drivers: USDHC: Enable detection using DAT3 pulldown

Enable USDHC host to detect inserted SD card via DAT3 line pulldown.

Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>

drivers/disk/Kconfig.sdmmc

@@ -41,6 +41,10 @@ config SDMMC_USDHC
 	  File system on a SDHC card accessed over
 	  NXP USDHC.
 
+if SDMMC_USDHC
+source "drivers/disk/Kconfig.usdhc"
+endif
+
 config SDMMC_STM32
 	bool "STM32 SDMMC driver"
 	depends on HAS_STM32CUBE

drivers/disk/Kconfig.usdhc

@@ -0,0 +1,18 @@
+# Copyright (c) 2021 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+# USDHC peripheral require the SD card to power cycle after DAT3 is
+# pulled low
+config SDMMC_USDHC_DAT3_PWR_TOGGLE
+	bool
+	help
+	  USDHC peripheral requires the SD card power to be cycled after DAT3 is
+	  pulled high, before the USDHC peripheral can detect the SD card via DAT3
+	  pull
+
+config SDMMC_USDHC_DAT3_PWR_DELAY
+	int
+	default 0
+	help
+	  Period in milliseconds to delay between powering off the SD card and
+	  applying power again, whenever the SD card power will be cycled.

drivers/disk/usdhc.c

@@ -388,6 +388,8 @@ struct usdhc_config {
 	uint8_t detect_pin;
 	gpio_dt_flags_t detect_flags;
 
+	bool detect_dat3;
+
 	bool no_1_8_v;
 
 	uint32_t data_timeout;
@@ -515,6 +517,9 @@ enum usdhc_xfer_data_type {
 #define CARD_BUS_STRENGTH_6 (6U)
 #define CARD_BUS_STRENGTH_7 (7U)
 
+#define USDHC_DAT3_PULL_DOWN 0U /*!< Data 3 pull down */
+#define USDHC_DAT3_PULL_UP 1U /*!< Data 3 pull up */
+
 enum usdhc_adma_flag {
 	USDHC_ADMA_SINGLE_FLAG = 0U,
 	USDHC_ADMA_MUTI_FLAG = 1U,
@@ -2604,6 +2609,33 @@ APP_SEND_OP_COND_AGAIN:
 
 static K_MUTEX_DEFINE(z_usdhc_init_lock);
 
+
+static int usdhc_dat3_pull(bool pullup, struct usdhc_priv *priv)
+{
+	int ret = 0U;
+
+	/* Call board specific function to pull down DAT3 */
+	imxrt_usdhc_dat3_pull(pullup);
+#ifdef CONFIG_SDMMC_USDHC_DAT3_PWR_TOGGLE
+	if (!pullup) {
+		/* Power off the card to clear DAT3 legacy status */
+		if (priv->pwr_gpio) {
+			ret = gpio_pin_set(priv->pwr_gpio, priv->config->pwr_pin, 0);
+			if (ret) {
+				return ret;
+			}
+			/* Delay for card power off to complete */
+			usdhc_millsec_delay(CONFIG_SDMMC_USDHC_DAT3_PWR_DELAY);
+			ret = gpio_pin_set(priv->pwr_gpio, priv->config->pwr_pin, 1);
+			if (ret) {
+				return ret;
+			}
+		}
+	}
+#endif
+	return ret;
+}
+
 static int usdhc_board_access_init(struct usdhc_priv *priv)
 {
 	const struct usdhc_config *config = priv->config;
@@ -2626,6 +2658,11 @@ static int usdhc_board_access_init(struct usdhc_priv *priv)
 		}
 	}
 
+	if (config->detect_dat3) {
+		priv->detect_type = SD_DETECT_HOST_DATA3;
+	}
+
+
 	if (priv->pwr_gpio) {
 		ret = gpio_pin_configure(priv->pwr_gpio,
 				config->pwr_pin,
@@ -2643,10 +2680,21 @@ static int usdhc_board_access_init(struct usdhc_priv *priv)
 
