Merges https://github.com/espressif/esp-idf/pull/8312
If we use I2C in slave mode, we can use input-only pin for SCL line (GPI 34-39).
But there is a problem in i2c_set_pin() which is called by i2c_param_config().
In case of using GPI as SCL the following statements are failed:
1. gpio_set_level(scl_io_num, I2C_IO_INIT_LEVEL);
Function fails because it cannot set level for input pin. As a result a ESP_LOGE() is called.
2. gpio_set_direction(scl_io_num, GPIO_MODE_INPUT_OUTPUT_OD);
Function fails because it accepts only GPIO pins. ESP_LOGE() is called, input mode is not enabled for the pin and as a result - no interrupts from the pin.
John
bcf7608cf8