fix(m5stack-tab5): power the SD card IO rail through the P4's LDO channel 4

components/m5stack-tab5/include/m5stack-tab5.hpp

@@ -746,6 +746,9 @@ class M5StackTab5 : public BaseComponent {
   static constexpr gpio_num_t sd_dat3_io = GPIO_NUM_42; // CS/DAT3
   static constexpr gpio_num_t sd_clk_io = GPIO_NUM_43;  // SCK/CLK
   static constexpr gpio_num_t sd_cmd_io = GPIO_NUM_44;  // MOSI/CMD
+  // The SD card's IO pads (GPIO39-44) are powered by the ESP32-P4's internal
+  // LDO channel 4 (LDO_VO4), which the SDMMC host has to switch on.
+  static constexpr int sd_ldo_channel = 4;
 
   // RS-485
   static constexpr gpio_num_t rs485_rx_io = GPIO_NUM_21;  // RX
@@ -927,6 +930,7 @@ class M5StackTab5 : public BaseComponent {
 
   // uSD Card
   sdmmc_card_t *sdcard_{nullptr};
+  void *sd_pwr_ctrl_handle_{nullptr}; // sd_pwr_ctrl_handle_t (on-chip LDO)
 
   // RTC
   std::atomic<bool> rtc_initialized_{false};

components/m5stack-tab5/src/sdcard.cpp

@@ -1,6 +1,7 @@
 #include "m5stack-tab5.hpp"
 
 #include <esp_vfs_fat.h>
+#include <sd_pwr_ctrl_by_on_chip_ldo.h>
 #include <sdmmc_cmd.h>
 
 namespace espp {
@@ -37,6 +38,24 @@ bool M5StackTab5::initialize_sdcard(const M5StackTab5::SdCardConfig &config) {
   // For setting a specific frequency, use host.max_freq_khz (range 400kHz - 20MHz for SDSPI)
   sdmmc_host_t host = SDMMC_HOST_DEFAULT();
   host.max_freq_khz = SDMMC_FREQ_HIGHSPEED; // 40MHz
+  host.slot = SDMMC_HOST_SLOT_0;
+
+  // The ESP32-P4 powers the SD card's IO pads from its internal LDO (LDO_VO4).
+  // Without a power control handle that rail stays off, the bus floats and
+  // card init fails (timeouts, or errors on the first data transfer). Same as
+  // M5Stack's own Tab5 BSP.
+  if (sd_pwr_ctrl_handle_ == nullptr) {
+    sd_pwr_ctrl_ldo_config_t ldo_config{};
+    ldo_config.ldo_chan_id = sd_ldo_channel;
+    sd_pwr_ctrl_handle_t pwr_ctrl_handle = nullptr;
+    ret = sd_pwr_ctrl_new_on_chip_ldo(&ldo_config, &pwr_ctrl_handle);
+    if (ret != ESP_OK) {
+      logger_.error("Failed to create the SD power control driver: {}", esp_err_to_name(ret));
+      return false;
+    }
+    sd_pwr_ctrl_handle_ = pwr_ctrl_handle;
+  }
+  host.pwr_ctrl_handle = static_cast<sd_pwr_ctrl_handle_t>(sd_pwr_ctrl_handle_);
 
   // This initializes the slot without card detect (CD) and write protect (WP) signals.
   // Modify slot_config.gpio_cd and slot_config.gpio_wp if your board has these signals.
@@ -47,6 +66,7 @@ bool M5StackTab5::initialize_sdcard(const M5StackTab5::SdCardConfig &config) {
   slot_config.d1 = sd_dat1_io;
   slot_config.d2 = sd_dat2_io;
   slot_config.d3 = sd_dat3_io;
+  slot_config.width = 4;
 
   logger_.debug("Mounting filesystem");
   ret = esp_vfs_fat_sdmmc_mount(mount_point, &host, &slot_config, &mount_config, &sdcard_);
@@ -59,6 +79,8 @@ bool M5StackTab5::initialize_sdcard(const M5StackTab5::SdCardConfig &config) {
                    "Make sure SD card is present and lines have pull-up resistors in place.",
                    esp_err_to_name(ret));
     }
+    sd_pwr_ctrl_del_on_chip_ldo(static_cast<sd_pwr_ctrl_handle_t>(sd_pwr_ctrl_handle_));
+    sd_pwr_ctrl_handle_ = nullptr;
     return false;
   }