[PATCH 6/9] board: ti: j721e: Add the missing part of exit retention for k3-ddrss (J7200)

[Thomas Richard]

Add the board specific part of the exit retention sequence for k3-ddrss

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>
---

 board/ti/j721e/evm.c | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/board/ti/j721e/evm.c b/board/ti/j721e/evm.c
index b4b94c8c69..e6f46f911a 100644
--- a/board/ti/j721e/evm.c
+++ b/board/ti/j721e/evm.c
@@ -533,15 +533,22 @@ err_free_gpio:
 
 #if (IS_ENABLED(CONFIG_SPL_BUILD) && IS_ENABLED(CONFIG_TARGET_J7200_R5_EVM))
 
+static struct udevice *pmica;
+static struct udevice *pmicb;
+
+#define GPIO_OUT_1        0x3D
+
 #define SCRATCH_PAD_REG_3 0xCB
 
 #define MAGIC_SUSPEND 0xBA
 
+#define DDR_RET_VAL BIT(1)
+#define DDR_RET_CLK BIT(2)
+
 static int resuming = -1;
 
 int board_is_resuming(void)
 {
-	struct udevice *pmica, *pmicb;
 	int ret;
 
 	if (resuming >= 0)
@@ -580,6 +587,24 @@ end:
 	return resuming;
 }
 
+void board_k3_ddrss_lpddr4_release_retention(void)
+{
+	int regval;
+
+	/* Set DDR_RET Signal Low on PMIC B */
+	regval = pmic_reg_read(pmicb, GPIO_OUT_1) & ~DDR_RET_VAL;
+
+	pmic_reg_write(pmicb, GPIO_OUT_1, regval);
+
+	/* Now toggle the CLK of the latch for DDR ret */
+	pmic_reg_write(pmicb, GPIO_OUT_1, regval | DDR_RET_CLK);
+	pmic_reg_write(pmicb, GPIO_OUT_1, regval & ~(DDR_RET_CLK));
+	pmic_reg_write(pmicb, GPIO_OUT_1, regval | DDR_RET_CLK);
+	pmic_reg_write(pmicb, GPIO_OUT_1, regval & ~(DDR_RET_CLK));
+
+	pmic_reg_write(pmica, 0x86, 0x3);
+}
+
 #endif /* CONFIG_SPL_BUILD && CONFIG_TARGET_J7200_R5_EVM */
 
 void spl_board_init(void)
-- 
2.39.2