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esp-idf/components/ulp/ulp_riscv/ulp_riscv_i2c.c
Sudeep Mohanty 2d331c0413 fix(lp-i2c): Fixed the generation of spurious I2C start with lp-i2c 
This commit fixes an issue with LP I2C and RTC I2C where in the
peripherals generated a spurious I2C start condition when initialized.
This caused some sensors to not respond properly to the following read
or write request.

Closes https://github.com/espressif/esp-idf/issues/14043
Closes https://github.com/espressif/esp-idf/issues/11608
2024-07-12 17:27:43 +02:00

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/*
* SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include "ulp_riscv_i2c.h"
#include "esp_check.h"
#include "soc/rtc_i2c_reg.h"
#include "soc/rtc_i2c_struct.h"
#include "soc/rtc_io_struct.h"
#include "soc/sens_reg.h"
#include "soc/clk_tree_defs.h"
#include "hal/i2c_ll.h"
#include "hal/misc.h"
#include "driver/rtc_io.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "sdkconfig.h"
static const char *RTCI2C_TAG = "ulp_riscv_i2c";
#define I2C_CTRL_SLAVE_ADDR_MASK (0xFF << 0)
#define I2C_CTRL_SLAVE_REG_ADDR_MASK (0xFF << 11)
#define I2C_CTRL_MASTER_TX_DATA_MASK (0xFF << 19)
#if CONFIG_IDF_TARGET_ESP32S3
#define ULP_I2C_CMD_RESTART 0 /*!<I2C restart command */
#define ULP_I2C_CMD_WRITE 1 /*!<I2C write command */
#define ULP_I2C_CMD_READ 2 /*!<I2C read command */
#define ULP_I2C_CMD_STOP 3 /*!<I2C stop command */
#define ULP_I2C_CMD_END 4 /*!<I2C end command */
#else
#define ULP_I2C_CMD_RESTART I2C_LL_CMD_RESTART /*!<I2C restart command */
#define ULP_I2C_CMD_WRITE I2C_LL_CMD_WRITE /*!<I2C write command */
#define ULP_I2C_CMD_READ I2C_LL_CMD_READ /*!<I2C read command */
#define ULP_I2C_CMD_STOP I2C_LL_CMD_STOP /*!<I2C stop command */
#define ULP_I2C_CMD_END I2C_LL_CMD_END /*!<I2C end command */
#endif // CONFIG_IDF_TARGET_ESP32S3
/* Use the register structure to access RTC_I2C and RTCIO module registers */
rtc_i2c_dev_t *i2c_dev = &RTC_I2C;
rtc_io_dev_t *rtc_io_dev = &RTCIO;
#define MICROSEC_TO_RTC_FAST_CLK(period) (period) * ((float)(SOC_CLK_RC_FAST_FREQ_APPROX) / (1000000.0))
/* Read/Write timeout (number of iterations)*/
#define ULP_RISCV_I2C_RW_TIMEOUT CONFIG_ULP_RISCV_I2C_RW_TIMEOUT
/* RTC I2C lock */
static portMUX_TYPE rtc_i2c_lock = portMUX_INITIALIZER_UNLOCKED;
static esp_err_t i2c_gpio_is_cfg_valid(gpio_num_t sda_io_num, gpio_num_t scl_io_num)
{
/* Verify that the SDA and SCL GPIOs are valid RTC I2C io pins */
ESP_RETURN_ON_ERROR(!rtc_gpio_is_valid_gpio(sda_io_num), RTCI2C_TAG, "RTC I2C SDA GPIO invalid");
ESP_RETURN_ON_ERROR(!rtc_gpio_is_valid_gpio(scl_io_num), RTCI2C_TAG, "RTC I2C SCL GPIO invalid");
/* Verify that the SDA and SCL line belong to the RTC IO I2C function group */
if ((sda_io_num != GPIO_NUM_1) && (sda_io_num != GPIO_NUM_3)) {
ESP_LOGE(RTCI2C_TAG, "SDA pin can only be configured as GPIO#1 or GPIO#3");
return ESP_ERR_INVALID_ARG;
}
if ((scl_io_num != GPIO_NUM_0) && (scl_io_num != GPIO_NUM_2)) {
