[PATCH v8 07/17] scsi: ufs: disable vccq if it's not needed by UFS device

From: Yaniv Gardi
Date: Thu Mar 10 2016 - 10:41:40 EST


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 <hare@xxxxxxx>
Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
Signed-off-by: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>

---
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 f8b458f..8ed7d4b 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);
@@ -4662,6 +4663,12 @@ 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);
@@ -4812,13 +4819,24 @@ 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,
@@ -4853,7 +4871,9 @@ 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);
@@ -4873,7 +4893,9 @@ 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);
@@ -4979,6 +5001,36 @@ 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

--
QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation