feat(i2c_master): Add an api for retrieveing handle via port,

Closes https://github.com/espressif/esp-idf/issues/13968

components/esp_driver_i2c/i2c_common.c

@@ -127,7 +127,7 @@ static esp_err_t s_i2c_bus_handle_acquire(i2c_port_num_t port_num, i2c_bus_handl
     return ret;
 }
 
-static bool i2c_bus_occupied(i2c_port_num_t port_num)
+bool i2c_bus_occupied(i2c_port_num_t port_num)
 {
     return s_i2c_platform.buses[port_num] != NULL;
 }

components/esp_driver_i2c/i2c_master.c

@@ -46,6 +46,15 @@ static const char *TAG = "i2c.master";
 #define I2C_FIFO_LEN(port_num) (SOC_I2C_FIFO_LEN)
 #endif
 
+// Use the platform to same master bus handle
+typedef struct i2c_master_bus_platform_t i2c_master_bus_platform_t;
+
+struct i2c_master_bus_platform_t {
+    i2c_master_bus_handle_t handle[SOC_I2C_NUM];
+};
+
+static i2c_master_bus_platform_t s_platform;
+
 static esp_err_t s_i2c_master_clear_bus(i2c_bus_handle_t handle)
 {
 #if !SOC_I2C_SUPPORT_HW_CLR_BUS
@@ -989,6 +998,7 @@ esp_err_t i2c_new_master_bus(const i2c_master_bus_config_t *bus_config, i2c_mast
     xSemaphoreGive(i2c_master->cmd_semphr);
 
     *ret_bus_handle = i2c_master;
+    s_platform.handle[i2c_port_num] = i2c_master;
     return ESP_OK;
 
 err:
@@ -1075,6 +1085,18 @@ esp_err_t i2c_master_bus_reset(i2c_master_bus_handle_t bus_handle)
     return ESP_OK;
 }
 
+esp_err_t i2c_master_get_bus_handle(i2c_port_num_t port_num, i2c_master_bus_handle_t *ret_handle)
+{
+    ESP_RETURN_ON_FALSE((port_num < SOC_I2C_NUM), ESP_ERR_INVALID_ARG, TAG, "invalid i2c port number");
+    if (i2c_bus_occupied(port_num) == false) {
+        ESP_LOGE(TAG, "this port has not been initialized, please initialize it first");
+        return ESP_ERR_INVALID_STATE;
+    } else {
+        *ret_handle = s_platform.handle[port_num];
+    }
+    return ESP_OK;
+}
+
 esp_err_t i2c_master_multi_buffer_transmit(i2c_master_dev_handle_t i2c_dev, i2c_master_transmit_multi_buffer_info_t *buffer_info_array, size_t array_size, int xfer_timeout_ms)
 {
     ESP_RETURN_ON_FALSE(i2c_dev != NULL, ESP_ERR_INVALID_ARG, TAG, "i2c handle not initialized");

components/esp_driver_i2c/i2c_private.h

@@ -252,6 +252,14 @@ esp_err_t i2c_select_periph_clock(i2c_bus_handle_t handle, soc_module_clk_t clk_
  */
 esp_err_t i2c_common_set_pins(i2c_bus_handle_t handle);
 
+/**
+ * @brief Check whether bus is acquired
+ *
+ * @param port_num number of port
+ * @return true if the bus is occupied, false if the bus is not occupied.
+*/
+bool i2c_bus_occupied(i2c_port_num_t port_num);
+
 #ifdef __cplusplus
 }
 #endif