ESP_LOGE(RTCI2C_TAG, "SCL pin can only be configured as GPIO#0 or GPIO#2");
return ESP_ERR_INVALID_ARG;
}
return ESP_OK;
}
static esp_err_t i2c_configure_io(gpio_num_t io_num, bool pullup_en)
{
/* Set the IO pin to high to avoid them from toggling from Low to High state during initialization. This can register a spurious I2C start condition. */
ESP_RETURN_ON_ERROR(rtc_gpio_set_level(io_num, 1), RTCI2C_TAG, "RTC GPIO failed to set level to high for %d", io_num);
/* Initialize IO Pin */
ESP_RETURN_ON_ERROR(rtc_gpio_init(io_num), RTCI2C_TAG, "RTC GPIO Init failed for GPIO %d", io_num);
/* Set direction to input+output */
ESP_RETURN_ON_ERROR(rtc_gpio_set_direction(io_num, RTC_GPIO_MODE_INPUT_OUTPUT_OD), RTCI2C_TAG, "RTC GPIO Set direction failed for %d", io_num);
/* Disable pulldown on the io pin */
ESP_RETURN_ON_ERROR(rtc_gpio_pulldown_dis(io_num), RTCI2C_TAG, "RTC GPIO pulldown disable failed for %d", io_num);
/* Enable pullup based on pullup_en flag */
if (pullup_en) {
ESP_RETURN_ON_ERROR(rtc_gpio_pullup_en(io_num), RTCI2C_TAG, "RTC GPIO pullup enable failed for %d", io_num);
} else {
ESP_RETURN_ON_ERROR(rtc_gpio_pullup_dis(io_num), RTCI2C_TAG, "RTC GPIO pullup disable failed for %d", io_num);
}
return ESP_OK;
}
static esp_err_t i2c_set_pin(const ulp_riscv_i2c_cfg_t *cfg)
{
gpio_num_t sda_io_num = cfg->i2c_pin_cfg.sda_io_num;
gpio_num_t scl_io_num = cfg->i2c_pin_cfg.scl_io_num;
bool sda_pullup_en = cfg->i2c_pin_cfg.sda_pullup_en;
bool scl_pullup_en = cfg->i2c_pin_cfg.scl_pullup_en;
/* Verify that the I2C GPIOs are valid */
ESP_RETURN_ON_ERROR(i2c_gpio_is_cfg_valid(sda_io_num, scl_io_num), RTCI2C_TAG, "RTC I2C GPIO config invalid");
// NOTE: We always initialize the SCL pin first, then the SDA pin.
// This order of initialization is important to avoid any spurious
// I2C start conditions on the bus.
/* Initialize SCL Pin */
ESP_RETURN_ON_ERROR(i2c_configure_io(scl_io_num, scl_pullup_en), RTCI2C_TAG, "RTC I2C SCL pin config failed");
/* Initialize SDA Pin */
ESP_RETURN_ON_ERROR(i2c_configure_io(sda_io_num, sda_pullup_en), RTCI2C_TAG, "RTC I2C SDA pin config failed");
/* Route SDA IO signal to the RTC subsystem */
rtc_io_dev->touch_pad[sda_io_num].mux_sel = 1;
/* Route SCL IO signal to the RTC subsystem */
rtc_io_dev->touch_pad[scl_io_num].mux_sel = 1;
/* Select RTC I2C function for SDA pin */
rtc_io_dev->touch_pad[sda_io_num].fun_sel = 3;
/* Select RTC I2C function for SCL pin */
rtc_io_dev->touch_pad[scl_io_num].fun_sel = 3;
/* Map the SDA and SCL signals to the RTC I2C controller */
if (sda_io_num == GPIO_NUM_1) {
rtc_io_dev->sar_i2c_io.sda_sel = 0;
} else {
rtc_io_dev->sar_i2c_io.sda_sel = 1;
}
if (scl_io_num == GPIO_NUM_0) {
rtc_io_dev->sar_i2c_io.scl_sel = 0;
} else {
rtc_io_dev->sar_i2c_io.scl_sel = 1;
}
return ESP_OK;
}
static esp_err_t i2c_set_timing(const ulp_riscv_i2c_cfg_t *cfg)
{
/* Convert all timing parameters from micro-seconds to period in RTC_FAST_CLK cycles.
