[PATCH v4] scsi: ufs-mediatek: fix ufs power down specs violation

[<peter.wang@mediatek.com>]

From: Peter Wang <peter.wang@mediatek.com>

As per specs, e.g, JESD220E chapter 7.2, while powering off
the ufs device, RST_N signal should be between VSS(Ground)
and VCCQ/VCCQ2. The power down sequence after fixing as below:

Power down:
1. Assert RST_N low
2. Turn-off VCC
3. Turn-off VCCQ/VCCQ2

Signed-off-by: Peter Wang <peter.wang@mediatek.com>
---
 drivers/scsi/ufs/ufs-mediatek.c |    4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index c55202b..47b4066 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -922,6 +922,7 @@ static void ufs_mtk_vreg_set_lpm(struct ufs_hba *hba, bool lpm)
 static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 {
 	int err;
+	struct arm_smccc_res res;
 
 	if (ufshcd_is_link_hibern8(hba)) {
 		err = ufs_mtk_link_set_lpm(hba);
@@ -941,6 +942,9 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
 			goto fail;
 	}
 
+	if (ufshcd_is_link_off(hba))
+		ufs_mtk_device_reset_ctrl(0, res);
+
 	return 0;
 fail:
 	/*
-- 
1.7.9.5