scsi: ufs: ufs-mediatek: Fix power down spec violation

[ Upstream commit c625b80b9d00f3546722cd77527f9697c8c4c911 ]

As per spec, 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:

Power down:

 1. Assert RST_N low

 2. Turn-off VCC

 3. Turn-off VCCQ/VCCQ2

Link: https://lore.kernel.org/r/1620813706-25331-1-git-send-email-peter.wang@mediatek.com
Reviewed-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Peter Wang <peter.wang@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 09d2ac20508b5a2ef4fcb7493488eb799b8a152b..aace13399a7f3f634937be20443d3894797b3d58 100644 (file)
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -824,6 +824,7 @@ 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);
@@ -844,6 +845,9 @@ static int ufs_mtk_suspend(struct ufs_hba *hba, enum ufs_pm_op pm_op)
                ufs_mtk_vreg_set_lpm(hba, true);
        }
 
+       if (ufshcd_is_link_off(hba))
+               ufs_mtk_device_reset_ctrl(0, res);
+
        return 0;
 }