* RTC_FAST_CLK = 8.5 MHz for esp32s2 and 17.5 MHz for esp32s3.
* The following calculations approximate the period for each parameter.
*/
float scl_low_period = MICROSEC_TO_RTC_FAST_CLK(cfg->i2c_timing_cfg.scl_low_period);
float scl_high_period = MICROSEC_TO_RTC_FAST_CLK(cfg->i2c_timing_cfg.scl_high_period);
float sda_duty_period = MICROSEC_TO_RTC_FAST_CLK(cfg->i2c_timing_cfg.sda_duty_period);
float scl_start_period = MICROSEC_TO_RTC_FAST_CLK(cfg->i2c_timing_cfg.scl_start_period);
float scl_stop_period = MICROSEC_TO_RTC_FAST_CLK(cfg->i2c_timing_cfg.scl_stop_period);
float i2c_trans_timeout = MICROSEC_TO_RTC_FAST_CLK(cfg->i2c_timing_cfg.i2c_trans_timeout);
float setup_time_start = (cfg->i2c_timing_cfg.scl_high_period + cfg->i2c_timing_cfg.sda_duty_period);
float hold_time_start = (cfg->i2c_timing_cfg.scl_start_period - cfg->i2c_timing_cfg.sda_duty_period);
float setup_time_data = (cfg->i2c_timing_cfg.scl_low_period - cfg->i2c_timing_cfg.sda_duty_period);
/* Verify timing constraints */
ESP_RETURN_ON_FALSE(cfg->i2c_timing_cfg.scl_low_period >= 1.3f, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "SCL low period cannot be less than 1.3 micro seconds");
// TODO: As per specs, SCL high period must be greater than 0.6 micro seconds but after tests it is found that we can have a the period as 0.3 micro seconds to
// achieve performance close to I2C fast mode. Therefore, this criteria is relaxed.
ESP_RETURN_ON_FALSE(cfg->i2c_timing_cfg.scl_high_period >= 0.3f, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "SCL high period cannot be less than 0.3 micro seconds");
ESP_RETURN_ON_FALSE(setup_time_start >= 0.6f, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "Setup time cannot be less than 0.6 micro seconds");
ESP_RETURN_ON_FALSE(hold_time_start >= 0.6f, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "Data hold time cannot be less than 0.6 micro seconds");
ESP_RETURN_ON_FALSE(cfg->i2c_timing_cfg.scl_stop_period >= 0.6f, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "Setup time cannot be less than 0.6 micro seconds");
ESP_RETURN_ON_FALSE(cfg->i2c_timing_cfg.sda_duty_period <= 3.45f, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "Data hold time cannot be greater than 3.45 micro seconds");
ESP_RETURN_ON_FALSE((setup_time_data * 1000) >= 250, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "Data setup time cannot be less than 250 nano seconds");
/* Verify filtering constrains
*
* I2C may have glitches on the transition edge, so the edge will be filtered in the design,
* which will also affect the value of the timing parameter register.
