock(%d), min=%d, max=%d",clk_speed,apb,(apb/8192),(apb/MIN_I2C_CLKS));
}
if(period < (MIN_I2C_CLKS/2) ){
period = (MIN_I2C_CLKS/2);
clk_speed = apb/(period*2);
log_w("APB Freq too slow, Reducing i2c Freq to %d Hz",clk_speed);
log_d("APB Freq too slow, Reducing i2c Freq to %d Hz",clk_speed);
} else if ( period> 4095) {
period = 4095;
clk_speed = apb/(period*2);
log_w("APB Freq too fast, Increasing i2c Freq to %d Hz",clk_speed);
log_d("APB Freq too fast, Increasing i2c Freq to %d Hz",clk_speed);
}
log_v("freq=%dHz",clk_speed);

uint32_t halfPeriod = period/2;
uint32_t quarterPeriod = period/4;
Expand All @@ -1633,14 +1677,19 @@ i2c_err_t i2cSetFrequency(i2c_t * i2c, uint32_t clk_speed)

I2C_FIFO_CONF_t f;

// Adjust Fifo thresholds based on frequency
f.val = i2c->dev->fifo_conf.val;
uint32_t a = (clk_speed / 50000L )+1;
if (a > 24) a=24;
f.rx_fifo_full_thrhd = 32 - a;
f.tx_fifo_empty_thrhd = a;
/* Adjust Fifo thresholds based on differential between cpu frequency and bus clock.
The fifo_delta is calculated such that at least INTERRUPT_CYCLE_OVERHEAD cpu clocks are
available when a Fifo interrupt is triggered. This allows enough room in the Fifo so that
interrupt latency does not cause a Fifo overflow/underflow event.
*/
log_v("cpu Freq=%dMhz, i2c Freq=%dHz",getCpuFrequencyMhz(),clk_speed);
uint32_t fifo_delta = (INTERRUPT_CYCLE_OVERHEAD/((getCpuFrequencyMhz()*1000000 / clk_speed)*10))+1;
if (fifo_delta > 24) fifo_delta=24;
f.rx_fifo_full_thrhd = 32 - fifo_delta;
f.tx_fifo_empty_thrhd = fifo_delta;
i2c->dev->fifo_conf.val = f.val; // set thresholds
log_v("Fifo threshold=%d",a);
log_v("Fifo delta=%d",fifo_delta);

//the clock num during SCL is low level
i2c->dev->scl_low_period.period = period;
Expand Down Expand Up @@ -1696,6 +1745,8 @@ uint32_t i2cGetStatus(i2c_t * i2c){
}
else return 0;
}


/* todo
22JUL18
need to add multi-thread capability, use dq.queueEvent as the group marker. When multiple threads
Expand Down
3 changes: 2 additions & 1 deletion libraries/Wire/src/Wire.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -30,7 +30,7 @@
#include "freertos/queue.h"
#include "Stream.h"

#define STICKBREAKER V1.0.1
#define STICKBREAKER 'V1.1.0'
#define I2C_BUFFER_LENGTH 128
typedef void(*user_onRequest)(void);
typedef void(*user_onReceive)(uint8_t*, int);
Expand Down Expand Up @@ -138,6 +138,7 @@ extern TwoWire Wire1;


/*
V1.1.0 08JAN2019 Support CPU Clock frequency changes
V1.0.2 30NOV2018 stop returning I2C_ERROR_CONTINUE on ReSTART operations, regain compatibility with Arduino libs
V1.0.1 02AUG2018 First Fix after release, Correct ReSTART handling, change Debug control, change begin()
to a function, this allow reporting if bus cannot be initialized, Wire.begin() can be used to recover
Expand Down