[PATCH v2 4/8] board: ti: j721e: Add resume detection for J7200

[Thomas Richard]

Add the capability to detect a resume.
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.

Based on the work of Gregory CLEMENT <gregory.clement at bootlin.com>

Signed-off-by: Thomas Richard <thomas.richard at bootlin.com>
Signed-off-by: Gregory CLEMENT <gregory.clement at bootlin.com>
---

(no changes since v1)

 board/ti/j721e/evm.c | 54 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/board/ti/j721e/evm.c b/board/ti/j721e/evm.c
index 38fe447d8f..b4b94c8c69 100644
--- a/board/ti/j721e/evm.c
+++ b/board/ti/j721e/evm.c
@@ -22,6 +22,9 @@
 #include <spl.h>
 #include <dm.h>
 #include <dm/uclass-internal.h>
+#if (IS_ENABLED(CONFIG_SPL_BUILD) && IS_ENABLED(CONFIG_TARGET_J7200_R5_EVM))
+#include <power/pmic.h>
+#endif
 
 #include "../common/board_detect.h"
 
@@ -528,6 +531,57 @@ err_free_gpio:
 	}
 }
 
+#if (IS_ENABLED(CONFIG_SPL_BUILD) && IS_ENABLED(CONFIG_TARGET_J7200_R5_EVM))
+
+#define SCRATCH_PAD_REG_3 0xCB
+
+#define MAGIC_SUSPEND 0xBA
+
+static int resuming = -1;
+
+int board_is_resuming(void)
+{
+	struct udevice *pmica, *pmicb;
+	int ret;
+
+	if (resuming >= 0)
+		goto end;
+
+	ret = uclass_get_device_by_name(UCLASS_PMIC,
+					"tps659413 at 48", &pmica);
+	if (ret) {
+		printf("Getting PMICA init failed: %d\n", ret);
+		resuming = 0;
+		goto end;
+	}
+	debug("%s: PMICA is detected (%s)\n", __func__, pmica->name);
+
+	ret = uclass_get_device_by_name(UCLASS_PMIC,
+					"lp876441 at 4c", &pmicb);
+	if (ret) {
+		printf("Getting PMICB init failed: %d\n", ret);
+		resuming = 0;
+		goto end;
+	}
+	debug("%s: PMICB is detected (%s)\n", __func__, pmicb->name);
+
+	if ((pmic_reg_read(pmica, SCRATCH_PAD_REG_3) == MAGIC_SUSPEND)) {
+		resuming = 1;
+		debug("%s: board is resuming\n", __func__);
+
+		/* clean magic suspend */
+		if (pmic_reg_write(pmica, SCRATCH_PAD_REG_3, 0))
+			printf("Failed to clean magic value for suspend detection in PMICA\n");
+	} else {
+		resuming = 0;
+		debug("%s: board is booting (no resume detected)\n", __func__);
+	}
+end:
+	return resuming;
+}
+
+#endif /* CONFIG_SPL_BUILD && CONFIG_TARGET_J7200_R5_EVM */
+
 void spl_board_init(void)
 {
 #if defined(CONFIG_ESM_K3) || defined(CONFIG_ESM_PMIC)
-- 
2.39.2