* Therefore, the following filtering constraints must be followed:
*/
ESP_RETURN_ON_FALSE(scl_stop_period > scl_high_period, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "SCL Stop period cannot be greater than SCL high period");
ESP_RETURN_ON_FALSE(sda_duty_period < scl_low_period, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "SDA duty period cannot be less than the SCL low period");
ESP_RETURN_ON_FALSE(scl_start_period > 8, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "SCL start period must be greater than 8 RTC_FAST_CLK cycles");
ESP_RETURN_ON_FALSE((scl_low_period + scl_high_period - sda_duty_period) > 8, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "SCL low + SCL high - SDA duty must be greater than 8 RTC_FAST_CLK cycles");
/* Verify SDA duty num constraints */
ESP_RETURN_ON_FALSE(sda_duty_period > 14, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "SDA duty period must be greater than 14 RTC_FAST_CLK cycles");
/* Set the RTC I2C timing parameters */
#if CONFIG_IDF_TARGET_ESP32S2
i2c_dev->scl_low.val = scl_low_period; // SCL low period
i2c_dev->scl_high.val = scl_high_period; // SCL high period
i2c_dev->sda_duty.val = sda_duty_period; // SDA duty cycle
i2c_dev->scl_start_period.val = scl_start_period; // Wait time after START condition
i2c_dev->scl_stop_period.val = scl_stop_period; // Wait time before END condition
i2c_dev->timeout.val = i2c_trans_timeout; // I2C transaction timeout
#elif CONFIG_IDF_TARGET_ESP32S3
i2c_dev->i2c_scl_low.val = scl_low_period; // SCL low period
i2c_dev->i2c_scl_high.val = scl_high_period; // SCL high period
i2c_dev->i2c_sda_duty.val = sda_duty_period; // SDA duty cycle
i2c_dev->i2c_scl_start_period.val = scl_start_period; // Wait time after START condition
i2c_dev->i2c_scl_stop_period.val = scl_stop_period; // Wait time before END condition
i2c_dev->i2c_to.val = i2c_trans_timeout; // I2C transaction timeout
#endif // CONFIG_IDF_TARGET_ESP32S2
return ESP_OK;
}
/*
* The RTC I2C controller follows the I2C command registers to perform read/write operations.
* The cmd registers have the following format:
*
* 31 30:14 13:11 10 9 8 7:0
* |----------|----------|---------|---------|----------|------------|---------|
* | CMD_DONE | Reserved | OPCODE |ACK Value|ACK Expect|ACK Check En|Byte Num |
* |----------|----------|---------|---------|----------|------------|---------|
*/
static void ulp_riscv_i2c_format_cmd(uint32_t cmd_idx, uint8_t op_code, uint8_t ack_val,
uint8_t ack_expected, uint8_t ack_check_en, uint8_t byte_num)
{
#if CONFIG_IDF_TARGET_ESP32S2
/* Reset cmd register */
i2c_dev->command[cmd_idx].val = 0;
/* Write new command to cmd register */
i2c_dev->command[cmd_idx].done = 0; // CMD Done
i2c_dev->command[cmd_idx].op_code = op_code; // Opcode
i2c_dev->command[cmd_idx].ack_val = ack_val; // ACK bit sent by I2C controller during READ.
// Ignored during RSTART, STOP, END and WRITE cmds.
i2c_dev->command[cmd_idx].ack_exp = ack_expected; // ACK bit expected by I2C controller during WRITE.
// Ignored during RSTART, STOP, END and READ cmds.
i2c_dev->command[cmd_idx].ack_en = ack_check_en; // I2C controller verifies that the ACK bit sent by the
// slave device matches the ACK expected bit during WRITE.
// Ignored during RSTART, STOP, END and READ cmds.
HAL_FORCE_MODIFY_U32_REG_FIELD(i2c_dev->command[cmd_idx], byte_num, byte_num); // Byte Num
#elif CONFIG_IDF_TARGET_ESP32S3
/* Reset cmd register */
i2c_dev->i2c_cmd[cmd_idx].val = 0;
/* Write new command to cmd register */
i2c_dev->i2c_cmd[cmd_idx].i2c_command_done = 0; // CMD Done
i2c_dev->i2c_cmd[cmd_idx].i2c_op_code = op_code; // Opcode
i2c_dev->i2c_cmd[cmd_idx].i2c_ack_val = ack_val; // ACK bit sent by I2C controller during READ.