 	if (!priv->detect_gpio) {
 		LOG_INF("USDHC detection other than GPIO");
-		/* DATA3 does not monitor card insertion */
+		if (config->detect_dat3) {
-		base->PROT_CTRL &= ~USDHC_PROT_CTRL_D3CD_MASK;
+			base->PROT_CTRL |= USDHC_PROT_CTRL_D3CD_MASK;
+			/* Pull down DAT3 */
+			usdhc_dat3_pull(USDHC_DAT3_PULL_DOWN, priv);
+		} else {
+			/* DATA3 does not monitor card insertion */
+			base->PROT_CTRL &= ~USDHC_PROT_CTRL_D3CD_MASK;
+		}
 		if ((base->PRES_STATE & USDHC_PRES_STATE_CINST_MASK) != 0) {
 			priv->inserted = true;
+			if (config->detect_dat3) {
+				usdhc_dat3_pull(USDHC_DAT3_PULL_UP, priv);
+				/* Disable DAT3 detect function */
+				base->PROT_CTRL &= ~USDHC_PROT_CTRL_D3CD_MASK;
+			}
 		} else {
 			priv->inserted = false;
 			return -ENODEV;
@@ -2853,6 +2901,7 @@ static int disk_usdhc_init(const struct device *dev)
 		DISK_ACCESS_USDHC_INIT_PWR(n)				\
 		DISK_ACCESS_USDHC_INIT_CD(n)				\
 		.no_1_8_v = DT_INST_PROP(n, no_1_8_v),			\
+		.detect_dat3 = DT_INST_PROP(n, detect_dat3),	\
 		.data_timeout = USDHC_DATA_TIMEOUT,			\
 		.endian = USDHC_LITTLE_ENDIAN,				\
 		.read_watermark = USDHC_READ_WATERMARK_LEVEL,		\

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

@@ -36,5 +36,13 @@ properties:
         When the external SD card circuit does not support 1.8V, add this
         property to disable 1.8v card voltage of SD card controller.
 
+    detect-dat3:
+      type: boolean
+      required: false
+      description: |
+        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.
+
     label:
       required: true

soc/arm/nxp_imx/rt/soc.h

@@ -32,6 +32,12 @@ void imxrt_usdhc_pinmux(uint16_t nusdhc,
 
 void imxrt_usdhc_pinmux_cb_register(usdhc_pin_cfg_cb cb);
 
+typedef void (*usdhc_dat3_cfg_cb)(bool pullup);
+
+void imxrt_usdhc_dat3_cb_register(usdhc_dat3_cfg_cb cb);
+
+void imxrt_usdhc_dat3_pull(bool pullup);
+
 #endif
 
 #ifdef __cplusplus

soc/arm/nxp_imx/rt/soc_rt10xx.c

@@ -261,6 +261,25 @@ void imxrt_usdhc_pinmux(uint16_t nusdhc, bool init,
 		g_usdhc_pin_cfg_cb(nusdhc, init,
 			speed, strength);
 }
+
+/* Usdhc driver needs to reconfigure the dat3 line to a pullup in order to
+ * detect an SD card on the bus. Expose a callback to do that here. The board
+ * must register this callback in its init function.
+ */
+static usdhc_dat3_cfg_cb g_usdhc_dat3_cfg_cb;
+
+void imxrt_usdhc_dat3_cb_register(usdhc_dat3_cfg_cb cb)
+{
+	g_usdhc_dat3_cfg_cb = cb;
+}
+
+void imxrt_usdhc_dat3_pull(bool pullup)
+{
+	if (g_usdhc_dat3_cfg_cb) {
+		g_usdhc_dat3_cfg_cb(pullup);
+	}
+}
+
 #endif
 
 /**

soc/arm/nxp_imx/rt/soc_rt11xx.c

@@ -426,6 +426,25 @@ void imxrt_usdhc_pinmux(uint16_t nusdhc, bool init,
 		g_usdhc_pin_cfg_cb(nusdhc, init,
 			speed, strength);
 }
+
+/* Usdhc driver needs to reconfigure the dat3 line to a pullup in order to
+ * detect an SD card on the bus. Expose a callback to do that here. The board
+ * must register this callback in its init function.
+ */
+static usdhc_dat3_cfg_cb g_usdhc_dat3_cfg_cb;
+
+void imxrt_usdhc_dat3_cb_register(usdhc_dat3_cfg_cb cb)
+{
+	g_usdhc_dat3_cfg_cb = cb;
+}
+
+void imxrt_usdhc_dat3_pull(bool pullup)
+{
+	if (g_usdhc_dat3_cfg_cb) {
+		g_usdhc_dat3_cfg_cb(pullup);
+	}
+}
+
 #endif
 
 /**