components/esp_driver_i2c/include/esp_private/i2c_platform.h

@@ -0,0 +1,36 @@
+/*
+ * SPDX-FileCopyrightText: 2023-2024 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include "esp_err.h"
+#include "driver/i2c_types.h"
+#include "hal/gpio_types.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Retrieves the I2C master bus handle for a specified I2C port number.
+ *
+ * This function retrieves the I2C master bus handle for the
+ * given I2C port number. Please make sure the handle has already been initialized, and this
+ * function would simply returns the existing handle. Note that the returned handle still can't be used concurrently
+ *
+ * @param port_num I2C port number for which the handle is to be retrieved.
+ * @param ret_handle Pointer to a variable where the retrieved handle will be stored.
+ * @return
+ *     - ESP_OK: Success. The handle is retrieved successfully.
+ *     - ESP_ERR_INVALID_ARG: Invalid argument, such as invalid port number
+ *     - ESP_ERR_INVALID_STATE: Invalid state, such as the I2C port is not initialized.
+ */
+esp_err_t i2c_master_get_bus_handle(i2c_port_num_t port_num, i2c_master_bus_handle_t *ret_handle);
+
+#ifdef __cplusplus
+}
+#endif

components/esp_driver_i2c/test_apps/i2c_test_apps/main/test_i2c_common.c

@@ -19,6 +19,7 @@
 #include "esp_private/periph_ctrl.h"
 #include "driver/gpio.h"
 #include "driver/i2c_master.h"
+#include "esp_private/i2c_platform.h"
 #include "esp_rom_gpio.h"
 #include "esp_log.h"
 #include "test_utils.h"
@@ -345,3 +346,19 @@ TEST_CASE("I2C master transaction receive check nack return value", "[i2c]")
     TEST_ESP_ERR(ESP_ERR_INVALID_STATE, i2c_master_receive(dev_handle, data_rd, DATA_LENGTH, -1));
     _test_i2c_del_bus_device(bus_handle, dev_handle);
 }
+
+TEST_CASE("Test get handle with known port", "[i2c]")
+{
+    i2c_master_bus_handle_t handle;
+    TEST_ESP_ERR(ESP_ERR_INVALID_ARG, i2c_master_get_bus_handle(10, &handle));
+    TEST_ESP_ERR(ESP_ERR_INVALID_STATE, i2c_master_get_bus_handle(0, &handle));
+
+    i2c_master_bus_handle_t bus_handle;
+    i2c_master_dev_handle_t dev_handle;
+    _test_i2c_new_bus_device(&bus_handle, &dev_handle);
+    TEST_ESP_OK(i2c_master_get_bus_handle(0, &handle));
+
+    // Check the handle retrieved is as same as original handle
+    TEST_ASSERT((uint32_t)bus_handle == (uint32_t)handle);
+    _test_i2c_del_bus_device(bus_handle, dev_handle);
+}

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

@@ -150,6 +150,27 @@ Once the :cpp:type:`i2c_device_config_t` structure is populated with mandatory p
     i2c_master_dev_handle_t dev_handle;
     ESP_ERROR_CHECK(i2c_master_bus_add_device(bus_handle, &dev_cfg, &dev_handle));
 
+Get I2C master handle via port
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Given that i2c master handle has been initialized in some module(e.g. an audio module), an another module(e.g. a video module) is not convenient to reused the handle. We have a helper function, :cpp:func:`i2c_master_get_bus_handle` for getting the initialized handle via port. However, please make sure the handle has already been initialized ahead of time. Otherwise an error would be reported.
+
+.. code:: c
+
+    // Source File 1
+    #include "driver/i2c_master.h"
+    i2c_master_bus_handle_t bus_handle;
+    i2c_master_bus_config_t i2c_mst_config = {
+        ... // same as others
+    };
+    ESP_ERROR_CHECK(i2c_new_master_bus(&i2c_mst_config, &bus_handle));
+
+    // Source File 2
+    #include "esp_private/i2c_platform.h"
+    #include "driver/i2c_master.h"
+    i2c_master_bus_handle_t handle;
+    ESP_ERROR_CHECK(i2c_master_get_bus_handle(0, &handle));
+
 .. only:: SOC_LP_I2C_SUPPORTED
 
     Install I2C master bus with LP I2C Peripheral