// Ignored during RSTART, STOP, END and WRITE cmds.
i2c_dev->i2c_cmd[cmd_idx].i2c_ack_exp = ack_expected; // ACK bit expected by I2C controller during WRITE.
// Ignored during RSTART, STOP, END and READ cmds.
i2c_dev->i2c_cmd[cmd_idx].i2c_ack_en = ack_check_en; // I2C controller verifies that the ACK bit sent by the
// slave device matches the ACK expected bit during WRITE.
// Ignored during RSTART, STOP, END and READ cmds.
HAL_FORCE_MODIFY_U32_REG_FIELD(i2c_dev->i2c_cmd[cmd_idx], i2c_byte_num, byte_num); // Byte Num
#endif // CONFIG_IDF_TARGET_ESP32S2
}
static inline esp_err_t ulp_riscv_i2c_wait_for_interrupt(int32_t ticks_to_wait)
{
uint32_t status = 0;
uint32_t to = 0;
esp_err_t ret = ESP_OK;
while (1) {
status = READ_PERI_REG(RTC_I2C_INT_ST_REG);
/* Return ESP_OK if Tx or Rx data interrupt bits are set. */
if ((status & RTC_I2C_TX_DATA_INT_ST) ||
(status & RTC_I2C_RX_DATA_INT_ST)) {
ret = ESP_OK;
break;
/* In case of error status, break and return ESP_FAIL */
#if CONFIG_IDF_TARGET_ESP32S2
} else if ((status & RTC_I2C_TIMEOUT_INT_ST) ||
#elif CONFIG_IDF_TARGET_ESP32S3
} else if ((status & RTC_I2C_TIME_OUT_INT_ST) ||
#endif // CONFIG_IDF_TARGET_ESP32S2
(status & RTC_I2C_ACK_ERR_INT_ST) ||
(status & RTC_I2C_ARBITRATION_LOST_INT_ST)) {
ret = ESP_FAIL;
break;
}
if (ticks_to_wait > -1) {
/* If the ticks_to_wait value is not -1, keep track of ticks and
* break from the loop once the timeout is reached.
*/
vTaskDelay(1);
to++;
if (to >= ticks_to_wait) {
ret = ESP_ERR_TIMEOUT;
break;
}
}
}
return ret;
}
void ulp_riscv_i2c_master_set_slave_addr(uint8_t slave_addr)
{
CLEAR_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, I2C_CTRL_SLAVE_ADDR_MASK);
SET_PERI_REG_BITS(SENS_SAR_I2C_CTRL_REG, 0xFF, slave_addr, 0);
}
void ulp_riscv_i2c_master_set_slave_reg_addr(uint8_t slave_reg_addr)
{
CLEAR_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, I2C_CTRL_SLAVE_REG_ADDR_MASK);
SET_PERI_REG_BITS(SENS_SAR_I2C_CTRL_REG, 0xFF, slave_reg_addr, 11);
}
/*
* I2C transactions when master reads one byte of data from the slave device:
*
* |--------|--------|---------|--------|--------|--------|--------|---------|--------|--------|--------|--------|
* | Master | START | SAD + W | | SUB | | SR | SAD + R | | | NACK | STOP |
* |--------|--------|---------|--------|--------|--------|--------|---------|--------|--------|--------|--------|
* | Slave | | | ACK | | ACK | | | ACK | DATA | | |
* |--------|--------|---------|--------|--------|--------|--------|---------|--------|--------|--------|--------|
*
* I2C transactions when master reads multiple bytes of data from the slave device:
*
* |--------|--------|---------|--------|--------|--------|--------|---------|--------|--------|--------|--------|--------|--------|
