Merge branch 'bugfix/delete_i2c_cmd_mux_semaphore_more_cleanly_v4.2' into 'release/v4.2'

dreiver/i2c: delete i2c cmd mux semaphore more cleanly (backport 4.2)

See merge request espressif/esp-idf!13401

components/driver/i2c.c

@@ -367,7 +367,9 @@ esp_err_t i2c_driver_delete(i2c_port_t i2c_num)
     p_i2c->intr_handle = NULL;
 
     if (p_i2c->cmd_mux) {
+        // Let any command in progress finish.
         xSemaphoreTake(p_i2c->cmd_mux, portMAX_DELAY);
+        xSemaphoreGive(p_i2c->cmd_mux);
         vSemaphoreDelete(p_i2c->cmd_mux);
     }
     if (p_i2c_obj[i2c_num]->cmd_evt_queue) {

components/driver/include/driver/i2c.h

@@ -68,6 +68,9 @@ esp_err_t i2c_driver_install(i2c_port_t i2c_num, i2c_mode_t mode, size_t slv_rx_
 /**
  * @brief I2C driver delete
  *
+ * @note This function does not guarantee thread safety.
+ *       Please make sure that no thread will continuously hold semaphores before calling the delete function.
+ *
  * @param i2c_num I2C port number
  *
  * @return

docs/en/api-reference/peripherals/i2c.rst

@@ -238,6 +238,7 @@ Delete Driver
 
 When the I2C communication is established with the function :cpp:func:`i2c_driver_install` and is not required for some substantial amount of time, the driver may be deinitialized to release allocated resources by calling :cpp:func:`i2c_driver_delete`.
 
+Before calling :cpp:func:`i2c_driver_delete` to remove i2c driver, please make sure that all threads have stopped using the driver in any way, because this function does not guarantee thread safety.
 
 Application Example
 -------------------