[PATCH 03/20] board: ti: j721e: Add resume detection for J721e/J7200

[Richard Genoud (TI)]

From: "Thomas Richard (TI)" <thomas.richard at bootlin.com>

Add the capability to detect a resume. This overrides the weak
function j7xx_board_is_resuming(void).
To detect the resume, SPL searches a magic value (0xBA) in a register
of PMICA.
This value is set by DM-Firmware during the suspend sequence.

Signed-off-by: Thomas Richard (TI) <thomas.richard at bootlin.com>
Co-developed-by: Gregory CLEMENT (TI) <gregory.clement at bootlin.com>
Signed-off-by: Gregory CLEMENT (TI) <gregory.clement at bootlin.com>
Co-developed-by: Richard Genoud (TI) <richard.genoud at bootlin.com>
Signed-off-by: Richard Genoud (TI) <richard.genoud at bootlin.com>
---
 board/ti/common/k3-lpm.h | 17 +++++++++++++++++
 board/ti/j721e/evm.c     | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)
 create mode 100644 board/ti/common/k3-lpm.h

diff --git a/board/ti/common/k3-lpm.h b/board/ti/common/k3-lpm.h
new file mode 100644
index 000000000000..a2141a0c25a8
--- /dev/null
+++ b/board/ti/common/k3-lpm.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Copyright (C) 2026, Texas Instruments Incorporated - https://www.ti.com/
+ * Copyright (C) 2026, Bootlin
+ */
+
+#ifndef __K3_LPM_H
+#define __K3_LPM_H
+
+/* Magic value in PMIC register to indicate the suspend state (SOC_OFF) */
+#define K3_LPM_MAGIC_SUSPEND 0xba
+
+/* PMIC register where the magic value resides */
+#define K3_LPM_SCRATCH_PAD_REG 0xcb
+
+#endif /* __K3_LPM_H */
+
diff --git a/board/ti/j721e/evm.c b/board/ti/j721e/evm.c
index 881392bd963a..67ff13828514 100644
--- a/board/ti/j721e/evm.c
+++ b/board/ti/j721e/evm.c
@@ -17,9 +17,11 @@
 #include <spl.h>
 #include <dm.h>
 #include <asm/arch/k3-ddr.h>
+#include <power/pmic.h>
 
 #include "../common/board_detect.h"
 #include "../common/fdt_ops.h"
+#include "../common/k3-lpm.h"
 
 #define board_is_j721e_som()	(board_ti_k3_is("J721EX-PM1-SOM") || \
 				 board_ti_k3_is("J721EX-PM2-SOM"))
@@ -469,6 +471,41 @@ err_free_gpio:
 	}
 }
 
+#if (IS_ENABLED(CONFIG_SPL_BUILD) && IS_ENABLED(CONFIG_TARGET_J7200_R5_EVM))
+
+bool j7xx_board_is_resuming(void)
+{
+	struct udevice *pmica;
+	int ret;
+
+	if (gd_k3_resuming() != K3_RESUME_STATE_UNKNOWN)
+		goto end;
+
+	ret = uclass_get_device_by_name(UCLASS_PMIC,
+					"pmic at 48", &pmica);
+	if (ret) {
+		printf("Getting PMICA init failed: %d\n", ret);
+		goto end;
+	}
+	debug("%s: PMICA is detected (%s)\n", __func__, pmica->name);
+
+	if (pmic_reg_read(pmica, K3_LPM_SCRATCH_PAD_REG) == K3_LPM_MAGIC_SUSPEND) {
+		debug("%s: board is resuming\n", __func__);
+		gd_set_k3_resuming(K3_RESUME_STATE_RESUMING);
+
+		/* clean magic suspend */
+		if (pmic_reg_write(pmica, K3_LPM_SCRATCH_PAD_REG, 0))
+			printf("Failed to clean magic value for suspend detection in PMICA\n");
+	} else {
+		debug("%s: board is booting (no resume detected)\n", __func__);
+		gd_set_k3_resuming(K3_RESUME_STATE_BOOTING);
+	}
+end:
+	return gd_k3_resuming() == K3_RESUME_STATE_RESUMING;
+}
+
+#endif /* CONFIG_SPL_BUILD && CONFIG_TARGET_J7200_R5_EVM */
+
 void spl_board_init(void)
 {
 	struct udevice *dev;