* | Master | START | SAD + W | | SUB | | SR | SAD + R | | | ACK | | NACK | STOP |
* |--------|--------|---------|--------|--------|--------|--------|---------|--------|--------|--------|--------|--------|--------|
* | Slave | | | ACK | | ACK | | | ACK | DATA | | DATA | | |
* |--------|--------|---------|--------|--------|--------|--------|---------|--------|--------|--------|--------|--------|--------|
*/
void ulp_riscv_i2c_master_read_from_device(uint8_t *data_rd, size_t size)
{
uint32_t i = 0;
uint32_t cmd_idx = 0;
esp_err_t ret = ESP_OK;
if (size == 0) {
// Quietly return
return;
}
/* By default, RTC I2C controller is hard wired to use CMD2 register onwards for read operations */
cmd_idx = 2;
/* Write slave addr */
ulp_riscv_i2c_format_cmd(cmd_idx++, ULP_I2C_CMD_WRITE, 0, 0, 1, 2);
/* Repeated START */
ulp_riscv_i2c_format_cmd(cmd_idx++, ULP_I2C_CMD_RESTART, 0, 0, 0, 0);
/* Write slave register addr */
ulp_riscv_i2c_format_cmd(cmd_idx++, ULP_I2C_CMD_WRITE, 0, 0, 1, 1);
if (size > 1) {
/* Read n - 1 bytes */
ulp_riscv_i2c_format_cmd(cmd_idx++, ULP_I2C_CMD_READ, 0, 0, 1, size - 1);
}
/* Read last byte + NACK */
ulp_riscv_i2c_format_cmd(cmd_idx++, ULP_I2C_CMD_READ, 1, 1, 1, 1);
/* STOP */
ulp_riscv_i2c_format_cmd(cmd_idx++, ULP_I2C_CMD_STOP, 0, 0, 0, 0);
/* Configure the RTC I2C controller in read mode */
SET_PERI_REG_BITS(SENS_SAR_I2C_CTRL_REG, 0x1, 0, 27);
/* Start RTC I2C transmission */
SET_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, SENS_SAR_I2C_START_FORCE);
SET_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, SENS_SAR_I2C_START);
portENTER_CRITICAL(&rtc_i2c_lock);
for (i = 0; i < size; i++) {
/* Poll for RTC I2C Rx Data interrupt bit to be set */
ret = ulp_riscv_i2c_wait_for_interrupt(ULP_RISCV_I2C_RW_TIMEOUT);
if (ret == ESP_OK) {
/* Read the data
*
* Unfortunately, the RTC I2C has no fifo buffer to help us with reading and storing
* multiple bytes of data. Therefore, we need to read one byte at a time and clear the
* Rx interrupt to get ready for the next byte.
*/
#if CONFIG_IDF_TARGET_ESP32S2
data_rd[i] = REG_GET_FIELD(RTC_I2C_DATA_REG, RTC_I2C_RDATA);
#elif CONFIG_IDF_TARGET_ESP32S3
data_rd[i] = REG_GET_FIELD(RTC_I2C_DATA_REG, RTC_I2C_I2C_RDATA);
#endif // CONFIG_IDF_TARGET_ESP32S2
/* Clear the Rx data interrupt bit */
SET_PERI_REG_MASK(RTC_I2C_INT_CLR_REG, RTC_I2C_RX_DATA_INT_CLR);
} else {
ESP_EARLY_LOGE(RTCI2C_TAG, "ulp_riscv_i2c: Read Failed!");
uint32_t status = READ_PERI_REG(RTC_I2C_INT_RAW_REG);
ESP_EARLY_LOGE(RTCI2C_TAG, "ulp_riscv_i2c: RTC I2C Interrupt Raw Reg 0x%"PRIx32"", status);
ESP_EARLY_LOGE(RTCI2C_TAG, "ulp_riscv_i2c: RTC I2C Status Reg 0x%"PRIx32"", READ_PERI_REG(RTC_I2C_STATUS_REG));
SET_PERI_REG_MASK(RTC_I2C_INT_CLR_REG, status);
break;
}
}
portEXIT_CRITICAL(&rtc_i2c_lock);
