scsi: ufs: ufs-mediatek: Disable unused VCCQx power rails

Some MediaTek UFS platforms support different VCCQx power rails, for
example, both 1.2v and 1.8v VCCQx, in a single kernel image.

To optimize the system power consumption, provide a way to disable and
release the unused power rail during the device probing.

Link: https://lore.kernel.org/r/20220616053725.5681-12-stanley.chu@mediatek.com
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/ufs/host/ufs-mediatek.c b/drivers/ufs/host/ufs-mediatek.c
index 34e51c0..bfe04a4 100644 (file)
--- a/drivers/ufs/host/ufs-mediatek.c
+++ b/drivers/ufs/host/ufs-mediatek.c
@@ -712,6 +712,29 @@ static int ufs_mtk_vreg_fix_vcc(struct ufs_hba *hba)
        return err;
 }
 
+static void ufs_mtk_vreg_fix_vccqx(struct ufs_hba *hba)
+{
+       struct ufs_vreg_info *info = &hba->vreg_info;
+       struct ufs_vreg **vreg_on, **vreg_off;
+
+       if (hba->dev_info.wspecversion >= 0x0300) {
+               vreg_on = &info->vccq;
+               vreg_off = &info->vccq2;
+       } else {
+               vreg_on = &info->vccq2;
+               vreg_off = &info->vccq;
+       }
+
+       if (*vreg_on)
+               (*vreg_on)->always_on = true;
+
+       if (*vreg_off) {
+               regulator_disable((*vreg_off)->reg);
+               devm_kfree(hba->dev, (*vreg_off)->name);
+               devm_kfree(hba->dev, *vreg_off);
+       }
+}
+
 /**
  * ufs_mtk_init - find other essential mmio bases
  * @hba: host controller instance
@@ -1241,6 +1264,7 @@ static void ufs_mtk_fixup_dev_quirks(struct ufs_hba *hba)
        }
 
        ufs_mtk_vreg_fix_vcc(hba);
+       ufs_mtk_vreg_fix_vccqx(hba);
 }
 
 static void ufs_mtk_event_notify(struct ufs_hba *hba,