drivers: sdhc: imx_usdhc: assume card is present if no detection method

The imx USDHC driver previously queried the peripheral's internal card
detect signal to check card presence if no card detect method was
configured. However, some boards do not route the card detect signal and
do not work correctly with the DAT3 detection method supported by this
peripheral. As a fallback, assume the card is present in the slot but
log a warning to the user.

Fixes #42227

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>
(cherry picked from commit 17f71e1)

drivers/sdhc/imx_usdhc.c

@@ -58,6 +58,7 @@ struct usdhc_config {
 	const struct gpio_dt_spec pwr_gpio;
 	const struct gpio_dt_spec detect_gpio;
 	bool detect_dat3;
+	bool detect_cd;
 	bool no_180_vol;
 	uint32_t data_timeout;
 	uint32_t read_watermark;
@@ -809,10 +810,18 @@ static int imx_usdhc_get_card_present(const struct device *dev)
 			imx_usdhc_dat3_pull(cfg, true);
 			USDHC_CardDetectByData3(cfg->base, false);
 		}
+	} else if (cfg->detect_cd) {
+		/*
+		 * Detect the card via the USDHC_CD signal internal to
+		 * the peripheral
+		 */
+		data->card_present = USDHC_DetectCardInsert(cfg->base);
 	} else if (cfg->detect_gpio.port) {
 		data->card_present = gpio_pin_get_dt(&cfg->detect_gpio) > 0;
 	} else {
-		data->card_present = USDHC_DetectCardInsert(cfg->base);
+		LOG_WRN("No card detection method configured, assuming card "
+			"is present");
+		data->card_present = true;
 	}
 	return ((int)data->card_present);
 }
@@ -1090,6 +1099,7 @@ static const struct sdhc_driver_api usdhc_api = {
 		.detect_gpio = GPIO_DT_SPEC_INST_GET_OR(n, cd_gpios, {0}),	\
 		.data_timeout = DT_INST_PROP(n, data_timeout),			\
 		.detect_dat3 = DT_INST_PROP(n, detect_dat3),			\
+		.detect_cd = DT_INST_PROP(n, detect_cd),			\
 		.no_180_vol = DT_INST_PROP(n, no_1_8_v),			\
 		.read_watermark = DT_INST_PROP(n, read_watermark),		\
 		.write_watermark = DT_INST_PROP(n, write_watermark),		\

dts/bindings/sdhc/nxp,imx-usdhc.yaml

@@ -66,3 +66,10 @@ properties:
       Enable the host to detect an SD card via the DAT3 line of the SD card
       connection. Requires the board to define a function to pull DAT3 low or
       high using pullup/pulldown resistors.
+
+  detect-cd:
+    type: boolean
+    description: |
+      Use the host's internal card detect signal (USDHC_CD) to detect the SD
+      card. This signal is available as an alternative to card detect via GPIO,
+      and should be connected to the SD slot's detect pin if used.