/* Clear the RTC I2C transmission bits */
CLEAR_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, SENS_SAR_I2C_START_FORCE);
CLEAR_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, SENS_SAR_I2C_START);
}
/*
* I2C transactions when master writes one byte of data to the slave device:
*
* |--------|--------|---------|--------|--------|--------|--------|--------|--------|
* | Master | START | SAD + W | | SUB | | DATA | | STOP |
* |--------|--------|---------|--------|--------|--------|--------|--------|--------|
* | Slave | | | ACK | | ACK | | ACK | |
* |--------|--------|---------|--------|--------|--------|--------|--------|--------|
*
* I2C transactions when master writes multiple bytes of data to the slave device:
*
* |--------|--------|---------|--------|--------|--------|--------|--------|--------|--------|--------|
* | Master | START | SAD + W | | SUB | | DATA | | DATA | | STOP |
* |--------|--------|---------|--------|--------|--------|--------|--------|--------|--------|--------|
* | Slave | | | ACK | | ACK | | ACK | | ACK | |
* |--------|--------|---------|--------|--------|--------|--------|--------|--------|--------|--------|
*/
void ulp_riscv_i2c_master_write_to_device(uint8_t *data_wr, size_t size)
{
uint32_t i = 0;
uint32_t cmd_idx = 0;
esp_err_t ret = ESP_OK;
if (size == 0) {
// Quietly return
return;
}
/* By default, RTC I2C controller is hard wired to use CMD0 and CMD1 registers for write operations */
cmd_idx = 0;
/* Write slave addr + reg addr + data */
ulp_riscv_i2c_format_cmd(cmd_idx++, ULP_I2C_CMD_WRITE, 0, 0, 1, 2 + size);
/* Stop */
ulp_riscv_i2c_format_cmd(cmd_idx++, ULP_I2C_CMD_STOP, 0, 0, 0, 0);
/* Configure the RTC I2C controller in write mode */
SET_PERI_REG_BITS(SENS_SAR_I2C_CTRL_REG, 0x1, 1, 27);
portENTER_CRITICAL(&rtc_i2c_lock);
for (i = 0; i < size; i++) {
/* Write the data to be transmitted */
CLEAR_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, I2C_CTRL_MASTER_TX_DATA_MASK);
SET_PERI_REG_BITS(SENS_SAR_I2C_CTRL_REG, 0xFF, data_wr[i], 19);
if (i == 0) {
/* Start RTC I2C transmission. (Needn't do it for every byte) */
SET_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, SENS_SAR_I2C_START_FORCE);
SET_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, SENS_SAR_I2C_START);
}
/* Poll for RTC I2C Tx Data interrupt bit to be set */
ret = ulp_riscv_i2c_wait_for_interrupt(ULP_RISCV_I2C_RW_TIMEOUT);
if (ret == ESP_OK) {
/* Clear the Tx data interrupt bit */
SET_PERI_REG_MASK(RTC_I2C_INT_CLR_REG, RTC_I2C_TX_DATA_INT_CLR);
} else {
ESP_EARLY_LOGE(RTCI2C_TAG, "ulp_riscv_i2c: Write Failed!");
uint32_t status = READ_PERI_REG(RTC_I2C_INT_RAW_REG);
ESP_EARLY_LOGE(RTCI2C_TAG, "ulp_riscv_i2c: RTC I2C Interrupt Raw Reg 0x%"PRIx32"", status);
