Merge branch 'feature/sdcard_custom_freq' into 'master'

[Storage] Enable SD card custom frequency setup

Closes IDFGH-7089

See merge request espressif/esp-idf!19038

examples/storage/sd_card/sdmmc/main/sd_card_example_main.c

@@ -46,6 +46,10 @@ void app_main(void)
     // production applications.
 
     ESP_LOGI(TAG, "Using SDMMC peripheral");
+
+    // By default, SD card frequency is initialized to SDMMC_FREQ_DEFAULT (20MHz)
+    // For setting a specific frequency, use host.max_freq_khz (range 400kHz - 40MHz for SDMMC)
+    // Example: for fixed frequency of 10MHz, use host.max_freq_khz = 10000;
     sdmmc_host_t host = SDMMC_HOST_DEFAULT();
 
     // This initializes the slot without card detect (CD) and write protect (WP) signals.

examples/storage/sd_card/sdspi/main/sd_card_example_main.c

@@ -52,7 +52,11 @@ void app_main(void)
     // production applications.
     ESP_LOGI(TAG, "Using SPI peripheral");
 
+    // By default, SD card frequency is initialized to SDMMC_FREQ_DEFAULT (20MHz)
+    // For setting a specific frequency, use host.max_freq_khz (range 400kHz - 20MHz for SDSPI)
+    // Example: for fixed frequency of 10MHz, use host.max_freq_khz = 10000;
     sdmmc_host_t host = SDSPI_HOST_DEFAULT();
+
     spi_bus_config_t bus_cfg = {
         .mosi_io_num = PIN_NUM_MOSI,
         .miso_io_num = PIN_NUM_MISO,