Some UFS devices don't require VCCQ rail for device operations hence
this change adds support to recognize such devices and remove vote for
the unused VCCQ rail.

Reviewed-by: Hannes Reinecke <h...@suse.de>
Signed-off-by: Subhash Jadavani <subha...@codeaurora.org>
Signed-off-by: Yaniv Gardi <yga...@codeaurora.org>

---
 drivers/scsi/ufs/ufs.h    |  1 +
 drivers/scsi/ufs/ufshcd.c | 60 +++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 57 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 8ec6356..b291fa6 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -501,6 +501,7 @@ struct ufs_vreg {
        struct regulator *reg;
        const char *name;
        bool enabled;
+       bool unused;
        int min_uV;
        int max_uV;
        int min_uA;
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 91a341b..987cf27 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -195,6 +195,7 @@ static int ufshcd_probe_hba(struct ufs_hba *hba);
 static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
                                 bool skip_ref_clk);
 static int ufshcd_setup_clocks(struct ufs_hba *hba, bool on);
+static int ufshcd_set_vccq_rail_unused(struct ufs_hba *hba, bool unused);
 static int ufshcd_uic_hibern8_exit(struct ufs_hba *hba);
 static int ufshcd_uic_hibern8_enter(struct ufs_hba *hba);
 static inline void ufshcd_add_delay_before_dme_cmd(struct ufs_hba *hba);
@@ -4593,6 +4594,12 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
                goto out;
 
        ufs_advertise_fixup_device(hba);
+
+       ret = ufshcd_set_vccq_rail_unused(hba,
+               (hba->dev_quirks & UFS_DEVICE_NO_VCCQ) ? true : false);
+       if (ret)
+               goto out;
+
        /* UFS device is also active now */
        ufshcd_set_ufs_dev_active(hba);
        ufshcd_force_reset_auto_bkops(hba);
@@ -4743,13 +4750,24 @@ static int ufshcd_config_vreg_load(struct device *dev, 
struct ufs_vreg *vreg,
 static inline int ufshcd_config_vreg_lpm(struct ufs_hba *hba,
                                         struct ufs_vreg *vreg)
 {
-       return ufshcd_config_vreg_load(hba->dev, vreg, UFS_VREG_LPM_LOAD_UA);
+       if (!vreg)
+               return 0;
+       else if (vreg->unused)
+               return 0;
+       else
+               return ufshcd_config_vreg_load(hba->dev, vreg,
+                                              UFS_VREG_LPM_LOAD_UA);
 }
 
 static inline int ufshcd_config_vreg_hpm(struct ufs_hba *hba,
                                         struct ufs_vreg *vreg)
 {
-       return ufshcd_config_vreg_load(hba->dev, vreg, vreg->max_uA);
+       if (!vreg)
+               return 0;
+       else if (vreg->unused)
+               return 0;
+       else
+               return ufshcd_config_vreg_load(hba->dev, vreg, vreg->max_uA);
 }
 
 static int ufshcd_config_vreg(struct device *dev,
@@ -4784,7 +4802,9 @@ static int ufshcd_enable_vreg(struct device *dev, struct 
ufs_vreg *vreg)
 {
        int ret = 0;
 
-       if (!vreg || vreg->enabled)
+       if (!vreg)
+               goto out;
+       else if (vreg->enabled || vreg->unused)
                goto out;
 
        ret = ufshcd_config_vreg(dev, vreg, true);
@@ -4804,7 +4824,9 @@ static int ufshcd_disable_vreg(struct device *dev, struct 
ufs_vreg *vreg)
 {
        int ret = 0;
 
-       if (!vreg || !vreg->enabled)
+       if (!vreg)
+               goto out;
+       else if (!vreg->enabled || vreg->unused)
                goto out;
 
        ret = regulator_disable(vreg->reg);
@@ -4910,6 +4932,36 @@ static int ufshcd_init_hba_vreg(struct ufs_hba *hba)
        return 0;
 }
 
+static int ufshcd_set_vccq_rail_unused(struct ufs_hba *hba, bool unused)
+{
+       int ret = 0;
+       struct ufs_vreg_info *info = &hba->vreg_info;
+
+       if (!info)
+               goto out;
+       else if (!info->vccq)
+               goto out;
+
+       if (unused) {
+               /* shut off the rail here */
+               ret = ufshcd_toggle_vreg(hba->dev, info->vccq, false);
+               /*
+                * Mark this rail as no longer used, so it doesn't get enabled
+                * later by mistake
+                */
+               if (!ret)
+                       info->vccq->unused = true;
+       } else {
+               /*
+                * rail should have been already enabled hence just make sure
+                * that unused flag is cleared.
+                */
+               info->vccq->unused = false;
+       }
+out:
+       return ret;
+}
+
 static int __ufshcd_setup_clocks(struct ufs_hba *hba, bool on,
                                        bool skip_ref_clk)
 {
-- 
1.8.5.2

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