ESP_EARLY_LOGE(RTCI2C_TAG, "ulp_riscv_i2c: RTC I2C Status Reg 0x%"PRIx32"", READ_PERI_REG(RTC_I2C_STATUS_REG));
SET_PERI_REG_MASK(RTC_I2C_INT_CLR_REG, status);
break;
}
}
portEXIT_CRITICAL(&rtc_i2c_lock);
/* Clear the RTC I2C transmission bits */
CLEAR_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, SENS_SAR_I2C_START_FORCE);
CLEAR_PERI_REG_MASK(SENS_SAR_I2C_CTRL_REG, SENS_SAR_I2C_START);
}
esp_err_t ulp_riscv_i2c_master_init(const ulp_riscv_i2c_cfg_t *cfg)
{
/* Clear any stale config registers */
WRITE_PERI_REG(RTC_I2C_CTRL_REG, 0);
WRITE_PERI_REG(SENS_SAR_I2C_CTRL_REG, 0);
/* Verify that the input cfg param is valid */
ESP_RETURN_ON_FALSE(cfg, ESP_ERR_INVALID_ARG, RTCI2C_TAG, "RTC I2C configuration is NULL");
/* Configure RTC I2C GPIOs */
ESP_RETURN_ON_ERROR(i2c_set_pin(cfg), RTCI2C_TAG, "Failed to configure RTC I2C GPIOs");
/* Reset RTC I2C */
#if CONFIG_IDF_TARGET_ESP32S2
i2c_dev->ctrl.i2c_reset = 1;
esp_rom_delay_us(20);
i2c_dev->ctrl.i2c_reset = 0;
#elif CONFIG_IDF_TARGET_ESP32S3
SET_PERI_REG_MASK(SENS_SAR_PERI_RESET_CONF_REG, SENS_RTC_I2C_RESET);
i2c_dev->i2c_ctrl.i2c_i2c_reset = 1;
esp_rom_delay_us(20);
i2c_dev->i2c_ctrl.i2c_i2c_reset = 0;
CLEAR_PERI_REG_MASK(SENS_SAR_PERI_RESET_CONF_REG, SENS_RTC_I2C_RESET);
#endif // CONFIG_IDF_TARGET_ESP32S2
/* Enable internal open-drain mode for SDA and SCL lines */
#if CONFIG_IDF_TARGET_ESP32S2
i2c_dev->ctrl.sda_force_out = 0;
i2c_dev->ctrl.scl_force_out = 0;
#elif CONFIG_IDF_TARGET_ESP32S3
i2c_dev->i2c_ctrl.i2c_sda_force_out = 0;
i2c_dev->i2c_ctrl.i2c_scl_force_out = 0;
#endif // CONFIG_IDF_TARGET_ESP32S2
#if CONFIG_IDF_TARGET_ESP32S2
/* Configure the RTC I2C controller in master mode */
i2c_dev->ctrl.ms_mode = 1;
/* Enable RTC I2C Clock gate */
i2c_dev->ctrl.i2c_ctrl_clk_gate_en = 1;
#elif CONFIG_IDF_TARGET_ESP32S3
/* For esp32s3, we need to enable the rtc_i2c clock gate before accessing rtc i2c registers */
SET_PERI_REG_MASK(SENS_SAR_PERI_CLK_GATE_CONF_REG, SENS_RTC_I2C_CLK_EN);
/* Configure the RTC I2C controller in master mode */
i2c_dev->i2c_ctrl.i2c_ms_mode = 1;
/* Enable RTC I2C Clock gate */
i2c_dev->i2c_ctrl.i2c_i2c_ctrl_clk_gate_en = 1;
#endif // CONFIG_IDF_TARGET_ESP32S2
/* Configure RTC I2C timing parameters */
ESP_RETURN_ON_ERROR(i2c_set_timing(cfg), RTCI2C_TAG, "Failed to configure RTC I2C timing");
/* Clear any pending interrupts */
WRITE_PERI_REG(RTC_I2C_INT_CLR_REG, UINT32_MAX);
/* Enable RTC I2C interrupts */
SET_PERI_REG_MASK(RTC_I2C_INT_ENA_REG, RTC_I2C_RX_DATA_INT_ENA |
RTC_I2C_TX_DATA_INT_ENA |
RTC_I2C_ARBITRATION_LOST_INT_ENA |
RTC_I2C_ACK_ERR_INT_ENA |
#if CONFIG_IDF_TARGET_ESP32S2
RTC_I2C_TIMEOUT_INT_ENA);
#elif CONFIG_IDF_TARGET_ESP32S3
RTC_I2C_TIME_OUT_INT_ENA);
#endif // CONFIG_IDF_TARGET_ESP32S2
return ESP_OK;
}
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