[PATCH v2 2/4] scsi: ufs: fix regulator set load and icc-level configuration

[Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>]

Currently if a regulator has "<name>-fixed-regulator"
property in device tree, it will skip current limit configuration.
This lead to a zero "max_uA" value in struct ufs_vreg.

However, "regulator_set_load" operation shall be required
on those regulators which specifically configured current
limit, otherwise a zero max_uA value may cause unexpected behavior
when this regulator is enabled or set as high power mode.

Similarly, in icc_level configuration flow, icc_level shall be
updated if specified regulator has also configured current limit,
otherwise a zero max_uA will lead to wrong icc_level which may
cause unexpected results after written to device.

Signed-off-by: Stanley Chu <stanley.chu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
---
 drivers/scsi/ufs/ufshcd.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 8b9a01073d62..61cdae74de62 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6279,19 +6279,19 @@ static u32 ufshcd_find_max_sup_active_icc_level(struct ufs_hba *hba,
 		goto out;
 	}
 
-	if (hba->vreg_info.vcc)
+	if (hba->vreg_info.vcc && hba->vreg_info.vcc->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vcc->max_uA,
 				POWER_DESC_MAX_ACTV_ICC_LVLS - 1,
 				&desc_buf[PWR_DESC_ACTIVE_LVLS_VCC_0]);
 
-	if (hba->vreg_info.vccq)
+	if (hba->vreg_info.vccq && hba->vreg_info.vccq->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vccq->max_uA,
 				icc_level,
 				&desc_buf[PWR_DESC_ACTIVE_LVLS_VCCQ_0]);
 
-	if (hba->vreg_info.vccq2)
+	if (hba->vreg_info.vccq2 && hba->vreg_info.vccq2->max_uA)
 		icc_level = ufshcd_get_max_icc_level(
 				hba->vreg_info.vccq2->max_uA,
 				icc_level,
@@ -6989,6 +6989,15 @@ static int ufshcd_config_vreg_load(struct device *dev, struct ufs_vreg *vreg,
 	if (!vreg)
 		return 0;
 
+	/*
+	 * "set_load" operation shall be required on those regulators
+	 * which specifically configured current limitation. Otherwise
+	 * zero max_uA may cause unexpected behavior when regulator is
+	 * enabled or set as high power mode.
+	 */
+	if (!vreg->max_uA)
+		return 0;
+
 	ret = regulator_set_load(vreg->reg, ua);
 	if (ret < 0) {
 		dev_err(dev, "%s: %s set load (ua=%d) failed, err=%d\n",
-- 
2.18.0